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diff --git a/17815-8.txt b/17815-8.txt new file mode 100644 index 0000000..9379108 --- /dev/null +++ b/17815-8.txt @@ -0,0 +1,11760 @@ +The Project Gutenberg EBook of Illusions, by James Sully + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Illusions + A Psychological Study + +Author: James Sully + +Release Date: February 21, 2006 [EBook #17815] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK ILLUSIONS *** + + + + +Produced by Thierry Alberto, Janet Blenkinship and the +Online Distributed Proofreaders Europe at +http://dp.rastko.net + + + + + + + + + + ~ILLUSIONS~ + + _A PSYCHOLOGICAL STUDY_ + + + BY + JAMES SULLY + AUTHOR OF "SENSATION AND INTUITION," "PESSIMISM," ETC. + + + THIRD EDITION + + + + + LONDON + KEGAN PAUL, TRENCH & CO., 1, PATERNOSTER SQUARE + 1887 + + (_The rights of translation and of reproduction are reserved_) + + + ~THE INTERNATIONAL SCIENTIFIC SERIES.~ + + VOL. XXXIV. + + + + +PREFACE. + + +The present volume takes a wide survey of the field of error, embracing +in its view not only the illusions of sense dealt with in treatises on +physiological optics, etc., but also other errors familiarly known as +illusions, and resembling the former in their structure and mode of +origin. I have throughout endeavoured to keep to a strictly scientific +treatment, that is to say, the description and classification of +acknowledged errors, and the explanation of these by a reference to +their psychical and physical conditions. At the same time, I was not +able, at the close of my exposition, to avoid pointing out how the +psychology leads on to the philosophy of the subject. Some of the +chapters were first roughly sketched out in articles published in +magazines and reviews; but these have been not only greatly enlarged, +but, to a considerable extent, rewritten. + J. S. + + _Hampstead, April, 1881._ + + + + + CONTENTS. + + + CHAPTER I. + + THE STUDY OF ILLUSION. + + Vulgar idea of Illusion, 1, 2; Psychological treatment of subject, + 3, 4; definition of Illusion, 4-7; Philosophic extension of idea, + 7, 8. + + + CHAPTER II. + + THE CLASSIFICATION OF ILLUSIONS. + + Popular and Scientific conceptions of Mind, 9, 10; Illusion and + Hallucination, 11-13; varieties of Immediate Knowledge, 13-16; four-fold + division of Illusions, 16-18. + + + CHAPTER III. + + ILLUSIONS OF PERCEPTION: GENERAL. + + _Psychology of Perception_:--The Psychological analysis of Perception, + 19, 20; Sensation and its discrimination, etc., 20, 21; interpretation + of Sensation, 22, 23; construction of material object, 23, 24; + recognition of object, specific and individual, 24-27; Preperception + and Perception, 27-31; Physiological conditions of Perception, 31-33; + Visual and other Sense-perception, 33, 34. + + _Illusions of Perception_:--Illusion of Perception defined, 35-38; + sources of Sense-illusion, 38-40: (a) confusion of + Sense-impression, 40-44; (b) misinterpretation of Sense-impression, 44; + Passive and Active misinterpretation, 44-46; Passive Illusions as + organically and extra-organically conditioned, 46-49. + + + CHAPTER IV. + + ILLUSIONS OF PERCEPTION--_continued_. + + A. _Passive Illusions (a) as determined by the Organism._ + _Results of Limits of Sensibility_:--Relation of quantity of Sensation to + that of Stimulus, 50-52; coalescence of simultaneous Sensations, + 52-55; after-effect of Stimulation, 55, 56; effects of prolonged + Stimulation, 56-58; Specific Energy of Nerves, 58, 59; localization + of Sensation, 59-62; Subjective Sensations, 62-64. + + _Results of Variation of Sensibility_:--Rise and fall of Sensibility, + 64-67; Paræsesthesia, 67, 68; _rationale_ of organically conditioned + Illusions, 68, 69. + + + CHAPTER V. + + ILLUSIONS OF PERCEPTION--_continued_. + + A. _Passive Illusions (b) as determined by the Environment._ + _Exceptional Relation of Stimulus to Organ_:--Displacement of organ, + etc., 70-72. + + _Exceptional Arrangement of Circumstances in the Environment_:-- + Misinterpretation of the direction and movement of objects, 72-75; + misperception of Distance, 75, 76; Illusions of depth, relief, and + solidity in Art, 77-81; Illusions connected with the perception of + objects through transparent coloured media, 82-84; visual transformation + of concave into convex form, 84-86; false recognition of + objects, 86, 87; inattention to Sense-impression in Recognition, + 87-91; suggestion taking the direction of familiar recurring experiences, + 91, 92. + + + CHAPTER VI. + + ILLUSIONS OF PERCEPTION--_continued_. + + B. _Active Illusions._ + + Preperception and Illusion, 93-95. + + _Voluntary Preperception_:--Choice of interpretation in the case of + visible movement, 95, 96; and in the case of flat projections of form, + 96-98; capricious interpretation of obscure impressions, 99, 100. + + _Involuntary Preperception_:--Effects of permanent Predisposition, + 101, 102; effects of partial temporary Preadjustment, 102-105; + complete Pro-adjustment or Expectation, 106-109; subordination of + Sense-impression to Preperception, 109-111; transition from Illusion + to Hallucination, 111, 112; rudimentary Hallucinations, 112-114; + developed Hallucinations, 114-116; Hallucination in normal life, + 116, 117; Hallucinations of insanity, 118-120; gradual development + of Sense-illusions, and continuity of normal and abnormal life; 120-123; + Sanity and Insanity distinguished, 123-126. + + + CHAPTER VII. + + DREAMS. + + Mystery of sleep, 127, 128; theories of Dreams, 128, 129; scientific + explanation of Dreams, 129, 130. + + _Sleep and Dreaming_:--Condition of organism during sleep, 131, 132; + Are the nervous centres ever wholly inactive during sleep? 132-134; + nature of cerebral activity involved in Dreams, 134-136; psychical + conditions of Dreams, 136-138. + + _The Dream as Illusion_:--External Sense-impressions as excitants of + Dream-images, 139-143; internal "subjective" stimuli in the sense-organs, + 143-145; organic sensations, 145-147; how sensations are + exaggerated in Dream-interpretation, 147-151. + + _The Dream as Hallucination_:--Results of direct central stimulation + 151-153; indirect central stimulation and association, 153-155. + + _The Form and Structure of Dreams_:--The incoherence of Dreams explained, + 156-161; coherence and unity of Dream as effected (a) by + coalescence and transformation of images, 161-163; (b) by aground-tone + of feeling, 164-168; (c) by the play of associative dispositions, + 168-172; (d) by the activities of selective attention stimulated by + the rational impulse to connect and to arrange, 172-176; examples + of Dreams, 176-179; limits of intelligence and rational activity in + Dreams, 180-182; Dreaming and mental disease, 182, 183; After-dreams + and Apparitions, 183-185. + + NOTE.--The Hypnotic Condition, 185-188. + + + CHAPTER VIII. + + ILLUSIONS OF INTROSPECTION. + + Illusions of Introspection defined, 189-192; question of the possibility + of illusory Introspection, 192-194; incomplete grasp of internal + feelings as such, 194-196; misobservation of internal feelings: Passive + Illusions, 196-199; Active Illusions, 199-202; malobservation of + subjective states, 202-205; Illusory Introspection in psychology and + philosophy, 205-208; value of the Introspective method, 208-211. + + + CHAPTER IX. + + OTHER QUASI-PRESENTATIVE ILLUSIONS: ERRORS OF INSIGHT. + + Emotion and Perception, 212; Æsthetic Intuition, 213; Subjective + Impressions of beauty misinterpreted, 213-216; analogous Emotional + Intuitions, 216, 217; Insight, its nature, 217-220; Passive Illusions + of Insight, 220-222; Active Illusions of Insight: projection of + individual feelings, 222-224; the poetic transformation of nature, + 224-226; special predispositions as falsifying Insight, 226-228; + value of faculty of Insight, 228-230. + + + CHAPTER X. + + ILLUSIONS OF MEMORY. + + Vulgar confidence in Memory, 231-233; definition of Memory, 233-235; + Psychology of Memory, 235-237; Physiology of Memory, 237, 238; + Memory as localization in the past, 238-241; Illusions of Memory + classified, 241-245. + + (1) _Illusions of Time-Perspective_:-- + + (a) Definite Localization of events: constant errors in retrospective + estimate of time, 245-249; varying errors: estimate of duration + during a period, 249-251; variations in retrospective estimate of + duration, 251-256. + + (b) Indefinite Localization: effect of vividness of mnemonic image + on the apparent distance of events, 256-258; isolated public events, + 258, 259; active element in errors of Localization, 259-261. + + (2) _Distortions of Memory_:--Transformation of past through + forgetfulness, 261-264; confusion of distinct recollections, 264-266; + Active Illusion: influence of present imaginative activity, 266-269; + exaggeration in recollections of remote experiences, 269, 270; action of + present feeling in transforming past, 270, 271. + + (3) _Hallucinations of Memory_:--Their nature, 271-273; past dreams taken + for external experiences, 273-277; past waking imagination taken + for external reality, 277-280; recollection of prenatal ancestral + experience, 280, 281; filling up gaps in recollection, 281-283. + _Illusions connected with, Personal Identity_:--Illusions of Memory and + Sense of identity, 283, 284; idea of permanent self, how built up, + 285-287; disturbances of sense of identity, 287-290; fallibility and + trustworthiness of Memory, 290-292. + + NOTE.--Momentary Illusions of Self-consciousness, 293. + + + CHAPTER XI. + + ILLUSIONS OF BELIEF. + + Belief as Immediate or Intuitive, 294-296; simple and compound + Belief, 296. + + A. _Simple Illusory Belief_:-- + + (1) Expectation: its nature, 297, 298; Is Expectation ever intuitive? + 298; Expectation and Inference from the past, 299-301; Expectation + of new kinds of experience, 301, 302; Permanent Expectations + of remote events, 302; misrepresentation of future duration, + 302-305; Imaginative transformation of future, 305-307. + + (2) Quasi-Expectations: anticipation of extra-personal experiences, + 307, 308; Retrospective Beliefs, 308-312. + + B. _Compound Illusory Belief_:-- + + (1) Representations of permanent things: their structure, 312; our + representations of others as illusory, 312-315; our representation + of ourselves as illusory, 315; Illusion of self-esteem, 316-318; + genesis of illusory opinion of self, 318-322; Illusion in our + representations of classes of things, 322, 323; and in our views + of the world as a whole, 323, 324; tendency of belief towards + divergence, 325; and towards convergence, 326, 327. + + + CHAPTER XII. + + RESULTS. + + Range of Illusion, 328-330; nature and causes of Illusion in general, + 331-334; Illusion identical with Fallacy, 334; Illusion as abnormal, + 336, 337; question of common error, 337-339; evolutionist's conception + of error as maladaptation, 339-344; common intuitions + tested only by philosophy, 344; assumptions of science respecting + external reality, etc., 344-346; philosophic investigation of these + assumptions, 346-348; connection between scientific and philosophic + consideration of Illusion, 348-350; correction of Illusion and its + implications, 351, 352; Fundamental Intuitions and modern psychology, + 352; psychology as positive science and as philosophy, 353-355; + points of resemblance between acknowledged Illusions and Fundamental + Intuitions, 355, 356; question of origin, and question of + validity, 356, 357; attitude of scientific mind towards philosophic + scepticism, 357-360; Persistent Intuitions must be taken as true, + 360, 361. + + + + +~ILLUSIONS.~ + + + + +CHAPTER I. + +THE STUDY OF ILLUSION. + + +Common sense, knowing nothing of fine distinctions, is wont to draw a +sharp line between the region of illusion and that of sane intelligence. +To be the victim of an illusion is, in the popular judgment, to be +excluded from the category of rational men. The term at once calls up +images of stunted figures with ill-developed brains, half-witted +creatures, hardly distinguishable from the admittedly insane. And this +way of thinking of illusion and its subjects is strengthened by one of +the characteristic sentiments of our age. The nineteenth century +intelligence plumes itself on having got at the bottom of mediæval +visions and church miracles, and it is wont to commiserate the feeble +minds that are still subject to these self-deceptions. + +According to this view, illusion is something essentially abnormal and +allied to insanity. And it would seem to follow that its nature and +origin can be best studied by those whose speciality it is to observe +the phenomena of abnormal life. Scientific procedure has in the main +conformed to this distinction of common sense. The phenomena of illusion +have ordinarily been investigated by alienists, that is to say, +physicians who are brought face to face with their most striking forms +in the mentally deranged. + +While there are very good reasons for this treatment of illusion as a +branch of mental pathology, it is by no means certain that it can be a +complete and exhaustive one. Notwithstanding the flattering supposition +of common sense, that illusion is essentially an incident in abnormal +life, the careful observer knows well enough that the case is far +otherwise. + +There is, indeed, a view of our race diametrically opposed to the +flattering opinion referred to above, namely, the humiliating judgment +that all men habitually err, or that illusion is to be regarded as the +natural condition of mortals. This idea has found expression, not only +in the cynical exclamation of the misanthropist that most men are fools, +but also in the cry of despair that sometimes breaks from the weary +searcher after absolute truth, and from the poet when impressed with the +unreality of his early ideals. + +Without adopting this very disparaging opinion of the intellectual +condition of mankind, we must recognize the fact that most men are +sometimes liable to illusion. Hardly anybody is always consistently +sober and rational in his perceptions and beliefs. A momentary fatigue +of the nerves, a little mental excitement, a relaxation of the effort of +attention by which we continually take our bearings with respect to the +real world about us, will produce just the same kind of confusion of +reality and phantasm, which we observe in the insane. To give but an +example: the play of fancy which leads to a detection of animal and +other forms in clouds, is known to be an occupation of the insane, and +is rightly made use of by Shakespeare as a mark of incipient mental +aberration in Hamlet; and yet this very same occupation is quite natural +to children, and to imaginative adults when they choose to throw the +reins on the neck of their phantasy. Our luminous circle of rational +perception is surrounded by a misty penumbra of illusion. Common sense +itself may be said to admit this, since the greatest stickler for the +enlightenment of our age will be found in practice to accuse most of his +acquaintance at some time or another of falling into illusion. + +If illusion thus has its roots in ordinary mental life, the study of it +would seem to belong to the physiology as much as to the pathology of +mind. We may even go further, and say that in the analysis and +explanation of illusion the psychologist may be expected to do more than +the physician. If, on the one hand, the latter has the great privilege +of observing the phenomena in their highest intensity, on the other +hand, the former has the advantage of being familiar with the normal +intellectual process which all illusion simulates or caricatures. To +this it must be added that the physician is naturally disposed to look +at illusion mainly, if not exclusively, on its practical side, that is, +as a concomitant and symptom of cerebral disease, which it is needful to +be able to recognize. The psychologist has a different interest in the +subject, being specially concerned to understand the mental antecedents +of illusion and its relation to accurate perception and belief. It is +pretty evident, indeed, that the phenomena of illusion form a region +common to the psychologist and the mental pathologist, and that the +complete elucidation of the subject will need the co-operation of the +two classes of investigator. + +In the present volume an attempt will be made to work out the +psychological side of the subject; that is to say, illusions will be +viewed in their relation to the process of just and accurate perception. +In the carrying out of this plan our principal attention will be given +to the manifestations of the illusory impulse in normal life. At the +same time, though no special acquaintance with the pathology of the +subject will be laid claim to, frequent references will be made to the +illusions of the insane. Indeed, it will be found that the two groups of +phenomena--the illusions of the normal and of the abnormal +condition--are so similar, and pass into one another by such insensible +gradations, that it is impossible to discuss the one apart from the +other. The view of illusion which will be adopted in this work is that +it constitutes a kind of border-land between perfectly sane and vigorous +mental life and dementia. + +And here at once there forces itself on our attention the question, What +exactly is to be understood by the term "illusion"? In scientific works +treating of the pathology of the subject, the word is confined to what +are specially known as illusions of the senses, that is to say, to false +or illusory perceptions. And there is very good reason for this +limitation, since such illusions of the senses are the most palpable +and striking symptoms of mental disease. In addition to this, it must be +allowed that, to the ordinary reader, the term first of all calls up +this same idea of a deception of the senses. + +At the same time, popular usage has long since extended the term so as +to include under it errors which do not counterfeit actual perceptions. +We commonly speak of a man being under an illusion respecting himself +when he has a ridiculously exaggerated view of his own importance, and +in a similar way of a person being in a state of illusion with respect +to the past when, through frailty of memory, he pictures it quite +otherwise than it is certainly known to have been. + +It will be found, I think, that there is a very good reason for this +popular extension of the term. The errors just alluded to have this in +common with illusions of sense, that they simulate the form of immediate +or self-evident cognition. An idea held respecting ourselves or +respecting our past history does not depend on any other piece of +knowledge; in other words, is not adopted as the result of a process of +reasoning. What I believe with reference to my past history, so far as I +can myself recall it, I believe instantaneously and immediately, without +the intervention of any premise or reason. Similarly, our notions of +ourselves are, for the most part, obtained apart from any process of +inference. The view which a man takes of his own character or claims on +society he is popularly supposed to receive intuitively by a mere act of +internal observation. Such beliefs may not, indeed, have all the +overpowering force which belongs to illusory perceptions, for the +intuition of something by the senses is commonly looked on as the most +immediate and irresistible kind of knowledge. Still, they must be said +to come very near illusions of sense in the degree of their self-evident +certainty. + +Taking this view of illusion, we may provisionally define it as any +species of error which counterfeits the form of immediate, self-evident, +or intuitive knowledge, whether as sense-perception or otherwise. +Whenever a thing is believed on its own evidence and not as a conclusion +from something else, and the thing then believed is demonstrably wrong, +there is an illusion. The term would thus appear to cover all varieties +of error which are not recognized as fallacies or false inferences. If +for the present we roughly divide all our knowledge into the two regions +of primary or intuitive, and secondary or inferential knowledge, we see +that illusion is false or spurious knowledge of the first kind, fallacy +false or spurious knowledge of the second kind. At the same time, it is +to be remembered that this division is only a very rough one. As will +appear in the course of our investigation, the same error may be called +either a fallacy or an illusion, according as we are thinking of its +original mode of production or of the form which it finally assumes; and +a thorough-going psychological analysis of error may discover that these +two classes are at bottom very similar. + +As we proceed, we shall, I think, find an ample justification for our +definition. We shall see that such illusions as those respecting +ourselves or the past arise by very much the same mental processes as +those which are discoverable in the production of illusory perceptions; +and thus a complete psychology of the one class will, at the same time, +contain the explanation of the other classes. + +The reader is doubtless aware that philosophers have still further +extended the idea of illusion by seeking to bring under it beliefs which +the common sense of mankind has always adopted and never begun to +suspect. Thus, according to the idealist, the popular notion (the +existence of which Berkeley, however, denied) of an external world, +existing in itself and in no wise dependent on our perceptions of it, +resolves itself into a grand illusion of sense. + +At the close of our study of illusions we shall return to this point. We +shall there inquire into the connection between those illusions which +are popularly recognized as such, and those which first come into view +or appear to do so (for we must not yet assume that there are such) +after a certain kind of philosophic reflection. And some attempt will be +made to determine roughly how far the process of dissolving these +substantial beliefs of mankind into airy phantasms may venture to go. + +For the present, however, these so-called illusions in philosophy will +be ignored. It is plain that illusion exists only in antithesis to real +knowledge. This last must be assumed as something above all question. +And a rough and provisional, though for our purpose sufficiently +accurate, demarcation of the regions of the real and the illusory seems +to coincide with the line which common sense draws between what all +normal men agree in holding and what the individual holds, whether +temporarily or permanently, in contradiction to this. For our present +purpose the real is that which is true for all. Thus, though physical +science may tell us that there is nothing corresponding to our +sensations of colour in the world of matter and motion which it +conceives as surrounding us; yet, inasmuch as to all men endowed with +the normal colour-sense the same material objects appear to have the +same colour, we may speak of any such perception as practically true, +marking it off from those plainly illusory perceptions which are due to +some subjective cause, as, for example, fatigue of the retina. + +To sum up: in treating of illusions we shall assume, what science as +distinguished from philosophy is bound to assume, namely, that human +experience is consistent; that men's perceptions and beliefs fall into a +consensus. From this point of view illusion is seen to arise through +some exceptional feature in the situation or condition of the +individual, which, for the time, breaks the chain of intellectual +solidarity which under ordinary circumstances binds the single member to +the collective body. Whether the common experience which men thus obtain +is rightly interpreted is a question which does not concern us here. For +our present purpose, which is the determination and explanation of +illusion as popularly understood, it is sufficient that there is this +general consensus of belief, and this may provisionally be regarded as +at least practically true. + + + + +CHAPTER II. + +THE CLASSIFICATION OF ILLUSIONS. + + +If illusion is the simulation of immediate knowledge, the most obvious +mode of classifying illusions would appear to be according to the +variety of the knowledge which they simulate. + +Now, the popular psychology that floats about in the ordinary forms of +language has long since distinguished certain kinds of unreasoned or +uninferred knowledge. Of these the two best known are perception and +memory. When I see an object before me, or when I recall an event in my +past experience, I am supposed to grasp a piece of knowledge directly, +to know something immediately, and not through the medium of something +else. Yet I know differently in the two cases. In the first I know by +what is called a presentative process, namely, that of sense-perception; +in the second I know by a representative process, namely, that of +reproduction, or on the evidence of memory. In the one case the object +of cognition is present to my perceptive faculties; in the other it is +recalled by the power of memory. + +Scientific psychology tends, no doubt, to break down some of these +popular distinctions. Just as the zoologist sometimes groups together +varieties of animals which the unscientific eye would never think of +connecting, so the psychologist may analyze mental operations which +appear widely dissimilar to the popular mind, and reduce them to one +fundamental process. Thus recent psychology draws no sharp distinction +between perception and recollection. It finds in both very much the same +elements, though combined in a different way. Strictly speaking, indeed, +perception must be defined as a presentative-representative operation. +To the psychologist it comes to very much the same thing whether, for +example, on a visit to Switzerland, our minds are occupied in +_perceiving_ the distance of a mountain or in _remembering_ some +pleasant excursion which we made to it on a former visit. In both cases +there is a reinstatement of the past, a reproduction of earlier +experience, a process of adding to a present impression a product of +imagination--taking this word in its widest sense. In both cases the +same laws of reproduction or association are illustrated. + +Just as a deep and exhaustive analysis of the intellectual operations +thus tends to identify their various forms as they are distinguished by +the popular mind, so a thorough investigation of the flaws in these +operations, that is to say, the counterfeits of knowledge, will probably +lead to an identification of the essential mental process which +underlies them. It is apparent, for example, that, whether a man +_projects_ some figment of his imagination into the external world, +giving it, present material reality, or whether (if I may be allowed the +term) he _retrojects_ it into the dim region of the past, and takes it +for a reality that has been he is committing substantially the same +blunder. The source of the illusion in both cases is one and the same. + +It might seem to follow from this that a scientific discussion of the +subject would overlook the obvious distinction between illusions of +perception and those of memory; that it would attend simply to +differences in the mode of origination of the illusion, whatever its +external form. Our next step, then, would appear to be to determine +these differences in the mode of production. + +That there are differences in the origin and source of illusion is a +fact which has been fully recognized by those writers who have made a +special study of sense-illusions. By these the term illusion is commonly +employed in a narrow, technical sense, and opposed to hallucination. An +illusion, it is said, must always have its starting-point in some actual +impression, whereas a hallucination has no such basis. Thus it is an +illusion when a man, under the action of terror, takes a stump of a +tree, whitened by the moon's rays, for a ghost. It is a hallucination +when an imaginative person so vividly pictures to himself the form of +some absent friend that, for the moment, he fancies himself actually +beholding him. Illusion is thus a partial displacement of external fact +by a fiction of the imagination, while hallucination is a total +displacement. + +This distinction, which has been adopted by the majority of recent +alienists[1], is a valuable one, and must not be lost sight of here. It +would seem, from a psychological point of view, to be an important +circumstance in the genesis of a false perception whether the +intellectual process sets out from within or from without. And it will +be found, moreover, that this distinction may be applied to all the +varieties of error which I propose to consider. Thus, for example, it +will be seen further on that a false recollection may set out either +from the idea of some actual past occurrence or from a present product +of the imagination. + +It is to be observed, however, that the line of separation between +illusion and hallucination, as thus defined, is a very narrow one. In by +far the largest number of hallucinations it is impossible to prove that +there is no modicum of external agency co-operating in the production of +the effect. It is presumable, indeed, that many, if not all, +hallucinations have such a basis of fact. Thus, the madman who projects +his internal thoughts outwards in the shape of external voices may, for +aught we know, be prompted to do so in part by faint impressions coming +from the ear, the result of those slight stimulations to which the organ +is always exposed, even in profound silence, and which in his case +assume an exaggerated intensity. And even if it is clearly made out that +there are hallucinations in the strict sense, that is to say, false +perceptions which are wholly due to internal causes, it must be conceded +that illusion shades off into hallucination by steps which it is +impossible for science to mark. In many cases it must be left an open +question whether the error is to be classed as an illusion or as a +hallucination.[2] + +For these reasons, I think it best not to make the distinction between +illusion and hallucination the leading principle of my classification. +However important psychologically, it does not lend itself to this +purpose. The distinction must be kept in view and illustrated as far as +possible. Accordingly, while in general following popular usage and +employing the term illusion as the generic name, I shall, when +convenient, recognize the narrow and technical sense of the term as +answering to a species co-ordinate with hallucination. + +Departing, then, from what might seem the ideally best order of +exposition, I propose, after all, to set out with the simple popular +scheme of faculties already referred to. Even if they are, +psychologically considered, identical operations, perception and memory +are in general sufficiently marked off by a speciality in the form of +the operation. Thus, while memory is the reproduction of something with +a special reference of consciousness to its past existence, perception +is the reproduction of something with a special reference to its present +existence as a part of the presented object. In other words, though +largely _representative_ when viewed as to its origin, perception is +_presentative_ in relation to the object which is supposed to be +immediately present to the mind at the moment.[3] Hence the convenience +of recognizing the popular classification, and of making it our +starting-point in the present case. + +All knowledge which has any appearance of being directly reached, +immediate, or self-evident, that is to say, of not being inferred from +other knowledge, may be divided into four principal varieties: Internal +Perception or Introspection of the mind's own feelings; +External Perception; Memory; and Belief, in so far as it simulates the +form of direct knowledge. The first is illustrated in a man's +consciousness of a present feeling of pain or pleasure. The second and +the third kinds have already been spoken of, and are too familiar to +require illustration. It is only needful to remark here that, under +perception, or rather in close conjunction with it, I purpose dealing +with the knowledge of other's feelings, in so far as this assumes the +aspect of immediate knowledge. The term belief is here used to include +expectations and any other kinds of conviction that do not fall under +one of the other heads. An instance of a seemingly immediate belief +would be a prophetic prevision of a coming disaster, or a man's +unreasoned persuasion as to his own powers of performing a difficult +task. + +It is, indeed, said by many thinkers that there are no legitimate +immediate beliefs; that all our expectations and other convictions about +things, in so far as they are sound, must repose on other genuinely +immediate knowledge, more particularly sense-perception and memory. +This difficult question need not be discussed here. It is allowed by all +that there is a multitude of beliefs which we hold tenaciously and on +which we are ready to act, which, to the mature mind, wear the +appearance of intuitive truths, owing their cogency to nothing beyond +themselves. A man's belief in his own merits, however it may have been +first obtained, is as immediately assured to him as his recognition of a +real object in the act of sense-perception. It may be added that many of +our every-day working beliefs about the world in which we live, though +presumably derived from memory and perception, tend to lose all traces +of their origin, and to simulate the aspect of intuitions. Thus the +proposition that logicians are in the habit of pressing on our +attention, that "Men are mortal," seems, on the face of it, to common +sense to be something very like a self-evident truth, not depending on +any particular facts of experience. + +In calling these four forms of cognition immediate, I must not, however, +be supposed to be placing them on the same logical level. It is plain, +indeed, to a reflective mind that, though each may be called immediate +in this superficial sense, there are perceptible differences in the +degree of their immediacy. Thus it is manifest, after a moment's +reflection, that expectation, so far as it is just, is not primarily +immediate in the sense in which purely presentative knowledge is so, +since it can be shown to follow from something else. So a general +proposition, though through familiarity and innumerable illustrations it +has acquired a self-evident character, is seen with a very little +inspection to be less fundamentally and essentially so than the +proposition, "I am now feeling pain;" and it will be found that even +with respect to memory, when the remembered event is at all remote, the +process of cognition approximates to a mediate operation, namely, one of +inference. What the relative values of these different kinds of +immediate knowledge are is a point which will have to be touched on at +the end of our study. Here it must suffice to warn the reader against +the supposition that this value is assumed to be identical. + +It might seem at a first glance to follow from this four-fold scheme of +immediate or quasi-immediate knowledge that there are four varieties of +illusion. And this is true in the sense that these four heads cover all +the main varieties of illusion. If there are only four varieties of +knowledge which can lay any claim to be considered immediate, it must be +that every illusion will simulate the form of one of these varieties, +and so be referable to the corresponding division. + +But though there are conceivably these four species of illusion, it does +not follow that there are any actual instances of each class +forthcoming. This we cannot determine till we have investigated the +nature and origin of illusory error. For example, it might be found that +introspection, or the immediate inspection of our own feelings or mental +states, does not supply the conditions necessary to the production of +such error. And, indeed, it is probable that most persons, antecedently +to inquiry, would be disposed to say that to fall into error in the +observation of what is actually going on in our own minds is +impossible. + +With the exception of this first division, however, this scheme may +easily be seen to answer to actual phenomena. That there are illusions +of perception is obvious, since it is to the errors of sense that the +term illusion has most frequently been confined. It is hardly less +evident that there are illusions of memory. The peculiar difficulty of +distinguishing between a past real event and a mere phantom of the +imagination, illustrated in the exclamation, "I either saw it or dreamt +it," sufficiently shows that memory is liable to be imposed on. Finally, +it is agreed on by all that the beliefs we are wont to regard as +self-evident are sometimes erroneous. When, for example, an imaginative +woman says she knows, by mere intuition, that something interesting is +going to happen, say the arrival of a favourite friend, she is plainly +running the risk of being self-deluded. So, too, a man's estimate of +himself, however valid for him, may turn out to be flagrantly false. + +In the following discussion of the subject I shall depart from the above +order in so far as to set out with illusions of sense-perception. These +are well ascertained, forming, indeed, the best-marked variety. And the +explanation of these has been carried much further than that of the +others. Hence, according to the rule to proceed from the known to the +unknown, there will be an obvious convenience in examining these first +of all. After having done this, we shall be in a position to inquire +whether there is anything analogous in the region of introspection or +internal perception. Our study of the errors of sense-perception will, +moreover, prove the best preparation for an inquiry into the nature and +mode of production of the remaining two varieties.[4] + +I would add that, in close connection with the first division, illusions +of perception, I shall treat the subtle and complicated phenomena of +dreams. Although containing elements which ought, according to +strictness, to be brought under one of the other heads, they are, as +their common appellation, "visions," shows, largely simulations of +external, and more especially visual, perception. + +Dreams are no doubt sharply marked off from illusions of +sense-perception by a number of special circumstances. Indeed, it may be +thought that they cannot be adequately treated in a work that aims +primarily at investigating the illusions of normal life, and should +rather be left to those who make the pathological side of the subject +their special study. Yet it may, perhaps, be said that in a wide sense +dreams are a feature of normal life. And, however this be, they have +quite enough in common with other illusions of perception to justify us +in dealing with them in close connection with these. + + + + +CHAPTER III. + +ILLUSIONS OF PERCEPTION: GENERAL. + + +The errors with which we shall be concerned in this chapter are those +which are commonly denoted by the term illusion, that is to say, those +of sense. They are sometimes called deceptions of the senses; but this +is a somewhat loose expression, suggesting that we can be deceived as to +sensation itself, though, as we shall see later on, this is only true in +a very restricted meaning of the phrase. To speak correctly, +sense-illusions must be said to arise by a simulation of the form of +just and accurate perceptions. Accordingly, we shall most frequently +speak of them as illusions of perception. + +In order to investigate the nature of any kind of error, it is needful +to understand the kind of knowledge it imitates, and so we must begin +our inquiry into the nature of illusions of sense by a brief account of +the psychology of perception; and, in doing this, we shall proceed best +by regarding this operation in its most complete form, namely, that of +visual perception. + +I may observe that in this analysis of perception I shall endeavour to +keep to known facts, namely, the psychical phenomena or events which +can be seen by the methods of scientific psychology to enter into the +mental content called the percept. I do not now inquire whether such an +analysis can help us to understand all that is meant by perception. This +point will have to be touched later on. Here it is enough to say that, +whatever our philosophy of perception may be, we must accept the +psychological fact that the concrete mental state in the act of +perception is built up out of elements, the history of which can be +traced by the methods of mental science. + + +_Psychology of Perception._ + +Confining ourselves for the present to the mental, as distinguished from +the physical, side of the operation, we soon find that perception is not +so simple a matter as it might at first seem to be. When a man on a hot +day looks at a running stream and "sees" the delicious coolness, it is +not difficult to show that he is really performing an act of mental +synthesis, or imaginative construction. To the sense-impression[5] which +his eye now gives him, he adds something which past experience has +bequeathed to his mind. In perception, the material of sensation is +acted on by the mind, which embodies in its present attitude all the +results of its past growth. Let us look at this process of synthesis a +little more closely. + +When a sensation arises in the mind, it may, under certain +circumstances, go unattended to. In that case there is no perception. +The sensation floats in the dim outer regions of consciousness as a +vague feeling, the real nature and history of which are unknown. This +remark applies not only to the undefined bodily sensations that are +always oscillating about the threshold of obscure consciousness, but to +the higher sensations connected with the special organs of perception. +The student in optics soon makes the startling discovery that his field +of vision has all through his life been haunted with weird shapes which +have never troubled the serenity of his mind just because they have +never been distinctly attended to. + +The immediate result of this process of directing the keen glance of +attention to a sensation is to give it greater force and distinctness. +By attending to it we discriminate it from other feelings present and +past, and classify it with like sensations previously received. Thus, if +I receive a visual impression of the colour orange, the first +consequence of attending to it is to mark it off from other +colour-impressions, including those of red and yellow. And in +recognizing the peculiar quality of the impression by applying to it the +term orange, I obviously connect it with other similar sensations called +by the same name. If a sensation is perfectly new, there cannot, of +course, be this process of classifying, and in this case the closely +related operation of discriminating it from other sensations is less +exactly performed. But it is hardly necessary to remark that, in the +mind of the adult, under ordinary circumstances, no perfectly new +sensation ever occurs. + +When the sensation, or complex sensation, is thus defined and +recognized, there follows the process of interpretation, by which I mean +the taking up of the impression as an element into the complex mental +state known as a percept. Without going into the philosophical question +of what this process of synthesis exactly means, I may observe that, by +common consent, it takes place to a large extent by help of a +reproduction of sensations of various kinds experienced in the past. +That is to say, the details in this act of combination are drawn from +the store of mental recollections to which the growing mind is ever +adding. In other words, the percept arises through a fusion of an actual +sensation with mental representations or "images" of sensation.[6] Every +element of the object that we thus take up in the act of perception, or +put into the percept, as its actual size, distance, and so on, will be +found to make itself known to us through mental images or revivals of +past experiences, such as those we have in handling the object, moving +to and from it, etc. It follows that if this is an essential ingredient +in the act of perception, the process closely resembles an act of +inference; and, indeed, Helmholtz distinctly calls the perception of +distance an unconscious inference or a mechanically performed act of +judgment. + +I have hinted that these recovered sensations include the feelings we +experience in connection with muscular activity, as in moving our limbs, +resisting or lifting heavy bodies, and walking to a distant object. +Modern psychology refers the eye's instantaneous recognition of the most +important elements of an object (its essential or "primary" qualities) +to a reinstatement of such simple experiences as these. It is, indeed, +these reproductions which are supposed to constitute the substantial +background of our percepts. + +Another thing worth noting with respect to this process of filling up a +sense-impression is that it draws on past sensations of the eye itself. +Thus, when I look at the figure of an acquaintance from behind, my +reproductive visual imagination supplies a representation of the +impressions I am wont to receive when the more interesting aspect of the +object, the front view, is present to my visual sense.[7] + +We may distinguish between different steps in the full act of visual +recognition. First of all comes the construction of a material object of +a particular figure and size, and at a particular distance; that is to +say, the recognition of a tangible thing having certain simple +space-properties, and holding a certain relation to other objects, and +more especially our own body, in space. This is the bare perception of +an object, which always takes place even in the case of perfectly new +objects, provided they are seen with any degree of distinctness. It is +to be added that the reference of a sensation of light or colour to such +an object involves the inclusion of a quality answering to the +sensation, as brightness, or blue colour, in the thing thus intuited. + +This part of the process of filling in, which is the most instantaneous, +automatic, and unconscious, may be supposed to answer to the most +constant and therefore the most deeply organized connections of +experience; for, speaking generally, we never have an impression of +colour, except when there are circumstances present which are fitted to +yield us those simple muscular and tactual experiences through which the +ideas of a particular form, size, etc., are pretty certainly obtained. + +The second step in this process of presentative construction is the +recognition of an object as one of a class of things, for example, +oranges, having certain special qualities, as a particular taste. In +this step the connections of experience are less deeply organized, and +so we are able to some extent, by reflection, to recognize it as a kind +of intellectual working up of the materials supplied us by the past. It +is to be noted that this process of recognition involves a compound +operation of classifying impressions as distinguished from that simple +operation by which a single impression, such as a particular colour, is +known. Thus the recognition of such an object as an orange takes place +by a rapid classing of a multitude of passive sensations of colour, +light, and shade, and those active or muscular sensations which are +supposed to enter into the visual perception of form. + +A still less automatic step in the process of visual recognition is that +of identifying individual objects, as Westminster Abbey, or a friend, +John Smith. The amount of experience that is here reproduced may be very +large, as in the case of recognizing a person with whom we have had a +long and intimate acquaintance. + +If the recognition of an object as one of a class, for example, an +orange, involves a compound process of classing impressions, that of an +individual object involves a still more complicated process. The +identification of a friend, simple as this operation may at first +appear, really takes place by a rapid classing of all the salient +characteristic features which serve as the visible marks of that +particular person. + +It is to be noted that each kind of recognition, specific and +individual, takes place by a consciousness of likeness amid unlikeness. +It is obvious that a new individual object has characters not shared in +by other objects previously inspected. Thus, we at once class a man with +a dark-brown skin, wearing a particular garb, as a Hindoo, though he may +differ in a host of particulars from the other Hindoos that we have +observed. In thus instantly recognizing him as a Hindoo, we must, it is +plain, attend to the points of similarity, and overlook for the instant +the points of dissimilarity. In the case of individual identification, +the same thing happens. Strictly speaking, no object ever appears +exactly the same to us on two occasions. Apart from changes in the +object itself, especially in the case of living beings, there are +varying effects of illumination, of position in relation to the eye, of +distance, and so on, which very distinctly affect the visual impression +at different times. Yet the fact of our instantly recognizing a familiar +object in spite of these fluctuations of appearance, proves that we are +able to overlook a very considerable amount of diversity when a certain +amount of likeness is present. + +It is further to be observed that in these last stages of perception we +approach the boundary line between perception and inference. To +recognize an object as one of a class is often a matter of conscious +reflection and judgment, even when the class is constituted by obvious +material qualities which the senses may be supposed to apprehend +immediately. Still more clearly does perception pass into inference when +the class is constituted by less obvious qualities, which require a +careful and prolonged process of recollection, discrimination, and +comparison, for their recognition. Thus, to recognize a man by certain +marks of gesture and manner as a military man or a Frenchman, though +popularly called a perception, is much more of an unfolded process of +conscious inference. And what applies to specific recognition applies +still more forcibly to individual recognition, which is often a matter +of very delicate conscious comparison and judgment. To say where the +line should be drawn here between perception and observation on the one +hand, and inference on the other, is clearly impossible. Our whole study +of the illusions of perception will serve to show that the one shades +off into the other too gradually to allow of our drawing a hard and fast +line between them. + +Finally, it is to be noted that these last stages of perception bring us +near the boundary line which separates objective experience as common +and universal, and subjective or variable experience as confined to one +or to a few. In the bringing of the object under a certain class of +objects there is clearly room for greater variety of individual +perception. For example, the ability to recognize a man as a Frenchman +turns on a special kind of previous experience. And this transition from +the common or universal to the individual experience is seen yet more +plainly in the case of individual recognition. To identify an object, +say a particular person, commonly presupposes some previous experience +or knowledge of this object, and the existence in the past of some +special relation of the recognizer to the recognized, if only that of an +observer. In fact, it is evident that in this mode of recognition we +have the transition from common perception to individual +recollection.[8] + +While we may thus distinguish different steps in the process of visual +recognition, we may make a further distinction, marking off a passive +and an active stage in the process. The one may be called the stage of +preperception, the other that of perception proper.[9] In the first the +mind holds itself in a passive attitude, except in so far as the +energies of external attention are involved. The impression here awakens +the mental images which answer to past experiences according to the +well-known laws of association. The interpretative image which is to +transform the impression into a percept is now being formed by a mere +process of suggestion. + +When the image is thus formed, the mind may be said to enter upon a more +active stage, in which it now views the impression through the image, or +applies this as a kind of mould or framework to the impression. This +appears to involve an intensification of the mental image, transforming +it from a representative to a presentative mental state, making it +approximate somewhat to the full intensity of the sensation. In many of +our instantaneous perceptions these two stages are indistinguishable to +consciousness. Thus, in most cases, the recognition of size, distance, +etc., takes place so rapidly that it is impossible to detect the two +phases here separated. But in the classification of an object, or the +identification of an individual thing, there is often an appreciable +interval between the first reception of the impression and the final +stage of complete recognition. And here it is easy to distinguish the +two stages of preperception and perception. The interpretative image is +slowly built up by the operation of suggestion, at the close of which +the impression is suddenly illumined as by a flash of light, and takes a +definite, precise shape. + +Now, it is to be noted that the process of preperception will be greatly +aided by any circumstance that facilitates the construction of the +particular interpretative image required. Thus, the more frequently a +similar process of perception has been performed in the past, the more +ready will the mind be to fall into the particular way of interpreting +the impression. As G.H. Lewes well remarks, "The artist sees details +where to other eyes there is a vague or confused mass; the naturalist +sees an animal where the ordinary eye only sees a form." This is but one +illustration of the seemingly universal mental law, that what is +repeatedly done will be done more and more easily. + +The process of preperception may be shortened, not only by means of a +_permanent_ disposition to frame the required interpretative scheme, the +residuum of past like processes, but also by means of any _temporary_ +disposition pointing in the same direction. If, for example, the mind of +a naturalist has just been occupied about a certain class of bird, that +is to say, if he has been dwelling on the _mental image_ of this bird, +he will recognize one at a distance more quickly than he would otherwise +have done. Such a simple mental operation as the recognition of one of +the less common flowers, say a particular orchid, will vary in duration +according as we have or have not been recently forming an image of this +flower. The obvious explanation of this is that the mental image of an +object bears a very close resemblance to the corresponding percept, +differing from it, indeed, in degree only, that is to say, through the +fact that it involves no actual sensation. Here again we see illustrated +a general psychological law, namely, that what the mind has recently +done, it tends (within certain limits) to go on doing. + +It is to be noticed, further, that the perception of a single object or +event is rarely an isolated act of the mind. We recognize and understand +the things that surround us through their relations one to another. +Sometimes the adjacent circumstances and events suggest a definite +expectation of the new impression. Thus, for example, the sound of a gun +heard during a walk in the country is instantly interpreted by help of +suggestions due to the previous appearance of the sportsman, and the act +of raising the gun to his shoulder. It may be added that the verbal +suggestions of others act very much like the suggestions of external +circumstances. If I am told that a gun is going to be fired, my mind is +prepared for it just as though I saw the sportsman.[10] + +More frequently the effect of such surrounding circumstances is to give +an air of familiarity to the new impression, to shorten the interval in +which the required interpretative image is forthcoming. Thus, when +travelling in Italy, the visual impression answering to a ruined temple +or a bareheaded friar is construed much more rapidly than it would be +elsewhere, because of the attitude of mind due to the surrounding +circumstances. In all such cases the process of preperception connected +with a given impression is effected more or less completely by the +suggestions of other and related impressions. + +It follows from all that has been just said that our minds are never in +exactly the same state of readiness with respect to a particular process +of perceptional interpretation. Sometimes the meaning of an impression +flashes on us at once, and the stage of preperception becomes +evanescent. At other times the same impression will fail for an +appreciable interval to divulge its meaning. These differences are, no +doubt, due in part to variations in the state of attention at the +moment; but they depend as well on fluctuations in the degree of the +mind's readiness to look at the impression in the required way. + +In order to complete this slight analysis of perception, we must look +for a moment at its physical side, that is to say, at the nervous +actions which are known or supposed with some degree of probability to +accompany it. + +The production of the sensation is known to depend on a certain external +process, namely, the action of some stimulus, as light, on the +sense-organ, which stimulus has its point of departure in the object, +such as it is conceived by physical science. The sensation arises when +the nervous process is transmitted through the nerves to the conscious +centre, often spoken of as the sensorium, the exact seat of which is +still a matter of some debate. + +The intensification of the sensation by the reaction of attention is +supposed to depend on some reinforcement of the nervous excitation in +the sensory centre proceeding from the motor regions, which are +hypothetically regarded as the centre of attention.[11] The +classification of the impression, again, is pretty certainly correlated +with the physical fact that the central excitation calls into activity +elements which have already been excited in the same way. + +The nervous counterpart of the final stage of perception, the synthesis +of the sensation and the mental representation, is not clearly +ascertained. A sensation clearly resembles a mental image in quality. It +is most obviously marked off from the image by its greater vividness or +intensity. Agreeably to this view, it is now held by a number of eminent +physiologists and psychologists that the nervous process underlying a +sensation occupies the same central region as that which underlies the +corresponding image. According to this theory, the two processes differ +in their degree of energy only, this difference being connected with the +fact that the former involves, while the latter does not involve, the +peripheral region of the nervous system. Accepting this view as on the +whole well founded, I shall speak of an ideational, or rather an +imaginational; and a sensational nervous process, and not of an +ideational and a sensational centre.[12] + +The special force that belongs to the representative element in a +percept, as compared with that of a pure "perceptional" image,[13] is +probably connected with the fact that, in the case of actual perception, +the nervous process underlying the act of imaginative construction is +organically united to the initial sensational process, of which indeed +it may be regarded as a continuation. + +For the physical counterpart of the two stages in the interpretative +part of perception, distinguished as the passive stage of preperception, +and the active stage of perception proper, we may, in the absence of +certain knowledge, fall back on the hypothesis put forward by Dr. J. +Hughlings Jackson, in the articles in _Brain_ already referred to, +namely, that the former answers to an action of the right hemisphere of +the brain, the latter to a subsequent action of the left hemisphere. The +expediting of the process of preperception in those cases where it has +frequently been performed before, is clearly an illustration of the +organic law that every function is improved by exercise. And the +temporary disposition to perform the process due to recent imaginative +activity, is explained at once on the physical side by the supposition +that an actual perception and a perceptional image involve the activity +of the same nervous tracts. For, assuming this to be the case, it +follows, from a well-known organic law, that a recent excitation would +leave a temporary disposition in these particular structures to resume +that particular mode of activity. + +What has here been said about visual perception will apply, _mutatis +mutandis_, to other kinds. Although the eye is the organ of perception +_par excellence_, our other senses are also avenues by which we intuit +and recognize objects. Thus touch, especially when it is finely +developed as it is in the blind, gives an immediate knowledge of +objects--a more immediate knowledge, indeed, of their fundamental +properties than sight. What makes the eye so vastly superior to the +organ of touch as an instrument of perception, is first of all the range +of its action, taking in simultaneously a large number of impressions +from objects at a distance as well as near; and secondly, though this +may seem paradoxical, the fact that it gives us so much indirectly, that +is, by way of association and suggestion. This is the interesting side +of visual perception, that, owing to the vast complex of distinguishable +sensations of light and colour of various qualities and intensities, +together with the muscular sensations attending the varying positions of +the organ, the eye is able to recognize at any instant a whole external +world with its fundamental properties and relations. The ear comes next +to the eye in this respect, but only after a long interval, since its +sensations (even in the case of musical combinations) do not +simultaneously order themselves in an indefinitely large group of +distinguishable elements, and since even the comparatively few +sensations which it is capable of simultaneously receiving, +being altogether passive--that is to say, having no muscular +accompaniments--impart but little and vague information respecting the +external order. It is plain, then, that in the study of illusion, where +the indirectly known elements are the thing to be considered, the eye, +and after this the ear, will mostly engage our attention.[14] + +So much it seemed needful to say about the mechanism of perception, in +order to understand the slight disturbances of this mechanism that +manifest themselves in sense-illusion. It may be added that our study of +these illusions will help still further to elucidate the exact nature of +perception. Normal mental life, as a whole, at once illustrates, and is +illustrated by, abnormal. And while we need a rough provisional theory +of accurate perception in order to explain illusory perception at all, +the investigation of this latter cannot fail to verify and even render +more complete the theory which it thus temporarily adopts. + + +_Illusions of Perception._ + +With this brief psychological analysis of perception to help us, let us +now pass to the consideration of the errors incident to the process, +with a view to classify them according to their psychological nature and +origin. + +And here there naturally arises the question, How shall we define an +illusion of perception? When trying to fix the definition of illusion in +general, I practically disposed of this question. Nevertheless, as the +point appears to me to be of some importance, I shall reproduce and +expand one or two of the considerations then brought forward. + +It is said by certain, philosophers that perception, as a whole, is an +illusion, inasmuch as it involves the fiction of a real thing +independent of mind, yet somehow present to it in the act of +sense-perception. But this is a question for philosophy, not for +science. Science, including psychology, assumes that in perception there +is something real, without inquiring what it may consist of, or what its +meaning may be. And though in the foregoing analysis of perception, +viewed as a complex mental phenomenon or psychical process, I have +argued that a percept gets its concrete filling up out of elements of +conscious experience or sensations, I have been careful not to contend +that the particular elements of feeling thus represented are the +_object_ of perception or the thing perceived. It may be that what we +mean by a single object with its assemblage of qualities is much more +than any number of such sensations; and it must be confessed that, on +the face of it, it seems to be much more. And however this be, the +question, What is meant by object; and is the common persuasion of the +existence of such an entity in the act of perception accurate or +illusory? must be handed over to philosophy. + +While in the following examination of sense-illusions we put out of +sight what certain philosophers say about the illusoriness of perception +as a whole, we shall also do well to leave out of account what physical +science is sometimes supposed to tell us respecting a constant element +of illusion in perception. The physicist, by reducing all external +changes to "modes of motion," appears to leave no room in his +world-mechanism for the secondary qualities of bodies, such as light +and heat, as popularly conceived. Yet, while allowing this, I think we +may still regard the attribution of qualities like colour to objects as +in the main correct and answering to a real fact. When a person says an +object is red, he is understood by everybody as affirming something +which is true or false, something therefore which either involves an +external fact or is illusory. It would involve an external fact whenever +the particular sensation which he receives is the result of a physical +action (other vibrations of a certain order), which would produce a like +sensation in anybody else in the same situation and endowed with the +normal retinal sensibility. On the other hand, an illusory attribution +of colour would imply that there is no corresponding physical agency at +work in the case, but that the sensation is connected with exceptional +individual conditions, as, for example, altered retinal sensibility. + +We are now, perhaps, in a position to frame a rough definition of an +illusion of perception as popularly understood. A large number of such +phenomena may be described as consisting in the formation of percepts or +quasi-percepts in the minds of individuals under external circumstances +which would not give rise to similar percepts in the case of other +people. + +A little consideration, however, will show that this is not an adequate +definition of what is ordinarily understood by an illusion of sense. +There are special circumstances which are fitted to excite a momentary +illusion in all minds. The optical illusions due to the reflection and +refraction of light are not peculiar to the individual, but arise in all +minds under precisely similar external conditions. + +It is plain that the illusoriness of a perception is in these cases +determined in relation to the sense-impressions of other moments and +situations, or to what are presumably better percepts than the present +one. Sometimes this involves an appeal from one sense to another. Thus, +there is the process of verification of sight by touch, for example, in +the case of optical images, a mode of perception which, as we have seen, +gives a more direct cognition of external quality. Conversely, there may +occasionally be a reference from touch to sight, when it is a question +of discriminating two points lying very close to one another. Finally, +the same sense may correct itself, as when the illusion of the +stereoscope is corrected by afterwards looking at the two separate +pictures. + +We may thus roughly define an illusion of perception as consisting in +the formation of a quasi-percept which is peculiar to an individual, or +which is contradicted by another and presumably more accurate percept. +Or, if we take the meaning of the word common to include both the +universal as contrasted with the individual experience, and the +permanent, constant, or average, as distinguished from the momentary and +variable percept, we may still briefly describe an illusion of +perception as a deviation from the common or collective experience. + + +_Sources of Sense-Illusion._ + +Understanding sense-illusion in this way, let us glance back at the +process of perception in its several stages or aspects, with the object +of discovering what room occurs for illusion. + +It appears at first as if the preliminary stages--the reception, +discrimination, and classification of an impression--would not offer the +slightest opening for error. This part of the mechanism of perception +seems to work so regularly and so smoothly that one can hardly conceive +a fault in the process. Nevertheless, a little consideration will show +that even here all does not go on with unerring precision. + +Let us suppose that the very first step is wanting--distinct attention +to an impression. It is easy to see that this will favour illusion by +leading to a confusion of the impression. Thus the timid man will more +readily fall into the illusion of ghost-seeing than a cool-headed +observant man, because he is less attentive to the actual impression of +the moment. This inattention to the sense-impression will be found to be +a great co-operating factor in the production of illusions. + +But if the sensation is properly attended to, can there be error through +a misapprehension of what is actually in the mind at the moment? To say +that there can may sound paradoxical, and yet in a sense this is +demonstrable. I do not mean that there is an observant mind behind and +distinct from the sensation, and failing to observe it accurately +through a kind of mental short-sightedness. What I mean is that the +usual psychical effect of the incoming nervous process may to some +extent be counteracted by a powerful reaction of the centres. In the +course of our study of illusions, we shall learn that it is possible for +the quality of an impression, as, for example, of a sensation of colour, +to be appreciably modified when there is a strong tendency to regard it +in one particular way. + +Postponing the consideration of these, we may say that certain illusions +appear clearly to take their start from an error in the process of +classifying or identifying a present impression. On the physical side, +we may say that the first stages of the nervous process, the due +excitation of the sensory centre in accordance with the form of the +incoming stimulation and the central reaction involved in the +recognition of the sensation, are incomplete. These are so limited and +comparatively unimportant a class, that it will be well to dispose of +them at once. + + +_Confusion of the Sense-Impression._ + +The most interesting case of such an error is where the impression is +unfamiliar and novel in character. I have already remarked that in the +mental life of the adult perfectly new sensations never occur. At the +same time, comparatively novel impressions sometimes arise. Parts of the +sensitive surface of the body which rarely undergo stimulation are +sometimes acted on, and at other times they receive partially new modes +of stimulation. In such cases it is plain that the process of classing +the sensation or recognizing it is not completed. It is found that +whenever this happens there is a tendency to exaggerate the intensity of +the sensation. The very fact of unfamiliarity seems to give to the +sensation a certain exciting character. As something new and strange, it +for the instant slightly agitates and discomposes the mind. Being unable +to classify it with its like, we naturally magnify its intensity, and +so tend to ascribe it to a disproportionately large cause. + +For instance, a light bandage worn about the body at a part usually free +from pressure is liable to be conceived as a weighty mass. The odd sense +of a big cavity in the mouth, which we experience just after the loss of +a tooth, is probably another illustration of this principle. And a third +example may also be supplied from the recollection of the dentist's +patient, namely, the absurd imagination which he tends to form as to +what is actually going on in his mouth when a tooth is being bored by a +modern rotating drill. It may be found that the same principle helps to +account for the exaggerated importance which we attach to the +impressions of our dreams. + +It is evident that all indistinct impressions are liable to be wrongly +classed. Sensations answering to a given colour or form, are, when +faint, easily confused with other sensations, and so an opening occurs +for illusion. Thus, the impressions received from distant objects are +frequently misinterpreted, and, as we shall see by-and-by, it is in this +region of hazy impression that imagination is wont to play its most +startling pranks. + +It is to be observed that the illusions arising from wrong +classification will be more frequent in the case of those senses where +discrimination is low. Thus, it is much easier in a general way to +confuse two sensations of smell than two sensations of colour. Hence the +great source of such errors is to be found in that mass of obscure +sensation which is connected with the organic processes, as digestion, +respiration, etc., together with those varying tactual and motor +feelings, which result from what is called the subjective stimulation of +the tactual nerves, and from changes in the position and condition of +the muscles. Lying commonly in what is known as the sub-conscious region +of mind, undiscriminated, vague, and ill-defined, these sensations, when +they come to be specially attended to, readily get misapprehended, and +so lead to illusion, both in waking life and in sleep. I shall have +occasion to illustrate this later on. + +With these sensations, the result of stimulations coming from remote +parts of the organism, may be classed the ocular impressions which we +receive in indirect vision. When the eye is not fixed on an object, the +impression, involving the activity of some-peripheral region of the +retina, is comparatively indistinct. This will be much more the case +when the object lies at a distance for which the eye is not at the time +accommodated. And in these circumstances, when we happen to turn our +attention to the impression, we easily misapprehend it, and so fall into +illusion. Thus, it has been remarked by Sir David Brewster, in his +_Letters on Natural Magic_ (letter vii.), that when looking through a +window at some object beyond, we easily suppose a fly on the window-pane +to be a larger object, as a bird, at a greater distance.[15] + +While these cases of a confusion or a wrong classification of the +sensation are pretty well made out, there are other illusions or +quasi-illusions respecting which it is doubtful whether they should be +brought under this head. For example, it was found by Weber, that when +the legs of a pair of compasses are at a certain small distance apart +they will be felt as two by some parts of the tactual surface of the +body, but only as one by other parts. How are we to regard this +discrepancy? Must we say that in the latter case there are two +sensations, only that, being so similar, they are confused one with +another? There seems some reason for so doing, in the fact that, by a +repeated exercise of attention to the experiment, they may afterwards be +recognized as two. + +We here come on the puzzling question, How much in the character of the +sensation must be regarded as the necessary result of the particular +mode of nervous stimulation at the moment, together with the laws of +sensibility, and how much must be put down to the reaction of the mind +in the shape of attention and discrimination? For our present purpose we +may say that, whenever a deliberate effort of attention does not suffice +to alter the character of a sensation, this may be pretty safely +regarded as a net result of the nervous process, and any error arising +may be referred to the later stages of the process of perception. Thus, +for example, the taking of the two points of a pair of compasses for +one, where the closest attention does not discover the error, is best +regarded as arising, not from a confusion of the sense-impression, but +from a wrong interpretation of a sensation, occasioned by an +overlooking of the limits of local discriminative sensibility. + + +_Misinterpretation of the Sense-Impression._ + +Enough has been said, perhaps, about those errors of perception which +have their root in the initial process of sensation. We may now pass to +the far more important class of illusions which are related to the later +stages of perception, that is to say, the process of interpreting the +sense-impression. Speaking generally, one may describe an illusion of +perception as a misinterpretation. The wrong kind of interpretative +mental image gets combined with the impression, or, if with Helmholtz we +regard perception as a process of "unconscious inference," we may say +that these illusions involve an unconscious fallacious conclusion. Or, +looking at the physical side of the operation, it may be said that the +central course taken by the nervous process does not correspond to the +external relations of the moment. + +As soon as we inspect these illusions of interpretation, we see that +they fall into two divisions, according as they are connected with the +process of _suggestion_, that is to say, the formation of the +interpretative image so far as determined by links of association with +the actual impression, or with an independent process of _preperception_ +as explained above. Thus, for example, we fall into the illusion of +hearing two voices when our shout is echoed back, just because the +second auditory impression irresistibly calls up the image of a second +shouter. On the other hand, a man experiences the illusion of seeing +spectres of familiar objects just after exciting his imagination over a +ghost-story, because the mind is strongly predisposed to frame this kind +of percept. The first class of illusions arises from without, the +sense-impression being the starting-point, and the process of +preperception being controlled by this. The second class arises rather +from within, from an independent or spontaneous activity of the +imagination. In the one case the mind is comparatively passive; in the +other it is active, energetically reacting on the impression, and +impatiently anticipating the result of the normal process of +preperception. Hence I shall, for brevity's sake, commonly speak of them +as Passive and Active Illusions.[16] + +I may, perhaps, illustrate these two classes of illusion by the simile +of an interpreter poring over an old manuscript. The first would be due +to some peculiarity in the document misleading his judgment, the second +to some caprice or preconceived notion in the interpreter's mind. + +It is not difficult to define conjecturally the physiological conditions +of these two large classes of illusion. On the physical side, an +illusion of sense, like a just perception, is the result of a fusion of +the nervous process answering to a sensation with a nervous process +answering to a mental image. In the case of passive illusions, this +fusion may be said to take place in consequence of some point of +connection between the two. The existence of such a connection appears +to be involved in the very fact of suggestion, and may be said to be +the organic result of frequent conjunctions of the two parts of the +nervous operation in our past history. In the case of active illusions, +however, which spring rather from the independent energy of a particular +mode of the imagination, this point of organic connection is not the +only or even the main thing. In many cases, as we shall see, there is +only a faint shade of resemblance between the present impression and the +mental image with which it is overlaid. The illusions dependent on +vivid, expectation thus answer much less to an objective conjunction of +past experiences than to a capricious subjective conjunction of mental +images. Here, then, the fusion of nervous processes must have another +cause. And it is not difficult to assign such a cause. The antecedent +activity of imagination doubtless involves as its organic result a +powerful temporary disposition in the nervous structures concerned to go +on acting. In other words, they remain in a state of sub-excitation, +which can be raised to full excitation by a slight additional force. The +more powerful this disposition in the centres involved in the act of +imagination, the less the additional force of external stimulus required +to excite them to full activity. + +Considering the first division, passive illusions, a little further, we +shall see that they may be broken up into two sub-classes, according to +the causes of the errors. In a general way we assume that the impression +always answers to some quality of the object which is perceived, and +varies with this; that, for example, our sensation of colour invariably +represents the quality of external colour which we attribute to the +object. Or, to express it physically, we assume that the external force +acting on the sense-organ invariably produces the same effect, and that +the effect always varies with the external cause. But this assumption, +though true in the main, is not perfectly correct. It supposes that the +organic conditions are constant, and that the organic process faithfully +reflects the external operation. Neither of these suppositions is +strictly true. Although in general we may abstract from the organism and +view the relation between the external fact and the mental impression as +direct, we cannot always do so. + +This being so, it is possible for errors of perception to arise through +peculiarities of the nervous organization itself. Thus, as I have just +observed, sensibility has its limits, and these limits are the +starting-point in a certain class of widely shared or _common_ +illusions. An example of this variety is the taking of the two points of +a pair of compasses for one by the hand, already referred to. Again, the +condition of the nervous structures varies indefinitely, so that one and +the same stimulus may, in the case of two individuals, or of the same +individual at different times, produce widely unlike modes of sensation. +Such variations are clearly fitted to lead to gross _individual_ errors +as to the external cause of the sensation. Of this sort is the illusory +sense of temperature which we often experience through a special state +of the organ employed. + +While there are these errors of interpretation due to some peculiarity +of the organization, there are others which involve no such peculiarity, +but arise through the special character or exceptional conformation of +the environment at the moment. Of this order are the illusions connected +with the reflection of light and sound. We may, perhaps, distinguish the +first sub-class as organically conditioned illusions, and the second as +extra-organically determined illusions. It may be added that the latter +are roughly describable as common illusions. They thus answer in a +measure to the first variety of organically conditioned illusions, +namely, those connected with the limits of sensibility. On the other +hand, the active illusions, being essentially individual or subjective, +may be said to correspond to the other variety of this class--those +connected with variations of sensibility. + +Our scheme of sense-illusions is now complete. First of all, we shall +take up the passive illusions, beginning with those which are +conditioned by special circumstances in the organism. After that we +shall illustrate those which depend on peculiar circumstances in the +environment. And finally, we shall separately consider what I have +called the active illusions of sense. + +It is to be observed that these illusions of perception properly so +called, namely, the errors arising from a wrong interpretation of an +impression, and, not from a confusion of one impression with another are +chiefly illustrated in the region of the two higher senses, sight and +hearing. For it is here, as we have seen, that the interpretative +imagination has most work to do in evolving complete percepts of +material, tangible objects, having certain relations in space, out of a +limited and homogeneous class of sensations, namely, those of light and +colour, and of sound. As I have before observed, tactual perception, in +so far as it is the recognition of an object of a certain size, +hardness, and distance from our body, involves the least degree of +interpretation, and so offers little room for error; it is only when +tactual perception amounts to the _recognition_ of an individual object, +clothed with secondary as well as primary qualities, that an opening for +palpable error occurs. + +With respect, however, to the first sub-class of these illusions, +namely, those arising from organic peculiarities which give a twist, so +to speak, to the sensation, no very marked contrast between the +different senses presents itself. So that in illustrating this group we +shall be pretty equally concerned with the various modes of perception +connected with the different senses. + +It may be said once for all that in thus marking off from one another +certain groups of illusion, I am not unmindful of the fact that these +divisions answer to no very sharp natural distinctions. In fact, it will +be found that one class gradually passes into the other, and that the +different characteristics here separated often combine in a most +perplexing way. All that is claimed for this classification is that it +is a convenient mode of mapping out the subject. + + + + +CHAPTER IV. + +ILLUSIONS OF PERCEPTION--_continued_. + +A. _Passive Illusions (a) as determined by the Organism._ + + +In dealing with the illusions which are related to certain peculiarities +in the nervous organism and the laws of sensibility, I shall commence +with those which are connected with certain limits of sensibility. + + +_Limits of Sensibility._ + +To begin with, it is known that the sensation does not always answer to +the external stimulus in its degree or intensity. Thus, a certain amount +of stimulation is necessary before any sensation arises. And this will, +of course, be greater when there is little or no attention directed to +the impression, that is to say, no co-operating central reaction. Thus +it happens that slight stimuli go overlooked, and here illusion may have +its starting-point. The most familiar example of such slight errors is +that of movement. When we are looking at objects, our ocular muscles are +apt to execute very slight movements which escape our notice. Hence we +tend, under certain circumstances, to carry over the retinal result of +the movement, that is to say, the impression produced by a shifting of +the parts of the retinal image to new nervous elements, to the object +itself, and so to transform a "subjective" into an "objective" movement. +In a very interesting work on apparent or illusory movements, Professor +Hoppe has fully investigated the facts of such slight movements, and +endeavoured to specify their causes.[17] + +Again, even when the stimulus is sufficient to produce a conscious +impression, the degree of the feeling may not represent the degree of +the stimulus. To take a very inconspicuous case, it is found by Fechner +that a given increase of force in the stimulus produces a less amount of +difference in the resulting sensations when the original stimulus is a +powerful one than when it is a feeble one. It follows from this, that +differences in the degree of our sensations do not exactly correspond to +objective differences. For example, we tend to magnify the differences +of light among objects, all of which are feebly illuminated, that is to +say, to see them much more removed from one another in point of +brightness than when they are more strongly illuminated. Helmholtz +relates that, owing to this tendency, he has occasionally caught +himself, on a dark night, entertaining the illusion that the +comparatively bright objects visible in twilight were self-luminous.[18] + +Again, there are limits to the conscious separation of sensations which +are received together, and this fact gives rise to illusion. In general, +the number of distinguishable sensations answers to the number of +external causes; but this is not always the case, and here we naturally +fall into the error of mistaking the number of the stimuli. Reference +has already been made to this fact in connection with the question +whether consciousness can be mistaken as to the character of a present +feeling. + +The case of confusing two impressions when the sensory fibres involved +are very near one another, has already been alluded to. Both in touch +and in sight we always take two or more points for one when they are +only separated by an interval that falls below the limits of local +discrimination. It seems to follow from this that our perception of the +world as a continuum, made up of points perfectly continuous one with +another may, for what we know, be illusory. Supposing the universe to +consist of atoms separated by very fine intervals, then it is +demonstrable that it would appear to our sensibility as a continuum, +just as it does now.[19] + +Two or more simultaneous sensations are indistinguishable from one +another, not only when they have nearly the same local origin, but under +other circumstances. The blending of partial sensations of tone in a +_klang_-sensation, and the coalescence in certain cases of the +impressions received by way of the two retinas, are examples of this. It +is not quite certain what determines this fusion of two simultaneous +feelings. It may be said generally that it is favoured by similarity +between the sensations;[20] by a comparative feebleness of one of the +feelings; by the fact of habitual concomitance, the two sensations +occurring rarely, if ever, in isolation; and by the presence of a mental +disposition to view them as answering to one external object. These +considerations help us to explain the coalescence of the retinal +impressions and its limits, the fusion of partial tones, and so on.[21] + +It is plain that this fusion of sensations, whatever its exact +conditions may be, gives rise to error or wrong interpretation of the +sense-impression. Thus, to take the points of two legs of a pair of +compasses for one point is clearly an illusion of perception. Here is +another and less familiar example. Very cold and smooth surfaces, as +those of metal, often appear to be wet. I never feel sure, after wiping +the blades of my skates, that they are perfectly dry, since they always +seem more or less damp to my hand. What is the reason of this? Helmholtz +explains the phenomenon by saying that the feeling we call by the name +of wetness is a compound sensation consisting of one of temperature and +one of touch proper. These sensations occurring together so frequently, +blend into one, and so we infer, according to the general instinctive +tendency already noticed, that there is one specific quality answering +to the feeling. And since the feeling is nearly always produced by +surfaces moistened by cold liquid, we refer it to this circumstance, and +speak of it as a feeling of wetness. Hence, when the particular +conjunction of sensations arises apart from this external circumstance, +we erroneously infer its presence.[22] + +The most interesting case of illusion connected with the fusion of +simultaneous sensations, is that of single vision, or the deeply +organized habit of combining the sensations of what are called the +corresponding points of the two retinas. This coalescence of two +sensations is so far erroneous since it makes us overlook the existence +of two distinct external agencies acting on different parts of the +sensitive surface of the body. And this is the more striking in the case +of looking at solid objects, since here it is demonstrable that the +forces acting on the two retinas are not perfectly similar. +Nevertheless, such a coalescence plainly answers to the fact that these +external agencies usually arise in one and the same object, and this +unity of the object is, of course, the all-important thing to be sure +of. + +This habit may, however, beget palpable illusion in another way. In +certain exceptional cases the coalescence does not take place, as when I +look at a distant object and hold a pencil just before my eyes.[23] And +in this case the organized tendency to take one visual impression for +one object asserts its force, and I tend to fall into the illusion of +seeing two separate pencils. If I do not wholly lapse into the error, it +is because my experience has made me vaguely aware that double images +under these circumstances answer to one object, and that if there were +really two pencils present I should have four visual impressions. + +Once more, it is a law of sensory stimulation that an impression +persists for an appreciable time after the cessation of the action of +the stimulus. This "after sensation" will clearly lead to illusion, in +so far as we tend to think of the stimulus as still at work. It forms, +indeed, as will be seen by-and-by, the simplest and lowest stage of +hallucination. Sometimes this becomes the first stage of a palpable +error. After listening to a child crying for some time the ear easily +deceives itself into supposing that the noise is continued when it has +actually ceased. Again, after taking a bandage from a finger, the +tingling and other sensations due to the pressure sometimes persist for +a good time, in which case they easily give rise to an illusion that the +finger is still bound. + +It follows from this fact of the reverberation of the nervous structures +after the removal of a stimulus, that whenever two discontinuous +stimulations follow one another rapidly enough, they will appear +continuous. This fact is a fruitful source of optical illusion. The +appearance of a blending of the stripes of colours on a rotating disc or +top, of the formation of a ring of light by swinging round a piece of +burning wood, and the illusion of the toy known as the thaumatrope, or +wheel of life, all depend on this persistence of retinal impression. +Many of the startling effects of sleight of hand are undoubtedly due in +part to this principle. If two successive actions or sets of +circumstances to which the attention of the spectator is specially +directed follow one another by a very narrow interval of time, they +easily appear continuous, so that there seems absolutely no time for the +introduction of an intermediate step.[24] + +There is another limit to sensibility which is in a manner the opposite +to the one just named. It is a law of nervous stimulation that a +continued activity of any structure results in less and less psychic +result, and that when a stimulus is always at work it ceases in time to +have any appreciable effect. The common illustration of this law is +drawn from the region of sound. A constant noise, as of a mill, ceases +to produce any conscious sensation. This fact, it is plain, may easily +become the commencement of an illusion. Not only may we mistake a +measure of noise for perfect silence,[25] we may misconceive the real +nature of external circumstances by overlooking some continuous +impression. + +Curious illustrations of this effect are found in optical illusions, +namely, the errors we make respecting the movement of stationary objects +after continued movement of the eyes. When, for example, in a railway +carriage we have for some time been following the (apparent) movement of +objects, as trees, etc., and turn our eyes to an apparently stationary +object, as the carpet of the compartment, this seems to move in the +contrary direction to that of the trees. Helmholtz's explanation of this +illusion is that when we suppose that we are fixing our eye on the +carpet we are really continuing to move it over the surface by reason of +the organic tendency, already spoken of, to go on doing anything that +has been done. But since we are unaware of this prolonged series of +ocular movements, the muscular feelings having become faint, we take the +impression produced by the sliding of the picture over the retina to be +the result of a movement of the object.[26] + +Another limit to our sensibility, which needs to be just touched on +here, is known by the name of the specific energy of the nerves. One and +the same nerve-fibre always reacts in a precisely similar way, whatever +the nature of the stimulus. Thus, when the optic nerve is stimulated in +any manner, whether by light, mechanical pressure, or an electric +current, the same effect, a sensation of light, follows.[27] In a usual +way, a given class of nerve-fibre is only stimulated by one kind of +stimulus. Thus, the retina, in ordinary circumstances, is stimulated by +light. Owing to this fact, there has arisen a deeply organized habit of +translating the impression in one particular way. Thus, I instinctively +regard a sensation received by means of the optic nerve as one caused by +light. + +Accordingly, whenever circumstances arise in which a like sensation is +produced by another kind of stimulus, we fall into illusion. The +phosphenes, or circles of light which are seen when the hinder part of +the eyeball is pressed, may be said to be illusory in so far as we +speak of them as perceptions of light, thus referring them to the +external physical agency which usually causes them. The same remark +applies to those "subjective sensations," as they are called, which are +known to have as their physical cause subjective stimuli, consisting, in +the case of sight, in varying conditions of the peripheral organ, as +increased blood-pressure. Strictly speaking, such simple feelings as +these appear to be, involve an ingredient of false perception: in saying +that we _perceive_ light at all, we go beyond the pure sensation, +interpreting this wrongly. + +Very closely connected with this limitation of our sensibility is +another which refers to the consciousness of the local seat, or origin +of the impression. This has so far its basis in the sensation itself as +it is well known that (within the limits of local discrimination, +referred to above) sensations have a particular "local" colour, which +varies in the case of each of the nervous fibres by the stimulation of +which they arise.[28] But though this much is known through a difference +in the sensibility, nothing more is known. Nothing can certainly be +ascertained by a mere inspection of the sensation as to the distance the +nervous process has travelled, whether from the peripheral termination +of the fibre or from some intermediate point. + +In a general way, we refer our sensations to the peripheral endings of +the nerves concerned, according to what physiologists have called "the +law of eccentricity." Thus I am said to feel the pain caused by a +bruise in the foot in the member itself. This applies also to some of +the sensations of the special senses. Thus, impressions of taste are +clearly localized in the corresponding peripheral terminations. + +With respect to the sense of smell, and still more to those of hearing +and sight, where the impression is usually caused by an object at a +distance from the peripheral organ, our attention to this external cause +leads us to overlook in part the "bodily seat" of the sensation. Yet +even here we are dimly aware that the sensation is received by way of a +particular part of the sensitive surface, that is to say, by a +particular sense-organ. Thus, though referring an odour to a distant +flower, we perceive that the sensation of odour has its bodily origin in +the nose. And even in the case of hearing and sight, we vaguely refer +the impressions, as such, to the appropriate sense-organ. There is, +indeed, in these cases a double local reference, a faint one to the +peripheral organ which is acted on, and a more distinct one to the +object or the force in the environment which acts on this. + +Now, it may be said that the act of localization is in itself distinctly +illusory, since it is known that the sensation first arises in +connection with the excitation of the sensory _centre_, and not of the +peripheral fibre.[29] Yet it must at least be allowed that this +localization of sensation answers to the important fact that, under +usual circumstances, the agency producing the sensation is applied at +this particular point of the organism, the knowledge of which point is +supposed by modern psychologists to have been very slowly learnt by the +individual and the race, through countless experiments with the moving +organ of touch, assisted by the eye. + +Similarly, the reference of the impression, in the case of hearing and +sight, to an object in the environment, though, as we have seen, from +one point of view illusory, clearly answers to a fact of our habitual +experience; for in an immense preponderance of cases at least a visual +or auditory impression does arise through the action on the sense-organ +of a force (ether or air waves) proceeding from a distant object. + +In some circumstances, however, even this element of practical truth +disappears, and the localization of the impression, both within and +without the organism, becomes altogether illusory. This result is +involved in the illusions, already spoken of, which arise from the +instinctive tendency to refer sensations to the ordinary kind of +stimulus. Thus, when a feeling resulting from a disturbance in the optic +nerve is interpreted as one of external light vaguely felt to be acting +on the eye, or one resulting from some action set up in the auditory +fibre as a sensation of external sound vaguely felt to be entering the +ear, we see that the error of localization is a consequence of the other +error already characterized. + +As I have already observed, an excitation of a nerve at any other point +than the peripheral termination, occurs but rarely in normal life. One +familiar instance is the stimulation of the nerve running to the hand +and fingers, by a sharp blow on the elbow over which it passes. As +everybody knows, this gives rise to a sense of pain at the _extremities_ +of the nerve. The most common illustration of such errors of +localization is found in subjective sensations, such as the impression +we sometimes have of something creeping over the skin, of a disagreeable +taste in the mouth, of luminous spots floating across the field of +vision, and so on. The exact physiological seat of these is often a +matter of conjecture only; yet it may safely be said that in many +instances the nervous excitation originates at some point considerably +short of its peripheral extremity: in which case there occurs the +illusion of referring the impressions to the peripheral sense-organ, and +to an external force acting on this. + +The most striking instances of these errors of localization are found in +abnormal circumstances. It is well known that a man who has lost a leg +refers all sensations arising from a stimulation of the truncated fibres +to his lost foot, and in some cases has even to convince himself of the +non-existence of his lost member by sight or touch. Patients often +describe these experiences in very odd language. "If," says one of Dr. +Weir Mitchell's patients, "I should say I am more sure of the leg which +ain't than the one which air, I guess I should be about correct."[30] + +There is good reason for supposing that this source of error plays a +prominent part in the illusions of the insane. Diseased centres may be +accompanied by disordered peripheral structures, and so subjective +sensation may frequently be the starting-point of the wildest illusions. +Thus, a patient's horror of poison may have its first origin in some +subjective gustatory sensation. Similarly, subjective tactual sensations +may give rise to gross illusions, as when a patient "feels" his body +attacked by foul and destructive creatures. + +It may be well to remark that this mistaken interpretation of the seat +or origin of subjective sensation is closely related to hallucination. +In so far as the error involves the ascription of the sensation to a +force external to the sense-organ, this part of the mental process must, +when there is no such force present, be viewed as hallucinatory. Thus, +the feeling of something creeping over the skin is an hallucination in +the sense that it implies the idea of an object external to the skin. +Similarly, the projection of an ocular impression due to retinal +disturbance into the external field of vision, may rightly be named an +hallucination. But the case is not always so clear as this. Thus, for +example, when a gustatory sensation is the result of an altered +condition of the saliva, it may be said that the error is as much an +illusion as an hallucination.[31] + +In a wide sense, again, all errors connected with those subjective +sensations which arise from a stimulation of the peripheral regions of +the nerve may be called illusions rather than hallucinations. Or, if +they must be called hallucinations, they may be distinguished as +"peripheral" from those "central" hallucinations which arise through an +internal automatic excitation of the sensory centre. It is plain from +this that the region of subjective sensation is an ambiguous region, +where illusion and hallucination mix and become confused. To this point +I shall have occasion to return by-and-by. + +I have now probably said enough respecting the illusions that arise +through the fact of there being fixed limits to our sensibility. The +_rationale_ of these illusions is that whenever the limit is reached, we +tend to ignore it and to interpret the impression in the customary way. + + +_Variations of Sensibility._ + +We will now pass to a number of illusions which depend on something +variable in the condition of our sensibility, or some more or less +exceptional organic circumstance. These variations may be momentary and +transient or comparatively permanent. The illusion arises in each case +from our ignoring the variation, and treating a given sensation under +all circumstances as answering to one objective cause. + +First of all, the variation of organic state may affect our mental +representation of the strength of the stimulus or external cause. Here +the fluctuation may be a temporary or a permanent one. The first case is +illustrated in the familiar example of taking a room to be brighter +than it is when emerging from a dark one. Another striking example is +that of our sense of the temperature of objects, which is known to be +strictly relative to a previous sensation, or more correctly to the +momentary condition of the organ. Yet, though every intelligent person +knows this, the deeply rooted habit of making sensation the measure of +objective quality asserts its sway, and frequently leads us into +illusion. The well-known experiment of first plunging one hand in cold +water, the other in hot, and then dipping them both in tepid, is a +startling example of this organized tendency. For here we are strongly +disposed to accept the palpable contradiction that the same water is at +once warm and cool. + +Far more important than these temporary fluctuations of sensibility are +the permanent alterations. Excessive fatigue, want of proper nutrition, +and certain poisons are well known to be causes of such changes. They +appear most commonly under two forms, exalted sensibility, or +hyperæsthesia, and depressed sensibility, or anæsthesia. In these +conditions flagrant errors are made as to the real magnitude of the +causes of the sensations. These variations may occur in normal life to +some extent. In fairly good health we experience at times strange +exaltations of tactual sensibility, so that a very slight stimulus, such +as the contact of the bed-clothes, becomes greatly exaggerated. + +In diseased states of the nervous system these variations of sensibility +become much more striking. The patient who has hyperæsthesia fears to +touch a perfectly smooth surface, or he takes a knock at the door to be +a clap of thunder. The hypochondriac may, through an increase of +organic sensibility, translate organic sensations as the effect of some +living creature gnawing at his vitals. Again, states of anæsthesia lead +to odd illusions among the insane. The common supposition that the body +is dead, or made of wood or of glass, is clearly referable in part to +lowered sensibility of the organism.[32] + +It is worth adding, perhaps, that these variations in sensibility give +rise not only to sensory but also to motor illusions. To take a homely +instance, the last miles of a long walk seem much longer than the first, +not only because the sense of fatigue leading us to dwell on the +transition of time tends to magnify the apparent duration, but because +the fatigued muscles and connected nerves yield a new set of sensations +which constitute an exaggerated standard of measurement. A number of +optical illusions illustrate the same thing. Our visual sense of +direction is determined in part by the feelings accompanying the action +of the ocular muscles, and so is closely connected with the perception +of movement, which has already been touched on. If an ocular muscle is +partially paralyzed it takes a much greater "effort" to effect a given +extent of movement than when the muscle is sound. Hence any movement +performed by the eye seems exaggerated. Hence, too, in this condition +objects are seen in a wrong direction; for the patient reasons that they +are where they would seem to be if he had executed a wider movement than +he really has. This may easily be proved by asking him to try to seize +the object with, his hand. The effect is exaggerated when complete +paralysis sets in, and no actual movement occurs in obedience to the +impulse from within.[33] + +Variations in the condition of the nerve affect not only the degree, but +also the quality of the sensation, and this fact gives rise to a new +kind of illusion. The curious phenomena of colour-contrast illustrate +momentary alterations of sensibility. When, after looking at a green +colour for a time, I turn my eye to a grey surface and see this of the +complementary rose-red hue, the effect is supposed to be due to a +temporary fatigue of the retina in relation to those ingredients of the +total light in the second case which answer to the partial light in the +first (the green rays).[34] + +These momentary modifications of sensibility are of no practical +significance, being almost instantly corrected. Other modifications are +more permanent. It was found by Himly that when the retina is +overexcitable every stimulus is raised in the spectrum scale of colours. +Thus, violet becomes red. An exactly opposite effect is observed when +the retina is torpid.[35] Certain poisons are known to affect the +quality of the colour-impression. Thus, santonin, when taken in any +quantity, makes all colourless objects look yellow. Severe pathological +disturbances are known to involve, in addition to hyperæsthesia and +anæsthesia, what, has been called paræsthesia, that is to say, that +condition in which the quality of sensation is greatly changed. Thus, +for example, to one in this state all food appears to have a metallic +taste, and so on. + +If we now glance back at the various groups of illusions just +illustrated, we find that they all have this feature in common: they +depend on the general mental law that when we have to do with the +unfrequent, the unimportant, and therefore unattended to, and the +exceptional, we employ the ordinary, the familiar, and the well-known as +our standard. Thus, whether we are dealing with sensations that fall +below the ordinary limits of our mental experience, or with those which +arise in some exceptional state of the organism, we carry the habits +formed in the much wider region of average every-day perception with us. +In a word, illusion in these cases always arises through what may, +figuratively at least, be described as the application of a rule, valid +for the majority of cases, to an exceptional case. + +In the varieties of illusion just considered, the circumstance that +gives the peculiarity to the case thus wrongly interpreted has been +referred to the organism. In the illusions to which we now pass, it will +be referred to the environment. At the same time, it is plain that there +is no very sharp distinction between the two classes. Thus, the visual +illusion produced by pressing the eyeball might be regarded not only as +the result of the organic law of the "specific energy" of the nerves, +but, with almost equal appropriateness, as the consequence of an +exceptional state of things in the environment, namely, the pressure of +a body on the retina. As I have already observed, the classification +here adopted is to be viewed simply as a rough expedient for securing +something like a systematic review of the phenomena. + + + + +CHAPTER V. + +ILLUSIONS OF PERCEPTION--_continued_. + +A. _Passive Illusions (b) as determined by the Environment._ + + +In the following groups of illusion we may look away from nervous +processes and organic disturbances, regarding the effect of any external +stimulus as characteristic, that is, as clearly marked off from the +effects of other stimuli, and as constant for the same stimulus. The +source of the illusion will be looked for in something exceptional in +the external circumstances, whereby one object or condition of an object +imitates the effect of another object or condition, to which, owing to a +large preponderance of experience, we at once refer it. + + +_Exceptional Relation of Stimulus to Organ._ + +A transition from the preceding to the following class of illusions is +to be met with in those errors which arise from a very exceptional +relation between the stimulus and the organ of sense. Such a state of +things is naturally interpreted by help of more common and familiar +relations, and so error arises. + +For example, we may grossly misinterpret the intensity of a stimulus +under certain circumstances. Thus, when a man crunches a biscuit, he has +an uncomfortable feeling that the noise as of all the structures of his +head being violently smashed is the same to other ears, and he may even +act on his illusory perception, by keeping at a respectful distance from +all observers. And even though he be a physiologist, and knows that the +force of sensation in this case is due to the propagation of vibrations +to the auditory centre by other channels than the usual one of the ear, +the deeply organized impulse to measure the strength of an external +stimulus by the intensity of the sensation asserts its force. + +Again, if we turn to the process of perceptional construction properly +so called, the reference of the sensation to a material object lying in +a certain direction, etc., we find a similar transitional form of +illusion. The most interesting case of this in visual perception is that +of a disturbance or displacement of the organ by external force. For +example, an illusory sense of direction arises by the simple action of +closing one eye, say the left, and pressing the other eyeball with one +of the fingers a little outwards, that is to the right. The result of +this movement is, of course, to transfer the retinal picture to new +nervous elements further to the right. And since, in this instance, the +displacement is not produced in the ordinary way by the activity of the +ocular muscle making itself known by certain feelings of movement, it is +disregarded altogether, and the direction of the objects is judged as +though the eye were stationary. + +A somewhat similar illusion as to direction occurs in auditory +perception. The sense of direction by the ear is known to be due in part +to the action of the auricle, or projecting part of the ear. This +collects the air-waves, and so adds to the intensity of the sounds, +especially those coming from in front, and thus assists in the +estimation of direction. This being so, if an artificial auricle is +placed in front of the ears; if, for example, the two hands are each +bent into a sort of auricle, and placed in front of the ears, the back +of the hand being in front, the sense of direction (as well as of +distance) is confused. Thus, sounds really travelling from a point in +front of the head will appear to come from behind it. + +Again, the perception of the unity of an object is liable to be +falsified by the introduction of exceptional circumstances into the +sense-organ. This is illustrated in the well-known experiment of +crossing two fingers, say the third and fourth, and placing a marble or +other small round object between them. Under ordinary circumstances, the +two lateral surfaces (that is, the outer surfaces of the two fingers) +now pressed by the marble, can only be acted on simultaneously by _two_ +objects having convex surfaces. Consequently, we cannot help feeling the +presence of two objects in this exceptional instance. The illusion is +analogous to that of the stereoscope, to be spoken of presently. + + +_Exceptional External Arrangements._ + +Passing now to those cases where the exceptional circumstance is +altogether exterior to the organ, we find a familiar example in the +illusions connected with the action of well-known physical forces, as +the refraction of light, and the reflection of light and sound. A stick +half-immersed in water always _looks_ broken, however well we may know +that the appearance is due to the bending of the rays of light. +Similarly, an echo always sounds as though it came from some object in +the direction in which the air-waves finally travel to the ear, though +we are perfectly sure that these undulations have taken a circuitous +course. It is hardly necessary to remind the reader that the deeply +organized tendency to mistake the direction of the visible or audible +object in these cases has from remote ages been made use of as a means +of popular delusion. Thus, we are told by Sir D. Brewster, in his +entertaining _Letters on Natural Magic_ (letter iv.), that the concave +mirror was probably used as the instrument for bringing the gods before +the people. The throwing of the images formed by such mirrors upon smoke +or against fire, so as to make them more distinct, seems to have been a +favourite device in the ancient art of necromancy. + +Closely connected with these illusions of direction with respect to +resting objects, are those into which we are apt to fall respecting the +movements of objects. What looks like the movement of something across +the field of vision is made known to us either by the feeling of the +ocular muscles, if the eye follows the object, or through the sequence +of locally distinct retinal impressions, if the eye is stationary. Now, +either of these effects may result, not only from the actual movement of +the object in a particular direction, but from our own movement in an +opposite direction; or, again, from our both moving in the first +direction, the object more rapidly than ourselves; or, finally, from our +both moving in an opposite direction to this, ourselves more rapidly +than the object. There is thus always a variety of conceivable +explanations, and the action of past experience and association shows +itself very plainly in the determination of the direction of +interpretation. Thus, it is our instinctive tendency to take apparent +movement for real movement, except when the fact of our own movement is +clearly present to consciousness, as when we are walking, or when we are +sitting behind a horse whose movement we see. And so when the sense of +our own movement becomes indistinct, as in a railway carriage, we +naturally drift into the illusion that objects, such as trees, telegraph +posts, and so on, are moving, when they are perfectly still. Under the +same circumstances, we are apt to suppose that a train which is just +shooting ahead of us is moving slowly. + +Similar uncertainties arise with respect to the relative movement of two +objects, the eye being supposed to be fixed in space. When two objects +seem to pass one another, it may be that they are both moving in +contrary directions, or that one only is moving, or finally, that both +are moving in the same direction, the one faster than the other. +Experience and habit here again suggest the interpretation which is most +easy, and not unfrequently produce illusion. Thus, when we watch clouds +scudding over the face of the moon, the latter seems moving rather than +the former, and the illusion only disappears when we fix the eye on the +moon and recognize that it is really stationary. The probable reason of +this is, as Wundt suggests, that experience has made it far easier for +us to think of small objects like the moon moving rapidly, than of large +masses like the clouds.[36] + +The perception of distance, still more than that of direction, is liable +to be illusory. Indeed, the visual recognition of distance, together +with that of solidity, has been the great region for the study of "the +deceptions of the senses." Without treating the subject fully here, I +shall try to describe briefly the nature and source of these +illusions.[37] + +Confining ourselves first of all to near objects, we know that the +smaller differences of distance in these cases are, if the eyes are at +rest, perceived by means of the dissimilar pictures projected on the two +retinas; or if they move, by this means, together with the muscular +feelings that accompany different degrees of convergence of the two +eyes. This was demonstrated by the famous experiments of Wheatstone. +Thus, by means of the now familiar stereoscope, he was able to produce a +perfect illusion of relief. The stereoscope may be said to introduce an +exceptional state of things into the spectator's environment. It +imitates, by means of two flat drawings, the dissimilar retinal pictures +projected by a single solid receding object, and the lenses through +which the eyes look are so constructed as to compel them to converge as +though looking on a single object. And so powerful is the tendency to +interpret this impression as one of solidity, that even though we are +aware of the presence of the stereoscopic apparatus, we cannot help +seeing the two drawings as a single solid object. + +In the case of more remote objects, there is no dissimilarity of the +retinal pictures or feelings of convergence to assist the eye in +determining distance. Here its judgment, which now becomes more of a +process of _conscious_ inference, is determined by a number of +circumstances which, through experience and association, have become the +signs of differences of depth in space. Among these are the degree of +indistinctness of the impression, the apparent or retinal magnitude (if +the object is a familiar one), the relations of linear perspective, as +the interruption of the outline of far objects by that of near objects, +and so on. In a process so complicated there is clearly ample room for +error, and wrong estimates of distance whenever unusual circumstances +are present are familiar to all. Thus, the inexperienced English +tourist, when in the clear atmosphere of Switzerland, where the +impressions from distant objects are more distinct than at home, +naturally falls into the illusion that the mountains are much nearer +than they are, and so fails to realize their true altitude. + +_Illusions of Art._ + +The imitation of solidity and depth by art is a curious and interesting +illustration of the mode of production of illusion. Here we are not, of +course, concerned with the question how far illusion is desirable in +art, but only with its capabilities of illusory presentment; which +capabilities, it may be added, have been fully illustrated in the +history of art. The full treatment of this subject would form a chapter +in itself; here I can only touch on its main features. + +Pictorial art working on a flat surface cannot, it is plain, imitate the +stereoscope, and produce a perfect sense of solidity. Yet it manages to +produce a pretty strong illusion. It illustrates in a striking manner +the ease with which the eye conceives relations of depth or relief and +solidity. If, for example, on a carpet, wall-paper, or dress, bright +lines are laid on a dark colour as ground, we easily imagine that they +are advancing. The reason of this seems to be that in our daily +experience advancing surfaces catch and reflect the light, whereas +retiring surfaces are in shadow.[38] + +The same principle is illustrated in one of the means used by the artist +to produce a strong sense of relief, namely, the cast shadow. A circle +drawn with chalk with a powerful cast shadow on one side will, without +any shading or modelling of the form, appear to stand out from the +paper, thus: + +[Illustration: FIG. 1.] + +The reason is that the presence of such a shadow so forcibly suggests to +the mind that the object is a prominent one intervening between the +light and the shaded surface.[39] + +Even without differences of light and shade, by a mere arrangement of +lines, we may produce a powerful sense of relief or solidity. A striking +example of this is the way in which two intersecting lines sometimes +appear to recede from the eye, as the lines _a a'_, _b b'_, in the next +drawing, which seem to belong to a regular pattern on the ground, at +which the eye is looking from above and obliquely. + +[Illustration: FIG. 2.] + +Again, the correct delineation of the projection of a regular +geometrical figure, as a cube, suffices to give the eye a sense of +relief. This effect is found to be the more striking in proportion to +the familiarity of the form. The following drawing of a long box-shaped +solid at once seems to stand out to the eye. + +[Illustration: FIG. 3.] + +This habitual interpretation of the flat in art as answering to objects +in relief, or having depth, can only be understood when it is remembered +that our daily experience gives us myriads of instances in which the +effect of such flat representations answers to solid receding forms. +That is to say, in the case of all distant objects, in the perception of +which the dissimilarity of the retinal pictures and the feeling of +convergence take no part, we have to interpret solidity, and relations +of nearer and further, by such signs as linear perspective and cast +shadow. On the other hand, it is only in the artificial life of indoors, +on our picture-covered walls, that we experience such effects without +discovering corresponding realities. Hence a deeply organized habit of +taking these impressions as answering to the solid and not to the flat. +If our experience had been quite different; if, for example, we had +been brought up in an empty room, amid painted walls, and had been +excluded from the sight of the world of receding objects outside, we +might easily have formed an exactly opposite habit of taking the actual +mountains, trees, etc., of the distant scene to be pictures laid on a +flat surface. + +[Illustration: FIG. 4.] + +It follows from this that, with respect to the distant parts of a scene, +pictorial art possesses the means of perfect imitation; and here we see +that a complete illusory effect is obtainable. I need but to refer to +the well-known devices of linear and aerial perspective, by which this +result is secured.[40] The value of these means of producing illusion at +the command of the painter, may be illustrated by the following fact, +which I borrow from Helmholtz. If you place two pieces of cardboard +which correspond to portions of one form at the sides and in front of a +third piece, in the way represented above, so as just to allow the eye +to follow the contour of this last, and then look at this arrangement +from a point at some little distance with one eye, you easily suppose +that it stands in front of the side pieces. The explanation of the +illusion is that this particular arrangement powerfully suggests that +the outline of the whole figure, of which the two side pieces are parts, +is broken by an intervening object. Owing to the force of these and +other suggestions, it is easy for the spectator, when attending to the +background of a landscape painting, to give himself up for a moment to +the pleasant delusion that he is looking at an actual receding scene. + +In connection with pictorial delusion, I may refer to the well-known +fact, that the eye in a portrait seems to follow the spectator, or that +a gun, with its muzzle pointing straight outwards, appears to turn as +the spectator moves.[41] These tricks of art have puzzled many people, +yet their effect is easily understood, and has been very clearly +explained by Sir D. Brewster, in the work already referred to (letter +v.). They depend on the fact that a painting, being a flat projection +only and not a solid, continues to present the front view of an object +which it represents wherever the spectator happens to stand. Were the +eye in the portrait a real eye, a side movement of the spectator would, +it is evident, cause him to see less of the pupil and more of the side +of the eyeball, and he would only continue to see the full pupil when +the eye followed him. We regard the eye in the picture as a real eye +having relief, and judge accordingly. + +We may fall into similar illusions respecting distance in auditory +perception. A change of wind, an unusual stillness in the air, is quite +sufficient to produce the sense that sounding objects are nearer than +they actually are. The art of the ventriloquist manifestly aims at +producing this kind of illusion. By imitating the dull effect of a +distant voice, he is able to excite in the minds of his audience a +powerful conviction that the sounds proceed from a distant point. There +is little doubt that ventriloquism has played a conspicuous part in the +arts of divination and magic. + + +_Misconception of Local Arrangement._ + +Let us now pass to a class of illusions closely related to those having +to do with distance, but involving some special kind of circumstance +which powerfully suggests a particular arrangement in space. One of the +most striking examples of these is the erroneous localization of a +quality in space, that is to say, the reference of it to an object +nearer, or further off than the right one. Thus, when we look through a +piece of yellow glass at a dull, wintry landscape, we are disposed to +imagine that we are looking at a sunny scene of preternatural warmth. A +moment's reflection would tell us that the yellow tint, with which the +objects appear to be suffused, comes from the presence of the glass; +yet, in spite of this, the illusion persists with a curious force. The +explanation is, of course, that the circumstances are exceptional, that +in a vast majority of cases the impression of colour belongs to the +object and not to an intervening medium,[42] and that consequently we +tend to ignore the glass, and to refer the colour to the objects +themselves. + +When, however, the fact of the existence of a coloured medium is +distinctly present to the mind, we easily learn to allow for this, and +to recognize one coloured surface correctly through a recognized medium. +Thus, we appear to ourselves to see the reflected images of the wall, +etc., of a room, in a bright mahogany table, not suffused with a reddish +yellow tint, as they actually are--and may be seen to be by the simple +device of looking at a small bit of the image through a tube, but in +their ordinary colour. We may be said to fall into illusion here in so +far as we overlook the exact quality of the impression actually made on +the eye. This point will be touched on presently. Here I am concerned to +show that this habit of allowing for the coloured medium may, in its +turn, occasionally lead to plain and palpable illusion. + +The most striking example of this error is to be met with among the +curious phenomena of colour-contrast already referred to. In many of +these cases the appearance of the contrasting colour is, as I have +observed, due to a temporary modification of the nervous substance. Yet +it is found that this organic factor does not wholly account for the +phenomena. For example, Meyer made the following experiment. He covered +a piece of green paper by a sheet of thin transparent white paper. The +colour of this double surface was, of course, a pale green. He then +introduced a scrap of grey paper between the two sheets, and found that, +instead of looking whitish as it really was, it looked rose-red. +Whatever the colour of the under sheet the grey scrap took the +complementary hue. If, however, the piece of grey paper is put outside +the thin sheet, it looks grey; and what is most remarkable is that when +a second piece is put outside, the scrap inside no longer wears the +complementary hue. + +There is here evidently something more than a change of organic +conditions; there is an action of experience and suggestion. The reason +of our seeing the scrap rose-red in one case and neutral grey in +another, is that in the first instance we vividly represent to ourselves +that we are looking at it through a greenish veil (which is, of course, +a part of the illusion); for rose-red seen through a greenish medium +would, as a matter of fact, be light grey, as this scrap is. Even if we +allow that there always exists after an impression of colour a temporary +organic disposition to see the complementary hue, this does not suffice +as an explanation of these cases; we have to conclude further that +imagination, led by the usual run of our experience, is here a +co-operant factor, and helps to determine whether the complementary tint +shall be seen or not. + + +_Misinterpretation of Form._ + +More complex and circumscribed associations take part in those errors +which we occasionally commit respecting the particular form of objects. +This has already been touched on in dealing with artistic illusion. The +disposition of the eye to attribute solidity to a flat drawing is the +more powerful in proportion to the familiarity of the form. Thus, an +outline drawing of a building is apt to stand out with special force. + +Another curious illustration of this is the phenomenon known as the +conversion of the concave mould or matrix of a medal into the +corresponding convex relief. If, says Helmholtz, the mould of a medal be +illuminated by a light falling obliquely so as to produce strong +shadows, and if we regard this with one eye, we easily fall into the +illusion that it is the original raised design, illuminated from _the +opposite side_. As a matter of fact, the visual impression produced by a +concave form with the light falling on one side, very closely resembles +that produced by a corresponding convex form with the light falling on +the other side. At the same time, it is found that the opposite mode of +conversion, that is to say, the transformation of the raised into the +depressed form, though occurring occasionally, is much less frequent. +Now, it may be asked, why should we tend to transform the concave into +the convex, rather than the convex into the concave? The reader may +easily anticipate the answer from what has been said about the deeply +fixed tendency of the eye to solidify a plane surface. We are rendered +much more familiar, both by nature and by art, with raised (_cameo_) +design than with depressed design (_intaglio_), and we instinctively +interpret the less familiar form by the more familiar. This explanation +appears to be borne out by the fact emphasized by Schroeder that the +illusion is much more powerful if the design is that of some well-known +object, as the human head or figure, or an animal form, or leaves.[43] + +Another illustration of this kind of illusion recently occurred in my +own experience. Nearly opposite to my window came a narrow space between +two detached houses. This was, of course, darker than the front of the +houses, and the receding parallel lines of the bricks appeared to cross +this marrow vertical shaft obliquely. I could never look at this without +seeing it as a convex column, round which the parallel lines wound +obliquely. Others saw it as I did, though not always with the same +overpowering effect. I can only account for this illusion by help of the +general tendency of the eye to solidify impressions drawn from the flat, +together with the effect of special types of experience, more +particularly the perception of cylindrical forms in trees, columns, etc. + +It may be added that a somewhat similar illustration of the action of +special types of experience on the perception of individual form may be +found in the region of hearing. The powerful disposition to take the +finely graduated cadences of sound produced by the wind for the +utterances of a Iranian voice, is due to the fact that this particular +form and arrangement of sound has deeply impressed itself on our minds, +in connection with numberless utterances of human feeling. + +_Illusions of Recognition._ + +As a last illustration of comparatively passive illusions, I may refer +to the errors which we occasionally commit in recognizing objects. As I +have already observed, the process of full and clear recognition, +specific and individual, involves a classing of a number of distinct +aspects of the object, such as colour, form, etc. Accordingly, when in a +perfectly calm state of mind we fall into illusion with respect to any +object plainly visible, it must be through some accidental resemblance +between the object and the other object or class of objects with which +we identify it. In the case of individual identification such illusions +are, of course, comparatively rare, since here there are involved so +many characteristic differences. On the other hand, in the case of +specific recognition there is ample room for error, especially in those +kinds of more subtle recognition to which I have already referred. To +"recognize" a person as a Frenchman or a military man, for example, is +often an erroneous process. Logicians have included this kind of error +under what they call "fallacies of observation." + +Errors of recognition, both specific and individual, are, of course, +more easy in the case of distant objects or objects otherwise +indistinctly seen. It is noticeable in these cases that, even when +perfectly cool and free from emotional excitement, we tend to interpret +such indistinct impressions according to certain favourite types of +experience, as the human face and figure. Our interpretative imagination +easily sees traces of the human form in cloud, rock, or tree-stump. + +Again, even when there is no error of recognition, in the sense of +confusing one object with other objects, there may be partial illusion. +I have remarked that the process of recognizing an object commonly +involves an overlooking of points of diversity in the object, or aspect +of the object, now present. And sometimes this inattention to what is +actually present includes an error as to the actual visual sensation of +the moment. Thus, for example, when I look at a sheet of white paper in +a feebly lit room, I seem to see its whiteness. If, however, I bring it +near the window, and let the sun fall on a part of it, I at once +recognize that what I have been seeing is not white, but a decided grey. +Similarly, when I look at a brick viaduct a mile or two off, I appear to +myself to recognize its redness. In fact, however, the impression of +colour which I receive from the object is not that of brick-red at all, +but a much less decided tint; which I may easily prove by bending my +head downwards and letting the scene image itself on the retina in an +unusual way, in which case the recognition of the object as a viaduct +being less distinct, I am better able to attend to the exact shade of +the colour. + +Nowhere is this inattention to the sensation of the moment exhibited in +so striking a manner as in pictorial art. A picture of Meissonier may +give the eye a representation of a scene in which the objects, as the +human figures and horses, have a distinctness that belongs to near +objects, but an apparent magnitude that belongs to distant objects. So +again, it is found that the degree of luminosity or brightness of a +pictorial representation differs in general enormously from that of the +actual objects. Thus, according to the calculations of Helmholtz,[44] a +picture representing a Bedouin's white raiment in blinding sunshine, +will, when seen in a fairly lit gallery, have a degree of luminosity +reaching only to about one-thirtieth of that of the actual object. On +the other hand, a painting representing marble ruins illuminated by +moonlight, will, under the same conditions of illumination, have a +luminosity amounting to as much as from ten to twenty thousand times +that of the object. Yet the spectator does not notice these stupendous +discrepancies. The representation, in spite of its vast difference, at +once carries the mind on to the actuality, and the spectator may even +appear to himself, in moments of complete absorption, to be looking at +the actual scene. + +The truly startling part of these illusions is, that the direct result +of sensory stimulation appears to be actually displaced by a mental +image. Thus, in the case of Meyer's experiment, of looking at the +distant viaduct, and of recognizing an artistic representation, +imagination seems in a measure to take the place of sensation, or to +blind the mind to what is actually before it. + +The mystery of the process, however, greatly disappears when it is +remembered that what we call a conscious "sensation" is really +compounded of a result of sensory stimulation and a result of central +reaction, of a purely passive impression and the mental activity +involved in attending to this and classing it.[45] This being so, a +sensation may be modified by anything exceptional in the mode of central +reaction of the moment. Now, in all the cases just considered, we have +one common feature, a powerful suggestion of the presence of a +particular object or local arrangement. This suggestion, taking the form +of a vivid mental image, dominates and overpowers the passive +impression. Thus, in Meyer's experiment, the mind is possessed by the +supposition that we are looking at the grey spot through a greenish +medium. So in the case of the distant viaduct, we are under the mastery +of the idea that what we see in the distance is a red brick structure. +Once more, in the instance of looking at the picture, the spectator's +imagination is enchained by the vivid representation of the object for +which the picture stands, as the marble ruins in the moonlight or the +Bedouin in the desert. + +It may be well to add that this mental uncertainty as to the exact +nature of a present impression is necessitated by the very conditions of +accurate perception. If, as I have said, all recognition takes place by +overlooking points of diversity, the mind must, in course of time, +acquire a habit of not attending to the exact quality of +sense-impressions in all cases where the interpretation seems plain and +obvious. Or, to use Helmholtz's words, our sensations are, in a general +way, of interest to us only as signs of things, and if we are sure of +the thing, we readily overlook the precise nature of the impression. In +short, we get into the way of attending only to what is essential, +constant, and characteristic in objects, and disregarding what is +variable and accidental.[46] Thus, we attend, in the first place, to the +form of objects, the most constant and characteristic element of all, +being comparatively inattentive to colour, which varies with distance, +atmospheric changes, and mode of illumination. So we attend to the +relative magnitude of objects rather than to the absolute, and to the +relative intensities of light and shade rather than to the absolute; for +in so doing we are noting what is constant for all distances and modes +of illumination, and overlooking what is variable. And the success of +pictorial art depends on the observance of this law of perception. + +These remarks at once point out the limits of these illusions. In normal +circumstances, an act of imagination, however vivid, cannot create the +semblance of a sensation which is altogether absent; it can only +slightly modify the actual impression by interfering with that process +of comparison and classification which enters into all definite +determination of sensational quality. + +Another great fact that has come to light in the investigation of these +illusions is that oft-recurring and familiar types of experience leave +permanent dispositions in the mind. As I said when describing the +process of perception, what has been frequently perceived is perceived +more and more readily. It follows from this that the mind will be +habitually disposed to form the corresponding mental images, and to +interpret impressions by help of these. The range of artistic suggestion +depends on this. A clever draughtsman can indicate a face by a few rough +touches, and this is due to the fact that the spectator's mind is so +familiarized, through recurring experience and special interest, with +the object, that it is ready to construct the requisite mental image at +the slightest external suggestion. And hence the risk of hasty and +illusory interpretation. + +These observations naturally conduct us to the consideration of the +second great group of sense-illusions, which I have marked off as active +illusions, where the action of a pre-existing intellectual disposition +becomes much more clearly marked, and assumes the form of a free +imaginative transformation of reality. + + + + +CHAPTER VI. + +ILLUSIONS OF PERCEPTION--_continued_. + +B. _Active Illusions._ + + +When giving an account of the mechanism of perception, I spoke of an +independent action of the imagination which tends to anticipate the +process of suggestion from without. Thus, when expecting a particular +friend, I recognize his form much more readily than when my mind has not +been preoccupied with his image. + +A little consideration will show that this process must be highly +favourable to illusion. To begin with, even if the preperception be +correct, that is to say, if it answer to the perception, the mere fact +of vivid expectation will affect the exact moment of the completed act +of perception. And recent experiment shows that in certain cases such a +previous activity of expectant attention may even lead to the illusory +belief that the perception takes place before it actually does.[47] + +A more palpable source of error resides in the risk of the formation of +an inappropriate preperception. If a wrong mental image happens to have +been formed and vividly entertained, and if the actual impression fits +in to a certain extent with this independently formed preperception, we +may have a fusion of the two which exactly simulates the form of a +complete percept. Thus, for example, in the case just supposed, if +another person, bearing some resemblance to our expected friend, chances +to come into view, we may probably stumble into the error of taking one +person for another. + +On the physical side, we may, agreeably to the hypothesis mentioned +above, express this result by saying that, owing to a partial identity +in the nervous processes involved in the anticipatory image and the +impression, the two tend to run one into the other, constituting one +continuous process. + +There are different ways in which this independent activity of the +imagination may falsify our perceptions. Thus, we may voluntarily choose +to entertain a certain image for the moment, and to look at the +impression in a particular way, and within certain limits such +capricious selection of an interpretation is effectual in giving a +special significance to an impression. Or the process of independent +preperception may go on apart from our volitions, and perhaps in spite +of these, in which case the illusion has something of the irresistible +necessity of a passive illusion. Let us consider separately each mode +of production. + + +_Voluntary Selection of Interpretation._ + +The action of a capricious exercise of the imagination in relation to an +impression is illustrated in those cases where experience and suggestion +offer to the interpreting mind an uncertain sound, that is to say, where +the present sense-signs are ambiguous. Here we obviously have a choice +of interpretation. And it is found that, in these cases, what we see +depends very much on what we wish to see. The interpretation adopted is +still, in a sense, the result of suggestion, but of one particular +suggestion which the fancy of the moment determines. Or, to put it +another way, the caprice of the moment causes the attention to focus +itself in a particular manner, to direct itself specially to certain +aspects and relations of objects. + +The eye's interpretation of movement, already referred to, obviously +offers a wide field for this play of selective imagination. When looking +out of the window of a railway carriage, I can at will picture to my +mind the trees and telegraph posts as moving objects. Sometimes the true +interpretation is so uncertain that the least inclination to view the +phenomenon in one way determines the result. This is illustrated in a +curious observation of Sinsteden. One evening, on approaching a windmill +obliquely from one side, which under these circumstances he saw only as +a dark silhouette against a bright sky, he noticed that the sails +appeared to go, now in one direction, now in another, according as he +imagined himself looking at the front or at the back of the +windmill.[48] + +In the interpretation of geometrical drawings, as those of crystals, +there is, as I have observed, a general tendency to view the flat +delineation as answering to a raised object, or a body in relief, +according to the common run of our experience. Yet there are cases where +experience is less decided, and where, consequently, we may regard any +particular line as advancing or receding. And it is found that when we +vividly imagine that the drawing is that of a convex or concave surface, +we see it to be so, with all the force of a complete perception. The +least disposition to see it in the other way will suffice to reverse the +interpretation. Thus, in the following drawing, the reader can easily +see at will something answering to a truncated pyramid, or to the +interior of a cooking vessel. + +[Illustration: FIG. 5.] + +Similarly, in the accompanying figure of a transparent solid, I can at +will select either of the two surfaces which approximately face the eye +and regard it as the nearer, the other appearing as the hinder surface +looked at through the body. + +[Illustration: FIG. 6.] + +Again, in the next drawing, taken from Schroeder, one may, by an effort +of will, see the diagonal step-like pattern, either as the view from +above of the edge of an advancing piece of wall at _a_, or as the view +from below of the edge of an advancing (overhanging) piece of wall at +_b_. + +[Illustration: FIG. 7.] + +These last drawings are not in true perspective on either of the +suppositions adopted, wherefore the choice is easier. But even when an +outline form is in perspective, a strenuous effort of imagination may +suffice to bring about a conversion of the appearance. Thus, if the +reader will look at the drawing of the box-like solid (Fig. 3, p. 79), +he will find that, after a trial or two, he succeeds in seeing it as a +_concave_ figure representing the coyer and two sides of a box as looked +at from within.[49] + +Many of my readers, probably, share in my power of variously +interpreting the relative position of bands or stripes on fabrics such +as wall-papers, according to wish. I find that it is possible to view +now this stripe or set of stripes as standing out in relief upon the +others as a ground, now these others as advancing out of the first as a +background. The difficulty of selecting either interpretation at will +becomes greater, of course, in those cases where there is a powerful +suggestion of some particular local arrangement, as, for example, the +case of patterns much brighter than the ground, and especially of such +as represent known objects, as flowers. Yet even here a strong effort of +imagination will often suffice to bring about a conversion of the first +appearance. + +A somewhat similar choice of interpretation offers itself in looking at +elaborate decorative patterns. When we strongly imagine any number of +details to be elements of one figure, they seem to become so; and a +given detail positively appears to alter in character according as it is +viewed as an element of a more or less complex figure. + +These examples show what force belongs to a vivid preconception, if this +happens to fit only very roughly the impression of the moment, that is +to say, if the interpretative image is one of the possible suggestions +of the impression. The play of imagination takes a wider range in those +cases where the impression is very indefinite in character, easily +allowing of a considerable variety of imaginative interpretation. + +I referred at the beginning of this account of sense-illusions to the +readiness with which the mind deceives itself with respect to the nature +and causes of the vague sensations which usually form the dim background +of our mental life. A person of lively imagination, by trying to view +these in a particular way, and by selectively attending to those aspects +of the sensation which answer to the caprice of the moment, may give a +variety of interpretations to one and the same set of sensations. For +example, it is very easy to get confused with respect to those tactual +and motor feelings which inform us of the position of our bodily +members. And so, when lying in bed, and attending to the sensations +connected with the legs, we may easily delude ourselves into supposing +that these members are arranged in a most eccentric fashion. Similarly, +by giving special heed to the sensations arising in connection with the +condition of the skin at any part, we may amuse ourselves with the +strangest fancies as to what is going on in these regions. + +Again, when any object of visual perception is indistinct or indefinite +in form, there is plainly an opening for this capricious play of fancy +in transforming the actual. This is illustrated in the well-known +pastime of discovering familiar forms, such as those of the human head +and animals, in distant rocks and clouds, and of seeing pictures in the +fire, and so on. The indistinct and indefinite shapes of the masses of +rock, cloud, or glowing coal, offer an excellent field for creative +fancy, and a person of lively imagination will discover endless forms in +what, to an unimaginative eye, is a formless waste. Johannes Müller +relates that, when a child, he used to spend hours in discovering the +outlines of forms in the partly blackened and cracked stucco of the +house that stood opposite to his own.[50] Here it is plain that, while +experience and association are not wholly absent, but place certain wide +limits on this process of castle-building, the spontaneous activity of +the percipient mind is the great determining force. + +So much as to the influence of a perfectly unfettered voluntary +attention on the determination of the stage of preperception, and, +through this, of the resulting interpretation. Let us now pass to cases +in which this direction of preperception follows not the caprice of the +moment, but the leading of some fixed predisposition in the +interpreter's mind. In these cases attention is no longer free, but +fettered, only it is now fettered rather from within than from without; +that is to say, the dominating preperception is much more the result of +an independent bent of the imagination than of some suggestion forced on +the mind by the actual impression of the moment. + +_Involuntary Mental Preadjustment._ + + +If we glance back at the examples of capricious selection just noticed, +we shall see that they are really limited not only by the character of +the impression of the time, but also by the mental habits of the +spectator. That is to say, we find that his fancy runs in certain +definite directions, and takes certain habitual forms. It has already +been observed that the percipient mind has very different attitudes with +respect to various kinds of impression. Towards some it holds itself at +a distance, while towards others it at once bears itself familiarly; the +former are such as answer to its previous habit and bent of imagination, +the latter such as do not so answer. + +This bent of the interpretative imagination assumes, as we have already +seen, two forms, that of a comparatively permanent disposition, and that +of a temporary state of expectation or mental preparedness. Illusion may +arise in connection with either of these forms. Let us illustrate both +varieties, beginning with those which are due to a lasting mental +disposition. + +It is impossible here to specify all the causes of illusion residing in +organized tendencies of the mind. The whole past mental life, with its +particular shade of experience, its ruling emotions, and its habitual +direction of fancy, serves to give a particular colour to new +impressions, and so to favour illusion. There is a "personal equation" +in perception as in belief--an amount of erroneous deviation from the +common average view of external things, which is the outcome of +individual temperament and habits of mind. Thus, a naturally timid man +will be in general disposed to see ugly and fearful objects where a +perfectly unbiased mind perceives nothing of the kind; and the forms +which these objects of dread will assume are determined by the character +of his past experience, and by the customary direction of his +imagination. + +In perfectly healthy states of mind this influence of temperament and +mental habit on the perception of external objects is, of course, very +limited; it shows itself more distinctly, as we shall see, in modifying +the estimate of things in relation to the æsthetic and other feelings. +This applies to the mythical poetical way of looking at nature--a part +of our subject to which we shall have to return later on. + +Passing now from the effect of such permanent dispositions, let us look +at the more striking results of temporary expectancy of mind. + +When touching on the influence of such a temporary mental attitude in +the process of correct perception, I remarked that this readiness of +mind might assume an indefinite or a definite form. We will examine the +effect of each kind in the production of illusion. + + +_Action of Sub-Expectation._ + +First of all, then, our minds may at the particular moment be disposed +to entertain any one of a vaguely circumscribed group of images. Thus, +to return to the example already referred to, when in Italy, we are in a +state of readiness to frame any of the images that we have learnt to +associate with this country. We may not be distinctly anticipating any +one kind of object, but are nevertheless in a condition of +_sub-expectation_ with reference to a large number of objects. +Accordingly, when an impression occurs which answers only very roughly +to one of the associated images, there is a tendency to superimpose the +image on the impression. In this way illusion arises. Thus, a man, when +strolling in a cathedral, will be apt to take any kind of faint hollow +sound for the soft tones of an organ. + +The disposition to anticipate fact and reality in this way will be all +the stronger if, as usually happens, the mental images thus lying ready +for use have an emotional colouring. Emotion is the great disturber of +all intellectual operations. It effects marvellous things, as we shall +presently see, in the region of illusory belief, and its influence is +very marked in the seemingly cooler region of external perception. The +effect of any emotional excitement appears to be to give a preternatural +vividness and persistence to the ideas answering to it, that is to say, +the ideas which are its excitants, or which are otherwise associated +with it. Owing to this circumstance, when the mind is under the +temporary sway of any feeling, as, for example, fear, there will be a +special readiness to interpret objects by help of images congruent with +the emotion. Thus, a man under the control of fear will be ready to see +any kind of fear-inspiring object whenever there is any resemblance to +such in the things actually present to his vision. The state of awe +which the surrounding circumstances of a spiritualist _séance_ inspires +produces a general readiness of mind to perceive what is strange, +mysterious, and apparently miraculous. + +It is worth noting, perhaps, that those delightful half-illusions which +imitative art seeks to produce are greatly favoured by such a temporary +attitude of the interpreting imagination. In the theatre, for example, +we are prepared for realizing the semblance of life that is to be +unfolded before us. We come knowing that what is to be performed aims at +representing a real action or actual series of events. We not improbably +work ourselves into a slightly excited state in anticipation of such a +representation. More than this, as the play progresses, the realization +of what has gone before produces a strong disposition to believe in the +reality of what is to follow. And this effect is proportionate to the +degree of coherence and continuity in the action. In this way, there is +a cumulative effect on the mind. If the action is good, the illusion, as +every play-goer knows, is most complete towards the end. + +Were it not for all this mental preparation, the illusory character of +the performance would be too patent to view, and our enjoyment would +suffer. A man is often aware of this when coming into a theatre during +the progress of a piece before his mind accommodates itself to the +meaning of the play. And the same thing is recognizable in the fact that +the frequenter of the theatre has his susceptibility to histrionic +delusion increased by acquiring a habit of looking out for the meaning +of the performance. Persons who first see a play, unless they be of +exceptional imagination and have thought much about the theatre--as +Charlotte Brontë, for instance--hardly feel the illusion at all. At +least, this is true of the opera, where the departure from reality is +so striking that the impression can hardly fail to be a ludicrous one, +till the habit of taking the performance for what it is intended to be +is fully formed.[51] + +A similar effect of intellectual preadjustment is observable in the +fainter degrees of illusion produced by pictorial art. Here the +undeceiving circumstances, the flat surface, the surroundings, and so +on, would sometimes be quite sufficient to prevent the least degree of +illusion, were it not that the spectator comes prepared to see a +representation of some real object. This is our state of mind when we +enter a picture gallery or approach what we recognize as a picture on +the wall of a room. A savage would not "realize" a slight sketch as soon +as one accustomed to pictorial representation, and ready to perform the +required interpretative act.[52] + +So much as to the effect of an indefinite state of sub-expectation in +misleading our perceptions. Let us now glance at the results of definite +preimagination, including what are generally known as expectations. + +_Effects of Vivid Expectation._ + + +Such expectations may grow out of some present objective facts, which +serve as signs of the expected event; or they may arise by way of verbal +suggestion; or, finally, they may be due to internal spontaneous +imagination. + +In the first place, then, the expectations may grow out of previous +perceptions, while, nevertheless, the direction of the expectation may +be a wrong one. Here the interpreting imagination is, in a large sense, +under the control of external suggestion, though, with respect to the +particular impression that is misconstrued, it may be regarded as acting +independently and spontaneously. + +Illustrations of this effect in producing illusion will easily occur to +the reader. If I happen to have heard that a particular person has been +a soldier or clergyman, I tend to see the marks of the class in this +person, and sometimes find that this process of recognition is +altogether illusory. Again, let us suppose that a person is expecting a +friend by a particular train. A passenger steps out of the train bearing +a superficial resemblance to his friend; in consequence of which he +falls into the error of false identification. + +The delusions of the conjuror depend on a similar principle. The +performer tells his audience that he is about to do a certain thing, for +example, take a number of animals out of a small box which is incapable +of holding them. The hearers, intent on what has been said, vividly +represent to themselves the action described. And in this way their +attention becomes bribed, so to speak, beforehand, and fails to notice +the inconspicuous movements which would at once clear up the mystery. +Similarly with respect to the illusions which overtake people at +spiritualist _séances_. The intensity of the expectation of a particular +kind of object excludes calm attention to what really happens, and the +slightest impressions which answer to signs of the object anticipated +are instantly seized by the mind and worked up into illusory +perceptions. + +It is to be noted that even when the impression cannot be made to tally +exactly with the expectation, the force of the latter often effects a +grotesque confusion of the perception. If, for example, a man goes into +a familiar room in the dark in order to fetch something, and for a +moment forgets the particular door by which he has entered, his definite +expectation of finding things in a certain order may blend with the +order of impressions experienced, producing for the moment a most +comical illusion as to the actual state of things. + +When the degree of expectation is unusually great, it may suffice to +produce something like the counterfeit of a real sensation. This happens +when the present circumstances are powerfully suggestive of an immediate +event. The effect is all the more powerful, moreover, in those cases +where the object or event expected is interesting or exciting, since +here the mental image gains in vividness through the emotional +excitement attending it. Thus, if I am watching a train off and know +from all the signs that it is just about to start, I easily delude +myself into the conviction that it has begun to start, when it is +really still.[53] An intense degree of expectation may, in such cases, +produce something indistinguishable from an actual sensation. This +effect is seen in such common experiences as that the sight of food +makes the mouth of a hungry man water; that the appearance of a surgical +instrument produces a nascent sensation of pain; and that a threatening +movement, giving a vivid anticipation of tickling, begets a feeling +which closely approximates to the result of actual tickling. + +One or two very striking instances of such imagined sensations are given +by Dr. Carpenter.[54] Here is one. An officer who superintended the +exhuming of a coffin rendered necessary through a suspicion of crime, +declared that he already experienced the odour of decomposition, though +it was afterwards found that the coffin was empty.[55] + +It is, of course, often difficult to say, in such cases as these, how +far elements of actual sensation co-operate in the production of the +illusions. Thus, in the case just mentioned, the odour of the earth may +have been the starting-point in the illusion. In many cases, however, an +imaginative mind appears to be capable of transforming a vivid +expectation into a nascent stage of sensation. Thus, a mother thinking +of her sick child in an adjoining room, and keenly on the alert for its +voice, will now and again fancy she really hears it when others hear +nothing at all. + + +_Transition to Hallucination._ + +It is plain that in these cases illusion approaches to hallucination. +Imagination, instead of waiting on sensation, usurps its place and +imitates its appearance. Such a "subjective" sensation produced by a +powerful expectation might, perhaps, by a stretch of language, be +regarded as an illusion, in the narrow sense, in so far as it depends on +the suggestive force of a complete set of external circumstances; on the +other hand, it is clearly an hallucination in so far as it is the +production of the semblance of an external impression without any +external agency corresponding to this. + +In the class of illusory expectations just considered the immediately +present environment still plays a part, though a much less direct part +than that observable in the first large group of illusions. We will now +pass to a second mode of illusory expectation, where imagination is +still more detached from the present surroundings. + +A common instance of this kind of expectation is the so-called +"intuition," or presentiment; that something is going to happen, which +expectation has no basis in fact. It does not matter whether the +expectation has arisen by way of another's words or by way of personal +inclinations. A strong wish for a thing will, in an exalted state of +mind, beget a vivid anticipation of it. This subject will be touched on +again under the Illusions of Belief. Here I am concerned to point out +that such presentiments are fertile sources of sense-illusion. The +history of Church miracles, visions, and the like amply illustrates the +effect of a vivid anticipation in falsifying the perceptions of external +things. + +In persons of a lively imagination any recent occupation of the mind +with a certain kind of mental image may suffice to beget something +equivalent to a powerful mode of expectation. For example, we are told +by Dr. Tuke that on one occasion a lady, whose imagination had been +dwelling on the subject of drinking fountains, "thought she saw in a +road a newly erected fountain, and even distinguished an inscription +upon it, namely, 'If any man thirst, let him come unto Me, and drink.' +She afterwards found that what she had actually seen was only a few +scattered stones."[56] In many cases there seems to be a temporary +preternatural activity of the imagination in certain directions, of +which no very obvious explanation is discoverable. Thus, we sometimes +find our minds dwelling on some absent friend, without being able to +give any reason for this mental preoccupation. And in this way arise +strong temporary leanings to illusory perception. It may be said, +indeed, that all unwonted activity of the imagination, however it +arises, has as its immediate result a temporary mode of expectation, +definite or indefinite, which easily confuses our perceptions of +external things. + +In proportion as this pre-existing imaginative impulse becomes more +powerful, the amount of actual impression necessary to transform the +mental image into an illusory perception becomes less; and, what is more +important, this transformation of the internal image involves a larger +and larger displacement of the actual impression of the moment. A man +whose mind is at the time strongly possessed by one kind of image, will +tend to project this outwards with hardly any regard to the actual +external circumstances. + +This state of things is most completely illustrated in many of the +grosser illusions of the insane. Thus, when a patient takes any small +objects, as pebbles, for gold and silver, under the influence of the +dominant idea of being a millionaire, it is obvious that external +suggestion has very little to do with the self-deception. The confusions +into which the patient often falls with respect to the persons before +him show the same state of mind; for in many cases there is no +discoverable individual resemblance between the person actually present +and the person for whom he is taken. + +It is evident that when illusion reaches this stage, it is scarcely +distinguishable from what is specially known as hallucination. As I have +remarked in setting out, illusion and hallucination shade one into the +other much too gradually for us to draw any sharp line of demarcation +between them. And here we see that hallucination differs from illusion +only in the proportion in which the causes are present. When the +internal imaginative impulse reaches a certain strength, it becomes +self-sufficient, or independent of any external impression. + +This intimate relation between the extreme form of active illusion and +hallucination may be seen, too, by examining the physical conditions of +each. As I have already remarked, active illusion has for its +physiological basis a state of sub-excitation, or an exceptional +condition of irritability in the structures engaged in the act of +interpretative imagination. The greater the degree of this irritability, +the less will be the force of external stimulation needed to produce the +effect of excitation, and the more energetic will be the degree of this +excitation. Moreover, it is plain that this increase in the strength of +the excitation will involve an extension of the area of excitation till, +by-and-by, the peripheral regions of the nervous system may be involved +just as in the case of external stimulation. This accounts for the +gradual displacement of the impression of the moment by the mental +image. It follows that when the irritability reaches a certain degree, +the amount of external stimulus needed may become a vanishing quantity, +or the state of sub-excitation may of itself develop into one of full +activity. + + +_Hallucinations._ + +I do not propose to go very fully into the description and explanation +of hallucinations here, since they fall to a large extent under the +category of distinctly pathological phenomena. Yet our study of +illusions would not be complete without a glance at this part of the +subject. + +Hallucination, by which I mean the projection of a mental image outwards +when there is no external agency answering to it, assumes one of two +fairly distinct forms: it may present itself either as a semblance of an +external impression with the minimum amount of interpretation, or as a +counterfeit of a completely developed percept. Thus, a visual +hallucination may assume the aspect of a sensation of light or colour +which we vaguely refer to a certain region of the external world, or of +a vision of some recognizable object. All of us frequently have +incomplete visual and auditory hallucinations of the first order, +whereas the complete hallucinations of the second order are +comparatively rare. The first I shall call rudimentary, the second +developed, hallucinations. + +Rudimentary hallucinations may have either a peripheral or a central +origin. They may first of all have their starting-point in those +subjective sensations which, as we have seen, are connected with certain +processes set up in the peripheral regions of the nervous system. Or, +secondly, they may originate in a certain preternatural activity of the +sensory centres, or "sensorium," in what has been called by German +physiologists an automatic excitation of the central structures, which +activity may probably diffuse itself downwards to the peripheral regions +of the nerves. Baillarger would call hallucinations of the former class +"psycho-sensorial," those of the latter class purely "psychical," +hallucinations.[57] + +It is often a matter of great difficulty to determine which part of the +nervous system is originally concerned in these rudimentary +hallucinations. It is probable that in normal life they are most +frequently due to peripheral disturbance. And it seems reasonable to +suppose that where the hallucination remains in this initial stage of a +very incompletely interpreted visual or auditory impression, whether in +normal or abnormal life, its real physiological source is the periphery. +For the automatic excitation of the centres would pretty certainly issue +in the semblance of some definite, familiar variety of sense-impression +which, moreover, as a part of a complex state known as a percept, would +instantly present itself as a completely formed quasi-percept. In truth, +we may pretty safely argue that if it is the centre which is directly +thrown into a state of activity, it will be thrown into the usual +complex, that is to say, _perceptional_, mode of activity. + +Let us now turn to hallucinations properly so called, that is to say, +completely developed quasi-percepts. These commonly assume the form of +visual or auditory hallucinations. Like the incomplete hallucinations, +they may have their starting-point either in some disturbance in the +peripheral regions of the nervous system or in the automatic activity of +the central structures: or, to use the language of Baillarger, we may +say that they are either "psycho-sensorial" or purely "psychical." A +subjective visual sensation, arising from certain conditions in the +retina and connected portions of the optic nerve, may by chance resemble +a familiar impression, and so be at once interpreted as an effect of a +particular external object. More frequently, however, the automatic +activity of the centres must be regarded, either in part or altogether, +as the physiological cause of the phenomenon. This is clearly the case +when, on the subjective side, the hallucination answers to a preceding +energetic activity of the imagination, as in the case of the visionary +and the monomaniac. Sometimes, however, as we have seen, the +hallucinatory percept answers to previous prolonged acts of perception, +leaving a kind of reverberation in the structures concerned; and in this +case it is obviously impossible to say whether the peripheral or central +regions (if either) have most to do with the hallucination.[58] + +The classifications of the causes of hallucination to be met with in the +works of pathologists, bear out the distinction just drawn. Griesinger +tells us (_op. cit._, pp. 94, 95) that the general causes of +hallucination are: (1) Local disease of the organ of sense; (2) a state +of deep exhaustion either of mind or of body; (3) morbid emotional +states, such as fear; (4) outward calm and stillness between sleeping +and waking; and (5) the action of certain poisons, as haschisch, opium, +belladonna. The first cause points pretty distinctly to a peripheral +origin, whereas the others appear to refer mainly, if not exclusively, +to central derangements. Excessive fatigue appears to predispose the +central structures to an abnormal kind of activity, and the same effect +may be brought about by emotional agitation and by the action of +poisons. The fourth case mentioned here, absence of external +stimulation, would naturally raise the nervous structures to an +exceptional pitch of excitability. Such a condition would, moreover, +prove favourable to hallucination by blurring the distinction between +mental image and actual impression. + + +_Hallucinations of Normal Life._ + +In normal life, perfect hallucinations, in the strict sense as distinct +from illusions, are comparatively rare. Fully developed persistent +hallucinations, as those of Nicolai, the Berlin bookseller, and of Mrs. +A----, the lady cited by Sir D. Brewster, in his _Letters on Natural +Magic_, point to the presence of incipient nervous disorder. In healthy +life, on the other hand, while everybody is familiar with subjective +sensations such as flying spots, phosphenes, ringing in the ears, few +fall into the error of seeing or hearing distinct recognizable objects +in the absence of all external impressions. In the lives of eminent men +we read of such phenomena as very occasional events. Malebranche, for +example, is said to have heard the voice of God calling him. Descartes +says that, after a long confinement, he was followed by an invisible +person, calling him to pursue his search for truth. Dr. Johnson narrates +that he once heard his absent mother calling him. Byron tells us that he +was sometimes visited by spectres. Goethe records that he once saw an +exact counterpart of himself coming towards him. Sir Walter Scott is +said to have seen a phantom of the dead Byron. It is possible that all +of us are liable to momentary hallucinations at times of exceptional +nervous exhaustion, though they are too fugitive to excite our +attention. + +When not brought on by exhaustion or artificial means, the +hallucinations of the sane have their origin in a preternatural power of +imagination. It is well known that this power can be greatly improved by +attention and cultivation. Goethe used to exercise himself in watching +for ocular spectra, and could at will transform these subjective +sensations into definite forms, such as flowers; and Johannes Müller +found he had the same power.[59] Stories are told of portrait painters +who could summon visual images of their sitters with a vividness equal +to that of reality, and serving all the purposes of their art. Mr. +Galton's interesting inquiries into the power of "visualizing" would +appear to prove that many people can at will sport on the confines of +the phantom world of hallucination. There is good reason to think that +imaginative children tend to confuse mental images and percepts.[60] + +_The Hallucinations of Insanity._ + + +The hallucinations of the insane are but a fuller manifestation of +forces that we see at work in normal life. Their characteristic is that +they simulate the form of distinctly present objects, the existence of +which is not instantly contradicted by the actual surroundings of the +moment.[61] The hallucinations have their origin partly in subjective +sensations, which are probably connected with peripheral disturbances, +partly and principally in central derangements.[62] These include +profound emotional changes, which affect the ruling mental tone, and +exert a powerful influence on the course of the mental images. The +hallucinations of insanity are due to a projection of mental images +which have, owing to certain circumstances, gained a preternatural +persistence and vividness. Sometimes it is the images that have been +dwelt on with passionate longing before the disease, sometimes those +which have grown most habitual through the mode of daily +occupation,[63] and sometimes those connected with some incident at or +near the time of the commencement of the disease. + +In mental disease, auditory hallucinations play a part no less +conspicuous than visual.[64] Patients frequently complain of having +their thoughts spoken to them, and it is not uncommon for them to +imagine that they are addressed by a number of voices at the same +time.[65] + +These auditory hallucinations offer a good opportunity for studying the +gradual growth of centrally originating hallucinations. In the early +stages of the disease, the patient partly distinguishes his +representative from his preservative sounds. Thus, he talks of sermons +being composed to him _in his head_. He calls these "internal voices," +or "voices of the soul." It is only when the disease gains ground and +the central irritability increases that these audible thoughts become +distinctly projected as external sounds into more or less definite +regions of the environment. And it is exceedingly curious to notice the +different directions which patients give to these sounds, referring them +now to a quarter above the head, now to a region below the floor, and so +on.[66] + + +_Range of Sense-Illusions._ + +And now let us glance back to see the path we have traversed. We set out +with an account of perfectly normal perception, and found, even here, in +the projection of our sensations of colour, sound, etc., into the +environment or to the extremities of the organism, something which, from +the point of view of physical science, easily wears the appearance of an +ingredient of illusion. + +Waiving this, however, and taking the word illusion as commonly +understood, we find that it begins when the element of imagination no +longer answers to a present reality or external fact in any sense of +this expression. In its lowest stages illusion closely counterfeits +correct perception in the balance of the direct factor, sensation, and +the indirect factor, mental reproduction or imagination. The degree of +illusion increases in proportion as the imaginative element gains in +force relatively to the present impression; till, in the wild illusions +of the insane, the amount of actual impression becomes evanescent. When +this point is reached, the act of imagination shows itself as a purely +creative process, or an hallucination. + +While we may thus trace the progress of illusion towards hallucination +by means of the gradual increase in force and extent of the imaginative, +or indirect, as opposed to the sensuous, or direct, element in +perception, we have found a second starting-point for this movement in +the mechanism of sensation, involving, as it does, the occasional +production of "subjective sensations." Such sensations constitute a +border-land between the regions of illusion in the narrow sense, and +hallucination. In their simplest and least developed form they may be +regarded, at least in the case of hearing and sight, as partly +hallucinatory; and they serve as a natural basis for the construction of +complete hallucinations, or hallucinatory percepts. + +In these different ways, then, the slight, scarcely noticeable illusions +of normal life lead up to the most startling hallucinations of abnormal +life. From the two poles of the higher centres of attention and +imagination on the one side, and the lower regions of nervous action +involved in sensation on the other side, issue forces which may, under +certain circumstances, develop into full hallucinatory percepts. Thus +closely is healthy attached to morbid mental life. There seems to be no +sudden break between our most sober every-day recognitions of familiar +objects and the wildest hallucinations of the demented. As we pass from +the former to the latter, we find that there is never any abrupt +transition, never any addition of perfectly new elements, but only that +the old elements go on combining in ever new proportions. + +The connection between the illusory side of our life and insanity may be +seen in another way. All illusion has as its negative condition an +interruption of the higher intellectual processes, the due control of +our mental representations by reflection and reason. In the case of +passive illusions, the error arises from our inability to subordinate +the suggestion made by some feature of the present impression to the +result of a fuller inspection of the object before us, or of a wider +reflection on the past. In other words, our minds are dominated by the +partial and the particular, to the exclusion of the total or the +general. In active illusions, again, the powers of judgment and +reflection, including those of calm perception itself, temporarily +vacate their throne in favour of imagination. And this same suspension +of the higher intellectual functions, the stupefaction of judgment and +reflection made more complete and permanent, is just what characterizes +insanity. + +We may, perhaps, express this point of connection between the illusions +of normal life and insanity by help of a physiological hypothesis. If +the nervous system has been slowly built up, during the course of human +history, into its present complex form, it follows that those nervous +structures and connections which have to do with the higher intellectual +processes, or which represent the larger and more general relations of +our experience, have been most recently evolved. Consequently, they +would be the least deeply organized, and so the least stable; that is +to say, the most liable to be thrown _hors de combat_. This is what +happens temporarily in the case of the sane, when the mind is held fast +by an illusion. And, in states of insanity, we see the process of +nervous dissolution beginning with these same nervous structures, and so +taking the reverse order of the process of evolution.[67] And thus, we +may say that throughout the mental life of the most sane of us, these +higher and more delicately balanced structures are constantly in danger +of being reduced to that state of inefficiency, which in its full +manifestation is mental disease. + +Does this way of putting the subject seem alarming? Is it an appalling +thought that our normal mental life is thus intimately related to +insanity, and graduates away into it by such fine transitions? A +moment's reflection will show that the case is not so bad as it seems. +It is well to remind ourselves that the brain is a delicately adjusted +organ, which very easily gets disturbed, and that the best of us are +liable to become the victims of absurd illusion if we habitually allow +our imaginations to be overheated, whether by furious passion or by +excessive indulgence in the pleasures of day-dreaming, or in the +intoxicating mysteries of spiritualist _séances_. But if we take care to +keep our heads cool and avoid unhealthy degrees of mental excitement, we +need not be very anxious on the ground of our liability to this kind of +error. As I have tried to show, our most frequent illusions are +necessarily connected with something exceptional, either in the +organism or in the environment. That is to say, it is of the nature of +illusion in healthy conditions of body and mind to be something very +occasional and relatively unimportant. Our perceptions may be regarded +as the reaction of the mind on the impressions borne in from the +external world, or as a process of adjustment of internal mental +relations to external physical relations. If this process is, in the +main, a right one, we need not greatly trouble, because it is not +invariably so. We should accept the occasional failure of the +intellectual mechanism as an inseparable accompaniment of its general +efficiency. + +To this it must be added that many of the illusions described above can +hardly be called cases of non-adaptation at all, since they have no +relation to the practical needs of life, and consequently are, in a +general way, unattended to. In other cases, again, namely, where the +precise nature of a present sensation, being practically an unimportant +matter, is usually unattended to, as in the instantaneous recognition of +objects by the eye under changes of illumination, etc., the illusion is +rather a part of the process of adaptation, since it is much more +important to recognize the permanent object signified by the sensation +than the precise nature of the present sensational "sign" itself. + +Finally, it should never be forgotten that in normal states of mind +there is always the possibility of rectifying an illusion. What +distinguishes abnormal from normal mental life is the persistent +occupation of the mind by certain ideas, so that there is no room for +the salutary corrective effect of reflection on the actual impression +of the moment, by which we are wont to "orientate," or take our bearings +as to the position of things about us. In sleep, and in certain +artificially produced states, much the same thing presents itself. +Images become realities just because they are not instantly recognized +as such by a reference to the actual surroundings of the moment. But in +normal waking life this power of correction remains with us. We may not +exercise it, it is true, and thus the illusion will tend to become more +or less persistent and recurring; for the same law applies to true and +to false perception: repetition makes the process easier. But if we only +choose to exert ourselves, we can always keep our illusions in a nascent +or imperfectly developed stage. This applies not only to those +half-illusions into which we voluntarily fall, but also to the more +irresistible passive illusions, and those arising from an over-excited +imagination. Even persons subject to hallucinations, like Nicolai of +Berlin, learn to recognize the unreal character of these phantasms. On +this point the following bit of autobiography from the pen of Coleridge +throws an interesting light. "A lady (he writes) once asked me if I +believed in ghosts and apparitions. I answered with truth and +simplicity, No, madam, I have seen far too many myself."[68] However +irresistible our sense-illusions may be, so long as we are under the +sway of particular impressions or mental images, we can, when resolved +to do so, undeceive ourselves by carefully attending to the actual +state of things about us. And in many cases, when once the correction is +made, the illusion seems an impossibility. By no effort of imagination +are we able to throw ourselves back into the illusory mental condition. +So long as this power of dispelling the illusion remains with us, we +need not be alarmed at the number and variety of the momentary +misapprehensions to which we are liable. + + + + +CHAPTER VII. + +DREAMS. + + +The phenomena of dreams may well seem at first sight to form a world of +their own, having no discoverable links of connection with the other +facts of human experience. First of all, there is the mystery of sleep, +which quietly shuts all the avenues of sense and so isolates the mind +from contact with the world outside. To gaze at the motionless face of a +sleeper temporarily rapt from the life of sight, sound, and +movement--which, being common to all, binds us together in mutual +recognition and social action--has always something awe-inspiring. This +external inaction, this torpor of sense and muscle, how unlike to the +familiar waking life, with its quick responsiveness and its overflowing +energy! And then, if we look at dreams from the inside, we seem to find +but the reverse face of the mystery. How inexpressibly strange does the +late night-dream seem to a person on waking! He feels he has been seeing +and hearing things no less real than those of waking life; but things +which belong to an unfamiliar world, an order of sights and a sequence +of events quite unlike those of waking experience; and he asks himself +in his perplexity where that once-visited region really lies, or by what +magic power it was suddenly and for a moment created for his vision. In +truth, the very name of dream suggests something remote and mysterious, +and when we want to characterize some impression or scene which by its +passing strangeness filled us with wonder, we naturally call it +dream-like. + + +_Theories of Dreams._ + +The earliest theories respecting dreams illustrate very clearly this +perception of the remoteness of dream-life from waking experience. By +the simple mind of primitive man this dream-world is regarded as similar +in its nature or structure to our common world, only lying remote from +this. The savage conceives that when he falls asleep, his second self +leaves his familiar body and journeys forth to unfamiliar regions, where +it meets the departed second selves of his dead ancestors, and so on. +From this point of view, the experience of the night, though equal in +reality to that of the day, is passed in a wholly disconnected +region.[69] + +A second and more thoughtful view of dreams, marking a higher grade of +intellectual culture, is that these visions of the night are symbolic +pictures unfolded to the inner eye of the soul by some supernatural +being. The dream-experience is now, in a sense, less real than it was +before, since the phantasms that wear the guise of objective realities +are simply images spread out to the spirit's gaze, or the direct +utterance of a divine message. Still, this mysterious contact of the +mind with the supernatural is regarded as a fact, and so the dream +assumes the appearance of a higher order of experience. Its one point of +attachment to the experience of waking life lies in its symbolic +function; for the common form which this supernatural view assumes is +that the dream is a dim prevision of coming events. Artemidorus, the +great authority on dream interpretation (_oneirocritics_) for the +ancient world, actually defines a dream as "a motion or fiction of the +soul in a diverse form signifying either good or evil to come;" and even +a logician like Porphyry ascribes dreams to the influence of a good +demon, who thereby warns us of the evils which another and bad demon is +preparing for us. The same mode of viewing dreams is quite common +to-day, and many who pride themselves on a certain intellectual culture, +and who imagine themselves to be free from the weakness of superstition, +are apt to talk of dreams as of something mysterious, if not distinctly +ominous. Nor is it surprising that phenomena which at first sight look +so wild and lawless, should still pass for miraculous interruptions of +the natural order of events.[70] + +Yet, in spite of this obvious and impressive element of the mysterious +in dream-life, the scientific impulse to illuminate the less known by +the better known has long since begun to play on this obscure subject. +Even in the ancient world a writer might here and there be found, like +Democritus or Aristotle, who was bold enough to put forward a natural +and physical explanation of dreams. But it has been the work of modern +science to provide something like an approximate solution of the +problem. The careful study of mental life in its intimate union with +bodily operations, and the comparison of dream-combinations with other +products of the imagination, normal as well as morbid, have gradually +helped to dissolve a good part of the mystery which once hung like an +opaque mist about the subject. In this way, our dream-operations have +been found to have a much closer connection with our waking experiences +than could be supposed on a superficial view. The materials of our +dreams are seen, when closely examined, to be drawn from our waking +experience. Our waking consciousness acts in numberless ways on our +dreams, and these again in unsuspected ways influence our waking mental +life.[71] Not only so, it is found that the quaint chaotic play of +images in dreams illustrates mental processes and laws which are +distinctly observable in waking thought. Thus, for example, the apparent +objective reality of these visions has been accounted for, without the +need of resorting to any supernatural agency, in the light of a vast +assemblage of facts gathered from the by-ways, so to speak, of waking +mental life. I need hardly add that I refer to the illusions of sense +dealt with in the foregoing chapters. + +Dreams are to a large extent the semblance of external perceptions. +Other psychical phenomena, as self-reflection, emotional activity, and +so on, appear in dream-life, but they do so in close connection with +these quasi-perceptions. The name "vision," given by old writers to +dreams, sufficiently points out this close affinity of the mental +phenomena to sense-perception; and so far as science is concerned, they +must be regarded as a peculiar variety of sense-illusion. Hence the +appropriateness of studying them in close connection with the illusions +of perception of the waking state. Though marked off by the presence of +very exceptional physiological conditions, they are largely intelligible +by help of these physiological and psychological principles which we +have just been considering. + + +_The State of Sleep._ + +The physiological explanation of dreams must, it is plain, set out with +an account of the condition of the organism known as sleep. While there +is here much that is uncertain, there are some things which are fairly +well known. Recent physiological observation has gone to prove that +during sleep all the activities of the organism are appreciably lowered. +Thus, for example, according to Testa, the pulse falls by about +one-fifth. This lowering of the organic functions appears, under +ordinary circumstances, to increase towards midnight, after which there +is a gradual rising. + +The nervous system shares in this general depression of the vital +activities. The circulation being slower, the process of reparation and +nutrition of the nerves is retarded, and so their degree of excitability +diminished. This is clearly seen in the condition of the peripheral +regions of the nervous system, including the sense-organs, which appear +to be but very slightly acted on by their customary stimuli. + +The nervous centres must participate in this lethargy of the system. In +other words, the activity of the central substance is lowered, and the +result of this is plainly seen in what is usually thought of as the +characteristic feature of sleep, namely, a transition from vigorous +mental activity or intense and clear consciousness, to comparative +inactivity or faint and obscure consciousness. The cause of this +condition of the centres is supposed to be the same as that of the +torpidity of all the other organs in sleep, namely, the retardation of +the circulation. But, though there is no doubt as to this, the question +of the proximate physiological conditions of sleep is still far from +being settled. Whether during sleep the blood-vessels of the brain are +fuller or less full than during waking, is still a moot point. Also the +qualitative condition of the blood in the cerebral vessels is still a +matter of discussion.[72] + +Since the effect of sleep is to lower central activity, the question +naturally occurs whether the nervous centres are ever rendered inactive +to such an extent as to interrupt the continuity of our conscious life. +This question has been discussed from the point of view of the +metaphysician, of the psychologist, and of the physiologist, and in no +case is perfect unanimity to be found. The metaphysical question, +whether the soul as a spiritual substance is capable of being wholly +inactive, or whether it is not in what seem the moments of profoundest +unconsciousness partially awake--the question so warmly discussed by the +Cartesians, Leibnitz, etc.--need not detain us here. + +Of more interest to us are the psychological and the physiological +discussions. The former seeks to settle the question by help of +introspection and memory. On the one side, it is urged against the +theory of unbroken mental activity, that we remember so little of the +lowered consciousness of sleep.[73] To this it is replied that our +forgetfulness of the contents of dream-consciousness, even if this were +unbroken, would be fully accounted for by the great dissimilarity +between dreaming and waking mental life. It is urged, moreover, on this +side that a sudden rousing of a man from sleep always discovers him in +the act of dreaming, and that this goes to prove the uniform connection +of dreaming and sleeping. This argument, again, may be met by the +assertion that our sense of the duration of our dreams is found to be +grossly erroneous; that, owing to the rapid succession of the images, +the _realization_ of which would involve a long duration, we enormously +exaggerate the length of dreams in retrospection.[74] From this it is +argued that the dream which is recalled on our being suddenly awakened +may have had its whole course during the transition state of waking. + +Again, the fact that a man may resolve, on going to sleep, to wake at a +certain hour, has often been cited in proof of the persistence of a +degree of mental activity even in perfectly sound sleep. The force of +this consideration, however, has been explained away by saying that the +anticipation of rising at an unusual hour necessarily produces a slight +amount of mental disquietude, which is quite sufficient to prevent sound +sleep, and therefore to expose the sleeper to the rousing action of +faint external stimuli. + +While the purely psychological method is thus wholly inadequate to solve +the question, physiological reasoning appears also to be not perfectly +conclusive. Many physiologists, not unnaturally desirous of upsetting +what they regard as a gratuitous metaphysical hypothesis, have +pronounced in favour of an absolutely dreamless or unconscious sleep. +From the physiological point of view, there is no mystery in a totally +suspended mental activity. On the other hand, there is much to be said +on the opposite side, and perhaps it may be contended that the purely +physiological evidence rather points to the conclusion that central +activity, however diminished during sleep, always retains a minimum +degree of intensity. At least, one would be disposed to argue in this +way from the analogy of the condition of the other functions of the +organism during sleep. Possibly this modicum of positive evidence may +more than outweigh any slight presumption against the doctrine of +unbroken mental activity drawn from the negative circumstance that we +remember so little of our dream-life.[75] + +Such being the state of physiological knowledge respecting the +immediate conditions of sleep, we cannot look for any certain +information on the nature of that residual mode of cerebral activity +which manifests itself subjectively in dreams. It is evident, indeed, +that this question can only be fully answered when the condition of the +brain as a whole during sleep is understood. Meanwhile we must be +content with vague hypotheses. + +It may be said, for one thing, that during sleep the nervous substance +as a whole is less irritable than during waking hours. That is to say, a +greater amount of stimulus is needed to produce any conscious +result.[76] This appears plainly enough in the case of the peripheral +sense-organs. Although these are not, as it is often supposed, wholly +inactive during sleep, they certainly require a more potent external +stimulus to rouse them to action. And what applies to the peripheral +regions applies to the centres. In truth, it is clearly impossible to +distinguish between the diminished irritability of the peripheral and +that of the central structures. + +At first sight it seems contradictory to the above to say that stimuli +which have little effect on the centres of consciousness during waking +life produce an appreciable result in sleep. Nevertheless, it will be +found that this is the case. Thus organic processes which scarcely make +themselves known to the mind in a waking state, may be shown to be the +originators of many of our dreams. This fact can only be explained on +the physical side by saying that the special cerebral activities +engaged in an act of attention are greatly liberated during sleep by the +comparative quiescence of the external senses. These activities, by +co-operating with the faint results of the stimuli coming from the +internal organs, serve very materially to increase their effect. + +Finally, it is to be observed that, while the centres thus respond with +diminished energy to peripheral stimuli, external and internal, they +undergo a direct, or "automatic," mode of excitation, being roused into +activity independently of an incoming nervous impulse. This automatic +stimulation has been plausibly referred to the action of the products of +decomposition accumulating in the cerebral blood-vessels.[77] It is +possible that there is something in the nature of this stimulation to +account for the force and vividness of its conscious results, that is to +say, of dreams. + + +_The Dream State._ + +Let us now turn to the psychic side of these conditions, that is to say, +to the general character of the mental states known as dreams. It is +plain that the closing of the avenues of the external senses, which is +the accompaniment of sleep, will make an immense difference in the +mental events of the time. Instead of drawing its knowledge from +without, noting its bearings in relation to the environment, the mind +will now be given over to the play of internal imagination. The activity +of fancy will, it is plain, be unrestricted by collision with external +fact. The internal mental life will expand in free picturesque +movement. + +To say that in sleep the mind is given over to its own imaginings, is to +say that the mental life in these circumstances will reflect the +individual temperament and mental history. For the play of imagination +at any time follows the lines of our past experience more closely than +would at first appear, and being coloured with emotion, will reflect the +predominant emotional impulses of the individual mind. Hence the saying +of Heraclitus, that, while in waking we all have a common world, in +sleep we have each a world of our own. + +This play of imagination in sleep is furthered by the peculiar attitude +of attention. When asleep the voluntary guidance of attention ceases; +its direction is to a large extent determined by the contents of the +mind at the moment. Instead of holding the images and ideas, and +combining them according to some rational end, the attention relaxes its +energies and succumbs to the force of imagination. And thus, in sleep, +just as in the condition of reverie or day-dreaming, there is an +abandonment of the fancy to its own wild ways. + +It follows that the dream-state will not appear to the mind as one of +fancy, but as one of actual perception, and of contact with present +reality. Dreams are clearly illusory, and, unlike the illusions of +waking life, are complete and persistent.[78] And the reason of this +ought now to be clear. First of all, the mind during sleep wants what M. +Taine calls the corrective of a present sensation. When awake under +ordinary circumstances, any momentary illusion is at once set right by a +new act of orientation. The superior vividness of the external +impression cannot leave us in any doubt, when calm and self-possessed, +whether our mental images answer to present realities or not. On the +other hand, when asleep, this reference to a fixed objective standard is +clearly impossible. Secondly, we may fairly argue that the mental images +of sleep approximate in character to external impressions. This they do +to some extent in point of intensity, for, in spite of the diminished +excitability of the centres, the mode of stimulation which occurs in +sleep may, as I have hinted, involve an energetic cerebral action. And, +however this be, it is plain that the image will gain a preternatural +force through the greatly narrowed range of attention. When the mind of +the sleeper is wholly possessed by an image or group of images, and the +attention kept tied down to these, there is a maximum reinforcement of +the images. But this is not all. When the attention is thus held captive +by the image, it approximates in character to an external impression in +another way. In our waking state, when our powers of volition are +intact, the external impression is characterized by its fixity or its +obdurate resistance to our wishes. On the other hand, the mental image +is fluent, accommodating, and disappears and reappears according to the +direction of our volitions. In sleep, through the suspension of the +higher voluntary power of attention, the mental image seems to lord it +over our minds just as the actual impression of waking life. + +This much may suffice, perhaps, by way of a general description of the +sleeping and dreaming state. Other points will make themselves known +after we have studied the contents and structure of dreams in detail. + +Dreams are commonly classified (_e.g._ by Wundt) with hallucinations, +and this rightly, since, as their common appellation of "vision" +suggests, they are for the most part the semblance of percepts in the +absence of external impressions. At the same time, recent research goes +to show that in many dreams something answering to the "external +impression" in waking perception is the starting-point. Consequently, in +order to be as accurate as possible, I shall divide dreams into +illusions (in the narrow sense) and hallucinations. + + +_Dream-Illusions._ + +By dream-illusions I mean those dreams which set out from some +peripheral nervous stimulation, internal or external. That the organic +processes of digestion, respiration, etc., act as stimuli to the centres +in sleep is well known. Thus, David Hartley assigns as the second great +source of dreams "states of the body."[79] But it is not so well known +to what an extent our dreams may be influenced by stimuli acting on the +exterior sense-organs. Let us first glance at the action of such +external stimuli. + + +_Action of External Stimuli._ + +During sleep the eyes are closed, and consequently the action of +external light on the retina impeded. Yet it is found that even under +these circumstances any very bright light suddenly introduced is capable +of stimulating the optic fibres, and of affecting consciousness. The +most common form of this is the effect of bright moonlight, and of the +early sun's rays. Krauss tells a funny story of his having once, when +twenty-six years old, caught himself, on waking, in the act of +stretching out his arms towards what his dream-fancy had pictured as the +image of his mistress. When fully awake, this image resolved itself into +the full moon.[80] It is not improbable, as Radestock remarks, that the +rays of the sun or moon are answerable for many of the dreams of +celestial glory which persons of a highly religious temperament are said +to experience. + +External sounds, when not sufficient to rouse the sleeper, easily +incorporate themselves into his dreams. The ticking of a watch, the +stroke of a clock, the hum of an insect, the song of a bird, the patter +of rain, are common stimuli to the dream-phantasy. M. Alf. Maury tells +us, in his interesting account of the series of experiments to which he +submitted himself in order to ascertain the result of external +stimulation on the mind during sleep, that when a pair of tweezers was +made to vibrate near his ear, he dreamt of bells, the tocsin, and the +events of June, 1848.[81] Most of us, probably, have gone through the +experience of impolitely falling asleep when some one was reading to us, +and of having dream-images suggested by the sounds that were still +indistinctly heard. Scherner gives an amusing case of a youth who was +permitted to whisper his name into the ear of his obdurate mistress, +the consequence of which was that the lady contracted a habit of +dreaming about him, which led to a felicitous change of feeling on her +part.[82] + +The two lower senses, smell and taste, seem to play a less-important +part in the production of dream-illusions. Radestock says that the odour +of flowers in a room easily leads to visual images of hot-houses, +perfumery shops, and so on; and it is probable that the contents of the +mouth may occasionally act as a stimulus to the organ of taste, and so +give rise to corresponding dreams. As Radestock observes, these lower +sensations do not commonly make known their quality to the sleeper's +mind. They become transformed at once into visual, instead of into +olfactory or gustatory percepts. That is to say, the dreamer does not +imagine himself smelling or tasting, but seeing an object. + +The contact of objects with the tactual organ is one of the best +recognized causes of dreams. M. Maury found that when his lips were +tickled, his dream-fancy interpreted the impression as of a pitch +plaster being torn off his face. An unusual pressure on any part of the +body, as, for example, from contact with a fellow-sleeper, is known to +give rise to a well-marked variety of dream. Our own limbs may even +appear as foreign bodies to our dream-imagination, when through pressure +they become partly paralyzed. Thus, on one occasion, I awoke from a +miserable dream, in which I felt sure I was grasping somebody's hand in +bed, and I was racked by terrifying conjectures as to who it might be. +When fully awake, I discovered that I had been lying on my right side, +and clasping the wrist of the right arm (which had been rendered +insensible by the pressure of the body) with the left hand. + +In close connection with these stimuli of pressure are those of muscular +movement, whether unimpeded or impeded. We need not enter into the +difficult question how far the "muscular sense" is connected with the +activity of the motor nerves, and how far with sensory fibres attached +to the muscular or the adjacent tissues. Suffice it to say that an +actual movement, a resistance to an attempted movement, or a mere +disposition to movement, whether consequent on a surplus of motor energy +or on a sensation of discomfort or fatigue in the part to be moved, +somehow or other makes itself known to our minds, even when we are +deprived of the assistance of vision. And these feelings of movement, +impeded or unimpeded, are common initial impulses in our +dream-experiences. It is quite a mistake to suppose that dreams are +built up out of the purely passive sensations of sight and hearing. A +close observation will show that in nearly every dream we imagine +ourselves either moving among the objects we perceive or striving to +move when some weighty obstacle obstructs us. All of us are familiar +with the common forms of nightmare, in which we strive hopelessly to +flee from some menacing evil, and this dream-experience, it may be +presumed, frequently comes from a feeling of strain in the muscles, due +to an awkward disposition of the limbs during sleep. The common +dream-illusion of falling down a vast abyss is plausibly referred by +Wundt to an involuntary extension of the foot of the sleeper. + + +_Action of Internal Stimuli._ + +Let us now pass from the action of stimuli lying outside the organism, +to that of stimuli lying within the peripheral regions of the +sense-organs. I have already spoken of the influence of subjective +sensations of sight, hearing, etc., on the illusions of waking life, and +it is now to be added that these sensations play an important part in +our dream-life. Johannes Müller lays great prominence on the part taken +by ocular spectra in the production of dreams. As he observes, the +apparent rays of light, light-patches, mists of light, and so on, due to +changes of blood-pressure in the retina, only manifest themselves +clearly when the eyes are closed and the more powerful effect of the +external stimulus cut off. These subjective spectra come into prominence +in the sleepy condition, giving rise to what M. Maury calls +"hallucinations hypnagogiques," and which he regards (after Gruithuisen) +as the chaos out of which the dream-cosmos is evolved.[83] They are +pretty certainly the starting-point in those picturesque dreams in which +figure a number of bright objects, such as beautiful birds, butterflies, +flowers, or angels. + +That the visual images of our sleep do often involve the peripheral +regions of the organ of sight, seems to be proved by the singular fact +that they sometimes persist after waking. Spinoza and Jean Paul Richter +both experienced this survival of dream-images. Still more pertinent is +the fact that the effects of retinal fatigue are producible by +dream-images. The physiologist Gruithuisen had a dream, in which the +principal feature was a violet flame, and which left behind it, _after +waking_, for an appreciable duration, a complementary image of a yellow +spot.[84] + +Subjective auditory sensations appear to be much less frequent causes of +dream-illusions than corresponding visual sensations. Yet the rushing, +roaring sound caused by the circulation of the blood in the ear is, +probably, a not uncommon starting-point in dreams. With respect to +subjective sensations of smell and taste, there is little to be said. On +the other hand, subjective sensations due to varying conditions in the +skin are a very frequent exciting cause of dreams. Variations in the +state of tension of the skin, brought about by alteration of position, +changes in the character of the circulation, the irradiation of heat to +the skin or the loss of the same, chemical changes,--these are known to +give rise to a number of familiar sensations, including those of +tickling, itching, burning, creeping, and so on; and the effects of +these sensations are distinctly traceable in our dreams. For example, +the exposure of a part of the body through a loss of the bed-clothes is +a frequent excitant of distressing dreams. A cold foot suggests that the +sleeper is walking over snow or ice. On the other hand, if the cold foot +happens to touch a warm part of the body, the dream-fancy constructs +images of walking on burning lava, and so on. + +These sensations of the skin naturally conduct us to the organic +sensations as a whole; that is to say, the feelings connected with the +varying condition of the bodily organs. These include the feelings which +arise in connection with the processes of digestion, respiration, and +circulation, and the condition of various organs according to their +state of nutrition, etc. During our waking life these organic feelings +coalesce for the most part, forming as the "vital sense" an obscure +background for our clear discriminative consciousness, and only come +forward into this region when very exceptional in character, as when +respiration or digestion is impeded, or when we make a special effort of +attention to single them out.[85] When we are asleep, however, and the +avenues of external perception are closed, they assume greater +prominence and distinctness. The centres, no longer called upon to react +on stimuli coming from without the organism, are free to react on +stimuli coming from its hidden recesses. So important a part, indeed, do +these organic feelings take in the dream-drama, that some writers are +disposed to regard them as the great, if not the exclusive, cause of +dreams. Thus, Schopenhauer held that the excitants of dreams are +impressions received from the internal regions of the organism through +the sympathetic nervous system.[86] + +It is hardly necessary, perhaps, to give many illustrations of the +effect of such organic sensations on our dreams. Among the most common +provocatives of dreams are sensations connected with a difficulty in +breathing, due to the closeness of the air or to the pressure of the +bed-clothes on the mouth. J. Börner investigated the influence of these +circumstances by covering with the bed-clothes the mouth and a part of +the nostrils of persons who were sound asleep. This was followed by a +protraction of the act of breathing, a reddening of the face, efforts to +throw off the clothes, etc. On being roused, the sleeper testified that +he had experienced a nightmare, in which a horrid animal seemed to be +weighing him down.[87] Irregularity of the heart's action is also a +frequent cause of dreams. It is not improbable that the familiar +dream-experience of flying arises from disturbances of the respiratory +and circulatory movements. + +Again, the effects of indigestion, and more particularly stomachic +derangement, on dreams are too well known to require illustration. It +may be enough to allude to the famous dream which Hood traces to an +excessive indulgence at supper. It is known that the varying condition +of the organs of secretion influences our dream-fancy in a number of +ways. + +Finally, it is to be observed that an injury done to any part of the +organism is apt to give rise to appropriate dream-images. In this way, +very slight disturbances which would hardly affect waking consciousness +may make themselves felt during sleep. Thus, for example, an incipient +toothache has been known to suggest that the teeth are being +extracted.[88] + +It is worth observing that the interpretation of these various orders of +sensations by the imagination of the dreamer takes very different forms +according to the person's character, previous experience, ruling +emotions, and so on. This is what is meant by saying that during sleep +every man has a world of his own, whereas, when awake, he shares in the +common world of perception. + + +_Dream-Exaggeration._ + +It is to be noticed, further, that this interpretation of sensation +during sleep is uniformly a process of exaggeration.[89] The exciting +causes of the feeling of discomfort, for example, are always absurdly +magnified. The reason of this seems to be that, owing to the condition +of the mind during sleep, the nature of the sensation is not clearly +recognizable. Even in the case of familiar external impressions, such as +the sound of the striking of a clock, there appears to be wanting that +simple process of reaction by which, in a waking condition of the +attention, a sense-impression is instantly discriminated and classed. In +sleep, as in the artificially induced hypnotic condition, the slighter +differences of quality among sensations are not clearly recognized. The +activity of the higher centres, which are concerned in the finer +processes of discrimination and classification, being greatly reduced, +the impression may be said to come before consciousness as something +novel and unfamiliar. And just as we saw that in waking life novel +sensations agitate the mind, and so lead to an exaggerated mode of +interpretation; so here we see that what is unfamiliar disturbs the +mind, rendering it incapable of calm attention and just interpretation. + +This failure to recognize the real nature of an impression is seen most +conspicuously in the case of the organic sensations. As I have remarked, +these constitute for the most part, in waking life, an undiscriminated +mass of obscure feeling, of which we are only conscious as the mental +tone of the hour. And in the few instances in which we do attend to them +separately, whether through their exceptional intensity or in +consequence of an extraordinary effort of discriminative attention, we +can only be said to perceive them, that is, recognize their local +origin, very vaguely. Hence, when asleep, these sensations get very +oddly misinterpreted. + +The localization of a bodily sensation in waking life means the +combination of a tactual and a visual image with the sensation. Thus, my +recognition of a twinge of toothache as coming from a certain tooth, +involves representations of the active and passive sensations which +touching and looking at the tooth would yield me. That is to say, the +feeling instantly calls up a compound mental image exactly answering to +a visual percept. This holds good in dream-interpretation too; the +interpretation is effected by means of a visual image. But since the +feeling is only very vaguely recognized, this visual image does not +answer to the bodily part concerned. Instead of this, the fancy of the +dreamer constructs some visual image which bears a vague resemblance to +the proper one, and is generally, if not always, an exaggeration of this +in point of extensive magnitude, etc. For example, a sensation arising +from pressure on the bladder, being dimly connected with the presence of +a fluid, calls up an image of a flood, and so on. + +This mode of dream-interpretation has by some writers been erected into +the typical mode, under the name of dream-symbolism. Thus Scherner, in +his interesting though somewhat fanciful work, _Das Leben des Traumes_, +contends that the various regions of the body regularly disclose +themselves to the dream-fancy under the symbol of a building or group of +buildings; a pain in the head calling up, for example, the image of +spiders on the ceiling, intestinal sensations exciting an image of a +narrow alley, and so on. Such theories are clearly an exaggeration of +the fact that the localization of our bodily sensations during sleep is +necessarily imperfect.[90] + +In many cases the image called up bears on its objective side no +discoverable resemblance to that of the bodily region or the exciting +cause of the sensation. Here the explanation must be looked for in the +subjective side of the sensation and mental image, that is to say, in +their emotional quality, as pleasurable or painful, distressing, +quieting, etc. It is to be observed, indeed, that in natural sleep, as +in the condition known as hypnotism, while differences of specific +quality in the sense-impressions are lost, the broad difference of the +pleasurable and the painful is never lost. It is, in fact, the +subjective emotional side of the sensation that uniformly forces itself +into consciousness. This being so, it follows that, speaking generally, +the sensations of sleep, both external and internal, or organic, will be +interpreted by what G.H. Lewes has called "an analogy of feeling;" that +is to say, by means of a mental image having some kindred emotional +character or colouring. + +Now, the analogy between the higher emotional and the bodily states is a +very close one. A sensation of obstruction in breathing has its exact +analogue in a state of mental embarrassment, a sensation of itching its +counterpart in mental impatience, and so on. And since these emotional +experiences are deeper and fuller than the sensations, the tendency to +exaggerate the nature and causes of these last would naturally lead to +an interpretation of them by help of these experiences. In addition to +this, the predominance of visual imagery in sleep would aid this +transformation of a bodily sensation into an emotional experience, since +visual perceptions have, as their accompaniments of pleasure and pain, +not sensations, but emotions.[91] + +Since in this vague interpretation of bodily sensation the actual +impression is obscured, and not taken up as an integral part into the +percept, it is evident that we cannot, strictly speaking, call the +process an imitation of an act of perception, that is to say, an +illusion. And since, moreover, the visual image by which the sensation +is thus displaced appears as a present object, it would, of course, be +allowable to speak of this as an hallucination. This substitution of a +more or less analogous visual image for that appropriate to the +sensation forms, indeed, a transition from dream-illusion, properly so +called, to dream-hallucination. + + +_Dream-Hallucinations._ + +On the physical side, these hallucinations answer to cerebral +excitations which are central or automatic, not depending on movements +transmitted from the periphery of the nervous system. Of these +stimulations some appear to be direct, and due to unknown influences +exerted by the state of nutrition of the cerebral elements, or the +action of the contents of the blood-vessels on these elements. + + +_Effects of Direct Central Stimulation._ + +That such action does prompt a large number of dream-images may be +regarded as fairly certain. First of all, it seems impossible to account +for all the images of dream-fancy as secondary phenomena connected by +links of association with the foregoing classes of sensation. However +fine and invisible many of the threads which hold together our ideas may +be, they will hardly explain the profusion and picturesque variety of +dream-imagery. Secondly, we are able in certain cases to infer with a +fair amount of certainty that a dream-image is due to such central +stimulation. The common occurrence that we dream of the more stirring +events, the anxieties and enjoyments of the preceding day, appears to +show that when the cerebral elements are predisposed to a certain kind +of activity, as they are after having been engaged for some time in this +particular work, they are liable to be excited by some stimulus brought +directly to bear on them during sleep. And if this is so, it is not +improbable that many of the apparently forgotten images of persons and +places which return with such vividness in dreams are excited by a mode +of stimulation which is for the greater part confined to sleep. I say +"for the greater part," because even in our indolent, listless moments +of waking existence such seemingly forgotten ideas sometimes return as +though by a spontaneous movement of their own and by no discoverable +play of association. + +It may be well to add that this immediate revival of impressions +previously received by the brain includes not only the actual +perceptions of waking life, but also the ideas derived from others, the +ideal fancies supplied by works of fiction, and even the images which +our unaided waking fancy is wont to shape for itself. Our daily +conjectures as to the future, the communications to us by others of +their thoughts, hopes, and fears,--these give rise to numberless vague +fugitive images, any one of which may become distinctly revived in +sleep.[92] This throws light on the curious fact that we often dream of +experiences and events quite unlike those of our individual life. Thus, +for example, the common construction by the dream-fancy of the +experience of flight in mid-air, and the creation of those weird forms +which the terror of a nightmare is wont to bring in its train, seem to +point to the past action of waking fancy. To imagine one's self flying +when looking at a bird is probably a common action with all persons, at +least in their earlier years, and images of preternaturally horrible +beings are apt to be supplied to most of us some time during life by +nurses or by books. + + +_Indirect Central Stimulation._ + +Besides these direct central stimulations, there are others which, in +contradistinction, may be called indirect, depending on some previous +excitation. These are, no doubt, the conditions of a very large number +of our dream-images. There must, of course, be some primary cerebral +excitation, whether that of a present peripheral stimulation, or that +which has been termed central and spontaneous; but when once this first +link of the imaginative chain is supplied, other links may be added in +large numbers through the operation of the forces of association. One +may, indeed, safely say that the large proportion of the contents of +every dream arise in this way. + +The very simplest type of dream excited by a present sensation contains +these elements. To take an example, I once dreamt, as a consequence of +the loud barking of a dog, that a dog approached me when lying down, and +began to lick my face. Here the play of the associative forces was +apparent: a mere sensation of sound called up the appropriate visual +image, this again the representation of a characteristic action, and so +on. So it is with the dreams whose first impulse is some central or +spontaneous excitation. A momentary sight of a face or even the mention +of a name during the preceding day may give the start to dream-activity; +but all subsequent members of the series of images owe their revival to +a tension, so to speak, in the fine threads which bind together, in so +complicated a way, our impressions and ideas. + +Among the psychic accompaniments of these central excitations visual +images, as already hinted, fill the most conspicuous place. Even +auditory images, though by no means absent, are much less numerous than +visual. Indeed, when there are the conditions for the former, it +sometimes happens that the auditory effect transforms itself into a +visual effect. An illustration of this occurred in my own experience. +Trying to fall asleep by means of the well-known device of counting, I +suddenly found myself losing my hold on the faint auditory effects, my +imagination transforming them into a visual spectacle, under the form of +a path of light stretching away from me, in which the numbers appeared +under the grotesque form of visible objects, tumbling along in glorious +confusion. + +Next to these visual phantasms, certain motor hallucinations seem to be +most prominent in dreams. By a motor hallucination, I mean the illusion +that we are actually moving when there is no peripheral excitation of +the motor organ. Just as the centres concerned in passive sensation are +susceptible of central stimulation, so are the centres concerned in +muscular sensation. A mere impulse in the centres of motor innervation +(if we assume these to be the central seat of the muscular feelings) may +suffice to give rise to a complete representation of a fully executed +movement. And thus in our sleep we seem to walk, ride, float, or fly. + +The most common form of motor hallucination is probably the vocal. In +the social encounters which make up so much of our sleep-experience, we +are wont to be very talkative. Now, perhaps, we find ourselves zealously +advocating some cause, now very fierce in denunciation, now very amusing +in witty repartee, and so on. This imagination of ourselves as speaking, +as distinguished from that of hearing others talking, must, it is clear, +involve the excitation of the structures engaged in the production of +the muscular feelings which accompany vocal action, as much as, if not +more than, the auditory centres. And the frequency of this kind of +dream-experience may be explained, like that of visual imagery, by the +habits of waking life. The speech impulse is one of the most deeply +rooted of all our impulses, and one which has been most frequently +exercised in waking life. + +_Combination of Dream-Elements._ + +It is commonly said that dreams are a grotesque dissolution of all +order, a very chaos and whirl of images without any discoverable +connection. On the other hand, a few writers claim for the mind in sleep +a power of arranging and grouping its incongruous elements in definite +and even life-like pictures. Each of these views is correct within +certain limits; that is to say, there are dreams in which the strangest +disorder seems to prevail, and others in which one detects the action of +a central control. Yet, speaking generally, sequences of dream-images +will be found to be determined by certain circumstances and laws, and so +far not to be haphazard or wholly chaotic. We have now to inquire into +the laws of these successions; and, first of all, we may ask how far the +known laws of association, together with the peculiar conditions of the +sleeping state, are able to account for the various modes of +dream-combination. We have already regarded mental association as +furnishing a large additional store of dream-imagery; we have now to +consider it as explaining the sequences and concatenations of our +dream-elements. + + +_Incoherence of Dreams._ + +First of all, then, let us look at the chaotic and apparently lawless +side of dreaming, and see whether any clue is discoverable to the centre +of this labyrinth. In the case of all the less elaborately ordered +dreams, in which sights and sounds appear to succeed one another in the +wildest dance (which class of dreams probably belongs to the deeper +stages of sleep), the mind may with certainty be regarded as purely +passive, and the mode of sequence may be referred to the action of +association complicated by the ever-recurring introduction of new +initial impulses, both peripheral and central. These are the dreams in +which we are conscious of being perfectly passive, either as spectators +of a strange pageant, or as borne away by some apparently extraneous +force through a series of the most diverse experiences. The flux of +images in these dreams is very much the same as that in certain waking +conditions, in which we relax attention, both external and internal, and +yield ourselves wholly to the spontaneous play of memory and fancy. + +It is plain at a glance that the simultaneous concurrence of wholly +disconnected initial impulses will serve to impress a measure of +disconnectedness on our dream-images. From widely remote parts of the +organism there come impressions which excite each its peculiar visual or +other image according as its local origin or its emotional tone is the +more distinctly present to consciousness. Now it is a subjective ocular +sensation suggesting a bouquet of lovely flowers, and close on its heels +comes an impression from the organs of digestion suggesting all manner +of obstacles, and so our dream-fancy plunges from a vision of flowers to +one of dreadful demons. + +Let us now look at the way in which the laws of association working on +the incongruous elements thus cast up into our dream-consciousness, will +serve to give a yet greater appearance of disorder and confusion to our +dream-combinations. According to these laws, any idea may, under +certain circumstances, call up another, if the corresponding impressions +have only once occurred together, or if the ideas have any degree of +resemblance, or, finally, if only they stand in marked contrast with one +another. Any accidental coincidence of events, such as meeting a person +at a particular foreign resort, and any insignificant resemblance +between objects, sounds, etc., may thus supply a path, so to speak, from +fact to dream-fancy. + +In our waking states these innumerable paths of association are +practically closed by the supreme energy of the coherent groups of +impressions furnished us from the world without through our organs of +sense, and also by the volitional control of internal thought in +obedience to the pressure of practical needs and desires. In dream-life +both of these influences are withdrawn, so that delicate threads of +association, which have no chance of exerting their pull, so to speak, +in our waking states, now make known their hidden force. Little wonder, +then, that the filaments which bind together these dream-successions +should escape detection, since even in our waking thought we so often +fail to see the connection which makes us pass in recollection from a +name to a visible scene or perhaps to an emotional vibration. + +It is worth noting that the origin of an association is often to be +looked for in one of those momentary half-conscious acts of waking +imagination to which reference has already been made. A friend, for +example, has been speaking to us of some common acquaintance, remarking +on his poor health. The language calls up, vaguely, a visual +representation of the person sinking in health and dying. An +association will thus be formed between this person and the idea of +death. A night or two after, the image of this person somehow recurs to +our dream-fancy, and we straightway dream that we are looking at his +corpse, watching his funeral, and so on. The links of the chain which +holds together these dream-images were really forged, in part, in our +waking hours, though the process was so rapid as to escape our +attention. It may be added, that in many cases where a juxtaposition of +dream-images seems to have no basis in waking life, careful reflection +will occasionally bring to light some actual conjunction of impressions +so momentary as to have faded from our recollection. + +We must remember, further, how great an apparent disorder will invade +our imaginative dream-life when the binding force of resemblance has +unchecked play. In waking thought we have to connect things according to +their essential resemblances, classifying objects and events for +purposes of knowledge or action, according to their widest or their most +important points of similarity. In sleep, on the contrary, the slightest +touch of resemblance may engage the mind and affect the direction of +fancy. In a sense we may be said, when dreaming, to discover mental +affinities between impressions and feelings, including those subtle +links of emotional analogy of which I have already spoken. This effect +is well illustrated in a dream recorded by M. Maury, in which he passed +from one set of images to another through some similarity of names, as +that between _corps_ and _cor_. Such a movement of fancy would, of +course, be prevented in full waking consciousness by a predominant +attention to the meaning of the sounds. + +It will be possible, I think, after a habit of analyzing one's dreams in +the light of preceding experience has been formed, to discover in a good +proportion of cases some hidden force of association which draws +together the seemingly fortuitous concourse of our dream-atoms. That we +should expect to do so in every case is unreasonable, since, owing to +the numberless fine ramifications which belong to our familiar images, +many of the paths of association followed by our dream-fancy cannot be +afterwards retraced. + +To illustrate the odd way in which our images get tumbled together +through the action of occult association forces, I will record a dream +of my own. I fancied I was at the house of a distinguished literary +acquaintance, at her usual reception hour. I expected the friends I was +in the habit of meeting there. Instead of this, I saw a number of +commonly dressed people having tea. My hostess came up and apologized +for having asked me into this room. It was, she said, a tea-party which +she prepared for poor people at sixpence a head. After puzzling over +this dream, I came to the conclusion that the missing link was a verbal +one. A lady who is a connection of my friend, and bears the same name, +assists her sister in a large kind of benevolent scheme. I may add that +I had not, so far as I could recollect, had occasion very recently to +think of this benevolent friend, but I had been thinking of my literary +friend in connection with her anticipated return to town. + +In thus seeking to trace, amid the superficial chaos of dream-fancy, +its hidden connections, I make no pretence to explain why in any given +case these particular paths of association should be followed, and more +particularly why a slender thread of association should exert a pull +where a stronger cord fails to do so. To account for this, it would be +necessary to call in the physiological hypothesis that among the nervous +elements connected with a particular element, _a_, already excited, +some, as _m_ and _n_, are at the moment, owing to the state of their +nutrition or their surrounding influences, more powerfully predisposed +to activity than other elements, as _b_ and _c_. + +The subject of association naturally conducts us to the second great +problem in the theory of dreams--the explanation of the order in which +the various images group themselves in all our more elaborate dreams. + + +_Coherence of Dreams._ + +A fully developed dream is a complex of many distinct illusory +sense-presentations: in this respect it differs from the illusions of +normal waking life, which are for the most part single and isolated. And +this complex of quasi-presentations appears somehow or other to fall +together into one whole scene or series of events, which, though it may +be very incongruous and absurdly impossible from a waking point of view, +nevertheless makes a single object for the dreamer's internal vision, +and has a certain degree of artistic unity. This plastic force, which +selects and binds together our unconnected dream-images, has frequently +been referred to as a mysterious spiritual faculty, under the name of +"creative fancy." Thus Cudworth remarks, in his _Treatise concerning +Eternal and Immutable Morality_: "That dreams are many times begotten by +the phantastical power of the soul itself ... is evident from the +orderly connection and coherence of imaginations which many times are +continued in a long chain or series." One may find a good deal of +mystical writing on the nature and activity of this faculty, especially +in German literature. The explanation of this element of organic unity +in dreams is, it may be safely said, the crux in the science of dreams. +That the laws of psychology help us to understand the sequences of +dream-images, we have seen. What we have now to ask is whether these +laws throw any light on the orderly grouping of the elements so brought +up in consciousness in the form of a connected experience. + +It is to be remarked at the outset that a singular kind of unity is +sometimes given to our dream-combinations by a total or partial +coalescence of different images. The conditions of such coalescence have +been referred to already.[93] Simultaneous impressions or images will +always tend to coalesce with a force which varies directly as the degree +of their similarity. Sometimes this coalescence is instantaneous and not +made known to consciousness. Thus, Radestock suggests that if the mind +of the sleeper is simultaneously invaded by an unpleasant sensation +arising out of some disturbance of the functions of the skin, and a +subjective visual sensation, the resulting mental image may be a +combination of the two, under the form of a caterpillar creeping over +the bodily surface. And the coalescence may even be prepared by +sub-conscious operations of waking imagination. Thus, for example, I +once spoke about the cheapness of hares to a member of my family, who +somewhat grimly suggested that they were London cats. I did not dwell on +the idea, but the following night I dreamt that I saw a big hybrid +creature, half hare, half cat, sniffing about a cottage. As it stood on +its hind legs and took a piece of food from a window-ledge, I became +sure that it was a cat. Here it is plain that the cynical observation of +my relative had, at the moment, partially excited an image of this +feline hare. In some dreams, again, we may become aware of the process +of coalescence, as when persons who at one moment were seen to be +distinct appear to our dream-fancy to run together in some third person. + +A very similar kind of unification takes place between sequent images +under the form of transformation. When two images follow one another +closely, and have anything in common, they readily assume the form of a +transmutation. There is a sort of overlapping of the mental images, and +so an appearance of continuity produced in some respects analogous to +that which arises in the wheel-of-life (thaumatrope) class of +sense-illusions. This would seem to account for the odd transformations +of personality which not unfrequently occur in dreams, in which a person +appears, by a kind of metempsychosis, to transfer his physical ego to +another, and in which the dreamer's own bodily phantom plays similar +freaks. And the same principle probably explains those dissolving-view +effects which are so familiar an accompaniment of dream-scenery.[94] + +But passing from this exceptional kind of unity in dreams, let us +inquire how the heterogeneous elements of our dream-fancy become ordered +and arranged when they preserve their separate existence. If we look +closely at the structure of our more finished dreams, we find that the +appearance of harmony, connectedness, or order, may be given in one of +two ways. There may, first of all, be a subjective harmony, the various +images being held together by an emotional thread. Or there may, +secondly, be an objective harmony, the parts of the dream, though +answering to no particular experiences of waking life, bearing a certain +resemblance to our habitual modes of experience. Let us inquire into the +way in which each kind of order is brought about. + + +_Lyrical Element in Dreams._ + +The only unity that belongs to many of our dreams is a subjective +emotional unity. This is the basis of harmony in lyrical poetry, where +the succession of images turns mainly on their emotional colouring. +Thus, the images that float before the mind of the Poet Laureate, in his +_In Memoriam_, clearly have their link of connection in their common +emotional tone, rather than in any logical continuity. Dreaming has been +likened to poetic composition, and certainly many of our dreams are +built upon a groundwork of lyrical feeling. They might be marked off, +perhaps, as our lyrical dreams. + +The way in which this emotional force acts in these cases has already +been hinted at. We have seen that the analogy of feeling is a common +link between dream-images. Now, if any shade of feeling becomes fixed +and dominant in the mind, it will tend to control all the images of the +time, allowing certain congruous ones to enter, and excluding +others.[95] If, for example, a feeling of distress occupies the mind, +distressing images will have the advantage in the struggle for existence +which goes on in the world of mind as well as in that of matter. We may +say that attention, which is here wholly a passive process, is +controlled by the emotion of the time, and bent in the direction of +congruent or harmonious images. + +Now, a ground-tone of feeling of a certain complexion, answering to the +sum of sensations arising in connection with the different organic +processes of the time, is a very frequent foundation of our +dream-structure. So frequent is it, indeed, that one might almost say +there is no dream in which it is not one great determining factor. The +analysis of a very large number of dreams has convinced me that traces +of this influence are discoverable in a great majority. + +I will give a simple illustration of this lyrical type of dream. A +little girl of about four years and three-quarters went with her parents +to Switzerland. On their way she was taken to the cathedral at +Strasburg, and saw the celebrated clock strike, and the figures of the +Apostles come out, etc. In Switzerland she stayed at Gimmelwald, near +Mürren, opposite a fine mass of snowy mountains. One morning she told +her father that she had had "such a lovely dream." She fancied she was +on the snow-peaks with her nurse, and walked on to the sky. There came +out of the sky "such beautiful things," just like the figures of the +clock. This vision of celestial things was clearly due to the fact that +both the clock and the snow-peaks touching the blue sky had powerfully +excited her imagination, filling her with much the same kind of emotion, +namely, wonder, admiration, and longing to reach an inaccessible height. + +Our feelings commonly have a gradual rise and fall, and the organic +sensations which so often constitute the emotional basis of our lyrical +dreams generally have stages of increasing intensity. Moreover, such a +persistent ground-feeling becomes reinforced by the images which it +sustains in consciousness. Hence a certain _crescendo_ character in our +emotional dreams, or a gradual rise to some culminating point or climax. + +This phase of dream can be illustrated from the experience of the same +little girl. When just five years old, she was staying at Hampstead, +near a church which struck the hours somewhat loudly. One morning she +related the following dream to her father (I use her own language). The +biggest bells in the world were ringing; when this was over the earth +and houses began to tumble to pieces; all the seas, rivers, and ponds +flowed together, and covered all the land with black water, as deep as +in the sea where the ships sail; people were drowned; she herself flew +above the water, rising and falling, fearing to fall in; she then saw +her mamma drowned, and at last flew home to tell her papa. The gradual +increase of alarm and distress expressed in this dream, having its +probable cause in the cumulative effect of the disturbing sound of the +church bells, must be patent to all. + +The following rather comical dream illustrates quite as clearly the +growth of a feeling of irritation and vexation, probably connected with +the development of some slightly discomposing organic sensation. I +dreamt I was unexpectedly called on to lecture to a class of young +women, on Herder. I began hesitatingly, with some vague generalities +about the Augustan age of German literature, referring to the three +well-known names of Lessing, Schiller, and Goethe. Immediately my +sister, who suddenly appeared in the class, took me up, and said she +thought there was a fourth distinguished name belonging to this period. +I was annoyed at the interruption, but said, with a feeling of triumph, +"I suppose you mean Wieland?" and then appealed to the class whether +there were not twenty persons who knew the names I had mentioned to one +who knew Wieland's name. Then the class became generally disorderly. My +feeling of embarrassment gained in depth. Finally, as a climax, several +quite young girls, about ten years and less, came and joined the class. +The dream broke off abruptly as I was in the act of taking these +children to the wife of an old college tutor, to protest against their +admission. + +It is worth noting, perhaps, that in this evolution of feeling in +dreaming the quality of the emotion may vary within certain limits. One +shade of feeling may be followed by another and kindred shade, so that +the whole dream still preserves a degree, though a less obvious degree, +of emotional unity. Thus, for example, a lady friend of mine once dreamt +that she was in church, listening to a well-known novelist of the more +earnest sort, preaching. A wounded soldier was brought in to be shot, +because he was mortally wounded, and had distinguished himself by his +bravery. He was then shot, but not killed, and, rolling over in agony, +exclaimed, "How long!" The development of an extreme emotion of horror +out of the vague feeling of awe which is associated with a church, gives +a curious interest to this dream. + + +_Verisimilitude in Dreams._ + +I must not dwell longer on this emotional basis of dreams, but pass to +the consideration of the second and objective kind of unity which +characterizes many of our more elaborate dream-performances. In spite of +all that is fitful and grotesque in dream-combination, it still +preserves a distant resemblance to our actual experience. Though no +dream reproduces a particular incident or chain of incidents in this +experience, though the dream-fancy invariably transforms the particular +objects, relations, and events of waking life, it still makes the order +of our daily experience its prototype. It fashions its imaginary world +on the model of the real. Thus, objects group themselves in space, and +act on one another conformably to these perceived space-relations; +events succeed one another in time, and are often seen to be connected; +men act from more or less intelligible motives, and so on. In this way, +though the dream-fancy sets at nought the particular relations of our +experience, it respects the general and constant relations. How are we +to account for this? + +It is said by certain philosophers that this superposition of the +relations of space, time, causation, etc., on the products of our +dream-fancy is due to the fact that all experience arises by a synthesis +of mental forms with the chaotic matter of sense-impressions. These +philosophers allow, however, that all particular connections are +determined by experience. Accordingly, what we have to do here is to +inquire how far this scientific method of explaining mental connections +by facts of experience will carry us. In other words, we have to ask +what light can be thrown on these tendencies of dream-imagination by +ascertained psychological laws, and more particularly by what are known +as the laws of association. + +These laws tell us that of two mental phenomena which occur together, +each will tend to recall the other whenever it happens to be revived. On +the physiological side, this means that any two parts of the nervous +structures which have acted together become in some way connected, so +that when one part begins to work the other will tend to work also. But +it is highly probable that a particular structure acts in a great many +different ways. Thus, it may be stimulated by unlike modes of stimuli, +or it may enter into very various connections with other structures. +What will follow from this? One consequence would appear to be that +there will be developed an organic connection between the two +structures, of such a kind that whenever one is excited the other will +be disposed to act somehow and anyhow, even when there is nothing in the +present mode of activity of the first structure to determine the second +to act in some one definite way, in other words, when this mode of +activity is, roughly speaking, novel. + +Let me illustrate this effect in one of the simplest cases, that of the +visual organ. If, when walking out on a dark night, a few points in my +retina are suddenly stimulated by rays of light, and I recognize some +luminous object in a corresponding direction, I am prepared to see +something above and below, to the right and to the left of this object. +Why is this? There may from the first have been a kind of innate +understanding among contiguous optic fibres, predisposing them to such +concerted action. But however this be, this disposition would seem to +have been largely promoted by the fact that, throughout my experience, +the stimulation of any retinal point has been connected with that of +adjoining points, either simultaneously by some second object, or +successively by the same object as the eye moves over it, or as the +object itself moves across the field of vision. + +When, therefore, in sleep any part of the optic centres is excited in a +particular way, and the images thus arising have their corresponding +loci in space assigned to them, there will be a disposition to refer any +other visual images which happen at the moment to arise in consciousness +to adjacent parts of space. The character of these other images will be +determined by other special conditions of the moment; their locality or +position in space will be determined by this organic connection. We may, +perhaps, call these tendencies to concerted action of some kind general +associative dispositions. + +Just as there are such dispositions to united action among various parts +of one organ of sense, so there may be among different organs, which are +either connected originally in the infant organism, or have +communications opened up by frequent coexcitation of the two. Such links +there certainly are between the organs of taste and smell, and between +the ear and the muscular system in general, and more particularly the +vocal organ.[96] A new odour often sets us asking how the object would +taste, and a series of sounds commonly disposes us to movement of some +kind or another. How far there may be finer threads of connection +between other organs, such as the eye and the ear, which do not betray +themselves amid the stronger forces of waking mental life, one cannot +say. Whatever their number, it is plain that they will exert their +influence within the comparatively narrow limits of dream-life, serving +to impress a certain character on the images which happen to be called +up by special circumstances, and giving to the combination a slight +measure of congruity. Thus, if I were dreaming that I heard some lively +music, and at the same time an image of a friend was anyhow excited, my +dream-fancy might not improbably represent this person as performing a +sequence of rhythmic movements, such as those of riding, dancing, etc. + +A narrower field for these general associative dispositions may be found +in the tendency, on the reception of an impression of a given character, +to look for a certain kind of second impression; though the exact nature +of this is unknown. Thus, for example, the form and colour of a new +flower suggest a scent, and the perception of a human form is +accompanied by a vague representation of vocal utterances. These general +tendencies of association appear to me to be most potent influences in +our dream-life. The many strange human forms which float before our +dream-fancy are apt to talk, move, and behave like men and women in +general, however little they resemble their actual prototypes, and +however little individual consistency of character is preserved by each +of them. Special conditions determine what they shall say or do; the +general associative disposition accounts for their saying or doing +something. + +We thus seem to find in the purely passive processes of association some +ground for that degree of natural coherence and rational order which our +more mature dreams commonly possess. These processes go far to explain, +too, that odd mixture of rationality with improbability, of natural +order and incongruity, which characterizes our dream-combinations. + + +_Rational Construction in Dreams._ + +Nevertheless, I quite agree with Herr Volkelt that association, even in +the most extended meaning, cannot explain all in the shaping of our +dream-pictures. The "phantastical power" which Cudworth talks about +clearly includes something besides. It is an erroneous supposition that +when we are dreaming there is a complete suspension of the voluntary +powers, and consequently an absence of all direction of the intellectual +processes. This supposition, which has been maintained by numerous +writers, from Dugald Stewart downwards, seems to be based on the fact +that we frequently find ourselves in dreams striving in vain to move the +whole body or a limb. But this only shows, as M. Maury remarks in the +work already referred to, that our volitions are frustrated through the +inertia of our bodily organs, not that these volitions do not take +place. In point of fact, the dreamer, not to speak of the somnambulist, +is often conscious of voluntarily going through a series of actions. +This exercise of volition is shown unmistakably in the well-known +instances of extraordinary intellectual achievements in dreams, as +Condillac's composition of a part of his _Cours d'Études_. No one would +maintain that a result of this kind was possible in the total absence of +intellectual action carefully directed by the will. And something of +this same control shows itself in all our more fully developed dreams. + +One manifestation of this voluntary activity in sleep is to be found in +those efforts of attention which not unfrequently occur. I have remarked +that, speaking roughly and in relation to the waking condition, the +state of sleep is marked by a subjection of the powers of attention to +the force of the mental images present to consciousness. Yet something +resembling an exercise of voluntary attention sometimes happens in +sleep. The intellectual feats just spoken of, unless, indeed, they are +referred to some mysterious unconscious mental operations, clearly +involve a measure of volitional guidance. All who dream frequently are +occasionally aware on awaking of having greatly exercised their +attention on the images presented to them during sleep. I myself am +often able to recall an effort to see beautiful objects, which +threatened to disappear from my field of vision, or to catch faint +receding tones of preternatural sweetness; and some dreamers allege that +they are able to retain a recollection of the feeling of strain +connected with such exercise of attention in sleep. + +The main function of this voluntary attention in dream-life is seen in +the selection of those images which are to pass the threshold of clear +consciousness. I have already spoken of a selective action brought about +by the ruling emotion. In this case, the attention is held captive by +the particular feeling of the moment. Also a selective process goes on +in the case of the action of those associative dispositions just +referred to. But in each of these cases the action of selective +attention is comparatively involuntary, passive, and even unconscious, +not having anything of the character of a conscious striving to compass +some end. Besides this comparatively passive play of selective +attention, there is an active play, in which there is a conscious wish +to gain an end; in other words, the operation of a definite motive. This +motive may be described as an intellectual impulse to connect and +harmonize what is present to the mind. The voluntary kind of selection +includes and transcends each of the involuntary kinds. It has as its +result an imitation of that order which is brought about by what I have +called the associative dispositions, only it consciously aims at this +result. And it is a process controlled by a feeling, namely, the +intellectual sentiment of consistency, which is not a mode of emotional +excitement enthralling the will, but a calm motive, guiding the +activities of attention. It thus bears somewhat the same relation to the +emotional selection already spoken of, as dramatic creation bears to +lyrical composition. + +This process of striving to seize some connecting link, or thread of +order, is illustrated whenever, in waking life, we are suddenly brought +face to face with an unfamiliar scene. When taken into a factory, we +strive to arrange the bewildering chaos of visual impressions under some +scheme, by help of which we are said to understand the scene. So, if on +entering a room we are plunged in _medias res_ of a lively conversation, +we strive to find a clue to the discussion. Whenever the meaning of a +scene is not at once clear, and especially whenever there is an +appearance of confusion in it, we are conscious of a painful feeling of +perplexity, which acts as a strong motive to ever-renewed attention.[97] + +In touching on this intellectual impulse to connect the disconnected, we +are, it is plain, approaching the question of the very foundations of +our intellectual structure. That there is this impulse firmly rooted in +the mature mind nobody can doubt; and that it manifests itself in early +life in the child's recurring "Why?" is equally clear. But how we are to +account for it, whether it is to be viewed as a mere result of the play +of associated fragments of experience, or as something involved in the +very process of the association of ideas itself, is a question into +which I cannot here enter. + +What I am here concerned to show is that the search for consistency and +connection in the manifold impressions of the moment is a deeply rooted +habit of the mind, and one which is retained in a measure during sleep. +When, in this state, our minds are invaded by a motley crowd of +unrelated images, there results a disagreeable sense of confusion; and +this feeling acts as a motive to the attention to sift out those +products of the dream-fancy which may be made to cohere. When once the +foundations of a dream-action are laid, new images must to some extent +fit in with this; and here there is room for the exercise of a distinct +impulse to order the chaotic elements of dream-fancy in certain forms. +The perception of any possible relation between one of the crowd of new +images ever surging above the level of obscure consciousness, and the +old group at once serves to detain it. The concentration of attention on +it, in obedience to this impulse to seek for an intelligible order, at +once intensifies it and fixes it, incorporating it into the series of +dream-pictures. + +Here is a dream which appears to illustrate this impulse to seek an +intelligible order in the confused and disorderly. After being occupied +with correcting the proofs of my volume on _Pessimism_, I dreamt that my +book was handed to me by my publisher, fully illustrated with coloured +pictures. The frontispiece represented the fantastic figure of a man +gesticulating in front of a ship, from which he appeared to have just +stepped. My publisher told me it was meant for Hamlet, and I immediately +reflected that this character had been selected as a concrete example of +the pessimistic tendency. I may add that, on awaking, I was distinctly +aware of having felt puzzled when dreaming, and of having striven to +read a meaning into the dream. + +The _rationale_ of this dream seems to me to be somewhat as follows. The +image of the completed volume represented, of course, a recurring +anticipatory image of waking life. The coloured plates were due probably +to subjective optical sensations simultaneously excited, which were made +to fit in (with or without an effort of voluntary attention) with the +image of the book under the form of illustrations. But this stage of +coherency did not satisfy the mind, which, still partly confused by the +incongruity of coloured plates in a philosophic work, looked for a +closer connection. The image of Hamlet was naturally suggested in +connection with pessimism. The effort to discover a meaning in the +pictures led to the fusion of this image with one of the subjective +spectra, and in this way the idea of a Hamlet frontispiece probably +arose. + +The whole process of dream-construction is clearly illustrated in a +curious dream recorded by Professor Wundt.[98] Before the house is a +funeral procession: it is the burial of a friend, who has in reality +been dead for some time past. The wife of the deceased bids him and an +acquaintance who happens to be with him go to the other side of the +street and join the procession. After she has gone away, his companion +remarks to him, "She only said that because the cholera rages over +yonder, and she wants to keep this side of the street to herself." Then +comes an attempt to flee from the region of the cholera. Returning to +his house, he finds the procession gone, but the street strewn with +rich nosegays; and he further observes crowds of men who seem to be +funeral attendants, and who, like himself, are hastening to join the +procession. These are, oddly enough, dressed in red. When hurrying on, +it occurs to him that he has forgotten to take a wreath for the coffin. +Then he wakes up with beating of the heart. + +The sources of this dream are, according to Wundt, as follows. First of +all, he had, on the previous day, met the funeral procession of an +acquaintance. Again, he had read of cholera breaking out in a certain +town. Once more, he had talked about the particular lady with this +friend, who had narrated facts which clearly proved her selfishness. The +hastening to flee from the infected neighbourhood and to overtake the +procession was prompted by the sensation of heart-beating. Finally, the +crowd of red bier-followers, and the profusion of nosegays, owed their +origin to subjective visual sensations, the "light-chaos" which often +appears in the dark. + +Let us now see for a moment how these various elements may have become +fused into a connected chain of events. First of all, it is clear that +this dream is built up on a foundation of a gloomy tone of feeling, +arising, as it would seem, from an irregularity of the heart's action. +Secondly, it owes its special structure and its air of a connected +sequence of events, to those tendencies, passive and active, to order +the chaotic of which I have been speaking. Let us try to trace this out +in detail. + +To begin with, we may suppose that the image of the procession occupies +the dreamer's mind. From quite another source the image of the lady +enters consciousness, bringing with it that of her deceased husband and +of the friend who has recently been talking about her. These new +elements adapt themselves to the scene, partly by the passive mechanism +of associative dispositions, and partly, perhaps, by the activity of +voluntary selection. Thus, the idea of the lady's husband would +naturally recall the fact of his death, and this would fall in with the +pre-existing scene under the form of the idea that he is the person who +is now being buried. The next step is very interesting. The image of the +lady is associated with the idea of selfish motives. This would tend to +suggest a variety of actions, but the one which becomes a factor of the +dream is that which is specially adapted to the pre-existing +representations, namely, of the procession on the further side of the +street, and the cholera (which last, like the image of the funeral, is, +we may suppose, due to an independent central excitation). That is to +say, the request of the lady, and its interpretation, are a _resultant_ +of a number of adaptative or assimilative actions, under the sway of a +strong desire to connect the disconnected, and a lively activity of +attention. Once more, the feeling of oppression of the heart, and the +subjective stimulation of the optic nerve, might suggest numberless +images besides those of anxious flight and of red-clad men and nosegays; +they suggest these, and not others, in this particular case, because of +the co-operation of the impulse of consistency, which, setting out with +the pre-existing mental images, selects from among many tendencies of +reproduction those which happen to chime in with the scene. + + +_The Nature of Dream-Intelligence._ + +It must not be supposed that this process of welding together the +chaotic materials of our dreams is ever carried out with anything like +the clear rational purpose of which we are conscious when seeking, in +waking life, to comprehend some bewildering spectacle. At best it is a +vague longing, and this longing, it may be added, is soon satisfied. +There is, indeed, something, almost pathetic in the facility with which +the dreamer's mind can be pacified with the least appearance of a +connection. Just as a child's importunate "Why?" is often silenced by a +ridiculous caricature of an explanation, so the dreamer's intelligence +is freed from its distress by the least semblance of a uniting order. + +It thus remains true with respect even to our most coherent dreams, that +there is a complete suspension, or at least a considerable retardation, +of the highest operations of judgment and thought; also a great +enfeeblement, to say the least of it, of those sentiments such as the +feeling of consistency and the sense of the absurd which are so +intimately connected with these higher intellectual operations. + +In order to illustrate how oddly our seemingly rational dreams +caricature the operations of waking thought, I may, perhaps, be allowed +to record two of my own dreams, of which I took careful note at the +time. + +On the first occasion I went "in my dream" to the "Stores" in August, +and found the place empty. A shopman brought me some large fowls. I +asked their price, and he answered, "Tenpence a pound." I then asked +their weight, so as to get an idea of their total cost, and he replied, +"Forty pounds." Not in the least surprised, I proceeded to calculate +their cost: 40x10=400÷12=33-1/3. But, oddly enough, I took this quotient +as pence, just as though I had not already divided by 12, and so made +the cost of a fowl to be 2s. 9d., which seemed to me a fair enough +price. + +In my second dream I was at Cambridge, among a lot of undergraduates. I +saw a coach drive up with six horses. Three undergraduates got out of +the coach. I asked them why they had so many horses, and they said, +"Because of the luggage." I then said, "The luggage is much more than +the undergraduates. Can you tell me how to express this in mathematical +symbols? This is the way: if _x_ is the weight of an undergraduate, then +_x_ + _x_.n represents the weight of an undergraduate and his luggage +together." I noticed that this sally was received with evident +enjoyment.[99] + +We may say, then, that the structure of our dreams, equally with the +fact of their completely illusory character, points to the conclusion +that during sleep, just as in the moments of illusion in waking life, +there is a deterioration of our intellectual life. The highest +intellectual activities answering to the least stable nervous +connections are impeded, and what of intellect remains corresponds to +the most deeply organized connections. + +In this way, our dream-life touches that childish condition of the +intelligence which marks the decadence of old age and the encroachments +of mental disease. The parallelism between dreams and insanity has been +pointed out by most writers on the subject. Kant observed that the +madman is a dreamer awake, and more recently Wundt has remarked that, +when asleep, we "can experience nearly all the phenomena which meet us +in lunatic asylums." The grotesqueness of the combinations, the lack of +all judgment as to consistency, fitness, and probability, are common +characteristics of the short night-dream of the healthy and the long +day-dream of the insane.[100] + +But one great difference marks off the two domains. When dreaming, we +are still sane, and shall soon prove our sanity. After all, the dream of +the sleeper is corrected, if not so rapidly as the illusion of the +healthy waker. As soon as the familiar stimuli of light and sound set +the peripheral sense-organs in activity, and call back the nervous +system to its complete round of healthy action, the illusion disappears, +and we smile at our alarms and agonies, saying, "Behold, it was a +dream!" + +On the practical side, the illusions and hallucinations of sleep must be +regarded as comparatively harmless. The sleeper, in healthy conditions +of sleep, ceases to be an agent, and the illusions which enthral his +brain have no evil practical consequences. They may, no doubt, as we +shall see in a future chapter, occasionally lead to a subsequent +confusion of fiction and reality in waking recollection. But with the +exception of this, their worst effect is probably the lingering sense of +discomfort which a "nasty dream" sometimes leaves with us, though this +may be balanced by the reverberations of happy dream-emotions which +sometimes follow us through the day. And however this be, it is plain +that any disadvantages thus arising are more than made good by the +consideration that our liability to these nocturnal illusions is +connected with the need of that periodic recuperation of the higher +nervous structures which is a prime condition of a vigorous intellectual +activity, and so of a triumph over illusion during waking life. + +For these reasons dreams may properly be classed with the illusions of +normal or healthy life, rather than with those of disease. They +certainly lie nearer this region than the very similar illusions of the +somnambulist, which with respect to their origin appear to be more +distinctly connected with a pathological condition of the nervous +system, and which, with respect to their practical consequences may +easily prove so disastrous. + + +_After-Dreams._ + +In concluding this account of dreams, I would call attention to the +importance of the transition states between sleeping and waking, in +relation to the production of sense-illusion. And this point may be +touched on here all the more appropriately, since it helps to bring out +the close relation between waking and sleeping illusion. The mind does +not pass suddenly and at a bound from the condition of dream-fancy to +that of waking perception. I have already had occasion to touch on the +"hypnagogic state," that condition of somnolence or "sleepiness" in +which external impressions cease to act, the internal attention is +relaxed, and the weird imagery of sleep begins to unfold itself. And +just as there is this anticipation of dream-hallucination in the +presomnial condition, so there is the survival of it in the postsomnial +condition. As I have observed, dreams sometimes leave behind them, for +an appreciable interval after waking, a vivid after-impression, and in +some cases even the semblance of a sense-perception. + +If one reflects how many ghosts and other miraculous apparitions are +seen at night, and when the mind is in a more or less somnolent +condition, the idea is forcibly suggested that a good proportion of +these visions are the _débris_ of dreams. In some cases, indeed, as that +of Spinoza, already referred to, the hallucination (in Spinoza's case +that of "a scurvy black Brazilian") is recognized by the subject himself +as a dream-image.[101] I am indebted to Mr. W.H. Pollock for a fact +which curiously illustrates the position here adopted. A lady was +staying at a country house. During the night and immediately on waking +up she had an apparition of a strange-looking man in mediæval costume, +a figure by no means agreeable, and which seemed altogether unfamiliar +to her. The next morning, on rising, she recognized the original of her +hallucinatory image in a portrait hanging on the wall of her bedroom, +which must have impressed itself on her brain before the occurrence of +the apparition, though she had not attended to it. Oddly enough, she now +learnt for the first time that the house at which she was staying had +the reputation of being haunted, and by the very same somewhat +repulsive-looking mediæval personage that had troubled her +inter-somnolent moments. The case seems to me to be typical with respect +to the genesis of ghosts, and of the reputation of haunted houses. + + * * * * * + +NOTE. + +THE HYPNOTIC CONDITION. + + +I have not in this chapter discussed the relation of dreaming to +hypnotism, or the state of artificially produced quasi-sleep, because +the nature of this last is still but very imperfectly understood. In +this condition, which is induced in a number of ways by keeping the +attention fixed on some non-exciting object, and by weak continuous and +monotonous stimulation, as stroking the skin, the patient can be made to +act conformably to the verbal or other suggestion of the operator, or to +the bodily position which he is made to assume. Thus, for example, if a +glass containing ink is given to him, with the command to drink, he +proceeds to drink. If his hands are folded, he proceeds to act as if he +were in church, and so on. + +Braid, the writer who did so much to get at the facts of hypnotism, and +Dr. Carpenter who has helped to make known Braid's careful researches, +regard the actions of the hypnotized subject as analogous to ideomotor +movements; that is to say, the movements due to the tendency of an idea +to act itself out apart from volition. On the other hand, one of the +latest inquirers into the subject, Professor Heidenhain, of Breslau, +appears to regard these actions as the outcome of "unconscious +perceptions" (_Animal Magnetism_, English translation, p. 43, etc.). + +In the absence of certain knowledge, it seems allowable to argue from +the analogy of natural sleep that the actions of the hypnotized patient +are accompanied with the lower forms of consciousness, including +sensation and perception, and that they involve dream-like +hallucinations respecting the external circumstances of the moment. +Regarding them in this light, the points of resemblance between +hypnotism and dreaming are numerous and striking. Thus, Dr. Heidenhain +tells us that the threshold or liminal value of stimulation is lowered +just as in ordinary sleep sense-activity as a whole is lowered. +According to Professor Weinhold, the hypnotic condition begins in a +gradual loss of taste, touch, and the sense of temperature; then sight +is gradually impaired, while hearing remains throughout the least +interfered with.[102] In this way, the mind of the patient is largely +cut off from the external world, as in sleep, and the power of +orientation is lost. Moreover, there are all the conditions present, +both positive and negative, for the hallucinatory transformation of +mental images into percepts just as in natural sleep. Thus, the higher +centres connected with the operations of reflection and reasoning are +thrown _hors de combat_ or, as Dr. Heidenhain has it, "inhibited." + +The condition of hypnotism is marked off from that of natural sleep, +first of all, by the fact that the accompanying hallucinations are +wholly due to external suggestion (including the effects of bodily +posture). Dreams may, as we have seen, be very faintly modified by +external influences, but during sleep there is nothing answering to the +perfect control which the operator exercises over the hypnotized +subject. The largest quantity of our "dream-stuff" comes, as we have +seen, from within and not from without the organism. And this fact +accounts for the chief characteristic difference between the natural and +the hypnotic dream. The former is complex, consisting of crowds of +images, and continually changing: the latter is simple, limited, and +persistent. As Braid remarks, the peculiarity of hypnotism is that the +attention is concentrated on a remarkably narrow field of mental images +and ideas. So long as a particular bodily posture is assumed, so long +does the corresponding illusion endure. One result of this, in +connection with that impairing of sensibility already referred to, is +the scope for a curious overriding of sense-impressions by the dominant +illusory percept, a process that we have seen illustrated in the active +sense-illusions of waking life. Thus, if salt water is tasted and the +patient is _told_ that it is beer, he complains that it is sour. + +In being thus in a certain rapport, though so limited and unintelligent +a rapport, with the external world, the mind of the hypnotized patient +would appear to be nearer the condition of waking illusion than is the +mind of the dreamer. It must be remembered, however, and this is the +second point of difference between dreaming and hypnotism, that the +hypnotized subject tends _to act out_ his hallucinations. His +quasi-percepts are wont to transform themselves into actions with a +degree of force of which we see no traces in ordinary sleep. Why there +should be this greater activity of the motor organs in the one condition +than in the other, seems to be a point as yet unexplained. All +sense-impressions and percepts are doubtless accompanied by some degree +of impulse to movement, though, for some reason or another, in natural +and healthy sleep these impulses are restricted to the stage of faint +nascent stirrings of motor activity which hardly betray themselves +externally. This difference, involving a great difference in the +possible practical consequences of the two conditions of natural and +hypnotic sleep, clearly serves to bring the latter condition nearer to +that of insanity than the former condition is brought. A strong +susceptibility to the hypnotic influence, such as Dr. Heidenhain +describes, might, indeed, easily prove a very serious want of +"adaptation of internal to external relations," whereas a tendency to +dreaming would hardly prove a maladaptation at all. + + + + +CHAPTER VIII. + +ILLUSIONS OF INTROSPECTION. + + +We have now, perhaps, sufficiently reviewed sense-illusions, both of +waking life and of sleep. And having roughly classified them according +to their structure and origin, we are ready to go forwards and inquire +whether the theory thus reached can be applied to other forms of +illusory error. And here we are compelled to inquire at the outset if +anything analogous to sense-illusion is to be found in that other great +region of presentative cognition usually marked off from external +perception as internal perception, self-reflection, or introspection. + + +_Illusions of Introspection defined._ + +This inquiry naturally sets out with the question: What is meant by +introspection? This cannot be better defined, perhaps, than by saying +that it is the mind's immediate reflective cognition of its own states +as such. + +In one sense, of course, everything we know may be called a mental +state, actual or imagined. Thus, a sense-impression is known, exactly +like any other feeling of the mind, as a mental phenomenon or mental +modification. Yet we do not usually speak of introspectively +recognizing a sensation. Our sense-impressions are marked off from all +other feelings by having an objective character, that is to say, an +immediate relation to the external world, so that in attending to one of +them our minds pass away from themselves in what Professor Bain calls +the attitude of objective regard. Introspection is confined to feelings +which want this intimate connection with the external region, and +includes sensation only so far as it is viewed apart from external +objects and on its mental side as a feeling, a process which is next to +impossible where the sensation has little emotional colour, as in the +case of an ordinary sensation of sight or of articulate sound. + +This being so, errors of introspection, supposing such to be found, will +in the main be sufficiently distinguished from those of perception. Even +an hallucination of sense, whether setting out from a subjective +sensation or not, always contains the semblance of a sense-impression, +and so would not be correctly classed with errors of introspection. + +Just as introspection must be marked off from perception, so must it be +distinguished from memory. It may be contended that, strictly speaking, +all introspection is retrospection, since even in attending to a present +feeling the mind is reflectively representing to itself the immediately +preceding momentary experience of that feeling. Yet the adoption of this +view does not hinder us from drawing a broad distinction between acts of +introspection and acts of memory. Introspection must be regarded as +confined to the knowledge of immediately antecedent mental states with +reference to which, no error of memory can be supposed to arise. + +It follows from this that an illusion of introspection could only be +found in connection with the apprehension of present or immediately +antecedent mental states. On the other hand, any illusions connected +with the consciousness of personal continuity and identity would fall +rather under the class of mnemonic than that of introspective error. + +Once more, introspection must be carefully distinguished from what I +have called belief. Some of our beliefs may be found to grow out of and +be compounded of a number of introspections. Thus, my conception of my +own character, or my psychological conception of mind as a whole, may be +seen to arise by a combination of the results of a number of acts of +introspection. Yet, supposing this to be so, we must still distinguish +between the single presentative act of introspection and the +representative belief growing out of it. + +It follows from this that, though an error of the latter sort might +conceivably have its origin in one of the former; though, for example, a +man's illusory opinion of himself might be found to involve errors of +introspection, yet the two kinds of illusion would be sufficiently +unlike. The latter would be a simple presentative error, the former a +compound representative error. + +Finally, in order to complete this preliminary demarcation of our +subject-matter, it is necessary to distinguish between an introspection +(apparent or real) of a feeling or idea, and a process of inference +based on this feeling. The term introspective knowledge must, it is +plain, be confined to what is or appears to be in the mind at the moment +of inspection. + +By observing this distinction, we are in a position to mark off an +_illusion_ of introspection from a _fallacy_ of introspection. The +former differs from the latter in the absence of anything like a +conscious process of inference. Thus, if we suppose that the derivation +by Descartes of the fact of the existence of God from his possession of +the idea to be erroneous, such a consciously performed act of reasoning +would constitute a fallacy rather than an illusion of introspection. + +We may, then, roughly define an illusion of introspection as an error +involved in the apprehension of the contents of the mind at any moment. +If we mistake the quality or degree of a feeling or the structure of a +complex mass of feeling, or if we confuse what is actually present to +the mind with some inference based on this, we may be said to fall into +an illusion of introspection. + +But here the question will certainly be raised: How can we conceive the +mind erring as to the nature of its present contents; and what is to +determine, if not my immediate act of introspection, what is present in +my mind at any moment? Indeed, to raise the possibility of error in +introspection seems to do away with the certainty of presentative +knowledge. + +If, however, the reader will recall what was said in an earlier chapter +about the possibility of error in recognizing the quality of a +sense-impression, he will be prepared for a similar possibility here. +What we are accustomed to call a purely presentative cognition is, in +truth, partly representative. A feeling as pure feeling is not known; it +is only known when it is distinguished, as to quality or degree, and so +classed or brought under some representation of a kind or description of +feeling, as acute, painful, and so on. The accurate recognition of an +impression of colour depends, as we have seen, on this process of +classing being correctly performed. Similarly, the recognition of +internal feelings implies the presence of the appropriate or +corresponding class-representation. Accordingly, if it is possible for a +wrong representation to get substituted for the right one, there seems +to be an opening for error. + +Any error that would thus arise can, of course, only be determined as +such in relation to some other act of introspection of the same mind. In +matters of internal perception other minds cannot directly assist us in +correcting error as they can in the case of external perception, though, +as we shall see by-and-by, they may do so indirectly. The standard of +reality directly applicable to introspective cognition is plainly what +the individual mind recognizes at its best moments, when the processes +of attention and classifying are accurately performed, and the +representation may be regarded with certainty as answering to the +feeling. In other words, in the sphere of internal, as in that of +external experience, the criterion of reality is the average and +perfect, as distinguished from the particular variable and imperfect act +of cognition. + +We see, then, that error in the process of introspection is at least +conceivable. And now let us examine this process a little further, in +order to find out what probabilities of error attach to it. + +To begin with, then, an act of introspection, to be complete, clearly +involves the apprehension of an internal feeling or idea as something +mental and marked off from the region of external experience. This +distinct recognition of internal states of mind as such, in opposition +to external impressions, is by no means easy, but presupposes a certain +degree of intellectual culture, and a measure of the power of abstract +attention. + + +_Confusion of Internal and External Experience._ + +Accordingly, we find that where this is wanting there is a manifest +disposition to translate internal feelings into terms of external +impressions. In this way there may arise a slight amount of habitual and +approximately constant error. Not that the process approaches to one of +hallucination; but only that the internal feelings are intuited as +having a cause or origin analogous to that of sense-impressions. Thus to +the uncultivated mind a sudden thought seems like an audible +announcement from without. The superstitious man talks of being led by +some good or evil spirit when new ideas arise in his mind or new +resolutions shape themselves. To the simple intelligence of the boor +every thought presents itself as an analogue of an audible voice, and he +commonly describes his rough musings as saying this and that to himself. +And this, mode of viewing the matter is reflected even, in the language +of cultivated persons. Thus we say, "The idea struck me," or "was borne +in on me," "I was forced to do so and so," and so on, and in this +manner we tend to assimilate internal to external mental phenomena. + +Much the same thing shows itself in our customary modes of describing +our internal feelings of pleasure and pain. When a man in a state of +mental depression speaks of having "a load" on his mind it is evident +that he is interpreting a mental by help of an analogy to a bodily +feeling. Similarly, when we talk of the mind being torn by doubt or worn +by anxiety. It would seem as though we tended mechanically to translate +mental pleasures and pains into the language of bodily sensations. + +The explanation of this deeply rooted tendency to a slightly illusory +view of our mental states is, I think, an easy one. For one thing, it +follows from the relation of the mental image to the sense-impression +that we should tend to assimilate the former to the latter as to its +nature and origin. This would account for the common habit of regarding +thoughts, which are of course accompanied by representatives of their +verbal symbols, as internal voices, a habit which is probably especially +characteristic of the child and the uncivilized man, as we have found it +to be characteristic of the insane. + +Another reason, however, must be sought for the habit of assimilating +internal feelings to external sensations. If language has been evolved +as an incident of social life, at once one of its effects and its +causes, it would seem to follow that it must have first shaped Itself to +the needs of expressing these common objective experiences which we +receive by way of our senses. Our habitual modes of thought, limited as +they are by language, retain traces of this origin. We cannot conceive +any mental process except by some vague analogy to a physical process. +In other words, we can even now only think with perfect clearness when +we are concerned with some object of common cognition. Thus, the sphere +of external sensation and of physical agencies furnishes us with the one +type of thinkable thing or object of thought, and we habitually view +subjective mental states as analogues of these. + +Still, it may be said that these slight nascent errors are hardly worth +naming, and the question would still appear to recur whether there are +other fully developed errors deserving to rank along with illusions of +sense. Do we, it may be asked, ever actually mistake the quality, +degree, or structure of our internal feelings in the manner hinted +above, and if so, what is the range of such error? In order to +appreciate the risks of such error, let us compare the process of +self-observation with that of external perception with respect to the +difficulties in the way of accurate presentative knowledge. + + +_Misreading of Internal Feelings._ + +First of all, it is noteworthy that a state of consciousness at any one +moment is an exceedingly complex thing. It is made up of a mass of +feelings and active impulses which often combine and blend in a most +inextricable way. External sensations come in groups, too, but as a rule +they do not fuse in apparently simple wholes as our internal feelings +often do. The very possibility of perception depends on a clear +discrimination of sense-elements, for example, the several sensations +of colour obtained by the stimulation of different parts of the +retina.[103] But no such clearly defined mosaic of feelings presents +itself in the internal region: one element overlaps and partly loses +itself in another, and subjective analysis is often an exceedingly +difficult matter. Our consciousness is thus a closely woven texture in +which the mental eye often fails to trace the several threads or +strands. Moreover, there is the fact that many of these ingredients are +exceedingly shadowy, belonging to that obscure region of +sub-consciousness which it is so hard to penetrate with the light of +discriminative attention. This remark applies with particular force to +that mass of organic feelings which constitutes what is known as +coenæsthesis; or vital sense. + +While, to speak figuratively, the minute anatomy of consciousness is +thus difficult with respect to longitudinal sections of the mental +column, it is no less difficult with respect to transverse sections. +Under ordinary circumstances, external impressions persist so that they +can be transfixed by a deliberate act of attention, and objects rarely +flit over the external scene so rapidly as to allow us no time for a +careful recognition of the impression. Not so in the case of the +internal region of mind. The composite states of consciousness just +described never remain perfectly uniform for the shortest conceivable +duration. They change continually, just as the contents of the +kaleidoscope vary with every shake of the instrument. Thus, one shade +of feeling runs into another in such a way that it is often impossible +to detect its exact quality; and even when the character of the feeling +does not change, its intensity is undergoing alterations so that an +accurate observation of its quantity is impracticable. Also, in this +unstable shifting internal scene features may appear for a duration too +short to allow of close recognition. In this way it happens that we +cannot sharply divide the feeling of the moment from its antecedents and +its consequents. + +If, now, we take these facts in connection with what has been said above +respecting the nature of the process of introspection, the probability +of error will be made sufficiently clear. To transfix any particular +feeling of the moment, to selectively attend to it, and to bring it +under the proper representation, is an operation that requires time, a +time which, though short, is longer than the fugitive character of so +much of our internal mental life allows. From all of which it would +appear to follow that it must be very easy to overlook, confuse, and +transform, both as to quality and as to quantity, the actual ingredients +of our internal consciousness. + +From these sources there spring a number of small errors of +introspection which, to distinguish them from others to be spoken of +presently, may be called passive. These would include all errors in +detecting what is in consciousness due to the intricacies of the +phenomena, and not aided by any strong basis. For example, a mental +state may fail to disclose its component parts to introspective +attention. Thus, a motive may enter into our action which is so +entangled with other feelings as to escape our notice. The fainter the +feeling the greater the difficulty of detaching it and inspecting it in +isolation. Again, an error of introspection may have its ground in the +fugitive character of a feeling. If, for example, a man is asked whether +a rapid action was a voluntary one, he may in retrospection easily +imagine that it was not so, when as a matter of fact the action was +preceded by a momentary volition. When a person exclaims, "I did a thing +inadvertently or mechanically," it often means that he did not note the +motive underlying the action. Such transitory feelings which cannot at +the moment be seized by an act of attention are pretty certain to +disappear at once, leaving not even a temporary trace in consciousness. + +We will now pass to the consideration of other illusions of +introspection more analogous to what I have called the active illusions +of perception. In our examination of these we found that a pure +representation may under certain circumstances simulate the appearance +of a presentation, that a mental image may approximate to a +sense-impression. In the case of the internal feelings this liability +shows itself in a still more striking form. + +The higher feelings or emotions are distinguished from the simple +sense-feelings in being largely representative. Thus, a feeling of +contentment at any moment, though no doubt conditioned by the bodily +state and the character of the organic sensations or coenæsthesis, +commonly depends for the most part on intellectual representations of +external circumstances or relations, and may be called an ideal +foretaste of actual satisfactions, such as the pleasures of success, of +companionship, and so on. This being so, it is easy for imagination to +call up a semblance of these higher feelings. Since they depend largely +on representation, a mere act of representation may suffice to excite a +degree of the feeling hardly distinguishable from the actual one. Thus, +to imagine myself as contented is really to see myself at the moment as +actually contented. Again, the actor, though, as we shall see by-and-by, +he does not feel all that the spectator is apt to attribute to him, +tends, when vividly representing to himself a particular shade of +feeling, to regard himself as actually feeling in this way. Thus, it is +said of Garrick, that when acting Richard III., he felt himself for the +moment to be a villain. + +We should expect from all this that in the act of introspection the mind +is apt, within certain limits, to find what it is prepared to find. And +since there is in these acts often a distinct wish to detect some +particular feeling, we can see how easy it must be for a man through +bias and a wrong focussing of the attention to deceive himself up to a +certain point with respect to the actual contents of his mind. + +Let us examine one of these active illusions a little more fully. It +would at first sight seem to be a perfectly simple thing to determine at +any given moment whether we are enjoying ourselves, whether our +emotional condition rises above the pleasure-threshold or point of +indifference and takes on a positive hue of the agreeable or +pleasurable. Yet there is good reason for supposing that people not +unfrequently deceive themselves on this matter. It is, perhaps, hardly +an exaggeration to say that most of us are capable of imagining that we +are having enjoyment when we conform to the temporary fashion of social +amusement. It has been cynically observed that people go into society +less in order to be happy than to seem so, and one may add that in this +semblance of enjoyment they may, provided they are not _blasé_, deceive +themselves as well as others. The expectation of enjoyment, the +knowledge that the occasion is intended to bring about this result, the +recognition of the external signs of enjoyment in others--all this may +serve to blind a man in the earlier stages of social amusement to his +actual mental condition. + +If we look closely into this variety of illusion, we shall see that it +is very similar in its structure and origin to that kind of erroneous +perception which arises from inattention to the actual impression of the +moment under the influence of a strong expectation of something +different. The representation of ourselves as entertained dislodges from +our internal field of vision our actual condition, relegating this to +the region of obscure consciousness. Could we for a moment get rid of +this representation and look at the real feelings of the time, we should +become aware of our error; and it is possible that the process of +becoming _blasé_ involves a waking up to a good deal of illusion of the +kind. + +Just as we can thus deceive ourselves within certain limits as to our +emotional condition, so we can mistake the real nature of our +intellectual condition. Thus, when an idea is particularly grateful to +our minds, we may easily imagine that we believe it, when in point of +fact all the time there is a sub-conscious process of criticism going +on, which if we attended to it for a moment would amount to a distinct +act of disbelief. Some persons appear to be capable of going on +habitually practising this petty deceit on themselves, that is to say, +imagining they believe what in fact they are strongly inclined to doubt. +Indeed, this remark applies to all the grateful illusions respecting +ourselves and others, which will have to be discussed by-and-by. The +impulse to hold to the illusion in spite of critical reflection, +involves the further introspective illusion of taking a state of doubt +for one of assurance. Thus, the weak, flattered man or woman manages to +keep up a sort of fictitious belief in the truth of the words which are +so pleasant to the ear. + +It is plain that the external conditions of life impose on the +individual certain habits of feeling which often conflict with his +personal propensities. As a member of society he has a powerful motive +to attribute certain feelings to himself, and this motive acts as a bias +in disturbing his vision of what is actually in his mind. While this +holds good of lighter matters, as that of enjoyment just referred to, it +applies still more to graver matters. Thus, for example, a man may +easily persuade himself that he feels a proper sentiment of indignation +against a perpetrator of some mean or cruel act, when as a matter of +fact his feeling is much more one of compassion for the previously liked +offender. In this way we impose on ourselves, disguising our real +sentiments by a thin veil of make-believe. + +So far I have spoken of an illusion of introspection as analogous to +the slight misapprehensions of sense-impression which were touched on in +connection with illusions of sense (Chapter III.). It is to be observed, +however, that the confusing of elements of consciousness, which is so +prominent a factor in introspective illusion, involves a species of +error closely analogous to a complete illusion of perception, that is to +say, one which involves a misinterpretation of a sense-impression. + +This variety of illusion is illustrated in the case in which a present +feeling or thought is confounded with some inference based on it. For +example, a present thought may, through forgetfulness, be regarded as a +new discovery. Its originality appears to be immediately made known in +the very freshness which characterizes it. Every author probably has +undergone the experience of finding that ideas which started up to his +mind as fresh creations, were unconscious reminiscences of his own or of +somebody else's ideas. + +In the case of present emotional states this liability to confuse the +present and the past is far greater. Here there is something hardly +distinguishable from an active illusion of sense-perception. In this +condition of mind a man often says that he has an "intuition" of +something supposed to be immediately given in the feeling itself. For +instance, one whose mind is thrilled by the pulsation of a new joy +exclaims, "This is the happiest moment of my life," and the assurance +seems to be contained in the very intensity of the feeling itself. Of +course, cool reflection will tell him that what he affirms is merely a +belief, the accuracy of which presupposes processes of recollection and +judgment, but to the man's mind at the moment the supremacy of this +particular joy is immediately intuited. And so with the assurance that +the present feeling, for example of love, is undying, that it is equal +to the most severe trials, and so on. A man is said to _feel_ at the +moment that it is so, though as the facts believed have reference to +absent circumstances and events, it is plain that the knowledge is by no +means intuitive. + +At such times our minds are in a state of pure feeling: intellectual +discrimination and comparison are no longer possible. In this way our +emotions in the moments of their greatest intensity carry away our +intellects with them, confusing the region of pure imagination with that +of truth and certainty, and even the narrow domain of the present with +the vast domain of the past and future. In this condition differences of +present and future may be said to disappear and the energy of the +emotion to constitute an immediate assurance of its existence +absolutely.[104] + +The great region for the illustration of these active illusions is that +of the moral and religious life. With respect to our real motives, our +dominant aspirations, and our highest emotional experiences, we are +greatly liable to deceive ourselves. The moralist and the theologian +have clearly recognized the possibilities of self-deception in matters +of feeling and impulse. To them it is no mystery that the human heart +should mistake the fictitious for the real, the momentary and evanescent +for the abiding. And they have recognized, too, the double bias in these +errors, namely, the powerful disposition to exaggerate the intensity and +persistence of a present feeling on the one hand, and on the other hand +to take a mere wish to feel in a particular way for the actual +possession of the feeling. + + +_Philosophic Illusions._ + +The opinion of theologians respecting the nature of moral introspection +presents a singular contrast to that entertained by some philosophers as +to the nature of self-consciousness. It is supposed by many of these +that in interrogating their internal consciousness they are lifted above +all risk of error. The "deliverance of consciousness" is to them +something bearing the seal of a supreme authority, and must not be +called in question. And so they make an appeal to individual +consciousness a final resort in all matters of philosophical dispute. + +Now, on the face of it, it does not seem probable that this operation +should have an immunity from all liability to error. For the matters +respecting which we are directed to introspect ourselves, are the most +subtle and complex things of our intellectual and emotional life. And +some of these philosophers even go so far as to affirm that the plain +man is quite equal to the niceties of this process. + +It has been brought as a charge against some of these same philosophers +that they have based certain of their doctrines on errors of +introspection. This charge must, of course, be received with some sort +of suspicion here, since it has been brought forward by avowed disciples +of an opposite philosophic school. Nevertheless, as there is from our +present disinterested and purely scientific point of view a presumption +that philosophers like other men are fallible, and since it is certain +that philosophical introspection does not materially differ from other +kinds, it seems permissible just to glance at some of these alleged +illusions in relation to other and more vulgar forms. Further reference +to them will be made at the end of our study. + +These so-called philosophical illusions will be found, like the vulgar +ones just spoken of, to illustrate the distinction drawn between passive +and active illusions. That is to say, the alleged misreading of +individual consciousness would result now from a confusion of distinct +elements, including wrong suggestion, due to the intricacies of the +phenomena, now from a powerful predisposition to read something into the +phenomena. + +A kind of illusion in which the passive element seems most conspicuous +would be the error into which the interrogator of the individual +consciousness is said to fall respecting simple unanalyzable states of +mind. On the face of it, it is not likely that a mere inward glance at +the tangle of conscious states should suffice to determine what is such +a perfectly simple mental phenomenon. Accordingly, when a writer +declares that an act of introspection demonstrates the simple +unanalyzable character of such a feeling as the sentiment of beauty or +that of moral approval, the opponent of this view clearly has some show +of argument for saying that this simplicity may be altogether illusory +and due to the absence of a perfect act of attention. Similarly, when it +is said that the idea of space contains no representations of muscular +sensation, the statement may clearly arise from the want of a +sufficiently careful kind of introspective analysis.[105] + +In most cases of these alleged philosophical errors, however, the active +and passive factors seem to combine. There are certain intricacies in +the mental phenomenon itself favouring the chances of error, and there +are independent predispositions leading the mind to look at the +phenomenon in a wrong way. This seems to apply to the famous declaration +of a certain school of thinkers that by an act of introspection we can +intuit the fact of liberty, that is to say, a power of spontaneous +determination of action superior to and regulative of the influence of +motives. It may be plausibly contended that this idea arises partly +from a mixing up of facts of present consciousness with inferences from +them, and partly from a natural predisposition of the mind to invest +itself with this supreme power of absolute origination.[106] + +In a similar way, it might be contended that other famous philosophic +dicta are founded on a process of erroneous introspection of subjective +mental states. In some cases, indeed, it seems a plausible explanation +to regard these illusions as mere survivals in attenuated shadowy form +of grosser popular illusions. But this is not yet the time to enter on +these, which, moreover, hardly fall perhaps under our definition of an +illusion of introspection. + + +_Value of the Introspective Method._ + +In drawing up this rough sketch of the illusions of introspection, I +have had no practical object in view. I have tried to look at the facts +as they are apart from any conclusions to be drawn from them. The +question how far the liability to error in any region of inquiry +vitiates the whole process is a difficult one; and the question whether +the illusions to which we are subject in introspection materially affect +the value of self-knowledge as a whole and consequently of the +introspective method in psychology, as many affirm, is too subtle a one +to be fully treated now. All that I shall attempt here is to show that +it does not do this any more than the risk of sense-illusion can be said +materially to affect the value of external observation. + +It is to be noted first of all that the errors of introspection are much +more limited than those of sense-perception. They broadly answer to the +slight errors connected with the discrimination and recognition of the +sense-impression. There is nothing answering to a complete hallucination +in the sphere of the inner mental life. It follows, too, from what has +been said above, that the amount of active error in introspection is +insignificant, since the representation of a feeling or belief is so +very similar to the actual experience of it. + +In brief, the errors of introspection, though numerous, are all too +slight to render the process of introspection as a whole unsound and +untrustworthy. Though, as we have seen, it involves, strictly speaking, +an ingredient of representation, this fact does not do away with the +broad distinction between presentative and representative cognition. +Introspection is presentative in the sense that the reality constituting +the object of cognition, the mind's present feeling, is as directly +present to the knowing mind as anything can be conceived to be. It may +be added that the power of introspection is a comparatively new +acquisition of the human race, and that, as it improves, the amount of +error connected with its operation may reasonably be expected to become +infinitesimal. + +It is often supposed by those who undervalue the introspective method in +psychology that there is a special difficulty in the detection of error +in introspection, owing to the fact that the object of inspection is +something individual and private, and not open to common scrutiny as the +object of external perception. Yet, while allowing a certain force to +this objection I would point out, first of all, that even in +sense-perception, what the individual mind is immediately certain of is +its own sensations. The relatively perfect certainty which finally +attaches to the presentative side of sense-perception is precisely that +which finally attaches to the results of introspection. + +In the second place, it may be said that the contrast between the inner +and the outer experience is much less than it seems. In many cases our +emotions are the direct result of a common external cause, and even when +they are not thus attached to some present external circumstance, we are +able, it is admitted, by the use of language, roughly to compare our +individual feelings. And such comparison is continually bringing to +light the fact that there is a continuity in our mental structure, that +our highest thoughts and emotions lead us back to our common +sense-impressions, and that consequently, in spite of all individual +differences of temperament and mental organization, our inner experience +is in all its larger features a common experience. + +I may add that this supposition of the common nature of our internal +experience, as a whole, not only underlies the science of psychology, +but is implied in the very process of detecting and correcting errors of +introspection. I do not mean that in matters of feeling "authority" is +to override "private judgment." Our last resort with respect to things +of the mind is, as I have said, that of careful self-inspection. And the +progress of psychology and the correction of illusion proceed by means +of an ever-improving exercise of the introspective faculty. Yet such +individual inspection can at least be _guided_ by the results of others' +similar inspection, and should be so guided as soon as a general +consensus in matters of internal experience is fairly made out. In point +of fact, the preceding discussion of illusions of introspection has +plainly rested on the sufficiently verified assumption that the calmest +and most efficient kind of introspection, in bringing to light what is +permanent as compared with what is variable in the individual cognition, +points in the direction of a common body of introspected fact. + + + + +CHAPTER IX. + +OTHER QUASI-PRESENTATIVE ILLUSIONS: ERRORS OF INSIGHT. + + +Besides the perception of external objects, and the inspection of our +internal mental states, there are other forms of quasi-presentative +cognition which need to be touched on here, inasmuch as they are +sometimes erroneous and illusory. + +In the last chapter I alluded to the fact that emotion may arise as the +immediate accompaniment of a sense-impression. When this is the case +there is a disposition to read into the external object a quality +answering to the emotion, just as there is a disposition to ascribe to +objects qualities of heat and cold answering to the sensations thus +called. And such a reference of an emotional result to an external +exciting cause approximates in character to an immediate intuition. The +cognition of the quality is instantaneous, and quite free from any +admixture of conscious inference. Accordingly, we have to inquire into +the illusory forms of such intuition, if such there be. + + +_Æsthetic Intuition._ + +Conspicuous among these quasi-presentative emotional cognitions is +æsthetic intuition, that is to say, the perception of an object as +beautiful. It is not necessary here to raise the question whether there +is, strictly speaking, any quality in things answering to the sentiment +of beauty in our minds: this is a philosophical and not a psychological +question, and turns on the further question, what we mean by object. All +that we need to assume here is that there are certain aspects of +external things, certain relations of form, together with a power of +exciting certain pleasurable ideas in the spectator's mind, which are +commonly recognized as the cause of the emotion of beauty, and indeed +regarded as constituting the embodiments of the objective quality, +beauty. Æsthetic intuition thus clearly implies the immediate assurance +of the existence of a common source of æsthetic delight, a source bound +up with an object of common sense-perception. And so we may say that to +call a thing beautiful is more or less distinctly to recognize it as a +cause of a present emotion, and to attribute to it a power of raising a +kindred emotion in other minds. + + +_Æsthetic Illusion._ + +According to this view of the matter, an illusion of æsthetic intuition +would arise whenever this power of affecting a number of minds +pleasurably is wrongly attributed, by an act of "intuition," to an +object of sense-perception, on the ground of a present personal +feeling. + +Now, this error is by no means unfrequent. Our delight in viewing +external things, though agreeing up to a certain point, does not agree +throughout. It is a trite remark that there is a large individual +factor, a considerable "personal equation," in matters of taste, as in +other matters. Permanent differences of natural sensibility, of +experience, of intellectual habits, and so on, make an object +æsthetically impressive and valuable to one man and not to another. Yet +these differences tend to be overlooked. The individual mind, filled +with delight at some spectacle, automatically projects its feeling +outwards in the shape of a cause of a common sentiment. And the force of +this impulse cannot be altogether explained as the effect of past +experiences and of association. It seems to involve, in addition, the +play of social instincts, the impulse of the individual mind to connect +itself in sympathy with the collective mind. + +Here, as in the other varieties of illusion already treated of, we may +distinguish between a passive and an active side; only in this case the +passive side must not be taken as corresponding to any common +suggestions of the object, as in the case of perception proper. So far +as an illusion of æsthetic intuition may be considered as passive, it +must be due to the effect of circumscribed individual associations with +the object. + +All agree that what is called beauty consists, to a considerable extent, +of a power of awaking pleasant suggestions, but in order that these +should constitute a ground of æsthetic value, they must be common, +participated in by all, or at least by an indefinite number. This will +be the case when the association rests on our common every-day +experiences, and our common knowledge of things, as in the case of the +peaceful beauty of an ascending curl of blue smoke in a woody landscape, +or the awful beauty of a lofty precipice. On the other hand, when the +experience and recollections, which are the source of the pleasure, are +restricted and accidental, any attribution of objective worth is +illusory. Thus, the ascription of beauty to one's native village, to +one's beloved friends, and so on, in so far as it carries the conviction +of objective worth, may imply a confusion of the individual with the +common experience. + +The active side of this species of illusions would be illustrated in +every instance of ascribing beauty to objects which is due, in a +considerable measure at least, to some pre-existing disposition in the +mind, whether permanent or temporary. A man brings his peculiar habits +of thought and feeling to the contemplation of objects, and the æsthetic +impression produced is coloured by these predispositions. Thus, a person +of a sad and gloomy cast of mind will be disposed to see a sombre beauty +where other eyes see nothing of the kind. And then there are all the +effects of temporary conditions of the imagination and the feelings. +Thus, the individual mind may be focussed in a certain way through the +suggestion of another. People not seldom see a thing to be beautiful +because they are told that it is so. It might not be well to inquire too +curiously how many of the frequenters of the annual art exhibitions use +their own eyes in framing their æsthetic judgments. Or the temporary +predisposition may reside in a purely personal feeling or desire +uppermost at the time. Our enjoyment of nature or of art is coloured by +our temporary mood. There are moments of exceptional mental +exhilaration, when even a commonplace scene will excite an appreciable +kind of admiration. Or there may be a strong wish to find a thing +beautiful begotten of another feeling. Thus, a lover desires to find +beauty in his mistress; or, having found it in her face and form, +desires to find a harmonious beauty in her mind. In these different ways +temporary accidents of personal feeling and imagination enter into and +determine our æsthetic intuition, making it deviate from the common +standard. This kind of error may even approximate in character to an +hallucination of sense when there is nothing answering to a common +source of æsthetic pleasure. Thus, the fond mother, through the very +force of her affection, will construct a beauty in her child, which for +others is altogether non-existent. + +What applies to the perception of beauty in the narrow sense will apply +to all other modes of æsthetic intuition, as that of the sublime and the +ludicrous, and the recognition of the opposite of beauty or the ugly. In +like manner, it will apply to moral intuition in so far as it is an +instantaneous recognition of a certain quality in a perceived action +based on, or at least conjoined with, a particular emotional effect. In +men's intuitive judgments respecting the right and the wrong, the noble +and base, the admirable and contemptible, and so on, we may see the same +kind of illusory universalizing of personal feeling as we have seen in +their judgments respecting the beautiful. And the sources of the error +are the same in the two cases. Accidents of experience, giving special +associations to the actions, will not unfrequently warp the individual +intuition. Ethical culture, like æsthetic culture, means a continual +casting aside of early illusory habits of intuition. And further, moral +intuition illustrates all those effects of feeling which we have briefly +traced in the case of æsthetic intuition. The perversions of the moral +intuition under the sway of prejudice are too familiar to need more than +a bare allusion. + + +_Nature of Insight._ + +There remains one further mode of cognition which approximates in +character to presentative knowledge, and is closely related to external +perception. I refer to the commonly called "intuitive" process by which +we apprehend the feelings and thoughts of other minds through the +external signs of movement, vocal sound, etc., which make up expression +and language. This kind of knowledge, which is not sufficiently marked +off from external perception on the one side and introspection on the +other, I venture to call Insight. + +I am well aware that this interpretation of the mental states of others +is commonly described as a process of inference involving a conscious +reference to our own similar experiences. I willingly grant that it is +often so. At the same time, it must be perfectly plain that it is not +always so. It is, indeed, doubtful whether in its first stages in early +life it is invariably so, for there seem to be good reasons for +attributing to the infant mind a certain degree of instinctive or +inherited capability in making out the looks and tones of others.[107] +And, however this may be, it is certain that with the progress of life a +good part of this interpretation comes to be automatic or unconscious, +approximating in character to a sense-perception. To recognize +contentment in a placid smile is, one would say, hardly less immediate +and intuitive than to recognize the coolness of a stream. + +We must, of course, all allow that the fusion of the presentative and +the representative element is, speaking generally, more complete in the +case of sense-perception than in that here considered. In spite of +Berkeley's masterly account of the _rationale_ of visual perception as +an interpretation of "visual language" and all that has confirmed it, +the plain man cannot, at the moment of looking at an object, easily +bring himself to admit that distance is not directly present to his +vision. On the other hand, on cool reflection, he will recognize that +the complacent benevolent sentiment is distinct from the particular +movements and changes in the eye and other features which express it. +Yet, while admitting this, I must contend that there is no very hard and +fast line dividing the two processes, but that the reading of others' +feelings approximates in character to an act of perception. + +An intuitive insight may, then, be defined as that instantaneous, +automatic, or "unconscious" mode of interpreting another's feeling +which occurs whenever the feeling is fully expressed, and when its signs +are sufficiently familiar to us. This definition will include the +interpretation of thoughts by means of language, though not, of course, +the belief in an objective fact grounded on a recognition of another's +belief. On the other hand, it will exclude all the more complex +interpretations of looks and words which imply conscious comparison, +reflection, and reasoning. Further, it will exclude a large part of the +interpretation of actions as motived, since this, though sometimes +approaching the intuitive form, is for the most part a process of +conjectural or doubtful inference, and wanting in the immediate +assurance which belongs to an intuitive reading of a present emotion or +thought. + +From this short account of the process of insight, its relation to +perception and introspection becomes pretty plain. On the one hand, it +closely resembles sense-perception, since it proceeds by the +interpretation of a sense-impression by means of a representative image. +On the other hand, it differs from sense-perception, and is more closely +allied to introspection in the fact that, while the process of +interpretation in the former case is a reconstruction of _external_ +experiences, in the latter case it is a reconstruction of _internal_ +experiences. To intuit another's feeling is clearly to represent to +ourselves a certain kind of internal experience previously known, in its +elements at least, by introspection, while these represented experiences +are distinctly referred to another personality. + +And now we see what constitutes the object of insight. This is, in part, +a common experience, as in the case of sense-perception and æsthetic +intuition, since to perceive another's feeling is implicitly to cognize +the external conditions of a common insight. But this is clearly not the +whole, nor even the main part of objective reality in this act of +cognition. An intuitive insight differs from a sense-perception in that +it involves an immediate assurance of the existence of a feeling +presentatively known, though not to our own minds. The object in insight +is thus a presentative feeling as in introspection, though not our own, +but another's. And so it differs from the object in sense-perception in +so far as this last involves sense-experiences, as muscular and tactual +feelings, which are not _at the moment_ presentatively known to any +mind. + + +_Illusions of Insight._ + +And now we are in a position, perhaps, to define an illusion of insight, +and to inquire whether there is anything answering to our definition. An +illusory insight is a quasi-intuition of another's feelings which does +not answer to the internal reality as presentatively known to the +subject himself. In spite of the errors of introspection dealt with in +the last chapter, nobody will doubt that, when it is a question between +a man's knowing what is at the moment in his own mind and somebody +else's knowing, logic, as well as politeness, requires us to give +precedence to the former. + +An illusion of insight, like the other varieties of illusion already +dealt with, may arise either by way of wrong suggestion or by way of a +warping preconception. Let us look at each of these sources apart. + +Our insights, like our perceptions, though intuitive in form, are +obviously determined by previous experience, association, and habit. +Hence, on its passive side, an illusion of insight may be described as a +wrong interpretation of a new or exceptional case. For example, having +associated the representation of a slight feeling of astonishment with +uplifted eyebrows, we irresistibly tend to see a face in which this is a +constant feature as expressing this particular shade of emotion. In this +way we sometimes fall into grotesque errors as to mental traits. And the +most practised physiognomist may not unfrequently err by importing the +results of his special circle of experiences into new and unlike cases. + +Much the same thing occurs in language. Our timbre of voice, our +articulation, and our vocabulary, like our physiognomy, have about them +something individual, and error often arises from overlooking this, and +hastily reading common interpretations into exceptional cases. The +misunderstandings that arise even among the most open and confiding +friends sufficiently illustrate this liability to error. + +Sometimes the error becomes more palpable, as, for example, when we +visit another country. A foreign language, when heard, provokingly +suggests all kinds of absurd meanings through analogies to our familiar +tongue. Thus, the Englishman who visits Germany cannot, for a time, hear +a lady use the expression, "Mein Mann," without having the amusing +suggestion that the speaker is wishing to call special attention to the +fact of her husband's masculinity. And doubtless the German who visits +us derives a similar kind of amusement from such involuntary +comparisons. + +A fertile source of illusory insight is, of course, conscious deception +on the part of others. The rules of polite society require us to be +hypocrites in a small way, and we have occasionally to affect the signs +of amiability, interest, and amusement, when our actual sentiment is one +of indifference, weariness, or even positive antipathy. And in this way +a good deal of petty illusion arises. Although we may be well aware of +the general untrustworthiness of this society behaviour, such is the +force of association and habit, that the bland tone and flattering word +irresistibly excite a momentary feeling of gratification, an effect +which is made all the more easy by the co-operation of the recipient's +own wishes, touched on in the last chapter. + +Among all varieties of this deception, that of the stage is the most +complete. The actor is a man who has elaborately trained himself in the +simulation of certain feelings. And when his acting is of the best +quality, and the proper bodily attitude, gesture, tone of voice, and so +on, are hit off, the force of the illusion completely masters us. For +the moment we lose sight of the theatrical surroundings, and see the +actor as really carried away by the passion which he so closely +imitates. Histrionic illusion is as complete as any artistic variety can +venture to be.[108] + +I have said that our insights are limited by our own mental experience, +and so by introspection. In truth, every interpretation of another's +look and word is determined ultimately, not by what we have previously +observed in others, but by what we have personally felt, or at least +have in a sense made our own by intense sympathy. Hence we may, in +general, regard an illusion of insight on the active side as a hasty +projection of our own feelings, thoughts, etc., into other minds. + +We habitually approach others with a predisposition to attribute to them +our own modes of thinking and feeling. And this predisposition will be +the more powerful, the more desirous we are for sympathy, and for that +confirmation of our own views which the reflection of another mind +affords. Thus, when making a new acquaintance, people are in general +disposed to project too much of themselves into the person who is the +object of inspection. They intuitively endow him with their own ideas, +ways of looking at things, prejudices of sentiment, and so on, and +receive something like a shock when later on they find out how different +he is from this first hastily formed and largely performed image. + +The same thing occurs in the reading of literature, and the appreciation +of the arts of expression generally. We usually approach an author with +a predisposition to read our own habits of thought and sentiment into +his words. It is probably a characteristic defect of a good deal of +current criticism of remote writers to attribute to them too much of our +modern conceptions and aims. Similarly, we often import our own special +feelings into the utterances of the poet and of the musical composer. +That much of this intuition is illusory, may be seen by a little +attention to the "intuitions" of different critics. Two readers of +unlike emotional organization will find incompatible modes of feeling in +the same poet. And everybody knows how common it is for musical critics +and amateurs to discover quite dissimilar feelings in the same +composition.[109] + +The effect of this active projection of personal feeling will, of +course, be seen most strikingly when there is a certain variety of +feeling actually excited at the time in the observer's mind. A man who +is in a particularly happy mood tends to reflect his exuberant gladness +on others. The lover, in the moment of exalted emotion, reads a response +to all his aspirations in his mistress's eyes. Again, a man will tend to +project his own present ideas into the minds of others, and so imagine +that they know what he knows; and this sometimes leads to a comical kind +of embarrassment, and even to a betrayal of something which it was the +interest of the person to keep to himself. Once more, in interpreting +language, we may sometimes catch ourselves mistaking the meaning, owing +to the presence of a certain idea in the mind at the time. Thus, if I +have just been thinking of Comte, and overhear a person exclaim, "I'm +positive," I irresistibly tend, for the moment, to ascribe to him an +avowal of discipleship to the great positivist. + + +_Poetic Illusion._ + +The most remarkable example of this projection of feeling is +undoubtedly illustrated in the poetic interpretation of inanimate +nature. The personification of tree, mountain, ocean, and so on, +illustrates, no doubt, the effect of association and external +suggestion; for there are limits to such personification. But +resemblance and suggestion commonly bear, in this case, but a small +proportion to active constructive imagination. One might, perhaps, call +this kind of projection the hallucination of insight, since there is +nothing objective corresponding to the interpretative image. + +The imaginative and poetic mind is continually on the look out for hints +of life, consciousness, and emotion in nature. It finds a certain kind +of satisfaction in this half-illusory, dream-like transformation of +nature. The deepest ground of this tendency must probably be looked for +in the primitive ideas of the race, and the transmission by inheritance +of the effect of its firmly fixed habits of mind. The undisciplined mind +of early man, incapable of distinguishing the object of perception from +the product of spontaneous imagination, and taking his own double +existence as the type of all existence, actually saw the stream, the +ocean, and the mountain as living beings; and so firmly rooted is this +way of regarding objects, that even our scientifically trained minds +find it a relief to relapse occasionally into it.[110] + +While there is this general imaginative disposition in the poetic mind +to endow nature with life and consciousness, there are special +tendencies to project the individual feelings into objects. Every +imaginative mind looks for reflections of its own deepest feelings in +the world about it. The lonely embittered heart, craving for sympathy, +which he cannot meet with in his fellow-man, finds traces of it in the +sighing of the trees or the moaning of the sad sea-wave. Our Poet +Laureate, in his great elegy, has abundantly illustrated this impulse of +the imagination to reflect its own emotional colouring on to inanimate +things: for example in the lines-- + + "The wild unrest that lives in woe + Would dote and pore on yonder cloud + That rises upward always higher, + And onward drags a labouring breast, + And topples round the dreary west, + A looming bastion fringed with fire." + +So far I have been considering active illusions of insight as arising +through the play of the impulse of the individual mind to project its +feelings outwards, or to see their reflections in external things. I +must now add that active illusion may be due to causes similar to those +which we have seen to operate in the sphere of illusory perception and +introspection. That is to say, there may be a disposition, permanent or +temporary, to ascribe a certain kind of feeling to others in accordance +with our wishes, fears, and so on. + +To give an illustration of the permanent causes, it is well known that a +conceited man will be disposed to attribute admiration of himself to +others. On the other hand, a shy, timid person will be prone to read +into other minds the opposite kind of feeling. + +Coming to temporary forces, we find that any expectation to meet with a +particular kind of mental trait in a new acquaintance will dispose the +observer hastily and erroneously to attribute corresponding feelings to +the person. And if this expectation springs out of a present feeling, +the bias to illusory insight is still more powerful. For example, a +child that fears its parent's displeasure will be prone to misinterpret +the parent's words and actions, colouring them according to its fears. +So an angry man, strongly desirous of making out that a person has +injured him, will be disposed to see signs of conscious guilt in this +person's looks or words. Similarly, a lover will read fine thoughts or +sentiments into the mind of his mistress under the influence of a strong +wish to admire. + +And what applies to the illusory interpretation of others' feelings +applies to the ascription of feelings to inanimate objects. This is due +not simply to the impulse to expand one's conscious existence through +far-reaching resonances of sympathy, but also to a permanent or +temporary disposition to attribute a certain kind of feeling to an +object. Thus, the poet personifies nature in part because his emotional +cravings prompt him to construct the idea of something that can be +admired or worshipped. Once more, the action of a momentary feeling when +actually excited is seen in the "mechanical" impulse of a man to +retaliate when he strikes his foot against an object, as a chair, which +clearly involves a tendency to attribute an intention to hurt to the +unoffending body, and the _rationale_ of which odd procedure is pretty +correctly expressed in the popular phrase: "It relieves the feelings." + +It is worth noting, perhaps, that these illusions of insight, like those +of perception, may involve an inattention to the actual impression of +the moment. To erroneously attribute a feeling to another through an +excess of sympathetic eagerness is often to overlook what a perfectly +dispassionate observer would see, as, for example, the immobility of the +features or the signs of a deliberate effort to simulate. This +inattention will, it is obvious, be greatest in the poetic attribution +of life and personality to natural objects, in so far as this +approximates to a complete momentary illusion. To see a dark overhanging +rock as a grim sombre human presence, is for the moment to view it under +this aspect only, abstracting from its many obvious unlikenesses. + +In the same manner, a tendency to read a particular meaning into a word +may lead to the misapprehension of the word. To give an illustration: I +was lately reading the fifth volume of G. H. Lewes's _Problems of Life +and Mind_. In reading the first sentence of one of the sections, I again +and again fell into the error of taking "The great Lagrange," for "The +great Language." On glancing back I saw that the section was headed "On +Language," and I at once recognized the cause of my error in the +pre-existence in my mind of the representative image of the word +"language." + +In concluding this short account of the errors of insight, I may observe +that their range is obviously much greater than that of the previously +considered classes of presentative illusion. This is, indeed, involved +in what has been said about the nature of the process. Insight, as we +have seen, though here classed with preservative cognition, occupies a +kind of border-land between immediate knowledge or intuition and +inference, shading off from the one to the other. And in the very nature +of the case the scope for error must be great. Even overlooking human +reticence, and, what is worse, human hypocrisy, the conditions of an +accurate reading of others' minds are rarely realized. If, as has been +remarked by a good authority, one rarely meets, even among intelligent +people, with a fairly accurate observer of external things, what shall +be said as to the commonly claimed power of "intuitive insight" into +other people's thoughts and feelings, as though it were a process above +suspicion? It is plain, indeed, on a little reflection, that, taking +into account what is required in the way of large and varied experience +(personal and social), a habit of careful introspection, as well as a +habit of subtle discriminative attention to the external signs of mental +life, and lastly, a freedom from prepossession and bias, only a very few +can ever hope even to approximate to good readers of character. + +And then we have to bear in mind that this large amount of error is apt +to remain uncorrected. There is not, as in the case of external +perception, an easy way of verification, by calling in another sense; a +misapprehension, once formed, is apt to remain, and I need hardly say +that errors in these matters of mutual comprehension have their palpable +practical consequences. All social cohesion and co-operation rest on +this comprehension, and are limited by its degree of perfection. Nay, +more, all common knowledge itself, in so far as it depends on a mutual +communication of impressions, ideas, and beliefs, is limited by the +fact of this great liability to error in what at first seems to be one +of the most certain kinds of knowledge. + +In view of this depressing amount of error, our solace must be found in +the reflection that this seemingly perfect instrument of intuitive +insight is, in reality, like that of introspection, in process of being +fashioned. Mutual comprehension has only become necessary since man +entered the social state, and this, to judge by the evolutionist's +measure of time, is not so long ago. A mental structure so complex and +delicate requires for its development a proportionate degree of +exercise, and it is not reasonable to look yet for perfect precision of +action. Nevertheless, we may hope that, with the advance of social +development, the faculty is continually gaining in precision and +certainty. And, indeed, this hope is already assured to us in the fact +that the faculty has begun to criticise itself, to distinguish between +an erroneous and a true form of its-operation. In fact, all that has +been here said about illusions of insight has involved the assumption +that intellectual culture sharpens the power and makes it less liable to +err. + + + + +CHAPTER X. + +ILLUSIONS OF MEMORY. + + +Thus far we have been dealing with Presentative Illusions, that is to +say, with the errors incident to the process of what may roughly be +called presentative cognition. We have now to pass to the consideration +of Representative Illusion, or that kind of error which attends +representative cognition in so far as it is immediate or +self-sufficient, and not consciously based on other cognition. Of such +immediate representative cognition, memory forms the most conspicuous +and most easily recognized variety. Accordingly, I proceed to take up +the subject of the Illusions of Memory.[111] + +The mystery of memory lies in the apparent immediateness of the mind's +contact with the vanished past. In "looking back" on our life, we seem +to ourselves for the moment to rise above the limitations of time, to +undo its work of extinction, seizing again the realities which its +on-rushing stream had borne far from us. Memory is a kind of +resurrection of the buried past: as we fix our retrospective glance on +it, it appears to start anew into life; forms arise within our minds +which, we feel sure, must faithfully represent the things that were. We +do not ask for any proof of the fidelity of this dramatic representation +of our past history by memory. It is seen to be a faithful imitation, +just because it is felt to be a revival of the past. To seek to make the +immediate testimony of memory more sure seems absurd, since all our ways +of describing and illustrating this mental operation assume that in the +very act of performing it we do recover a part of our seemingly "dead +selves." + +To challenge the veracity of a person's memory is one of the boldest +things one can do in the way of attacking deep-seated conviction. Memory +is the peculiar domain of the individual. In going back in recollection +to the scenes of other years he is drawing on the secret store-house of +his own consciousness, with which a stranger must not intermeddle. To +cast doubt on a person's memory is commonly resented as an impertinence, +hardly less rude than to question his reading of his own present mental +state. Even if the challenger professedly bases his challenge on the +testimony of his own memory, the challenged party is hardly likely to +allow the right of comparing testimonies. He can in most cases boldly +assert that those who differ from him are lacking in _his_ power of +recollection. The past, in becoming the past, has, for most people, +ceased to be a common object of reference; it has become a part of the +individual's own inner self, and cannot be easily dislodged or shaken. + +Yet, although people in general are naturally disposed to be very +confident about matters of recollection, reflective persons are pretty +sure to find out, sooner or later, that they occasionally fall into +errors of memory. It is not the philosopher who first hints at the +mendacity of memory, but the "plain man" who takes careful note of what +really happens in the world of his personal experience. Thus, we hear +persons, quite innocent of speculative doubt, qualifying an assertion +made on personal recollection by the proviso, "unless my memory has +played me false." And even less reflective persons, including many who +pride themselves on their excellent memory, will, when sorely pressed, +make a grudging admission that they may, after all, be in error. Perhaps +the weakest degree of such an admission, and one which allows to the +conceding party a semblance of victory, is illustrated in the "last +word" of one who has boldly maintained a proposition on the strength of +individual recollection, but begins to recognize the instability of his +position: "I either witnessed the occurrence or dreamt it." This is +sufficient to prove that, with all people's boasting about the +infallibility of memory, there are many who have a shrewd suspicion that +some of its asseverations will not bear a very close scrutiny. + + +_Psychology of Memory._ + +In order to understand the errors of memory, we must proceed, as in the +case of illusions of perception, by examining a little into the nature +of the normal or correct process. + +An act of recollection is said by the psychologist to be purely +representative in character, whereas perception is partly +representative, partly preservative. To recall an object to the mind is +to reconstruct the percept in the absence of a sense-impression.[112] + +An act of memory is obviously distinguished from one of simple +imagination by the presence of a conscious reference to the past. Every +recollection is an immediate reapprehension of some past object or +event. However vague this reference may be, it must be there to +constitute the process one of recollection. + +The every-day usages of language do not at first sight seem to +consistently observe this distinction. When a boy says, "I remember my +lesson," he appears to be thinking of the present only, and not +referring to the past. In truth, however, there is a vague reference to +the fact of retaining a piece of knowledge through a given interval of +time. + +Again, when a man says, "I recollect your face," this means, "Your face +seems familiar to me." Here again, though there is no definite reference +to the past, there is a vague and indefinite one. + +It is plain from this definition that recollection is involved in all +recognition or identification. Merely to be aware that I have seen a +person before implies a minimum exercise of memory. Yet we may roughly +distinguish the two actions of perception and recollection in the +process of recognition. The mere recognition of an object does not +imply the presence of a distinct representative or mnemonic image. In +point of fact, in so far as recognition is assimilation, it cannot be +said to imply a _distinct_ act of memory at all. It is only when +similarity is perceived amid difference, only when the accompaniments or +surroundings of the object as previously seen, differencing it from the +object as now seen, are brought up to the mind that we may be said +distinctly to recall the past. And our state of mind in recognizing an +object or person is commonly an alternation between these two acts of +separating the mnemonic image from the percept and so recalling or +recollecting the past, and fusing the image and the percept in what is +specifically marked off as recognition.[113] + +Although I have spoken of memory as a reinstatement in representative +form of external experience, the term must be understood to include +every revival of a past experience, whether external or internal, which +is recognized as a revival. In a general way, the recallings of our +internal feelings take place in close connection with the recollection +of external circumstances or events, and so they may be regarded as +largely conditioned by the laws of this second kind of reproduction. + +The old conceptions of mind, which regarded every mental phenomenon as a +manifestation of an occult spiritual substance, naturally led to the +supposition that an act of recollection involves the continued, +unbroken existence of the reproductive or mnemonic image in the hidden +regions of the mind. To recollect is, according to this view, to draw +the image out of the dark vaults of unconscious mind into the upper +chamber of illumined consciousness. + +Modern psychology recognizes no such pigeonhole apparatus in unconscious +mind. On the purely psychical side, memory is nothing but an occasional +reappearance of a past mental experience. And the sole mental conditions +of this reappearance are to be found in the circumstances of the moment +of the original experience and in those of the moment of the +reappearance. + +Among these are to be specially noted, first of all, the degree of +impressiveness of the original experience, that is to say, the amount of +interest it awakened and of attention it excited. The more impressive +any experience, the greater the chances of its subsequent revival. +Moreover, the absence of impressiveness in the original experience may +be made good either by a repetition of the actual experience or, in the +case of non-recurring experiences, by the fact of previous mnemonic +revivals. + +In the second place, the pre-existing mental states at the time of +revival are essential conditions. It is now known that every +recollection is determined by some link of association, that every +mnemonic image presents itself in consciousness only when it has been +preceded by some other mental state, presentative or representative, +which is related to the image. This relation may be one of contiguity, +that is to say, the original experiences may have occurred at the same +time or in close succession; or one of similarity (partial and not +amounting to identity), as where the sight of one place or person +recalls that of another place or person. Finally, it is to be observed +that recollection is often an act, in the full sense of that term, +involving an effort of voluntary attention at the moment of revival. + +Modern physiology has done much towards helping us to understand the +nervous conditions of memory. The biologist regards memory as a special +phase of a universal property of organic structure, namely, +modifiability by the exercise of function, or the survival after any +particular kind of activity of a disposition to act again in that +particular way. The revival of a mental impression in the weaker form of +an image is thus, on its physical side, due in part to this remaining +functional disposition in the central nervous tracts concerned. And so, +while on the psychical or subjective side we are unable to find anything +permanent in memory, on the physical or objective side we do find such a +permanent substratum. + +With respect to the special conditions of mnemonic revival at any time, +physiology is less explicit. In a general way, it informs us that such a +reinstatement of the past is determined by the existence of certain +connections between the nervous structures concerned in the reviving and +revived mental elements. Thus, it is said that when the sound of a name +calls up in the mind a visual image of a person seen some time since, it +is because connections have been formed between particular regions and +modes of activity of the auditory and the visual centres. And it is +supposed that the existence of such connections is somehow due to the +fact that the two regions acted simultaneously in the first instance, +when the sight of the person was accompanied by the hearing of his name. +In other words, the centres, as a whole, will tend to act at any future +moment in the same complex way in which they have acted in past moments. + +All this is valuable hypothesis so far as it goes, though it plainly +leaves much unaccounted for. As to why this reinstatement of a total +cerebral pulsation in consequence of the re-excitation of a portion of +the same should be accompanied by the specific mode of consciousness +which we call recollection of something past, it is perhaps unreasonable +to ask of physiology any sort of explanation.[114] + +Thus far as to the general or essential characteristics of memory on its +mental and its bodily side. But what we commonly mean by memory is, on +its psychical side at least, much more than this. We do not say that we +properly recollect a thing unless we are able to refer it to some more +or less clearly defined region of the past, and to localize it in the +succession of experiences making up our mental image of the past. In +other words, though we may speak of an imperfect kind of recollection +where this definite reference is wanting, we mean by a perfect form of +memory something which includes this reference. + +Without entering just now upon a full analysis of what this reference to +a particular region of the past means, I may observe that it takes place +by help of an habitual retracing of the past, or certain portions of it, +that is to say, a regressive movement of the imagination along the lines +of our actual experience. Setting out from the present moment, I can +move regressively to the preceding state of consciousness, to the +penultimate, and so on. The fact that each distinct mental state is +continuous with the preceding and the succeeding, and in a certain sense +overlaps these, makes any portion of our experience essentially a +succession of states of consciousness, involving some rudimentary idea +of time. And thus, whether I anticipate a future event or recall a past +one, my imagination, setting out from the present moment, constructs a +sequence of experiences of which the one particularly dwelt on is the +other term or boundary. And our idea of the position of this last in +time, like that of an object in space, is one of a relation to our +present position, and is determined by the length of the sequence of +experiences thus run over by the imagination.[115] It may be added that +since the imagination can much more easily follow the actual order of +experience than conceive it as reversed, the retrospective act of memory +naturally tends to complete itself by a return movement forwards from +the remembered event to the present moment. + +In practice this detailed retracing of successive moments of mental life +is confined to very recent experiences. If I try to localize in time a +remote event, I am content with placing it in relation to a series of +prominent events or landmarks which serves me as a rough scheme of the +past. The formation of such a mnemonic framework is largely due to the +needs of social converse, which proceeds by help of a common standard of +reference. This standard is supplied by those objective, that is to say, +commonly experienced regularities of succession which constitute the +natural and artificial divisions of the years, seasons, months, weeks, +etc. The habit of recurring to these fixed divisional points of the past +renders a return of imagination to any one of them more and more easy. A +man has a definite idea of "a year ago" which the child wants, just +because he has had so frequently to execute that vague regressive +movement by which the idea arises. And though, as our actual point in +time moves forward, the relative position of any given landmark is +continually changing, the change easily adapts itself to that scheme of +time-divisions which holds good for any present point. + +Few of our recollections of remote events involve a definite reference +to this system of landmarks. The recollections of early life are, in the +case of most people, so far as they depend on individual memory, very +vaguely and imperfectly localized. And many recent experiences which are +said to be half forgotten, are not referred to any clearly assignable +position in time. One may say that in average cases definite +localization characterizes only such supremely interesting personal +experiences as spontaneously recur again and again to the mind. For the +rest it is confined to those facts and events of general interest to +which our social habits lead us repeatedly to go back.[116] + +The consciousness of personal identity is said to be bound up with +memory. That is to say, I am conscious of a continuous permanent self +under all the varying surface-play of the stream of consciousness, just +because I can, by an act of recollection, bring together any two +portions of this stream of experience, and so recognize the unbroken +continuity of the whole. If this is so, it would seem to follow from the +very fragmentary character of our recollections that our sense of +identity is very incomplete. As we shall see presently, there is good +reason to look upon, this consciousness of continuous personal existence +as resting only in part on memory, and mainly on our independently +formed representation of what has happened in the numberless and often +huge lacunæ of the past left by memory. + +Having thus a rough idea of the mechanism of memory to guide us, we may +be able to investigate the illusions incident to the process. + + +_Illusions of Memory._ + +By an illusion of memory we are to understand a false recollection or a +wrong reference of an idea to some region of the past. It might, +perhaps, be roughly described as a wrong interpretation of a special +kind of mental image, namely, what I have called a mnemonic image. + +Mnemonic illusion is thus distinct from mere forgetfulness or imperfect +memory. To forget or be doubtful about a past event is one thing; to +seem to ourselves to remember it when we afterwards find that the fact +was otherwise than we represented it in the apparent act of recollection +is another thing. Indistinctness of recollection, or the decay of +memory, is, as we shall soon see, an important co-operant condition of +mnemonic illusion, but does not constitute it, any more than haziness of +vision or disease of the visual organ, though highly favourable to +optical illusion, can be said to constitute it. + +We may conveniently proceed in our detailed examination of illusions of +memory, by distinguishing between three facts which appear to be +involved in every complete and accurate process of recollection. When I +distinctly recall an event, I am immediately sure of three things: (1) +that something did really happen to me; (2) that it happened in the way +I now think; and (3) that it happened when it appears to have happened. +I cannot be said to recall a past event unless I feel sure on each of +these points. Thus, to be able to say that an event happened at a +particular date, and yet unable to describe how it happened, means that +I have a very incomplete recollection. The same is true when I can +recall an event pretty distinctly, but fail to assign it its proper +date. This being so, it follows that there are three possible openings, +and only three, by which errors of memory may creep in. And, as a matter +of fact, each of these openings will be found to let in one class of +mnemonic illusion. Thus we have (1) false recollections, to which there +correspond no real events of personal history; (2) others which +misrepresent the manner of happening of the events; and (3) others which +falsify the date of the events remembered. + +It is obvious, from a mere glance at this threefold classification, that +illusions of memory closely correspond to visual illusions. Thus, class +(1) may be likened to the optical illusions known as subjective +sensations of light, or ocular spectra. Here we can prove that there is +nothing actually seen in the field of vision, and that the semblance of +a visible object arises from quite another source than that of ordinary +external light-stimulation, and by what may be called an accident. +Similarly, in the case of the first class of mnemonic illusions, we +shall find that there is nothing actually recollected, but that the +mnemonic spectra or phantoms of recollected objects can be accounted for +in quite another way. Such illusions come nearest to hallucinations in +the region of memory. + +Again, class (2) has its visual analogue in those optical illusions +which depend on effects of haziness and of the action of refracting +media interposed between the eye and the object; in which cases, though +there is some real thing corresponding to the perception, this is seen +in a highly defective, distorted, and misleading form. In like manner, +we can say that the images of memory often get obscured, distorted, and +otherwise altered when they have receded into the dim distance, and are +looked back upon through a long space of intervening mental experience. +Finally, class (3) has its visual counterpart in erroneous perceptions +of distance, as when, for example, owing to the clearness of the +mountain atmosphere and the absence of intervening objects, the side of +the Jungfrau looks to the inexperienced tourist at Wengernalp hardly +further than a stone's throw. It will be found that when our memory +falsifies the date of an event, the error arises much in the same way as +a visual miscalculation of distance. + +This threefold division of illusions of memory is plainly a rather +superficial one, and not based on distinctions of psychological nature +or origin. In order to make our treatment of the subject scientific as +well as popular, it will be necessary to introduce the distinction +between the passive and the active factor under each head. It will be +found, I think, without forcing the analogy too far, that here, as in +the case of the illusions of perception and introspection, error is +attributable now to misleading suggestion on the part of the mental +content of the moment, now to a process of incorporating into this +content a mental image not suggested by it, but existing independently. + +If we are to proceed as we did in the case of the illusions of sense, +and take up the lower stages of error first of all, we shall need to +begin with the third class of errors, those of localization in time, or +of what may be called mnemonic perspective. It has been already observed +that the definite localization of a mnemonic image is only an occasional +accompaniment of what is loosely called recollection. Hence, error as +to the position of an event in the past chain of events would seem to +involve the least degree of violation of the confidence which we are +wont to repose in memory. After this, we may proceed to the discussion +of the second class, which I may call distortions of the mnemonic +picture. And, finally, we may deal with the most signal and palpable +variety of error of memory, namely, the illusions which I have called +mnemonic spectra. + + +_Illusions of Perspective: A. Definite Localization._ + +In order to understand these errors of mnemonic perspective, we shall +have to inquire more closely than we have yet done into the +circumstances which customarily determine our idea of the degree of +propinquity or of remoteness of a past event. And first of all, we will +take the case of a complete act of recollection when the mind is able to +travel back along an uninterrupted series of experiences to a definitely +apprehended point. Here there would seem, at first sight, to be no room +for error, since this movement of retrospective imagination may be said +to involve a direct measurement of the distance, just as a sweep of the +eye over the ground between a spectator and an object affords a direct +measurement of the intervening space. + +Modern science, however, tells us that this mode of measurement is by no +means the simple and accurate process which it at first seems to be. In +point of fact, there is something like a constant error in all such +retrospective measurement. Vierordt has proved experimentally, by making +a person try to reproduce the varying time-intervals between the +strokes of the pendulum of a metronome, that when the interval is a very +small one, we uniformly tend to exaggerate it in retrospection; when a +large one, to regard it, on the contrary, as less than it actually +was.[117] + +A mere act of reflection will convince any one that when he tries to +conceive a very small interval, say a quarter of a second, he is likely +to make it too great. On the other hand, when we try to conceive a year, +we do not fully grasp the whole extent of the duration. This is proved +by the fact that merely by spending more time over the attempt, and so +recalling a larger number of the details of the period, we very +considerably enlarge our first estimate of the duration. And this leads +to great discrepancies in the appreciation of the relative magnitudes of +past sections of time. Thus, as Wundt observes, though in retrospect +both a month and a year seem too short, the latter is relatively much +more shortened than the former.[118] + +The cause of this constant error in the mode of reproducing durations +seems to be connected with the very nature of the reproductive act. It +must be borne in mind that this act is itself, like the experience which +it represents, a mental process, occupying time, and that consequently +it may very possibly reflect its time-character on the resulting +judgment. Thus, since it certainly takes more than a quarter of a second +to pass in imagination from one impression to another, it may be that we +tend to confound this duration with that which we try to represent. +Similarly, the fact that in the act of reproductive imagination we +under-estimate a longer interval between two impressions, say those of +the slow beats of a colliery engine, may be accounted for by the +supposition that the imagination tends to pass from the one impression +to the succeeding one too rapidly.[119] + +The gross misappreciation of duration of long periods of time, while it +may illustrate the principle just touched on, clearly involves the +effect of other and more powerful influences. A mere glance at what is +in our mind when we recall such a period as a month or a year, shows +that there is no clear concrete representation at all. Time, it has been +often said, is known only so far as filled with concrete contents or +conscious experiences, and a perfect imagination of any particular +period of past time would involve a retracing of all the successive +experiences which have gone to make up this section of our life. This, I +need not say, never happens, both because, on the one hand, memory does +not allow of a complete reproduction of any segment of our experience, +and because, on the other hand, such an imaginative reproduction, even +if possible, would clearly occupy as much time as the experience +itself.[120] + +When I call up an image of the year just closing, what really happens is +a rapid movement of imagination over a series of prominent events, among +which the succession of seasons probably occupies the foremost place, +serving, as I have remarked, as a framework for my retrospective +picture. Each of the events which I thus run over is really a long +succession of shorter experiences, which, however, I do not separately +represent to myself. My imaginative reproduction of such a period is +thus essentially a greatly abbreviated and symbolic mode of +representation. It by no means corresponds to the visual imagination of +a large magnitude, say that of the length of sea horizon visible at any +one moment, which is complete in an instant, and quite independent of a +successive imagination of its parts or details. It is essentially a very +fragmentary and defective numerical idea, in which, moreover, the real +quantitative value of the units is altogether lost sight of. + +Now, it seems to follow from this that there is something illusory in +all our recallings of long periods of the past. It is by no means +strictly correct to say that memory ever reinstates the past. It is more +true to say that we see the past in retrospect as greatly foreshortened. +Yet even this is hardly an accurate account of what takes place, since, +when we look at an object foreshortened in perspective, we see enough to +enable us imaginatively to reconstruct the actual size of the object, +whereas in the case of time-perspective no such reconstruction is even +indirectly possible. + +It is to be added that this constant error in time-reproduction is +greater in the case of remote periods than of near ones of the same +length. Thus, the retrospective estimate of a duration far removed from +the present, say the length of time passed at a particular school, is +much more superficial and fragmentary than that of a recent +corresponding period. So that the time-vista of the past is seen to +answer pretty closely to a visible perspective in which the amount of +apparent error due to foreshortening increases with the distance. + +In practice, however, this defect in the imagination of duration leads +to no error. Although, as a concrete image answering to some definite +succession of experiences a year is a gross misrepresentation, as a +general concept implying a collection of a certain number of similar +successions of experience it is sufficiently exact. That is to say, +though we cannot imagine the _absolute_ duration of any such cycle of +experience, we can, by the simple device of conceiving certain durations +as multiples of others, perfectly well compare different periods of +times, and so appreciate their _relative_ magnitudes. + +Leaving, then, this constant error in time-appreciation, we will pass to +the variable and more palpable errors in the retrospective measurement +of time. Each person's experience will have told him that in estimating +the distance of a past event by a mere retrospective sense of duration, +he is liable to extraordinary fluctuations of judgment. Sometimes when +the clock strikes we are surprised at the rapidity of the hour. At other +times the timepiece seems rather to have lagged behind its usual pace. +And what is true of a short interval is still more true of longer +intervals, as months and years. The understanding of these fluctuations +will be promoted by our brief glance at the constant errors in +retrospective time-appreciation. + +And here it is necessary to distinguish between the sense of duration +which we have during any period, and the retrospective sense which +survives the period, for these do not necessarily agree. The former +rests mainly on our prospective sense of time, whereas the latter must +be altogether retrospective.[121] + +Our estimate of time as it passes is commonly said to depend on the +amount of consciousness which we are giving to the fact of its +transition. Thus, when the mind is unoccupied and suffering from +_ennui_, we feel time to move sluggishly. On the other hand, interesting +employment, by diverting the thoughts from time, makes it appear to move +at a more rapid pace. This fact is shown in the common expressions which +we employ, such as "to kill time," and the German _Langweile_. +Similarly, it is said that when we are eagerly anticipating an event, as +the arrival of a friend, the mere fact of dwelling on the interval makes +it appear to swell out.[122] + +This view is correct in the main, and is seen, indeed, to follow from +the great psychological principle that what we attend to exists for us +more, has more reality, and so naturally seems greater than what we do +not attend to. At the same time, this principle must be supplemented by +another consideration. Suppose that I am very desirous that time should +not pass quickly. If, for example, I am enjoying myself or indulging in +idleness, and know that I have to be off to keep a not very agreeable +engagement in a quarter of an hour, time will seem to pass too rapidly; +and this not because my thoughts are diverted from the fact of its +transition, for, on the contrary, they are reverting to it more than +they usually do, but because my wish to lengthen the interval leads me +to represent the unwelcome moment as further off than it actually is, in +other words, to construct an ideal representation of the period in +contrast with which the real duration looks miserably short. + +Our estimate of duration, when it is over, depends less on this +circumstance of having attended to its transition than on other +considerations. Wundt, indeed, seems to think that the feeling +accompanying the actual flow of time has no effect on the surviving +subjective appreciation; but this must surely be an error, since our +mental image of any period is determined by the character of its +contents. Wundt says that when once a tedious waiting is over, it looks +short because we instantly forget the feeling of tedium. My +self-observation, as well as the interrogation of others, has satisfied +me, on the contrary, that this feeling distinctly colours the +retrospective appreciation. Thus, when waiting at a railway station for +a belated train, I am distinctly aware that each quarter of an hour +looks long, not only as it passes, but when it is over. In fact, I am +disposed to express my feeling as one of disappointment that only so +short an interval has passed since I last looked at my watch. + +Nevertheless, I am ready to allow that, though a feeling of tedium, or +the contrary feeling of irritation at the rapidity of time, will linger +for an appreciable interval and colour the retrospective estimate of +time, this backward view is chiefly determined by other considerations. +As Wundt remarks, we have no sense of time's slowness during sleep, yet +on waking we imagine that we have been dreaming for an immensely long +period. This retrospective appreciation is determined by the number and +the degree or intensity of the experiences, and, what comes very much to +the same thing, by the amount of unlikeness, freshness, and +discontinuity characterizing these experiences. + +Time, as I have already hinted, is known under the form of a succession +of different conscious experiences. Unbroken uniformity would give us no +sense of time, because it would give us no conscious experience at all. +Strictly speaking, there is no such thing as a perfectly uniform mental +state extending through an appreciable duration. In looking at one and +the same object, even in listening to one and the same tone, I am in no +two successive fractions of a second in exactly the same state of mind. +Slight alterations in the strength of the sensation,[123] in the degree +or direction of attention, and in the composition of that penumbra of +vague images which it calls up, occur at every distinguishable fraction +of time. + +This being so, it would seem to follow that the greater the number of +clearly marked changes, and the more impressive and exciting these +transitions, the fuller will be our sense of time. And this is borne out +by individual reflection. When striking and deeply interesting events +follow one another very rapidly, as when we are travelling, duration +appears to swell out. + +It is possible that such a succession of stirring experiences may beget +a vague consciousness of time at each successive moment, and apart from +retrospection, simply by force of the change. In other words, without +our distinctly attending to time, a series of novel impressions might, +by giving us the consciousness of change, make us dimly aware of the +numerical richness of our experiences. But, however this be, there is no +doubt that, in glancing back on such a succession of exciting +transitions of mental condition, time appears to expand enormously, just +as it does in looking back on our dream-experience, or that rapid series +of intensified feelings which, according to De Quincey and others, is +produced by certain narcotics. + +The reason of this is plain. Such a type of successive experience offers +to the retrospective imagination a large number of distinguishable +points, and since this mode of estimating time depends, as we have seen, +on the extent of the process of filling in, time will necessarily appear +long in this case. On the other hand, when we have been engaged in very +ordinary pursuits, in which few deeply interesting or exciting events +have impressed themselves on memory, our retrospective picture will +necessarily be very much of a blank, and consequently the duration of +the period will seem to be short. + +I observed that this retrospective appreciation of time depended on the +degree of connection between the successive experiences. This condition +is very much the same as the other just given, namely, the degree of +uniformity of the experiences, since the more closely the successive +stages of the experience are connected--as when, for example, we are +going through our daily routine of work--the more quiet and unexciting +will be the transition from each stage to its succeeding one. And on the +other hand, all novelty of impression and exciting transition of +experience clearly involves a want of connection. Wundt thinks the +retrospective estimate of a connected series of experiences, such as +those of our daily round of occupations, is defective just because the +effort of attention, which precedes even an imaginative reproduction of +an impression, so quickly accommodates itself in this case to each of +the successive steps, whereas, when the experiences to be recalled are +disconnected, the effort requires more time. In this way, the estimate +of a past duration would be coloured by the sense of time accompanying +the reproductive process itself. This may very likely be the case, yet I +should be disposed to attach most importance to the number of +distinguishable items of experience recalled. + +Our representation of the position of a given event in the past is, as I +have tried to show, determined by the movement of imagination in going +back to it from the present. And this is the same thing as to say that +it depends on our retrospective sense of the intervening space. That is +to say, the sense of distance in time, as in space, is the recognition +of a term to a movement. And just as the distance of an object will seem +greater when there are many intervening objects affording points of +measurement, than when there are none (as on the uniform surface of the +sea), so the distance of an event will vary with the number of +recognized intervening points. + +The appreciation of the distance of an event in time does not, however, +wholly depend on the character of this movement of imagination. Just as +the apparent distance of a visible object depends _inter alia_ on the +distinctness of the retinal impression, so the apparent temporal +remoteness of a past event depends in part on the degree of intensity +and clearness of the mnemonic image. This is seen even in the case of +those images which we are able distinctly to localize in the +time-perspective. For a series of exciting experiences intervening +between the present and a past event appears not only _directly_ to add +to our sense of distance by constituting an apparently long interval, +but _indirectly_ to add to it by giving an unusual degree of faintness +to the recalled image. An event preceding some unusually stirring series +of experiences gets thrust out of consciousness by the very engrossing +nature of the new experiences, and so tends to grow more faint and +ghost-like than it would otherwise have done. + +The full force of this circumstance is best seen in the fact that a very +recent event, bringing with it a deep mental shock and a rapid stirring +of wide tracts of feeling and thought, may get to look old in a +marvellously short space of time. An announcement of the loss of a dear +friend, when sudden and deeply agitating, will seem remote even after an +hour of such intense emotional experience. And the same twofold +consideration probably explains the well-known fact that a year seems +much shorter to the adult than to the child. The novel and comparatively +exciting impressions of childhood tend to fill out time in retrospect, +and also to throw back remote events into a dimly discernible region. + +Now, this same circumstance, the degree of vividness or of faintness of +the mnemonic image, is that which determines our idea of distance when +the character of the intervening experiences produces no appreciable +effect.[124] This is most strikingly illustrated in those imperfect +kinds of recollection in which we are unable to definitely localize the +mnemonic image. To the consideration of these we will now turn. + + +B. _Indefinite Localization._ + +Speaking roughly and generally, we may say that the vividness of an +image of memory decreases in proportion as the distance of the event +increases. And this is the rule which we unconsciously apply in +determining distance in time. Nevertheless, this rule gives us by no +means an infallible criterion of distance. The very fact that different +people so often dispute about the dates and the order of past events +experienced in common, shows pretty plainly that images of the same age +tend to arise in the mind with very unequal degrees of vividness. + +Sometimes pictures of very remote incidents may suddenly present +themselves to our minds with a singular degree of brightness and force. +And when this is the case, there is a disposition to think of them as +near. If the relations of the event to other events preceding and +succeeding it are not remembered, this momentary illusion will persist. +We have all heard persons exclaim, "It seems only yesterday," under the +sense of nearness which accompanies a recollection of a remote event +when vividly excited. The most familiar instance of such lively +reproduction is the feeling which we experience on revisiting the scene +of some memorable event. At such a time the past may return with +something of the insistence of a present perceived reality. In passing +from place to place, in talking with others, and in reading, we are +liable to the sudden return by hidden paths of association of images of +incidents that had long seemed forgotten, and when they thus start up +fresh and vigorous, away from their proper surroundings, they invariably +induce a feeling of the propinquity of the events. + +In many cases we cannot say why these particular images, long buried in +oblivion, should thus suddenly regain so much vitality. There seems, +indeed, to be almost as much that is arbitrary and capricious in the +selection by memory of its vivid images as in the selection of its +images as a whole; and, this being so, it is plain that we are greatly +exposed to the risk of illusion from this source. + +There is an opposite effect in the case of recent occurrences that, for +some reason or another, have left but a faint impression on the memory; +though this fact is not, perhaps, so familiar as the other. I met a +friend, we will suppose, a few days since at my club, and we exchanged a +few words. My mind was somewhat preoccupied at the time, and the +occurrence did not stamp itself on my recollection. To-day I meet him +again, and he reminds me of a promise I made him at the time. His +reminder suffices to restore a dim image of the incident, but the fact +of its dimness leads to the illusion that it really happened much longer +ago, and it is only on my friend's strong assurances, and on reasoning +from other data that it must have occurred the day he mentions, that I +am able to dismiss the illusion. + +The most striking examples of the illusory effect of mere vividness, +involving a complete detachment of the event from the prominent +landmarks of the past, are afforded by public events which lie outside +the narrower circle of our personal life, and which do not in the +natural course of things become linked to any definitely localized +points in the field of memory. These events may be very stirring and +engrossing for the time, but in many cases they pass out of the mind +just as suddenly as they entered it. We have no occasion to revert to +them, and if by chance we are afterwards reminded of them, they are +pretty certain to look too near, just because the fact of their having +greatly interested us has served to render their images particularly +vivid. + +A curious instance of this illusory effect was supplied not long since +by the case of the ex-detectives, the expiration of whose term of +punishment (three years) served as an occasion for the newspapers to +recall the event of their trial and conviction. The news that three +years had elapsed since this well-remembered occurrence proved very +startling to myself, and to a number of my friends, all of us agreeing +that the event did not seem to be at more than a third of its real +distance. More than one newspaper commented on the apparent rapidity of +the time, and this shows pretty plainly that there was some cause at +work, such as I have suggested, producing a common illusion. + +I have treated of these illusions connected with the estimate of past +time and the dating of past events as passive illusions, not involving +any active predisposition on the part of the imagination. At the same +time, it is possible that error in these matters may occasionally depend +on a present condition of the feelings and the imagination. It seems +plain that since the apparent degree of remoteness of an event not +distinctly localized in the past varies inversely as the degree of +vividness of the mnemonic image, any conscious concentration of mind on +a recollection will tend to bring it too near. In this way, then, an +illusory propinquity may be given to a recalled event through a mere +desire to dwell on it, or even a capricious wish to deceive one's self. + +When, for example, old friends come together and talk over the days of +yore, there is a gradual reinstatement of seemingly lost experiences, +which often partakes of the character of a semi-voluntary process of +self-delusion. Through the cumulative effect of mutual reminder, +incident after incident returns, adding something to the whole picture +till it acquires a degree of completeness, coherence, and vividness that +render it hardly distinguishable from a very recent experience. The +process is like looking at a distant object through a field-glass. +Mistiness disappears, fresh details come into view, till we seem to +ourselves to be almost within reach of the object. + +Where the mind habitually goes back to some painful circumstance under +the impulse of a morbid disposition to nurse regret, this momentary +illusion may become recurring, and amount to a partial confusion of the +near and the remote in our experience. An injury long brooded on seems +at length a thing that continually moves forward as we move; it always +presents itself to our memories as a very recent event. In states of +insanity brought on by some great shock, we see this morbid tendency to +resuscitate the dead past fully developed, and remote events and +circumstances becoming confused with present ones. + +On the other hand, in more healthy states of mind there presents itself +an exactly opposite tendency, namely, an impulse of the will to banish +whatever when recalled gives pain to the furthest conceivable regions of +the past. Thus, when we have lost something we cherished dearly, and the +recollection of it brings fruitless longing, we instinctively seek to +expel the recollection from our minds. The very feeling that what has +been can never again be, seems to induce this idea of a vast remoteness +of the vanished reality. When, moreover, the lost object was fitted to +call forth the emotion of reverence, the impulse to magnify the +remoteness of the loss may not improbably be reinforced by the +circumstance that everything belonging to the distant past is fitted on +that account to excite a feeling akin to reverence. So, again, any +rupture in our mental development may lead us to exaggerate the distance +of some past portion of our experience. When we have broken with our +former selves, either in the way of worsening or bettering, we tend to +project these further into the past. + +It is only when the sting of the recollection is removed, when, for +example, the calling up of the image of a lost friend is no longer +accompanied with the bitterness of futile longing, that a healthy mind +ventures to nourish recollections of such remote events and to view +these as part of its recent experiences. In this case the mnemonic image +becomes transformed into a kind of present emotional possession, an +element of that idealized and sublimated portion of our experience with +which all imaginative persons fill up the emptiness of their actual +lives, and to which the poet is wont to give an objective embodiment in +his verse. + + +_Distortions of Memory._ + +It is now time to pass to the second group of illusions of memory, +which, according to the analogy of visual errors, may be called +atmospheric illusions. Here the degree of error is greater than in the +case of illusions of time-perspective, since the very nature of the +events or circumstances is misconceived. We do not recall the event as +it happened, but see it in part only, and obscured, or bent and +distorted as by a process of refraction. Indeed, this transformation of +the past does closely correspond with the transformation of a visible +object effected by intervening media. Our minds are such refracting +media, and the past reappears to us not as it actually was when it was +close to us, but in numerous ways altered and disguised by the +intervening spaces of our conscious experience. + +To begin with, what we call recollection is uniformly a process of +softening the reality. When we appear to ourselves to realize events of +the remote past, it is plain that our representation in a general way +falls below the reality: the vividness, the intensity of our impressions +disappears. More particularly, so far as our experiences are emotional, +they tend thus to become toned down by the mere lapse of time and the +imperfections of our reproductive power. That which we seem to see in +the act of recollection is thus very different from the reality. + +Not only is there this general deficiency in mnemonic representation, +there are special deficiencies due to the fact of oblivescence. Our +memories restore us only fragments of our past life. And just as objects +seen imperfectly at a great distance may assume a shape quite unlike +their real one, so an inadequate representation of a past event by +memory often amounts to misrepresentation. When revisiting a place that +we have not seen for many years, we are apt to find that our +recollection of it consisted only of some insignificant details, which +arranged themselves in our minds into something oddly unlike the actual +scene. So, too, some accidental accompaniment of an incident in early +life is preserved, as though it were the main feature, serving to give +quite a false colouring to the whole occurrence. + +It seems quite impossible to account for these particular survivals, +they appear to be so capricious. When a little time has elapsed after an +event, and the attendant circumstances fade away from memory, it is +often difficult to say why we were impressed with it as we afterwards +prove to have been. It is no doubt possible to see that many of the +recollections of our childhood owe their vividness to the fact of the +exceptional character of the events; but this cannot always be +recognized. Some of them seem to our mature minds very oddly selected, +although no doubt there are in every case good reasons, if we could only +discover them, why those particular incidents rather than any others +should have been retained. + +The liability to error resulting from mere oblivescence and the +arbitrary selection of mental images is seen most plainly, perhaps, in +our subsequent representation and estimate of whole periods of early +life. Our idea of any stage of our past history, as early childhood, or +school days, is built up out of a few fragmentary intellectual relics +which cannot be certainly known to answer to the most important and +predominant experiences of the time. When, for example, we try to decide +whether our school days were our happiest days, as is so often alleged, +it is obvious that we are liable to fall into illusion through the +inadequacy of memory to preserve characteristic or typical features, and +none but these. We cannot easily recall the ordinary every-day level of +feeling of a distant period of life, but rather think of exceptional +moments of rejoicing or depression. The ordinary man's idea of the +emotional experience of his school days is probably built up out of a +few scrappy recollections of extraordinary and exciting events, such as +unexpected holidays, success in the winning of prizes, famous "rows" +with the masters, and so on. + +Besides the impossibility of getting at the average and prevailing +mental tone of a distant section of life, there is a special difficulty +in determining the degree of happiness of the past, arising from the +fact that our memory for pleasures and for pains may not be equally +good. Most people, perhaps, can recall the enjoyments of the past much +more vividly than the sufferings. On the other hand, there seem to be +some who find the retention of the latter the easier of the two. This +fact should not be forgotten in reading the narrative of early hardships +which some recent autobiographies have given us. + +Not only does our idea of the past become inexact by the mere decay and +disappearance of essential features, it becomes positively incorrect +through the gradual incorporation of elements that do not properly +belong to it. Sometimes it is easy to see how these extraneous ideas get +imported into our mental representation of a past event. Suppose, for +example, that a man has lost a valuable scarf-pin. His wife suggests +that a particular servant, whose reputation does not stand too high, has +stolen it. When he afterwards recalls the loss, the chances are that he +will confuse the fact with the conjecture attached to it, and say he +remembers that this particular servant did steal the pin. Thus, the past +activity of imagination serves to corrupt and partially falsify +recollections that have a genuine basis of fact. + +It is evident that this class of mnemonic illusions approximates in +character to illusions of perception. When the imagination supplies the +interpretation at the very time, and the mind reads this into the +perceived object, the error is one of perception. When the addition is +made afterwards, on reflecting upon the perception, the error is one of +memory. The "fallacies of testimony" which depend on an adulteration of +pure observation with inference and conjecture, as, for example, the +inaccurate and wild statements of people respecting their experiences at +spiritualist _séances_, while they illustrate the curious blending of +both kinds of error, are probably much oftener illusions of memory than +of perception.[125] + +Although in many cases we can account to ourselves for this confusion of +fact and imagination, in other cases it is difficult to see any close +relation between the fact remembered and the foreign element imported +into it. An idea of memory seems sometimes to lose its proper moorings, +so to speak; to drift about helplessly among other ideas, and finally, +by some chance, to hook itself on to one of these, as though it +naturally belonged to it. Anybody who has had an opportunity of +carefully testing the truthfulness of his recollection of some remote +event in early life will have found how oddly extraneous elements become +incorporated into the memorial picture. Incidents get put into wrong +places, the wrong persons are introduced into a scene, and so on. Here +again we may illustrate the mnemonic illusion by a visual one. When a +tree standing before or behind a house and projecting above or to the +side of it is not sharply distinguished from the latter, it may serve to +give it a very odd appearance. + +These confusions of the mental image may arise even when only a short +interval has elapsed. In the case of many of the fleeting impressions +that are only half recollected, this kind of error is very easy. Thus, +for example, I may have lent a book to a friend last week. I really +remember the act of lending it, but have forgotten the person. But I am +not aware of this. The picture of memory has unknowingly to myself been +filled up by this unconscious process of shifting and rearrangement, and +the idea of another person has by some odd accident got substituted for +that of the real borrower. If we could go deeply enough into the matter, +we should, of course, be able to explain why this particular confusion +arose. We might find, for example, that the two persons were associated +in my mind by a link of resemblance, or that I had dealings with the +other person about the same time. Similarly, when we manage to join an +event to a wrong place, we may find that it is because we heard of the +occurrence when staying at the particular locality, or in some other way +had the image of the place closely associated in our minds with the +event. But often we are wholly unable to explain the displacement. + +So far I have been speaking of the passive processes by which the past +comes to wear a new face to our imaginations. In these our present +habits of feeling and thinking take no part; all is the work of the +past, of the decay of memory, and the gradual confusion of images. This +process of disorganization may be likened to the action of damp on some +old manuscript, obliterating some parts, altering the appearance of +others, and even dislocating certain portions. Besides this passive +process of transformation, there is a more active one in which our +present minds co-operate. In memory, as in perception and introspection, +there is a process of preparation or preadjustment of mind, and here +will be found room for what I had called active error. This may be +illustrated by the operation of "interpreting" an old manuscript which +has got partially obliterated, or of "restoring" a faded picture; in +each of which operations error will be pretty sure to creep in through +an importation of the restorer's own ideas into the relic of the past. + +Just as when distant objects are seen mistily our imaginations come into +play, leading us to fancy that we see something completely and +distinctly, so when the images of memory become dim, our present +imagination helps to restore them, putting a new patch into the old +garment. If only there is some relic of the past event preserved, a bare +suggestion of the way in which it may have happened will often suffice +to produce the conviction that it actually did happen in this way. The +suggestions that naturally arise in our minds at such times will bear +the stamp of our present modes of experience and habits of thought. +Hence, in trying to reconstruct the remote past, we are constantly in +danger of importing our present selves into our past selves. + +The kind of illusion of memory which thus depends on the spontaneous or +independent activity of present imagination is strikingly illustrated in +the curious cases of mistaken identity with which the proceedings of +our law courts supply us from time to time. When a witness in good +faith, but erroneously, affirms that a man is the same as an old +acquaintance of his, we may feel sure that there is some striking point +or points of similarity between the two persons. But this of itself +would only partly account for the illusion, since we often see new faces +that, by a number of curious points of affinity, call up in a +tantalizing way old and familiar ones. What helps in this case to +produce the illusion is the preconception that the present man is the +witness's old friend. That is to say, his recollection is partly true, +though largely false. He does really recall the similar feature, +movement, or tone of voice; he only seems to himself to recall the rest +of his friend's appearance; for, to speak correctly, he projects the +present impression into the past, and constructs his friend's face out +of elements supplied by the new one. Owing to this cause, an illusion of +memory is apt to multiply itself, one man's assertion of what happened +producing by contagion a counterfeit of memory's record in other minds. + +I said just now that we tend to project our present modes of experience +into the past. We paint our past in the hues of the present. Thus we +imagine that things which impressed us in some remote period of life +must answer to what is impressive in our present stage of mental +development. For example, a person recalls a hill near the home of his +childhood, and has the conviction that it was of great height. On +revisiting the place he finds that the eminence is quite insignificant. +How can we account for this? For one thing, it is to be observed that to +his undeveloped childish muscles the climbing to the top meant a +considerable expenditure of energy, to be followed by a sense of +fatigue. The man remembers these feelings, and "unconsciously reasoning" +by present experience, that is to say, by the amount of walking which +would now produce this sense of fatigue, imagines that the height was +vastly greater than it really was. Another reason is, of course, that a +wider knowledge of mountains has resulted in a great alteration of the +man's standard of height. + +From this cause arises a tendency generally to exaggerate the +impressions of early life. Youth is the period of novel effects, when +all the world is fresh, and new and striking impressions crowd in +thickly on the mind. Consequently, it takes much less to produce a given +amount of mental excitation in childhood than in after-life. In looking +back on this part of our history, we recall for the most part just those +events and scenes which deeply stirred our minds by their strangeness, +novelty, etc., and so impressed themselves on the tablet of our memory; +and it is this sense of something out of the ordinary beat that gives +the characteristic colour to our recollection. In other words, we +remember something as wonderful, admirable, exceptionally delightful, +and so on, rather than as a definitely imagined event. This being so, we +unconsciously transform the past occurrence by reasoning from our +present standard of what is impressive. Who has not felt an unpleasant +disenchantment on revisiting some church, house, or park that seemed a +wondrous paradise to his young eyes? All our feelings are capable of +leading us into this kind of illusion. What seemed beautiful or awful +to us as children, is now pictured in imagination as corresponding to +what moves our mature minds to delight or awe. One cannot help wondering +what we should think of our early heroes or heroines if we could see +them again with our adult eyes exactly as they were. + +While the past may thus take on an illusory hue through the very +progress of our experience and our emotional life, it may become further +transformed by a more conscious process, namely, the idealizing touch of +a present feeling. The way in which the emotions of love, reverence, and +so on, thus transform their lost objects is too well known to need +illustration. Speaking generally, we may say that in healthy minds the +play of these impulses of feeling results in a softening of the harsher +features of the past, and in an idealization of its happier and brighter +aspects. As Wordsworth says, we may assign to Memory a pencil-- + + "That, softening objects, sometimes even + Outstrips the heart's demand; + + "That smoothes foregone distress, the lines + Of lingering care subdues, + Long-vanished happiness refines, + And clothes in brighter hues."[126] + +Enough has now been said, perhaps, to show in how many ways our +retrospective imagination transforms the actual events of our past life. +So thoroughly, indeed, do the relics of this past get shaken together in +new kaleidoscopic combinations, so much of the result of later +experiences gets imported into our early years, that it may well be +asked whether, if the record of our actual life were ever read out to +us, we should be able to recognize it. It looks as though we could be +sure of recalling only recent events with any degree of accuracy and +completeness. As soon as they recede at any considerable distance from +us, they are subject to a sort of atmospheric effect. Much grows +indistinct and drops altogether out of sight, and what is still seen +often takes a new and grotesquely unlike shape. More than this, the play +of fancy, like the action of some refracting medium, bends and distorts +the outlines of memory's objects, making them wholly unlike the +originals. + + +_Hallucinations of Memory._ + +We will now go on to the third class of mnemonic error, which I have +called the spectra of memory, where there is not simply a transformation +of the past event, but a complete imaginative creation of it. This class +of error corresponds, as I have observed, to an hallucination in the +region of sense-perception. And just as we distinguished between those +hallucinations of sense which arise first of all through some +peripherally caused subjective sensation, and those which want even this +element of reality and depend altogether on the activity of imagination, +so we may mark off two classes of mnemonic hallucination. The false +recollection may correspond to something past--and to this extent be a +recollection--though not to any objective fact, but only to a subjective +representation of such a fact, as, for example, a dream. In this case +the imitation of the mnemonic process may be very definite and complete. +Or the false recollection may be wholly a retrojection of a present +mental image, and so by no stretch of language be deserving of the name +recollection. + +It is doubtful whether by any effort of will a person could bring +himself to regard a figment of his present imagination as representative +of a past reality. Definite and complete hallucinations of this sort do +not in normal circumstances arise. It seems necessary for a complete +illusion of memory that there should be something past and recovered at +the moment, though this may not be a real personal experience.[127] On +the other hand, it is possible, as we shall presently see, under certain +circumstances, to create out of present materials, and in a vague and +indefinite shape, pure phantoms of past experience, that is to say, +quasi-mnemonic images to which there correspond no past occurrences +whatever. + +All recollection, as we have seen, takes place by means of a present +mental image which returns with a certain degree of vividness, and is +instantaneously identified with some past event. In many cases this +instinctive process of identification proves to be legitimate, for, as a +matter of fact, real impressions are the first and the commonest source +of such lively mnemonic images. But it is not always so. There are other +sources of our mental imagery which compete, so to speak, with the +region of real personal experience. And sometimes these leave behind +them a vivid image having all the appearance of a genuine mnemonic +image. When this is so, it is impossible by a mere introspective glance +to detect the falsity of the message from the past. We are in the same +position as the purchaser in a jet market, where a spurious commodity +has got inextricably mixed up with the genuine, and there is no ready +criterion by which he can distinguish the true from the false. Such a +person, if he purchases freely, is pretty sure to make a number of +mistakes. Similarly, all of us are liable to take counterfeit mnemonic +images for genuine ones; that is to say, to fall into an illusion of +"recollecting" what never really took place. + +But what, it may be asked, are these false and illegitimate sources of +mnemonic images, these unauthorized mints which issue a spurious mental +coinage, and so confuse the genuine currency? They consist of two +regions of our internal mental life, which most closely resemble the +actual perception of real things in vividness and force, namely, +dream-consciousness and waking imagination. Each of these may introduce +into the mind vivid images which afterwards tend, under certain +circumstances, to assume the guise of recollections of actual events. + +That our dream-experience may now and again lead us into illusory +recollection has already been hinted. And it is easy to understand why +this is so. When dreaming we have, as we have seen, a mental experience +which closely approximates in intensity and reality to that of waking +perception. Consequently, dreams may leave behind them, for a time, +vivid images which simulate the appearance of real images of memory. +Most of us, perhaps, have felt this after-effect of dreaming on our +waking thoughts. It is sometimes very hard to shake off the impression +left by a vivid dream, as, for example, that a dead friend has returned +to life. During the day that follows the dream, we have at intermittent +moments something like an assurance that we have seen our lost friend; +and though we immediately correct the impression by reflecting that we +are recalling but a dream, it tends to revive within us with a strange +pertinacity. + +In addition to this proximate effect of a dream in disturbing the normal +process of recollection, there is reason to suppose that dreams may +exert a more remote effect on our memories. So widely different in its +form is our dreaming from our waking experience, that our dreams are +rarely recalled as wholes with perfect distinctness. They revive in us +only as disjointed fragments, and only for brief moments when some +accidental resemblance in the present happens to stir the latent trace +they have left on our minds. We get sudden flashes out of our +dream-world, and the process is too rapid, too incomplete for us to +identify the region whence the flashes come. + +It is highly probable that our dreams are, to a large extent, answerable +for the sense of familiarity that we sometimes experience in visiting a +new locality or in seeing a new face. If, as we have found some of the +best authorities saying, we are, when asleep, always dreaming more or +less distinctly, and if, as we know, dreaming is a continual process of +transformation of our waking impressions in new combinations, it is not +surprising that our dreams should sometimes take the form of forecasts +of our waking life, and that consequently objects and scenes of this +life never before seen should now and again wear a familiar look. + +That some instances of this puzzling sense of familiarity can be +explained in this way is proved. Thus, Paul Radestock, in the work +_Schlaf und Traum_, already quoted, tells us: "When I have been taking a +walk, with my thoughts quite unfettered, the idea has often occurred to +me that I had seen, heard, or thought of this or that thing once before, +without being able to recall when, where, and in what circumstances. +This happened at the time when, with a view to the publication of the +present work, I was in the habit of keeping an exact record of my +dreams. Consequently, I was able to turn to this after these +impressions, and on doing so I generally found the conjecture confirmed +that I had previously dreamt something like it." Scientific inquiry is +often said to destroy all beautiful thoughts about nature and life; but +while it destroys it creates. Is it not almost a romantic idea that just +as our waking life images itself in our dreams, so our dream-life may +send back some of its shadowy phantoms into our prosaic every-day world, +touching this with something of its own weird beauty? + +Not only may dreams beget these momentary illusions of memory, they may +give rise to something like permanent illusions. If a dream serves to +connect a certain idea with a place or person, and subsequent experience +does not tend to correct this, we may keep the belief that we have +actually witnessed the event. And we may naturally expect that this +result will occur most frequently in the case of those who habitually +dream vividly, as young children. + +It seems to me that many of the quaint fancies which children get into +their heads about things they hear of arise in this way. I know a person +who, when a child, got the notion that when his baby-brother was weaned, +he was taken up on a grassy hill and tossed about. He had a vivid idea +of having seen this curious ceremony. He has in vain tried to get an +explanation of this picturesque rendering of an incident of babyhood +from his friends, and has come to the conclusion that it was the result +of a dream. If, as seems probable, children's dreams thus give rise to +subsequent illusions of memory, the fact would throw a curious light on +some of the startling quasi-records of childish experience to be met +with in autobiographical literature. + +Odd though it may at first appear, old age is said to resemble youth in +this confusion of dream-recollection with the memory of waking +experience. Dr. Carpenter[128] tells us of "a lady of advanced age +who ... continually dreams about passing events, and seems entirely unable +to distinguish between her dreaming and her waking experiences, +narrating the former with implicit belief in them, and giving directions +based on them." This confusion in the case of the old may possibly +arise not from an increase in the intensity of the dreams, but from a +decrease in the intensity of the waking impressions. As Sir Henry +Holland remarks,[129] in old age life approaches to the state of a +dream. + +The other source of what may, by analogy with the hallucinations of +sense, be called the peripherally originating spectra of memory is +waking imagination. In certain morbid conditions of mind, and in the +case of the few healthy minds endowed with special imaginative force, +the products of this mental activity, may, as we saw when dealing with +illusions of perception, closely resemble dreams in their vividness and +apparent actuality. When this is the case, illusions of memory may arise +at once just as in the case of dreams. This will happen more easily when +the imagination has for some time been occupied with the same group of +ideal scenes, persons, or events. To Dickens, as is well known, his +fictitious characters were for the time realities, and after he had +finished his story their forms and their doings lingered with him, +assuming the aspect of personal recollections. So, too, the energetic +activity of imagination which accompanies a deep and absorbing sympathy +with another's painful experiences, may easily result in so vivid a +realization of all their details as to leave an after-sense of +_personal_ suffering. All highly sympathetic persons who have closely +accompanied beloved friends through a great sorrow have known something +of this subsequent feeling. + +The close connection and continuity between normal and abnormal states +of mind is illustrated in the fact that in insanity the illusion of +taking past imaginations for past realities becomes far more powerful +and persistent. Abercrombie (_Intellectual Powers_, Part III. sec. iv. § +2, "Insanity") speaks of "visions of the imagination which have formerly +been indulged in of that kind which we call waking dreams or +castle-building recurring to the mind in this condition, and now +believed to have a real existence." Thus, for example, one patient +believed in the reality of the good luck previously predicted by a +fortune-teller. Other writers on mental disease observe that it is a +common thing for the monomaniac to cherish the delusion that he has +actually gained the object of some previous ambition, or is undergoing +some previously dreaded calamity. + +Nor is it necessary to these illusions of memory that there should be +any exceptional force of imagination. A fairly vivid representation to +ourselves of anything, whether real or fictitious, communicated by +others, will often result in something very like a personal +recollection. In the case of works of history and fiction, which adopt +the narrative tense, this tendency to a subsequent illusion of memory is +strengthened by the disposition of the mind at the moment of reading to +project itself backwards as in an act of recollection. This is a point +which will be further dealt with in the next chapter. + +In most cases, however, illusions of memory growing out of previous +activities of the imagination appear only after the lapse of some time, +when in the natural course of things the mental images derived from +actual experience would sink to a certain degree of faintness. Habitual +novel-readers often catch themselves mistaking the echo of some passage +in a good story for the trace left by an actual event. A person's name, +a striking saying, and even an event itself, when we first come across +it or experience it, may for a moment seem familiar to us, and to recall +some past like impression, if it only happens to resemble something in +the works of a favourite novelist. And so, too, any recital of another's +experience, whether oral or literary, if it deeply interests us and +awakens a specially vivid imagination of the events described, may +easily become the starting-point of an illusory recollection. + +Children are in the habit of "drinking in" with their vigorous and eager +imaginations what is told them and read to them, and hence they are +specially likely to fall into this kind of error. Not only so: when they +grow up and their early recollections lose their definiteness, becoming +a few fragments saved from a lost past, it must pretty certainly happen +that if any ideas derived from these recitals are preserved, they will +simulate the form of memories. Thus, I have often caught myself for a +moment under the sway of the illusion that I actually visited the +Exhibition of 1851, the reason being that I am able to recall the +descriptions given to me of it by my friends, and the excitement +attending their journey to London on the occasion. It is to be added +that repetition of the act of imagination will tend still further to +deepen the subsequent feeling that we are recollecting something. As +Hartley well observes, a man, by repeating a story, easily comes to +suppose that he remembers it.[130] + +Here, then, we have another source of error that we must take into +account in judging of the authenticity of an autobiographical narration +of the events of childhood. The more imaginative the writer, the greater +the risk of illusion from this source as well as from that of +dream-fancies. It is highly probable, indeed, that in such full and +explicit records of very early life as those given by Rousseau, by +Goethe, or by De Quincey, some part of the quasi-narrative is based on +mental images which come floating down the stream of time, not from the +substantial world of the writer's personal experience, but from the airy +region of dream-land or of waking fancy. + +It is to be added that even when the quasi-recollection does answer to a +real event of childish history, it may still be an illusion. The fact +that others, in narrating events to us, are able to awaken imaginations +that afterwards appear as past realities, suggests that much of our +supposed early recollection owes its existence to what our parents and +friends have from time to time told us respecting the first stages of +our history.[131] We see, then, how much uncertainty attaches to all +autobiographical description of very early life. + +Modern science suggests another possible source of these distinct +spectra of memory. May it not happen that, by the law of hereditary +transmission, which is now being applied to mental as well as bodily +phenomena, ancestral experiences will now and then reflect themselves +in our mental life, and so give rise to apparently personal +recollections? No one can say that this is not so. When the infant first +steadies his eyes on a human face, it may, for aught we know, experience +a feeling akin to that described above, when through a survival of +dream-fancy we take some new scene to be already familiar. At the age +when new emotions rapidly develop themselves, when our hearts are full +of wild romantic aspirations, do there not seem to blend with the eager +passion of the time deep resonances of a vast and mysterious past, and +may not this feeling be a sort of reminiscence of prenatal, that is, +ancestral experience? + +This idea is certainly a fascinating one, worthy to be a new scientific +support for the beautiful thought of Plato and of Wordsworth. But in our +present state of knowledge, any reasoning on this supposition would +probably appear too fanciful. Some day we may find out how much +ancestral experience is capable of bequeathing in this way, whether +simply shadowy, undefinable mental tendencies, or something like +definite concrete ideas. If, for example, it were found that a child +that was descended from a line of seafaring ancestors, and that had +never itself seen or heard of the "dark-gleaming sea," manifested a +feeling of recognition when first beholding it, we might be pretty sure +that such a thing as recollection of prenatal events does take place. +But till we have such facts, it seems better to refer the "shadowy +recollections" to sources which fall within the individual's own +experience. + +We may now pass to those hallucinations of memory which are analogous to +the _centrally_ excited hallucinations of sense-perception. As I have +observed, these are necessarily vague and imperfectly developed. + +I have already had occasion to touch on the fact of the vast amount of +our forgotten experience. And I observed that forgetfulness was a common +negative condition of mnemonic illusion. I have now to complete this +statement by the observation that total forgetfulness of any period or +stage of our past experience necessarily tends to a vague kind of +hallucination. In looking back on the past, we see no absolute gaps in +the continuity of our conscious life; our image of this past is +essentially one of an unbroken series of conscious experiences. But if +through forgetfulness a part of the series is effaced from memory, how, +it may be asked, is it possible to construct this perfectly continuous +line? The answer is that we fill up such lacunæ vaguely by help of some +very imperfectly imagined common type of conscious experience. Just as +the eye sees no gap in its field of vision corresponding to the "blind +spot" of the retina, but carries its impression over this area, so +memory sees no lacuna in the past, but carries its image of conscious +life over each of the forgotten spaces. + +Sometimes this process of filling in gaps in the past becomes more +complete. Thus, for example, in recalling a particular night a week or +so ago, I instinctively represent it to myself as so many hours of lying +in bed with the waking sensations appropriate to the circumstances, as +those of bodily warmth and rest, and of the surrounding silence and +darkness. + +It is apparent that I cannot conceive myself apart from some mode of +conscious experience. In thinking of myself in any part of the past or +future in which there is actually no consciousness, or of which the +conscious content is quite unknown to me, I necessarily imagine myself +as consciously experiencing something. If I picture myself under any +definitely conceived circumstances, I irresistibly import into my mental +image the feelings appropriate to these surroundings. In this way, +people tend to imagine themselves after death as lying in the grave, +feeling its darkness and its chilliness. If the circumstances of the +time are not distinctly represented, the conception of the conscious +experience which constitutes that piece of the ego is necessarily vague, +and seems generally to resolve itself into a representation of ourselves +as dimly _self-conscious_. What this consciousness of self consists of +is a point that will be taken up presently. + + +_Illusions with respect to Personal Identity._ + +It would seem to follow from these errors in imaginatively filling up +our past life, that our consciousness of personal identity is by no +means the simple and exact process which it is commonly supposed to be. +I have already remarked that the very fact of there being so large a +region of the irrevocable in our past experience proves our +consciousness of personal continuity to be largely a matter of +inference, or of imaginative conjecture, and not simply of immediate +recollection. Indeed, it may be said that our power of ignoring whole +regions of the past and of leaping complacently over huge gaps in our +memory and linking on conscious experience with conscious experience, +involves an illusory sense of continuity, and so far of personal +identity. Thus, our ordinary image of our past life, if only by omitting +the very large fraction passed in sleep, in at least an approximately +unconscious state, clearly contains an ingredient of illusion.[132] + +It is to be added that the numerous falsifications of our past history, +which our retrospective imagination is capable of perpetrating, make our +representation of ourselves at different moments and in different stages +of our past history to a considerable extent illusory. Thus, though to +mistake a past dream-experience for a waking one may not be to lose or +confuse the sense of identity, since our dreams are, after all, a part +of our experience, yet to imagine that we have ourselves seen what we +have only heard from another or read is clearly to confuse the +boundaries of our identity. And with respect to longer sections of our +history, it is plain that when we wrongly assimilate our remote to our +present self, and clothe our childish nature with the feelings and the +ideas of our adult life, we identify ourselves overmuch. In this way, +through the corruption of our memory, a kind of sham self gets mixed up +with the real self, so that we cannot, strictly speaking, be sure that +when we project a mnemonic image into the remote past we are not really +running away from our true personality. + +So far I have been touching only on slight errors in the recognition of +that identical self which is represented as persisting through all the +fluctuations of conscious life. Other and grosser illusions connected +with personal identity are also found to be closely related to defects +or disturbances of the ordinary mnemonic process, and so can be best +treated here. In order to understand these, we must inquire a little +into the nature of our idea and consciousness of a persistent self. +Here, again, I would remind the reader that I am treating the point only +so far as it can be treated scientifically or empirically, that is to +say, by examining what concrete facts or data of experience are taken up +into the idea of self. I do not wish to foreclose the philosophic +question whether anything more than this empirical content is involved +in the conception. + +My idea of myself as persisting appears to be built up of certain +similarities in the succession of my experiences. Thus, my permanent +self consists, on the bodily side, of a continually renewable perception +of my own organism, which perception is mainly visual and tactual, and +which remains pretty constant within certain limits of time. With this +objective similarity is closely conjoined a subjective similarity. Thus, +the same sensibilities continue to characterize the various parts of my +organism. Similarly, there are the higher intellectual, emotional, and +moral peculiarities and dispositions. My idea of my persistent self is +essentially a collective image representing a relatively unchanging +material object, endowed with unchanging sensibilities and forming a +kind of support for permanent higher mental attributes. + +The construction of this idea of an enduring unchanging ego is rendered +very much easier by the fact that certain concrete feelings are +approximately constant elements in our mental life. Among these must be +ranked first that dimly discriminated mass of organic sensation which in +average states of health is fairly constant, and which stands in sharp +contrast to the fluctuating external sensations. These feelings enter +into and profoundly colour each person's mental image of himself. In +addition to this, there are the frequently recurring higher feelings, +the dominant passions and ideas which approximate more or less closely +to constant factors of our conscious experience. + +This total image of the ego becomes defined and rendered precise by a +number of distinctions, as that between my own body or that particular +material object with which are intimately united all my feelings, and +other material objects in general; then between my organism and other +human organisms, with which I learn to connect certain feelings +answering to my own, but only faintly represented instead of actually +realized feelings. To these prime distinctions are added others, hardly +less fundamental, as those between my individual bodily appearance and +that of other living bodies, between my personal and characteristic +modes of feeling and thinking and those of others, and so on. + +Our sense of personal identity may be said to be rooted in that special +side of the mnemonic process which consists in the linking of all +sequent events together by means of a thread of common consciousness. It +is closely connected with that smooth, gliding movement of imagination +which appears to involve some more or less distinct consciousness of the +uniting thread of similarity. And so long as this movement is possible, +so long, that is to say, as retrospective imagination detects the common +element, which we may specifically call the recurring consciousness of +self, so long is there the undisturbed assurance of personal identity. +Nay, more, even when such a recognition might seem to be difficult, if +not impossible, as in linking together the very unlike selves, viewed +both on their objective and subjective sides, of childhood, youth, and +mature life, the mind manages, as we have seen, to feign to itself a +sufficient amount of such similarity. + +But this process of linking stage to stage, of discerning the common or +the recurring amid the changing and the evanescent, has its limits. +Every great and sudden change in our experience tends, momentarily at +least, to hinder the smooth reflux of imagination. It makes too sharp a +break in our conscious life, so that imagination is incapable of +spanning the gap and realizing the then and the now as parts of a +connected continuous tissue.[133] + +These changes may be either objective or subjective. Any sudden +alteration of our bodily appearance sensibly impedes the movement of +imagination. A patient after a fever, when he first looks in the glass, +exclaims, "I don't know myself." More commonly the bodily changes which +affect the consciousness of an enduring self are such as involve +considerable alterations of coenæsthesis, or the mass of stable +organic sensation. Thus, the loss of a limb, by cutting off a portion of +the old sensations through which the organism may be said to be +immediately felt, and by introducing new and unfamiliar feelings, will +distinctly give a shock to our consciousness of self. + +Purely subjective changes, too, or, to speak correctly, such as are +known subjectively only, will suffice to disturb the sense of personal +unity. Any great moral shock, involving something like a revolution in +our recurring emotional experience, seems at the moment to rupture the +bond of identity. And even some time after, as I have already remarked, +such cataclysms in our mental geology lead to the imaginative thrusting +of the old personality away from the new one under the form of a "dead +self."[134] + +We see, then, that the failure of our ordinary assurance of personal +identity is due to the recognition of difference without similarity. It +arises from an act of memory--for the mind must still be able to recall +the past, dimly at least--but from a memory which misses its habitual +support in a recognized element of constancy. If there is no memory, +that is to say, if the past is a complete blank, the mind simply feels a +rupture of identity without any transformation of self. This is our +condition on awaking from a perfectly forgotten period of sleep, or from +a perfectly unconscious state (if such is possible) when induced by +anæsthetics. Such gaps are, as we have seen, easily filled up, and the +sense of identity restored by a kind of retrospective "skipping." On the +other hand, the confusion which arises from too great and violent a +transformation of our _remembered_ experiences is much less easily +corrected. As long as the recollection of the old feelings remains, and +with this the sense of violent contrast between the old and the new +ones, so long will the illusion of two sundered selves tend to recur. + +The full development of this process of imaginative fission or cleavage +of self is to be met with in mental disease. The beginnings of such +disease, accompanied as they commonly are with disturbances of bodily +sensations and the recurring emotions, illustrate in a very interesting +way the dependence of the recognition of self on a certain degree of +uniformity in the contents of consciousness. The patient, when first +aware of these changes, is perplexed, and often regards the new feelings +as making up another self, a foreign _Tu_, as distinguished from the +familiar _Ego_. And sometimes he expresses the relation between the old +and the new self in fantastic ways, as when he imagines the former to be +under the power of some foreign personality. + +When the change is complete, the patient is apt to think of his former +self as detached from his present, and of his previous life as a kind of +unreal dream; and this fading away of the past into shadowy unreal forms +has, as its result, a curious aberration in the sense of time. Thus, it +is said that a patient, after being in an asylum only one day, will +declare that he has been there a year, five years, and even ten +years.[135] This confusion as to self naturally becomes the +starting-point of illusions of perception; the transformation of self +seeming to require as its logical correlative (for there is a crude +logic even in mental disease) a transformation of the environment. When +the disease is fully developed under the particular form of monomania, +the recollection of the former normal self commonly disappears +altogether, or fades away into a dim image of some perfectly separate +personality. A new ego is now fully substituted for the old. In other +and more violent forms of disease (dementia) the power of connecting the +past and present may disappear altogether, and nothing but the _disjecta +membra_ of an ego remain. + + * * * * * + +Enough has, perhaps, been said to show how much of uncertainty and of +self-deception enters into the processes of memory. This much-esteemed +faculty, valuable and indispensable though it certainly is, can clearly +lay no claim to that absolute infallibility which is sometimes said to +belong to it. Our individual recollection, left to itself, is liable to +a number of illusions even with regard to fairly recent events, and in +the case of remote ones it may be said to err habitually and uniformly +in a greater or less degree. To speak plainly, we can never be certain +on the ground of our personal recollection alone that a distant event +happened exactly in the way and at the time that we suppose. Nor does +there seem to be any simple way by mere reflection on the contents of +our memory of distinguishing what kinds of recollection are likely to be +illusory. + +How, then, it may be asked, can we ever be certain that we are +faithfully recalling the actual events of the past? Given a fairly good, +that is, a cultivated memory, it may be said that in the case of very +recent events a man may feel certain that, when the conditions of +careful attention at the time to what really happened were present, a +distinct recollection is substantially correct. Also it is obvious that +with respect to all repeated experiences our memories afford practically +safe guides. When memory becomes the basis of some item of generalized +knowledge, as, for example, of the truth that the pain of indigestion +has followed a too copious indulgence in rich food, there is little room +for an error of memory properly so called. On the other hand, when an +event is not repeated in our experience, but forms a unique link in our +personal history, the chances of error increase with the distance of the +event; and here the best of us will do well to have resort to a process +of verification or, if necessary, of correction. + +In order thus to verify the utterances of memory, we must look beyond +our own internal mental states to some external facts. Thus, the +recollections of our early life may often be tested by letters written +by ourselves or our friends at the time, by diaries, and so on. When +there is no unerring objective record to be found, we may have recourse +to the less satisfactory method of comparing our recollections with +those of others. By so doing we may reach a rough average recollection +which shall at least be free from any individual error corresponding to +that of personal equation in perception. But even thus we cannot be sure +of eliminating all error, since there may be a cause of illusion acting +on all our minds alike, as, for example, the extraordinary nature of the +occurrence, which would pretty certainly lead to a common exaggeration +of its magnitude, etc., and since, moreover, this process of comparing +recollections affords an opportunity for that reading back a present +preconception into the past to which reference has already been made. + +The result of our inquiry is less alarming than it looks at first sight. +Knowledge is valuable for action, and error is chiefly hurtful in so far +as it misdirects conduct. Now, in a general way, we do not need to act +upon a recollection of single remote events; our conduct is sufficiently +shaped by an accurate recollection of single recent events, together +with those bundles of recollections of recurring events and sequences of +events which constitute our knowledge of ourselves and our common +knowledge of the world about us. Nature has done commendably well in +endowing us with the means of cultivating our memories up to this point, +and we ought not to blame her for not giving us powers which would only +very rarely prove of any appreciable practical service to us. + + + + +NOTE. + +MOMENTARY ILLUSIONS OF SELF-CONSCIOUSNESS. + + +The account of the apparent ruptures in our personal identity given in +this chapter may help us to understand the strange tendency to confuse +self with other objects which occasionally appears in waking +consciousness and in dreams. These errors may be said generally to be +due to the breaking up of the composite image of self into its +fragments, and the regarding of certain of these only. Thus, the +momentary occurrence of partial illusion in intense sympathy with +others, including that imaginative projection of self into inanimate +objects, to which reference has already been made, may be said to depend +on exclusive attention to the subjective aspect of self, to the total +disregard of the objective aspect. In other words, when we thus +momentarily "lose ourselves," or merge our own existence in that of +another object, we clearly let drop out of sight the visual +representation of our own individual organism. On the other hand, when +in dreams we double our personality, or represent to ourselves an +external self which becomes the object of visual perception, it is +probably because we isolate in imagination the objective aspect of our +personality from the other and subjective aspect. It is not at all +unlikely that the several confusions of self touched on in this chapter +have had something to do with the genesis of the various historical +theories of a transformed existence, as, for example, the celebrated +doctrine of metempsychosis. + + + + +CHAPTER XI. + +ILLUSIONS OF BELIEF. + + +Our knowledge is commonly said to consist of two large +varieties--Presentative and Representative. Representative knowledge, +again, falls into two chief divisions. The first of these is Memory, +which, though not primary or original, like presentative knowledge, is +still regarded as directly or intuitively certain. The second division +consists of all other representative knowledge besides memory, +including, among other varieties, our anticipations of the future, our +knowledge of others' past experience, and our general knowledge about +things. There is no one term which exactly hits off this large sphere of +cognition: I propose to call it Belief. I am aware that this is by no +means a perfect word for my purpose, since, on the one hand, it suggests +that every form of this knowledge must be less certain than presentative +or mnemonic knowledge, which cannot be assumed; and since, on the other +hand, the word is so useful a one in psychology, for the purpose of +marking off the subjective fact of assurance in all kinds of cognition. +Nevertheless, I know not what better one I could select in order to +make my classification answer as closely as a scientific treatment will +allow to the deeply fixed distinctions of popular psychology. + +It might at first seem as if perception, introspection, and memory must +exhaust all that is meant by immediate, or self-evident, knowledge, and +as if what I have here called belief must be uniformly mediate, +derivate, or inferred knowledge. The apprehension of something now +present to the mind, externally or internally, and the reapprehension +through the process of memory of what was once so apprehended, might +appear to be the whole of what can by any stretch of language be called +direct cognition of things. This at least would seem to follow from the +empirical theory of knowledge, which regards perception and memory as +the ground or logical source of all other forms of knowledge. + +And even if we suppose, with some philosophers, that there are certain +innate principles of knowledge, it seems now to be generally allowed +that these, apart from the particular facts of experience, are merely +abstractions; and that they only develop into complete knowledge when +they receive some empirical content, which must be supplied either by +present perception or by memory. So that in this case, too, all definite +concrete knowledge would seem to be either presentative cognition, +memory, or, lastly, some mode of inference from these. + +A little inquiry into the mental operations which I here include under +the name belief will show, however, that they are by no means uniformly +process of inference. To take the simplest form of such knowledge, +anticipation of some personal experience: this may arise quite apart +from recollection, as a spontaneous projection of a mental image into +the future. A person may feel "intuitively certain" that something is +going to happen to him which does not resemble anything in his past +experience. Not only so; even when the expectation corresponds to a bit +of past experience, this source of the expectation may, under certain +circumstances, be altogether lost to view, and the belief assume a +secondarily automatic or intuitive character. Thus, a man may have first +entertained a belief in the success of some undertaking as the result of +a rough process of inference, but afterwards go on trusting when the +grounds for his confidence are wholly lost sight of. + +This much may suffice for the present to show that belief sometimes +approximates to immediate, or self-evident, conviction. How far this is +the case will come out in the course of our inquiry into its different +forms. This being so, it will be needful to include in our present study +the errors connected with the process of belief in so far as they +simulate the immediate instantaneous form of illusion. + +What I have here called belief may be roughly distinguished into simple +and compound belief. By a simple belief I mean one which has to do with +a single event or fact. It includes simple modes of expectation, as well +as beliefs in single past facts not guaranteed by memory. A compound +belief, on the other hand, has reference to a number of events or facts. +Thus, our belief in the continued existence of a particular object, as +well as our convictions respecting groups or classes of events, must be +regarded as compound, since they can be shown to include a number of +simple beliefs. + + +A. _Simple Illusory Belief: Expectation._ + +It will be well to begin our inquiry by examining the errors connected +with simple expectations, so far as these come under our definition of +illusion. And here, following our usual practice, we may set out with a +very brief account of the nature of the intellectual process in its +correct form. For this purpose we shall do well to take a complete or +definite anticipation of an event as our type.[136] + +The ability of the mind to move forward, forecasting an order of events +in time, is clearly very similar to its power of recalling events. Each +depends on the capability of imagination to represent a sequence of +events or experiences. The difference between the two processes is that +in anticipation the imagination setting out from the present traces the +succession of experiences in their actual order, and not in the reverse +order. It would thus appear to be a more natural and easy process than +recollection, and observation bears out this conclusion. Any object +present to perception which is associated with antecedents and +consequents with the same degree of cohesion, calls up its consequents +rather than its antecedents. The spectacle of the rising of the sun +carries the mind much more forcibly forwards to the advancing morning +than backwards to the receding night. And there is good reason to +suppose that in the order of mental development the power of distinctly +expecting an event precedes that of distinctly recollecting one. Thus, +in the case of the infant mind, as of the animal intelligence, the +presence of signs of coming events, as the preparation of food, seems to +excite distinct and vivid expectation.[137] + +As a mode of assurance, expectation is clearly marked off from memory, +and is not explainable by means of this. It is a fundamentally distinct +kind of conviction. So far as we are capable of analyzing it, we may say +that its peculiarity is its essentially active character. To expect a +thing is to have stirred the active impulses, including the powers of +attention; it is to be on the alert for it, to have the attention +already focussed for it, and to begin to rehearse the actions which the +actual happening of the event--for example, the approach of a welcome +object--would excite. It thus stands in marked contrast to memory, which +is a passive attitude of mind, becoming active only when it gives rise +to the expectation of a recurrence of the event.[138] + +And now let us pass to the question whether expectation ever takes the +form of immediate knowledge. It may, perhaps, be objected that the +anticipation of something future cannot be knowledge at all in the sense +in which the perception of something present or the recollection of +something past is knowledge. But this objection, when examined closely, +appears to be frivolous. Because the future fact has not yet come into +the sphere of actual existence, it is none the less the object of a +perfect assurance.[139] + +But, even if it is conceded that expectation is knowledge, the objection +may still be urged that it cannot be immediate, since it is the very +nature of expectation to ground itself on memory. I have already hinted +that this is not the case, and I shall now try to show that what is +called expectation covers much that is indistinguishable from immediate +intuitive certainty, and consequently offers room for an illusory form +of error. + +Let us set out with the simplest kind of expectation, the anticipation +of something about to happen within the region of our personal +experience, and similar to what has happened before. And let the coming +of the event be first of all suggested by some present external fact or +sign. Suppose, for example, that the sky is heavy, the air sultry, and +that I have a bad headache; I confidently anticipate a thunderstorm. It +would commonly be said that such an expectation is a kind of inference +from the past. I remember that these appearances have been followed by a +thunderstorm very often, and I infer that they will in this new case be +so followed. + +To this, however, it may be replied that in most cases there is no +conscious going back to the past at all. As I have already remarked, +anticipation is pretty certainly in advance of memory in early life. And +even after the habit of passing from the past to the future, from memory +to expectation, has been formed, the number of the past repetitions of +experience would prevent the mind's clearly reverting to them. And, +further, the very force of habit would tend to make the transition from +memory to expectation more and more rapid, automatic, and unconscious. +Thus it comes about that all distinctly suggested approaching events +seem to be expected by a kind of immediate act of belief. The present +signs call up the representation of the coming event with all the force +of a direct intuition. At least, it may be said that if a process of +inference, it is one which has the minimum degree of consciousness. + +It might still be urged that the mind passes from the _present_ facts as +signs, and so still performs a kind of reasoning process. This is, no +doubt, true, and differentiates expectation from perception, in which +there is no conscious transition from the presented to the represented. +Still I take it that this is only a process of reasoning in so far as +the sign is consciously generalized, and this is certainly not true of +early expectations, or even of any expectations in a wholly uncultivated +mind. + +For these reasons I think that any errors involved in such an +anticipation may, without much forcing, be brought under our definition +of illusion. When due altogether to the immediate force of suggestion in +a present object or event, and not involving any conscious transition +from past to future, or from general truth to particular instance, these +errors appear to me to have more of the character of illusions than of +that of fallacies. + +Much the same thing may be said about the vivid anticipations of a +familiar kind of experience called up by a clear and consecutive verbal +suggestion. When a man, even with an apparent air of playfulness, tells +me that something is going to happen, and gives a consistent consecutive +account of this, I have an anticipation which is not consciously +grounded on any past experience of the value of human testimony in +general, or of this person's testimony in particular, but which is +instantaneous and quasi-immediate. Consequently, any error connected +with the mental act approximates to an illusion. + +So far I have supposed that the anticipated event is a recurring one, +that is to say, a kind of experience which has already become familiar +to us. This, however, holds good only of a very few of our experiences. +Our life changes as it progresses, both outwardly and inwardly. Many of +our anticipations, when first formed, involve much more than a +reproduction of a past experience, namely, a complex act of constructive +imagination. Our representations of these untried experiences, as, for +example, those connected with a new set of circumstances, a new social +condition, a new mode of occupation, and so on, are clearly at the first +far from simple processes of inference from the past. They are put +together by the aid of many fragmentary images, restored by distinct +threads of association, yet by a process so rapid as to appear like an +intuition. Indeed, the anticipation of such new experiences more often +resembles an instantaneous imaginative intuition than a process of +conscious transition from old experiences. In the case of these +expectations, then, there would clearly seem to be room for illusion +from the first. + +But even supposing that the errors connected with the first formation of +an expectation cannot strictly be called illusory, we may see that such +simple expectation will, in certain cases, tend to grow into something +quite indistinguishable from illusion. I refer to expectations of +_remote_ events which allow of frequent renewal. Even supposing the +expectation to have originated from some rational source, as from a +conscious inference from past experience, or from the acceptance of +somebody's statement, the very habit of cherishing the anticipation +tends to invest it with an automatic self-sufficient character. To all +intents and purposes the prevision becomes intuitive, by which I mean +that the mind is at the time immediately certain that something is going +to happen, without needing to fall back on memory or reflection. This +being so, whenever the initial process of inference or quasi-inference +happens to have been bad, an illusory expectation may arise. In other +words, the force of repetition and habit tends to harden what may, in +its initial form, have resembled a kind of fallacy into an illusion. + +And now let us proceed further. When a permanent expectation is thus +formed, there arises the possibility of processes which favour illusion +precisely analogous to those which we have studied in the case of +memory. + +In the first place, the habit of imagining a future event is attended +with a considerable amount of illusion as to time or remoteness. After +what has been said respecting the conditions of such error in the case +of memory, a very few words will suffice here. + +It is clear, then, in the first place, that the mind will tend to +shorten any period of future time, and so to antedate, so to speak, a +given event, in so far as the imagination is able clearly and easily to +run over its probable experiences. From this it follows that repeated +forecastings of series of events, by facilitating the imaginative +process, tend to beget an illusory appearance of contraction in the time +anticipated. Moreover, since in anticipation so much of each division of +the future time-line is unknown, it is obviously easy for the expectant +imagination to skip over long intervals, and so to bring together widely +remote events. + +In addition to this general error, there are more special errors. As in +the case of recollection, vividness of mental image suggests +propinquity; and accordingly, all vivid anticipations, to whatever cause +the vividness may be owing, whether to powerful suggestion on the part +of external objects, to verbal suggestion, or to spontaneous imagination +and feeling, are apt to represent their objects as too near. + +It follows that an event intensely longed for, in so far as the +imagination is busy in representing it, will seem to approach the +present. At the same time, as we have seen, an event much longed for +commonly appears to be a great while coming, the explanation being that +there is a continually renewed contradiction between anticipation and +perception. The self-adjustment of the mind in the attitude of +expectant attention proves again and again to be vain and futile, and it +is this fact which brings home to it the slowness of the sequences of +perceived fact, as compared with the rapidity of the sequences of +imagination. + +When speaking of the retrospective estimate of time, I observed that the +apparent distance of an event depends on our representation of the +intervening time-segment. And the same remark applies to the prospective +estimate. Thus, an occurrence which we expect to happen next week will +seem specially near if we know little or nothing of the contents of the +intervening space, for in this case the imagination does not project the +experience behind a number of other distinctly represented events. + +Finally, it is to be remarked that the prospective appreciation of any +duration will tend to err relatively by way of excess, where the time is +exceptionally filled out with clearly expected and deeply interesting +experiences. To the imagination of the child, a holiday, filled with new +experiences, appears to be boundless. + +Thus far I have assumed that the date of the future event is a matter +which might be known. It is, however, obvious, from the very nature of +knowledge with respect to the future, that we may sometimes be certain +of a thing happening to us without knowing with any degree of +definiteness when it will happen. In the case of these temporally +undefined expectations, the law already expounded holds good that all +vividness of representation tends to lend the things represented an +appearance of approaching events. On the other hand, there are some +events, such as our own death, which our instinctive feelings tend to +banish to a region so remote as hardly to be realized at all. + +So much with respect to errors in the localizing of future events. + +In the second place, a habit of imagining a future event or group of +events will give play to those forces which tend to transform a mental +image. In other words, the habitual indulgence of a certain anticipation +tends to an illusory view, not only of the "when?" but also of the +"how?" of the future event. These transformations, due to subtle +processes of emotion and intellect, and reflecting the present habits of +these, exactly resemble those by which a remembered event becomes +gradually transformed. Thus, we carry on our present habits of thought +and feeling into the remote future, foolishly imagining that at a +distant period of life, or in greatly altered circumstances, we shall +desire and aim at the same things as now in our existing circumstances. +In close connection with this forward projection of our present selves, +there betrays itself a tendency to look on future events as answering to +our present desires and aspirations. In this way, we are wont to soften, +beautify, and idealize the future, marking it off from the hard +matter-of-fact present. + +The less like the future experience to our past experience, or the more +remote the time anticipated, the greater the scope for such imaginative +transformation. And from this stage of fanciful transformation of a +future reality to the complete imaginative creation of such a reality, +the step is but a small one. Here we reach the full development of +illusory expectation, that which corresponds to hallucination in the +region of sense-perception. + +In order to understand these extreme forms of illusory expectation, it +will be necessary to say something more about the relation of +imagination to anticipation in general. There are, I conceive, good +reasons for saying that any kind of vivid imagination tends to pass into +a semblance of an expectation of a coming personal experience, or an +event that is about to happen within the sphere of our own observation. +It has long been recognized by writers, among whom I may mention Dugald +Stewart, that to distinctly imagine an event or object is to feel for +the moment a degree of belief in the corresponding reality. Now, I have +already said that expectation is probably a more natural and an earlier +developed state of mind than memory. And so it seems probable that any +mental image which happens to take hold on the mind, if not recognized +as one of memory, or as corresponding to a fact in somebody else's +experience, naturally assumes the form of an expectation of a personal +experience. The force of the expectation will vary in general as the +vividness and persistence of the mental image. Moreover, it follows, +from what has been said, that this force of imagination will determine +what little time-character we ever give to these wholly ungrounded +illusions. + +We see, then, that any process of spontaneous imagination will tend to +beget some degree of illusory expectation. And among the agencies by +which such ungrounded imagination arises, the promptings of feeling play +the most conspicuous part. A present emotional excitement may give to an +imaginative anticipation, such as that of the prophetic enthusiast, a +reality which approximates to that of an actually perceived object. And +even where this force of excitement is wanting, a gentle impulse of +feeling may suffice to beget an assurance of a distant reality. The +unknown recesses of the remote future offer, indeed, the field in which +the illusory impulses of our emotional nature have their richest +harvest. + + "Thus, from afar, each dim discover'd scene + More pleasing seems than all the past hath been; + And every form, that Fancy can repair + From dark oblivion, glows divinely there." + +The recurring emotions, the ruling aspirations, find objects for +themselves in this veiled region. Feelings too shy to burst forth in +unseemly anticipation of the immediate future, modestly satisfy +themselves with this remote prospect of satisfaction. And thus, there +arises the half-touching, half-amusing spectacle of men and women +continually renewing illusory hopes, and continually pushing the date of +their realization further on as time progresses and brings no actual +fruition. + +So far I have spoken of such expectations as refer to future personal +experience only. Growing individual experience and the enlargement of +this by the addition of social experience enable us to frame a number of +other beliefs more or less similar to the simple expectations just dealt +with. Thus, for example, I can forecast with confidence events which +will occur in the lives of others, and which I shall not even witness; +or again, I may even succeed in dimly descrying events, such as +political changes or scientific discoveries, which will happen after my +personal experience is at an end. Once more, I can believe in something +going on now at some distant and even inaccessible point of the +universe, and this appears to involve a conditional expectation, and to +mean that I am certain that I or anybody else would see the phenomenon, +if we could at this moment be transported to the spot. + +All such previsions are supposed to be formed by a process of inference +from personal experience, including the trustworthiness of testimony. +Even allowing, however, that this was so in the first stages of the +belief, it is plain that, by dint of frequent renewal, the expectation +would soon cease to be a process of inference, and acquire an apparently +self-evident character. This being so, if the expectation is not +adequately grounded to start with, it is very likely to develop into an +illusion. And it is to be added that these permanent anticipations may +have their origin much more in our own wishes or emotional promptings +than in fact and experience. The mind undisciplined by scientific +training is wont to entertain numerous beliefs of this sort respecting +what is now going on in unvisited parts of the world, or what will +happen hereafter in the distant future. The remote, and therefore +obscure, in space and in time has always been the favourite region for +the projection of pleasant fancies. + +Once more, besides these oblique kinds of expectation, I may form other +seemingly simple beliefs, to which the term expectation seems less +clearly applicable. Thus, on waking in the morning and finding the +ground covered with snow, my imagination moves backwards, as in the +process of memory, and realizes the spectacle of the softly falling +snow-flakes in the hours of the night. The oral communication of others' +experience, including the traditions of the race, enables me to set out +from any present point of time, and reconstruct complex chains of +experience of vast length lying beyond the bounds of my own personal +recollection. + +I need not here discuss what the exact nature of such beliefs is. J.S. +Mill identifies them with expectations. Thus, according to him, my +belief in the nocturnal snowstorm is the assurance that I should have +seen it had I waited up during the night. So my belief in Cicero's +oratory resolves itself into the conviction that I should have heard +Cicero under certain conditions of time and place, which is identical +with my expectation that I shall hear a certain speaker to-morrow if I +go to the House of Commons.[140] However this be, the thing to note is +that such retrospective beliefs, when once formed, tend to approximate +in character to recollections. This is true even of new beliefs in +recent events directly made known by present objective consequences or +signs, as the snowstorm. For in this case there is commonly no conscious +comparison of the present signs with previously known signs, but merely +a direct quasi-mnemonic passage of mind from the present fact to its +antecedent. And it is still more true of long-entertained retrospective +beliefs. When, for example, the original grounds of an historical +hypothesis are lost sight of, and after the belief has hardened and +solidified by time, it comes to look much more like a recollection than +an expectation. As a matter of fact, we have seen, when studying the +illusions of memory, that our personal experience does become confused +with that of others. And one may say that all long-cherished +retrospective beliefs tend to become assimilated to recollections. + +Here then, again, there seems to be room for illusion to arise. Even in +the case of a recent past event, directly made known by present +objective signs, the mind is liable to err just as in the case of +forecasting an immediately approaching event. And such error has all the +force of an illusion: its contradiction is almost as great a shock as +that of a recollection. When, for example, I enter my house, and see a +friend's card lying on the table, I so vividly represent to myself the +recent call of my friend, that when I learn the card is an old one which +has accidentally been put on the table, I experience a sense of +disillusion very similar to that which attends a contradicted +perception. The early crude stages of physical science abundantly +illustrate the genesis of such illusions. + +It may be added that if there be any feeling present in the mind at the +time, the barest suggestion of something having happened will suffice to +produce the immediate assurance. Thus, an angry person is apt to hastily +accuse another of having done certain things on next to no evidence. The +love of the marvellous seems to have played a conspicuous part in +building up and sustaining the fanciful hypotheses which mark the dawn +of physical science. + +Verbal suggestion is a common mode of producing this semblance of a +recollected event. By means of the narrative style, it vividly suggests +the idea that the events described belong to the past, and excites the +imagination to a retrospective construction of them as though they were +remembered events. Hence the power of works of fiction on the ordinary +mind. Even when there is no approach to an illusion of perception, or to +one of memory in the strict sense, the reading of a work of fiction +begets at the moment a retrospective belief that has a certain +resemblance to a recollection. + +All such illusions as those just illustrated, if not afterwards +corrected, tend to harden into yet more distinctly "intuitive" errors. +Thus, for example, one of the crude geological hypotheses, of which Sir +Charles Lyell tells us,[141] would, by the mere fact of being kept +before the mind, tend to petrify into a hard fixed belief. And this +process of hardening is seen strikingly illustrated in the case of +traditional errors, especially when these fall in with our own emotional +propensities. Our habitual representations of the remote historical past +are liable to much the same kind of error as our recollections of early +personal experience. The wrong statements of others and the promptings +of our own fancies may lead in the first instance to a filling up of the +remote past with purely imaginary shapes. Afterwards the particular +origin of the belief is forgotten, and the assurance assumes the aspect +of a perfectly intuitive conviction. The hoary traditional myths +respecting the golden age, and so on, and the persistent errors of +historians under the sway of a strong emotional bias, illustrate such +illusions. + +So much as to simple illusions of belief, or such as involve single +representations only. Let us now pass to compound illusions, which +involve a complex group of representations. + + +B. _Compound Illusory Belief._ + +A familiar example of a compound belief is the belief in a permanent or +persistent individual object of a certain character. Such an idea, +whatever its whole meaning may be--and this is a disputed point in +philosophy--certainly seems to include a number of particular +representations, corresponding to direct personal recollections, to the +recollections of others, and to numerous anticipations of ourselves and +of others. And if the object be a living creature endowed with feelings, +our idea of it will contain, in addition to these represented +perceptions of ourselves or of others, a series of represented insights, +namely, such as correspond to the inner experience of the being, so far +as this is known or imagined. + +It would thus seem that the idea which we habitually carry about with us +respecting a complex individual object is a very composite idea. In +order to see this more fully, let us inquire into what is meant by our +belief in a person. My idea of a particular friend contains, among other +things, numbers of vague representations of his habitual modes of +feeling and acting, and numbers of still more vague expectations of how +he will or might feel and act in certain circumstances. + +Now, it is plain that such a composite idea must have been a very slow +growth, involving, in certain stages of its formation, numerous +processes of inference or quasi-inference from the past to the future. +But in process of time these elements fuse inseparably: the directly +known and the inferred no longer stand apart in my mind; my whole +conception of the individual as he has been, is, and will be, seems one +indivisible cognition; and this cognition is so firmly fixed and +presents itself so instantaneously to the mind when I think of the +object, that it has all the appearance of an intuitive conviction. + +If this is a fairly accurate description of the structure of these +compound representations and of their attendant beliefs, it is easy to +see how many openings for error they cover. To begin with, my +representation of so complex a thing as a concrete personality must +always be exceedingly inadequate and fragmentary. I see only a few +facets of the person's many-sided mind and character. And yet, in +general, I am not aware of this, but habitually identify my +representation with the totality of the object. + +More than this, a little attention to the process by which these +compound beliefs arise will disclose the fact that this apparently +adequate representation of another has arisen in part by other than +logical processes. If the blending of memory and expectation were simply +a mingling of facts with correct inferences from these, it might not +greatly matter; but it is something very different from this. Not only +has our direct observation of the person been very limited, even that +which we have been able to see has not been perfectly mirrored in our +memory. It has already been remarked that recollection is a selective +process, and this truth is strikingly illustrated in the growth of our +enduring representations of things. What stamps itself on my memory is +what surprised me or what deeply interested me at the moment. And then +there are all the risks of mnemonic illusion to be taken into account as +well. Thus, my idea of a person, so far even as it is built up on a +basis of direct personal recollection, is essentially a fragmentary and +to some extent a misleading representation. + +Nor is this all. My habitual idea of a person is a resultant of forces +of memory conjoined with other forces. Among these are to be reckoned +the influence of illusory perception or insight, my own and that of +others. The amount of misinterpretation of the words and actions of a +single human being during the course of a long acquaintance must be very +considerable. To these must be added the effect of erroneous single +expectations and reconstructions of past experiences, in so far as these +have not been distinctly contradicted and dissipated. All these errors, +connected with single acts of observing or inferring the feelings and +doings of another, have their effect in distorting the subsequent total +representation of the person. + +Finally, we must include a more distinct ingredient of active illusion, +namely, all the complex effects of the activity of imagination as led, +not by fact and experience, but by feeling and desire. Our permanent +idea of another reflects all that we have fondly imagined the person +capable of doing, and thus is made up of an ideal as well as a real +actually known personality. And this result of spontaneous imagination +must be taken to include the ideals entertained by others who are likely +to have influenced us by their beliefs.[142] + +Enough has probably been said to show how immensely improbable it is +that our permanent cognition of so complex an object as a particular +human being should be at all an accurate representation of the reality, +how much of the erroneous is certain to get mixed up with the true. And +this being so, we may say that our apparently simple direct cognition of +a given person, our assurance of what he is and will continue to be, is +to some extent illusory. + + +_Illusion of Self-Esteem._ + +Let us now pass to another case of compound representation, where the +illusory element is still more striking. I refer to the idea of self +which each of us habitually carries about with him. Every man's opinion +of himself, as a whole, is a very complex mental product, in which facts +known by introspection no doubt play a part, but probably only a very +subordinate part. It is obvious, from what has been said about the +structure of our habitual representations of other individuals, that our +ordinary representation of ourselves will be tinged with that mass of +error which we have found to be connected with single acts of +introspection, recollections of past personal experience, and illusory +single expectations of future personal experiences. How large an opening +for erroneous conviction here presents itself can only be understood by +a reference to certain deeply fixed impulses and feelings connected +with, the very consciousness of self, and favouring what I have marked +off as active illusion. I shall try to show very briefly that each man's +intuitive persuasion of his own powers, gifts, or importance--in brief, +of his own particular value, contains, from the first, a palpable +ingredient of active illusion. + +Most persons, one supposes, have with more or less distinct +consciousness framed a notion of their own value, if not to the world +generally, at least to themselves. And this notion, however undefined it +may be, is held to with a singular tenacity of belief. The greater part +of mankind, indeed, seem never to entertain the question whether they +really possess points of excellence. They assume it as a matter +perfectly self-evident, and appear to believe in their vaguely conceived +worth on the same immediate testimony of consciousness by which they +assure themselves of their personal existence. Indeed, the conviction of +personal consequence may be said to be a constant factor in most men's +consciousness. However restrained by the rules of polite intercourse, it +betrays its existence and its energy in innumerable ways. It displays +itself most triumphantly when the mind is suddenly isolated from other +minds, when other men unite in heaping neglect and contempt on the +believer's head. In these moments he proves an almost heroic strength of +confidence, believing in himself and in his claims to careful +consideration when all his acquaintance are practically avowing their +disbelief. + +The intensity of this belief in personal value may be observed in very +different forms. The young woman who, quite independently of others' +opinion, and even in defiance of it, cherishes a conviction that her +external attractions have a considerable value; the young man who, in +the face of general indifference, persists in his habit of voluble talk +on the supposition that he is conferring on his fellow-creatures the +fruits of profound wisdom; and the man of years whose opinion of his own +social importance and moral worth is quite disproportionate to the +estimation which others form of his claims--these alike illustrate the +force and pertinacity of the belief. + +There are, no doubt, many exceptions to this form of self-appreciation. +In certain robust minds, but little given to self-reflection, the idea +of personal value rarely occurs. And then there are timid, sensitive +natures that betray a tendency to self-distrust of all kinds, and to an +undue depreciation of personal merit. Yet even here traces of an impulse +to think well of self will appear to the attentive eye, and one can +generally recognize that this impulse is only kept down by some other +stronger force, as, for example, extreme sensitiveness to the judgment +of others, great conscientiousness, and so on. And however this be, it +will be allowed that the average man rates himself highly. + +It is to be noticed that this persuasion of personal value or excellence +is, in common, very vague. A man may have a general sense of his own +importance without in the least being able to say wherein exactly his +superiority lies. Or, to put it another way, he may have a strong +conviction that he stands high in the scale of morally deserving +persons, and yet be unable to define his position more nearly. Commonly, +the conviction seems to be only definable as an assurance of a +superlative of which the positive and comparative are suppressed. At +most, his idea of his moral altitude resolves itself into the +proposition, "I am a good deal better than Mr. A. or Mr. B." Now, it is +plain that in these intuitive judgments on his own excellence, the man +is making an assertion with respect, not only to inner subjective +feelings which he only can be supposed to know immediately, but also to +external objective facts which are patent to others, namely, to certain +active tendencies and capabilities, to the direction of external conduct +in certain lines.[143] Hence, if the assertion is erroneous, it will be +in plain contradiction to others' perceptions of his powers or moral +endowments. And this is what we actually find. A man's self-esteem, in a +large preponderance of cases, is plainly in excess of others' esteem of +him. What the man conceives himself to be differs widely from what +others conceive him to be. + + "Oh wad some power the giftie gie us, + To see oursels as others see us!" + +Now, whence comes this large and approximately uniform discrepancy +between our self-esteem and others' esteem of us? By trying to answer +this question we shall come to understand still better the processes by +which the most powerful forms of illusion are generated. + +It is, I think, a matter of every-day observation that children manifest +an apparently instinctive disposition to magnify self as soon as the +vaguest idea of self is reached. It is very hard to define this feeling +more precisely than by terming it a rudimentary sense of personal +importance. It may show itself in very different ways, taking now a more +active form, as an impulse of self-assertion, and a desire to enforce +one's own will to the suppression of others' wills, and at another time +wearing the appearance of a passive emotion, an elementary form of +_amour propre_. And it is this feeling which forms the germ of the +self-estimation of adults. For in truth all attribution of value +involves an element of feeling, as respect, and of active desire, and +the ascription of value to one's self is in its simplest form merely the +expression of this state of mind. + +But how is it, it may be asked, that this feeling shows itself +instinctively as soon as the idea of self begins to arise in +consciousness? The answer to this question is to be found, I imagine, in +the general laws of mental development. All practical judgments like +that of self-estimation are based on some feeling which is developed +before it; and, again, the feeling itself is based on some instinctive +action which, in like manner, is earlier than the feeling. Thus, for +example, an Englishman's judgment that his native country is of +paramount value springs out of a long-existent sentiment of patriotism, +which sentiment again may be regarded as having slowly grown up about +the half-blindly followed habit of defending and furthering the +interests of one's nation or tribe. In a similar way, one suspects, the +feeling of personal worth, with its accompanying judgment, is a product +of a long process of instinctive action. + +What this action is it is scarcely necessary to remind the reader. Every +living organism strives, or acts as if it consciously strove, to +maintain its life and promote its well-being. The actions of plants are +clearly related to the needs of a prosperous existence, individual first +and serial afterwards. The movements of the lower animals have the same +end. Thus, on the supposition that man has been slowly evolved from +lower forms, it is clear that the instinct of self-promotion must be the +deepest and most ineradicable element of his nature, and it is this +instinct which directly underlies the rudimentary sentiment of +self-esteem of which we are now treating. + +This instinct will appear, first of all, as the unreflecting organized +habit of seeking individual good, of aiming at individual happiness, and +so of pushing on the action of the individual will. This impulse shows +itself in distinct form as soon as the individual is brought into +competition with another similarly constituted being. It is the force +which displays itself in all opposition and hostility, and it tends to +limit and counteract the gregarious instincts of the race. In the next +place, as intelligence expands, this instinctive action becomes +conscious pursuit of an end, and at this stage the thing pursued +attracts to itself a sentiment. The individual now consciously desires +his own happiness as contrasted with that of others, knowingly aims at +enlarging his own sphere of action to the diminution of others' spheres. +Here we have the nascent sentiment of self-esteem, on which all later +judgments respecting individual importance are, in part at least, +founded. + +Thus, we see that long before man had arrived at an idea of self there +had been growing up an emotional predisposition to think well of self. +And in this way we may understand how it is that this sentiment of +self-esteem shows itself immediately and instinctively in the child's +mind as soon as its unfolding consciousness is strong enough to grasp +the first rough idea of personal existence. Far down, so to speak, below +the surface of distinct consciousness, in the intricate formation of +ganglion-cell and nerve-fibre, the connections between the idea of self +and this emotion of esteem have been slowly woven through long ages of +animal development. + +Here, then, we seem to have the key to the apparently paradoxical fact +that a man, with all his superior means of studying his own feelings, +commonly esteems himself, in certain respects at least, less accurately +than a good external observer would be capable of doing. In forming an +opinion of ourselves we are exposed to the full force of a powerful +impulse of feeling. This impulse, acting as a bias, enters more or less +distinctly into our single acts of introspection, into our attempts to +recall our past doings, into our insights into the meaning of others' +words and actions as related to ourselves (forming the natural +disposition to enjoy flattery), and finally into our wild dreams as to +our future achievements. It is thus the principal root of that gigantic +illusion of self-conceit, which has long been recognized by practical +sense as one of the greatest obstacles to social action; and by art as +one of the most ludicrous manifestations of human weakness. + +If there are all these openings for error in the beliefs we go on +entertaining respecting individual things, including ourselves, there +must be a yet larger number of such openings in those still more +compound beliefs which we habitually hold respecting collections or +classes of things. A single illusion of perception or of memory may +suffice to give rise to a wholly illusory belief in a class of objects, +for example, ghosts. The superstitious beliefs of mankind abundantly +illustrate this complexity of the sources of error. And in the case of +our every-day beliefs respecting real classes of objects, these sources +contribute a considerable quota of error. We may again see this by +examining our ordinary beliefs respecting our fellow-men. + +A moment's consideration will show that our prevailing views respecting +any section of mankind, say our fellow-countrymen, or mankind at large, +correspond at best to a very loose process of reasoning. The accidents +of our personal experience and opportunities of observation, the +traditions which coloured our first ideas, the influence of our dominant +feelings in selecting for attention and retention certain aspects of the +complex object, and in idealizing this object,--these sources of passive +and active illusion, must, to say the least, have had as much to do with +our present solidified and seemingly "intuitive" knowledge as anything +that can be called the exercise of individual judgment and reasoning +power. + +The force of this observation and the proof that such widely generalized +beliefs are in part illusory, is seen in the fact that men of unlike +experience and unlike temperament form such utterly dissimilar views of +the same object. Thus, as Mr. Spencer has shown,[144] in looking at +things national there may be not only a powerful patriotic bias at work +in the case of the vulgar Philistine, but also a distinctly +anti-patriotic bias in the case of the over-fastidious seeker after +culture. And I need hardly add that the different estimates of mankind +held with equal assurance by the cynic, the misanthropist, and the +philanthropic vindicator of his species, illustrate a like diversity of +the psychological conditions of belief. + +Finally, illusion may enter into that still wider collection of beliefs +which make up our ordinary views of life and the world as a whole. Here +there reflect themselves in the plainest manner the accidents of our +individual experience and the peculiar errors to which our intellectual +and emotional conformation disposes us. The world is for us what we feel +it to be; and we feel it to be the cause of our particular emotional +experience. Just as we have found that our environment helps to +determine our idea of self and personal continuity, so, conversely, our +inner experience, our remembered or imagined joys and sorrows throw a +reflection on the outer world, giving it its degree of worth. Hence the +contradictory, and consequently to some extent at least illusory, views +of the optimist and the pessimist, "intuitions" which, I have tried to +show elsewhere, are connected with deeply rooted habits of feeling, and +are antecedent to all reasoned philosophic systems. + +If proof were yet wanted that these wide-embracing beliefs may to some +extent be illusory, it would be found in the fact that they can be +distinctly coloured by a temporary mood or mental tone. As I have more +than once had occasion to remark, a feeling when present tends to colour +all the ideas of the time. And when out of sorts, moody, and +discontented, a man is prone to find a large objective cause of his +dissatisfaction in a world out of joint and not moving to his mind. + +It is evident that all the permanent beliefs touched on in this chapter +must constitute powerful predispositions with respect to any particular +act of perception, insight, introspection, or recollection. In other +words, these persistent beliefs, so far as individual or personal, are +but another name for those fixed habits of mind which, in the case of +each one of us, constitute our intellectual bias, and the source of the +error known as personal equation. And it may be added that, just as +these erroneous beliefs existing in the shape of fixed prejudices +constitute a bias to new error, so they act as powerful resisting forces +in relation to new truth and the correction of error. + +In comparing these illusions of belief with those of perception and +memory, we cannot fail to notice their greater compass or range, in +other words, the greater extent of the region of fact misrepresented. +Even if they are less forcible and irresistible than these errors, they +clearly make up for this by the area which they cover. + +Another thing to be observed with respect to these comprehensive beliefs +is that where, as here, so many co-operant conditions are at work, the +whole amount of common objective agreement is greatly reduced. In other +words, individual peculiarities of intellectual conformation, emotional +temperament, and experience have a far wider scope for their influence +in these beliefs than they have in the case of presentative cognitions. +At the same time, it is noteworthy that error much more rapidly +propagates itself here than in the case of our perceptions or +recollections. As we have seen, these beliefs all include much more than +the results of the individual's own experience. They offer a large field +for the influence of personal ascendency, of the contagion of sympathy, +and of authority and tradition. As a consequence of this, the illusions +of belief are likely to be far more persistent than those of perception +or of memory; for not only do they lose that salutary process of +correction which comparison with the experience of others affords, but +they may even be strengthened and upheld to some extent by such social +influences. + +And here the question might seem to obtrude itself, whether, in relation +to such a fluctuating mass of belief as that just reviewed, in which +there appears to be so little common agreement, we can correctly speak +of anything as objectively determinable. If illusion and error as a +whole are defined by a reference to what is commonly held true and +certain, what, it may be asked, becomes of the so-called illusions of +belief? + +This question will have to be fully dealt with in the following chapter. +Here it may be sufficient to remark that amid all this apparent +deviation of belief from a common standard of truth, there is a clear +tendency to a rational consensus. Thought, by disengaging what is really +matter of permanent and common cognition, both in the individual and +still more in the class,[145] and fixing this quantum of common +cognition in the shape of accurate definitions and universal +propositions, is ever fighting against and restraining the impulses of +individual imagination towards dissociation and isolation of belief. And +this same process of scientific control of belief is ever tending to +correct widespread traditional forms of error, and to erect a new and +better standard of common cognition. + +This scientific regulation of belief only fails where the experiences +which underlie the conceptions are individual, variable, and subjective. +Hence there is no definite common conception of the value of life and of +the world, just because the estimate of this value must vary with +individual circumstances, temperament, etc. All that can be looked for +here in the way of a common standard or norm is a rough average +estimate. And this common-sense judgment serves practically as a +sufficient criterion of truth, at least in relation to such extreme +one-sidedness of view as approaches the abnormal, that is to say, one of +the two poles of irrational exaltation, or "joy-madness," and abject +melancholy, which, appear among the phenomena of mental disease.[146] + + + + +CHAPTER XII. + +RESULTS. + + +The foregoing study of illusions may not improbably have had a +bewildering effect on the mind of the reader. To keep the mental eye, +like the bodily eye, for any time intently fixed on one object is apt to +produce a feeling of giddiness. And in the case of a subject like +illusion, the effect is enormously increased by the disturbing character +of the object looked at. Indeed, the first feeling produced by our +survey of the wide field of illusory error might be expressed pretty +accurately by the despondent cry of the poet-- + + "Alas! it is delusion all: + The future cheats us from afar, + Nor can we be what we recall, + Nor dare we think on what we are." + +It must be confessed that our study has tended to bring home to the mind +the wide range of the illusory and unreal in our intellectual life. In +sense-perception, in the introspection of the mind's own feelings, in +the reading of others' feelings, in memory, and finally in belief, we +have found a large field for illusory cognition. And while illusion has +thus so great a depth in the individual mind, it has a no less striking +breadth or extent in the collective human mind. No doubt its grosser +forms manifest themselves most conspicuously in the undisciplined mind +of the savage and the rustic; yet even the cultivated mind is by no +means free from its control. In truth, most of the illusions illustrated +in this work are such as can be shared in by all classes of mind. + +In view of this wide far-reaching area of ascertained error, the mind +naturally asks, What are the real limits of illusory cognition, and how +can we be ever sure of having got beyond them? This question leads us on +to philosophical problems of the greatest consequence, problems which +can only be very lightly touched in this place. Before approaching +these, let us look back a little more carefully and gather up our +results, reflect on the method which we have been unconsciously +adopting, and inquire how far this scientific mode of procedure will +take us in determining what is the whole range of illusory cognition. + +We have found an ingredient of illusion mixed up with all the popularly +recognized forms of immediate knowledge. Yet this ingredient is not +equally conspicuous in all cases. First of all, illusion varies very +considerably in its degree of force and persistence. Thus, in general, a +presentative illusion is more coercive than a representative; an +apparent reality present to the mind is naturally felt to be more +indubitable than one absent and only represented. On the other hand, a +representative illusion is often more enduring than a presentative, that +is to say, less easily found out. It is to be added that a good deal of +illusion is only partial, there being throughout an under-current of +rational consciousness, a gentle play of self-criticism, which keeps the +error from developing into a perfect self-delusion. This remark applies +not only to the innocent illusions of art, but also to many of our +every-day illusions, both presentative and representative. In many +cases, indeed, as, for example, in looking at a reflection in a mirror, +the illusion is very imperfect, remaining in the nascent stage. + +Again, a little attention to the facts here brought together will show +that the proportion of illusory to real knowledge is far from being the +same in each class of immediate or quasi-immediate cognition. Thus, with +respect to the great distinction between presentative and representative +knowledge, it is to be observed that, in so far as any act of cognition +is, strictly speaking, presentative, it does not appear to admit of +error. The illusions of perception are connected with the representative +side of the process, and are numerous just because this is so extensive. +On the other hand, in introspection, where the scope of independent +representation is so limited, the amount of illusion is very +inconsiderable, and may in practice be disregarded. So again, to take a +narrower group of illusions, we find that in the recalling of distant +events the proportion of error is vastly greater than in the recalling +of near events. + +So much as to the extent of illusion as brought to light by our +preceding study. Let us now glance at the conclusions obtained +respecting its nature and its causes. + +_Causes of Illusion._ + +Looking at illusion as a whole, and abstracting from the differences of +mental mechanism in the processes of perception, memory, etc., we may +say that the _rationale_ or mode of genesis of illusion is very much the +same throughout. Speaking broadly, one may describe all knowledge as a +correspondence of representation with fact or experience, or as a stable +condition of the representation which cannot be disturbed by new +experiences. It does not matter, for our present purpose, whether the +fact represented is supposed to be directly present, as in presentative +cognition; or to be absent, either as something past or future, or +finally as a "general fact," that is to say, the group of facts (past +and future) embodied in a universal proposition.[147] + +In general this accordance between our representations and facts is +secured by the laws of our intellectual mechanism. It follows from the +principles of association that our simple experiences, external and +internal, will tend to reflect themselves in perception, memory, +expectation, and general belief, in the very time-connections in which +they actually occur. To put it briefly, facts which occur together will +in general be represented together, and they will be the more perfectly +co-represented in proportion to the frequency of this concurrence. + +Illusion, as distinguished from correct knowledge, is, to put it +broadly, deviation of representation from fact. This is due in part to +limitations and defects in the intellectual mechanism itself, such as +the imperfections of the activities of attention, discrimination, and +comparison, in relation to what is present. Still more is it due to the +control of our mental processes by association and habit. These forces, +which are at the very root of intelligence, are also, in a sense, the +originators of error. Through the accidents of our experience or the +momentary condition of our reproductive power, representations get +wrongly grouped with presentations and with one another; wrongly +grouped, that is to say, according to a perfect or ideal standard, +namely, that the grouping should always exactly agree with the order of +experience as a whole, and the force of cohesion be proportionate to the +number of the conjunctions of this experience. + +This great source of error has been so abundantly illustrated under the +head of Passive Illusions that I need not dwell on it further. It is +plain that a passive error of perception, or of expectation, is due in +general to a defective grouping of elements, to a grouping which +answers, perhaps, to the run of the individual's actual experience, but +not to a large and complete common experience.[148] Similarly, an +illusory general belief is plainly a welding together of elements (here +concepts, answering to innumerable representative images) in +disagreement with the permanent connections of experience. Even a +passive illusion of memory, in so far as it involves a rearrangement of +successive representations, shows the same kind of defect. + +In the second place, this incorrect grouping maybe due, not to defects +in attention and discrimination, combined with insufficiently grounded +association, but to the independent play of constructive imagination and +the caprices of feeling. This is illustrated in what I have called +Active Illusions, whether the excited perceptions and the hallucinations +of sense, or the fanciful projections of memory or of expectation. Here +we have a force directly opposed to that of experience. Active illusion +arises, not through the imperfections of the intellectual mechanism, but +through a palpable interference with this mechanism. It is a regrouping +of elements which simulates the form of a suggestion by experience, but +is, in reality, the outcome of the individual mind's extra-intellectual +impulses. + +We see, then, that, in spite of obvious differences in the form, the +process in all kinds of immediate cognition is fundamentally identical. +It is essentially a bringing together of elements, whether similar or +dissimilar and associated by a link of contiguity, and a viewing of +these as connected parts, of a whole; it is a process of synthesis. And +illusion, in all its forms, is bad grouping or carelessly performed +synthesis. This holds good even of the simplest kinds of error in which +a presentative element is wrongly classed; and it holds good of those +more conspicuous errors of perception, memory, expectation, and compound +belief, in which representations connect themselves in an order not +perfectly answering to the objective order. + +This view of the nature and causes of illusion is clearly capable of +being expressed in physical language. Bad grouping of psychical elements +is equivalent to imperfect co-ordination of their physical, that is to +say, nervous, conditions, imperfect in the evolutionist's sense, as not +exactly according with external relations. So far as illusions of +suggestion (passive illusions) are concerned, the error is connected +with organized tendencies, due to a limited action of experience. On the +other hand, illusions of preconception (active illusions) usually +involve no such deeply fixed or permanent organic connections, but +merely a temporary confluence of nerve-processes.[149] The nature of the +physical process is best studied in the case of errors of +sense-perception. Yet we may hypothetically argue that even in the case +of the most complex errors, as those of memory and of belief, there is +implied a deviation in the mode of connection of nervous structures +(whether the connection be permanent or temporary) from the external +order of facts. + +And now we are in a position to see whether illusion is ultimately +distinguishable from other modes of error, namely, those incident to +conscious processes of reasoning. It must have been plain to an +attentive reader throughout our exposition that, in spite of our +provisional distinction, no sharp line can be drawn between much of +what, on the surface, looks like immediate knowledge, and consciously +derived or inferred knowledge. On its objective side, reasoning may be +roughly defined as a conscious transition of mind from certain facts or +relations of facts to other facts or relations recognized as similar. +According to this definition, a fallacy would be a hasty, unwarranted +transition to new cases not identical with the old. And a good part of +immediate knowledge is fundamentally the same, only that here, through +the exceptional force of association and habit, the transition is too +rapid to be consciously recognized. Consequently, illusion becomes +identified at bottom with fallacious inference: it may be briefly +described as collapsed inference. Thus, illusory perception and +expectation are plainly a hasty transition of mind from old to new, from +past to present, conjunctions of experience.[150] And, as we have seen, +an illusory general belief owes its existence to a coalescence of +representations of known facts or connections with products of +imagination which simulate the appearance of inferences from these +facts. + +In the case of memory, in so far as it is not aided by reasoning from +present signs, there seems to be nothing like a movement of inference. +It is evident, indeed, that memory is involved in and underlies every +such transition of thought. Illusions of memory illustrate rather a +process of wrong classing, that is to say, of wrongly identifying the +present mental image with past fact, which is the initial step in all +inference. In this way they closely resemble those slight errors of +perception which are due to erroneous classing of sense-impressions. But +since the intellectual process involved in assimilating mental elements +is very similar to that implied in assimilating complex groups of such +elements, we may say that even in these simple kinds of error there is +something which resembles a wrong classing of relations, something, +therefore, which approximates in character to a fallacy. + +By help of this brief review of the nature and causes of illusion, we +see that in general it may be spoken of as deviation of individual from +common experience. This applies to passive illusion in so far as it +follows from the accidents of individual experience, and it still more +obviously applies to active illusion as due to the vagaries of +individual feeling and constructive imagination. We might, perhaps, +characterize all illusion as partial view, partial both in the sense of +being incomplete, and in the other sense of being that to which the mind +by its peculiar predispositions inclines. This being so, we may very +roughly describe all illusion as abnormal. Just as hallucination, the +most signal instance of illusion, is distinctly on the border-land of +healthy and unhealthy mental life; just as dreams are in the direction +of such unhealthy mental action; so the lesser illusions of memory and +so on are abnormal in the sense that they imply a departure from a +common typical mode of intellectual action. + +It is plain, indeed, that this is the position we have been, taking up +throughout our discussion of illusion. We have assumed that what is +common and normal is true, or answers to what is objectively real. Thus, +in dealing with errors of perception, we took for granted that the +common percept--meaning by this what is permanent in the individual and +the general experience--is at the same time the true percept. So in +discussing the illusions of memory we estimated objective time by the +judgment of the average man, free from individual bias, and apart from +special circumstances favourable to error. Similarly, in the case of +belief, true belief was held to be that which men in general, or in the +long run, or on the average, hold true, as distinguished from what the +individual under variable and accidental influences holds true. And even +in the case of introspection we found that true cognition resolved +itself into a consensus or agreement as to certain psychical facts. + + +_Criterion of Illusion._ + +Now, it behoves us here to examine this assumption, with the view of +seeing how far it is perfectly sound. For it may be that what is +commonly held true does not in all cases strictly answer to the real, in +which case our idea of illusion would have to be extended so as to +include certain common beliefs. This question was partly opened up at +the close of the last chapter. It will be found that the full +discussion of it carries us beyond the scientific point of view +altogether. For the present, however, let us see what can be said about +it from that standpoint of positive science to which we have hitherto +been keeping. + +Now, if by common be meant what has been shared by all minds or the +majority of minds up to a particular time, a moment's inspection of the +process of correcting illusion will show that science assumes the +possibility of a common illusion. In the history of discovery, the first +assault on an error was the setting up of the individual against the +society. The men who first dared to say that the sun did not move round +the earth found to their cost what it was to fly in the face of a +common, though illusory, perception of the senses.[151] + +If, however, by common be understood what is permanently and unshakably +held true by men in proportion as their minds become enlightened, then +science certainly does assume the truth of common perception and belief. +Thus, the progress of the physical sciences may be described as a +movement towards a new, higher, and more stable consensus of ideas and +beliefs. In point of fact, the truths accepted by men of science already +form a body of common belief for those who are supposed by all to have +the means of testing the value of their convictions. And the same +applies to the successive improvements in the conceptions of the moral +sciences, for example, history and psychology. Indeed, the very meaning +of science appears to be a body of common cognition to which all minds +converge in proportion to their capabilities and opportunities of +studying the particular subject-matter concerned. + +Not only so, from a strictly scientific point of view it might seem +possible to prove that common cognition, as defined above, must in +general be true cognition. I refer here to the now familiar method of +the evolutionist. + +According to this doctrine, which is a scientific method in so far as it +investigates the historical developments of mind or the order of mental +phenomena in time, cognition may be viewed as a part of the result of +the interaction of external agencies and the organism, as an incident of +the great process of adaptation, physical and psychical, of organism to +environment. In thus looking at cognition, the evolutionist is making +the assumption which all science makes, namely, that correct views are +correspondences between internal (mental) relations and external +(physical) relations, incorrect views disagreements between these +relations. From this point of view he may proceed to argue that the +intellectual processes must tend to conform to external facts. All +correspondence, he tells us, means fitness to external conditions and +practical efficiency, all want of correspondence practical incompetence. +Consequently, those individuals in whom the correspondence was more +complete and exact would have an advantage in the struggle for existence +and so tend to be preserved. In this way the process of natural +selection, by separately adjusting individual representations to +actualities, would make them converge towards a common meeting-point or +social standard of true cognition. That is to say, by eliminating or at +least greatly circumscribing the region of individual illusion, natural +selection would exclude the possibility of a persistent common illusion. + +Not only so, the evolutionist may say that this coincidence between +common beliefs and true beliefs would be furthered by social as well as +individual competition. A community has an advantage in the struggle +with other communities when it is distinguished by the presence of the +conditions of effective co-operation, such as mutual confidence. Among +these conditions a body of true knowledge seems to be of the first +importance, since conjoint action always presupposes common beliefs, +and, to be effective action, implies that these beliefs are correct. +Consequently, it may be argued, the forces at work in the action of man +on man, of society on the individual, in the way of assimilating belief, +must tend, in the long run, to bring about a coincidence between +representations and facts. Thus, in another way, natural selection would +help to adjust our ideas to realities, and to exclude the possibility of +anything like a permanent common error. + +Yet once more, according to Mr. Herbert Spencer, the tendency to +agreement between our ideas and the environment would be aided by what +he calls the direct process of adaptation. The exercise of a function +tends to the development of that function. Thus, our acts of perception +must become more exact by mere repetition. So, too, the representations +and concepts growing out of perceptions must tend to approximate to +external facts by the direct action of the environment on our physical +and psychical organism; for external relations which are permanent will, +in the long run, stamp themselves on our nervous and mental structure +more deeply and indelibly than relations which are variable and +accidental. + +It would seem, from all this, that so long as we are keeping to the +scientific point of view, that is to say, taking for granted that there +is something objectively real answering to our perceptions and +conceptions, the question of the possibility of a universal or +(permanently) common illusion does not arise. Yet a little more +reflection will show us that it may arise in a way. So far as the +logical sufficiency of the social consensus or common belief is accepted +as scientifically proved, it is open to suspicion on strictly scientific +grounds. The evolutionist's proof involves one or two assumptions which +are not exactly true. + +In the first place, it is not strictly correct to say that all illusion +involves a practical unfitness to circumstances. At the close of our +investigation of particular groups of illusion, for example, those of +perception and memory, it was pointed out that many of the errors +reviewed were practically harmless, being either momentary and +evanescent, or of such a character as not to lead to injurious action. +And now, by glancing back over the field of illusion as a whole, we may +see the same thing. The day-dreams in which some people are apt to +indulge respecting the remote future have little effect on their +conduct. So, too, a man's general view of the world is often unrelated +to his daily habits of life. It seems to matter exceedingly little, in +general, whether a person take up the geocentric or the heliocentric +conception of the cosmic structure, or even whether he adopt an +optimistic or pessimistic view of life and its capabilities. + +So inadequate, indeed, does the agency of natural selection seem to be +to eliminate illusion, that it may even be asked whether its tendency +may not be sometimes to harden and fix rather than to dissolve and +dissipate illusory ideas and beliefs. It will at once occur to the +reader that the illusion of self-esteem, discussed in the last chapter, +may have been highly useful as subserving individual self-preservation. +In a similar way, it has been suggested by Schopenhauer that the +illusion of the lover owes its force and historical persistence to its +paramount utility for the preservation of the species. And to pass from +a recurring individual to a permanently common belief, it is maintained +by the same pessimist and his followers that what they regard as the +illusion of optimism, namely, the idea that human life as a whole is +good, grows out of the individual's irrational love of life, which is +only the same instinctive impulse of self-preservation appearing as +conscious desire. Once more, it has been suggested that the belief in +free-will, even if illusory, would be preserved by the process of +evolution, owing to its paramount utility in certain stages of moral +development. All this seems to show at least the possibility of a kind +of illusion which would tend to perpetuate itself, and to appear as a +permanent common belief. + +Now, so far as this is the case, so far as illusion is useful or only +harmless, natural selection cannot, it is plain, be counted on to weed +it out, keeping it within the narrow limits of the exceptional and +individual. Natural selection gets rid of what is harmful only, and is +indifferent to what is practically harmless. + +It may, however, still be said that the process of direct adaptation +must tend to establish such a consensus of true belief. Now, I do not +wish for a moment to dispute that the growth of intelligence by the +continual exercise of its functions tends to such a consensus: this is +assumed to be the case by everybody. What I want to point out is that +there is no scientific proof of this position. + +The correspondence of internal to external relations is obviously +limited by the modes of action of the environment on the organism, +consequently by the structure of the organism itself. Scientific men are +familiar with the idea that there may be forces in the environment which +are practically inoperative on the organism, there being no +corresponding mode of sensibility. And even if it be said that our +present knowledge of the material world, including the doctrine of the +conservation of energy, enables us to assert that there is no mode of +force wholly unknown to us, it can still be contended that the +environment may, for aught we know, be vastly more than the forces of +which, owing to the nature of our organism, we know it to be composed. +In short, since, on the evolution theory viewed as a scientific +doctrine, the real external world does not directly mirror itself in our +minds, but only indirectly brings our perceptions and representations +into adjustment by bringing into adjustment the nervous organism with +which they are somehow connected, it is plain that we cannot be certain +of adequately apprehending the external reality which is here assumed to +exist. + +Science, then, cannot prove, but must assume the coincidence between +permanent common intuitions and objective reality. To raise the question +whether this coincidence is perfect or imperfect, whether all common +intuitions known to be persistent are true or whether there are any that +are illusory, is to pass beyond the scientific point of view to another, +namely, the philosophic. Thus, our study of illusion naturally carries +us on from scientific to philosophic reflection. Let me try to make this +still more clear. + + +_Transition to Philosophic View._ + +All science makes certain assumptions which it never examines. Thus, the +physicist assumes that when we experience a sensation we are acted on by +some pre-existing external object which is the cause, or at least one +condition, of the sensation. While resolving the secondary qualities of +light, sound, etc., into modes of motion, while representing the object +very differently from the unscientific mind, he agrees with this in +holding to the reality of something external, regarding this as +antecedent to and therefore as independent of the particular mind which +receives the sense-impression. Again, he assumes the uniformity of +nature, the universality of the causal relation, and so on. + +Similarly, the modern psychologist, when confining himself within the +limits of positive science, and treating mind phenomenally or +empirically, or, in other words, tracing the order of mental states in +time and assigning their conditions, takes for granted much the same as +physical science does. Thus, as our foregoing analysis of perception +shows, he assumes that there is an external cause of our sensations, +that there are material bodies in space, which act on our sense-organs +and so serve as the condition of our sense-impressions. More than this, +he regards, in the way that has been illustrated in this work, the +percept itself, in so far as it is a process in time, as the normal +result of the action of such external agents on our nerve-structures, in +other words, as the effect of such action in the case of the healthy and +perfect nervous organism with the average organized dispositions, +physical and psychical; in which case he supposes the percept to +correspond, in certain respects at least, with the external cause as +made known by physical science. And, on the other hand, he looks on a +false or illusory percept as arising in another way not involving, as +its condition, the pre-existence of a corresponding material body or +physical agent. And in this view of perception, as of other mental +phenomena, the psychologist clearly takes for granted the principle that +all mental events conform to the law of causation. Further, he assumes +that the individual mind is somehow, in a way which it is not his +province to inquire into, one and the same throughout, and so on. + +The doctrine of evolution, too, in so far as scientific--that is, aiming +at giving an account of the historical and pre-historical developments +of the collective mind in time--agrees with psychology in making like +assumptions. Thus, it conceives an external agency (the environment) as +the cause of our common sensations and perceptions. That is to say, it +represents the external world as somehow antecedent to, and so +apparently independent of, the perceptions which are adjusted to it. And +all this shows that science, while removed from vulgar unenlightened +opinion, takes sides with popular thought in assuming the truth of +certain fundamental ideas or so-called intuitive beliefs, into the exact +meaning of which it does not inquire. + +When the meaning of these assumptions is investigated, we pass out of +the scientific into the philosophic domain. Philosophy has to critically +investigate the data of popular thought and of science. It has to +discover exactly what is implied in these fundamental principles. Then +it has to test their value by erecting a final criterion of truth, by +probing the structure of cognition to the bottom, and determining the +proper organ of certain or accurate knowledge; or, to put it another +way, it has to examine what is meant by reality, whether there is +anything real independently of the mind, and if so, what. In doing this +it inquires not only what common sense means by its object-world clothed +in its variegated garment of secondary qualities, its beauty, and so on, +but also what physical science means by its cosmic mechanism of sensible +and extra-sensible matter in motion: whether there is any kind of +objective reality belonging to the latter which does not also belong to +the former; and how the two worlds are related one to another. That is +to say, he asks whether the bodies in space assumed to exist by the +physicist as the antecedent conditions of particular sensations and +percepts are independent of mind and perception generally.[152] + +In doing all this, philosophy is theoretically free to upset as much of +popular belief of the persistent kind as it likes. Nor can science find +fault with it so long as it keeps to its own sphere, and does not +directly contradict any truth which science, by the methods proper to +it, is able to establish. Thus, for example, if philosophy finds that +there is nothing real independently of mind, science will be satisfied +so long as it finds a meaning for its assumed entities, such as space, +external things, and physical causes.[153] + +The student of philosophy need not be told that these imposing-looking +problems respecting cognition, making, up what the Germans call the +"Theory of Cognition," and the cognate problem respecting the nature of +reality, are still a long way from being settled. To-day, as in the days +of Plato and Aristotle, are argued, in slightly altered forms, the vexed +questions, What is true cognition? Is it a mere efflux from sensation, +a passive conformity of representation to sensation (sensualism or +empiricism)? or is it, on the other hand, a construction of active +thought, involving certain necessary forms of intelligence (rationalism +or intuitivism)? + +Again, how are we to shape to ourselves real objective existence? Is it +something wholly independent of the mind (realism)? and if so, is this +known to be what we--meaning here common people and men of science +alike--represent it as being (natural realism), or something different +(transfigured realism)? Or is it, on the contrary, something involving +mind (idealism)? and if so, is it a strictly phenomenal distinction +within our conscious experience (empirical idealism, phenomenalism), or +one of the two poles of subject and object constituted by every act of +thought (rational idealism)? These are some of the questions in +philosophy which still await their final answer. + +Philosophy being thus still a question and not a solution, we need not +here trouble ourselves about its problems further than to remark on +their close connection with our special subject, the study of illusion. + +Our brief reference to some of the principal inquiries of philosophy +shows that it tends to throw doubt on things which the unreflecting +popular mind holds to be indubitable. Different schools of philosophy +have shown themselves unequally concerned about these so-called +intuitive certainties. In general it may be said that philosophy, +though, as I have remarked, theoretically free to set up its own +standard of certainty, has in practice endeavoured to give a meaning +to, and to find a justification for the assumptions or first principles +of science. On the other hand, it has not hesitated, when occasion +required, to make very light of the intuitive beliefs of the popular +mind as interpreted by itself. Thus, rationalists of the Platonic type +have not shrunk from pronouncing individual impressions and objects +illusory, an assertion which certainly seems to be opposed to the +assumptions of common sense, if not to those of science. On the other +hand, the modern empirical or association school is quite ready to +declare that the vulgar belief in an external world, so far as it +represents this as independent of mind,[154] is an illusion; that the +so-called necessary beliefs respecting identity, uniformity, causation, +etc., are not, strictly speaking, necessary; and so on. And in these +ways it certainly seems to come into conflict with popular convictions, +or intuitive certainties, as they present themselves to the unreflecting +intelligence. + +Philosophy seems, then, to be a continuation of that process of +detecting illusion with which science in part concerns itself. Indeed, +it is evident that our special study has a very close connection with +the philosophic inquiry. What philosophy wants is something intuitively +certain as its starting-point, some _point d'appui_ for its +construction. The errors incident to the process of reasoning do not +greatly trouble it, since these can, in general, be guarded against by +the rules of logic. But error in the midst of what, on the face of it, +looks like intuitive knowledge naturally raises the question, Is there +any kind of absolutely certain cognition, any organ for the accurate +perception of truth? And this intimate relation between the scientific +and the philosophic consideration of illusion is abundantly illustrated +in the history of philosophy. The errors of sense, appearing in a region +which to the vulgar seems so indubitable, have again and again set men +thinking on the question, "What is the whole range of illusion? Is +perception, as popularly understood, after all, a big hallucination? Is +our life a dream?"[155] + +On the other hand, if our study of the wide range of illusion is fitted +to induce that temper of mind which is said to be the beginning of +philosophy, that attitude of universal doubt expressed by Descartes in +his famous maxim, _De omnibus dubitandum_, a consideration of the +process of correction is fitted to lead the mind on to the determination +of the conditions of accurate knowledge. It is evident, indeed, that the +very conception of an illusion implies a criterion of certainty: to call +a thing illusory, is to judge it by reference to some accepted standard +of truth. + +The mental processes involved in detecting, resisting, and overcoming +illusion, are a very interesting subject for the psychologist, though we +have not space here to investigate them fully. Turning to presentative, +and more particularly sense-illusions, we find that the detection of an +illusion takes place now by an appeal from one sense to another, for +example, from sight to touch, by way of verification;[156] now (as in +Myer's experiment) by a reference from sense and presentation altogether +to representation or remembered experience and a process of reasoning; +and now, (as in the illusions of art) conversely, by a transition of +mind from what is suggested to the actual sense-impression of the +moment. In the sphere of memory, again, illusion is determined, as such, +now by attending more carefully to the contents of memory, now by a +process of reasoning from some presentative cognition. Finally, errors +in our comprehensive general representations of things are known to be +such partly by reasoning from other conceptions, and partly by a +continual process of reduction of representation to presentation, the +general to the particular. I may add that the correction of illusion by +an act of reflection and reasoning, which brings the part into +consistent relation with the whole of experience, includes throughout +the comparison of the individual with the collective or social +experience.[157] + +We may, perhaps, roughly summarize these operations by saying that they +consist in the control of the lower automatic processes (association or +suggestion) by the higher activities of conscious will. This activity of +will takes the form now of an effort of attention to what is directly +present to the mind (sense-impression, internal feeling, mnemonic image, +etc.), now of conscious reflection, judgment, and reasoning, by which +the error is brought into relation to our experience as a whole, +individual and collective. + +It is for the philosopher to investigate the inmost nature of these +operations as they exhibit themselves in our every-day individual +experience, and in the large intellectual movements of history. In no +better way can he arrive at what common sense and science regard as +certain cognition, at the kinds of knowledge on which they are wont to +rely most unhesitatingly. + +There is one other relation of our subject to philosophic problems which +I have purposely left for final consideration. Our study has consisted +mainly in the psychological analysis of illusions supposed to be known +or capable of being known as such. Now, the modern association school +professes to be able to resolve some of the so-called intuitions of +common sense into elements exactly similar to those into which we have +here been resolving what are acknowledged by all as illusions. This fact +would seem to point to a close connection between the scientific study +of illusion and the particular view of these fundamental intuitions +taken by one philosophic school. In order to see whether there is really +this connection, we must reflect a little further on the nature of the +method which we have been pursuing. + +I have already had occasion to rise the expression "scientific +psychology," or psychology as a positive science, and the meaning of +this expression must now be more carefully considered. As a positive +science, psychology is limited to the function of analyzing mental +states, and of tracing their origin in previous and more simple mental +states. It has, strictly speaking, nothing to do with the question of +the legitimacy or validity of any mental act. + +Take a percept, for example. Psychology can trace its parentage in +sensation, the mode in which it has come by its contents in the laws of +association. But by common consent, a percept implies a presentative +apprehension of an object now present to sense. Is this valid or +illusory? This question psychology, as science, does not attempt to +answer. It would not, I conceive, answer it even if it were able to make +out that the whole mental content in the percept can be traced back to +elementary sensations and their combinations. For the fact that in the +chemistry of mind elements may combine in perfectly new forms does not +disprove that the forms thus arising, whether sentiments or +quasi-cognitions, are invalid. Much less can psychology dispute the +validity of a percept if it cannot be sure that the mind adds nothing to +sensation and its grouping; that in the genesis of the perceptive state, +with its intuition of something external and now present as object, +nothing like a form of intelligence is superimposed on the elements of +sensation, giving to the result of their coalescence the particular +unity which we find. Whether psychology as a positive science can ever +be sure of this: whether, that is to say, it can answer the question, +"How do we come by the idea of object?" without assuming some particular +philosophic or extra-scientific theory respecting the ultimate nature of +mind, is a point which I purposely leave open. + +I would contend, then, that the psychologist, in tracing the genesis of +the percept out of previous mental experiences, no more settles the +question, What is the object of perception? than the physicist settles +it in referring the sense-impression (and so the percept) to a present +material agent as its condition. + +The same applies to our idea of self. I may discover the concrete +experiences which supply the filling in of the idea, and yet not settle +the question, Does intelligence add anything in the construction of the +form of this idea? and still less settle the question whether there is +any real unity answering to the idea. + +If this is a correct distinction, if psychology, as science, does not +determine questions of validity or objective meaning but only of +genesis, if it looks at mental states in relation only to their temporal +and causal concomitants and not to their objects, it must follow that +our preceding analysis of illusion involves no particular philosophic +theory as to the nature of intelligence, but, so far as accurate, +consists of scientific facts which all philosophic theories of +intelligence must alike be prepared to accept. And I have little doubt +that each of the two great opposed doctrines, the intuitive and the +associational, would claim to be in a position to take up these facts +into its particular theory, and to view them in its own way. + +But in addition to this scientific psychology, there is another +so-called psychology, which is, strictly speaking, philosophic. This, I +need hardly say, is the association philosophy. It proceeds by analyzing +certain cognitions and sentiments into their elements, and straightway +declaring that they mean nothing more than these. That is to say, the +associationist passes from genesis to validity, from the history of a +conscious state to its objective meaning. Thus, from showing that an +intuitive belief, say that in causation, is not original (in the +individual or at least in the race), it goes on to assert that it is not +a valid immediate cognition at all. Now, I am not concerned here to +inquire into the logical value of this transition, but simply to point +out that it is extra-scientific and distinctly philosophic. If logically +justifiable, it is so because of some plainly _philosophic_ assumption, +as that made by Hume, namely, that all ideas not derived from +impressions are to this extent fictitious or illusory. + +And now we are in a position to understand the bearing of our scientific +analysis of acknowledged illusions on the associationist's treatment of +the alleged illusions of common sense. There is no doubt, I think, that +some of the so-called intuitions of common sense have points of analogy +to acknowledged illusions. For example, the conviction in the act of +perception that something external to the mind and independent of it +exists, has a certain superficial resemblance to an hallucination of +sense; and moreover, the associationist seeks to explain it by means of +these very processes which underlie what is recognized by all as +sense-illusion.[158] Again, it may be said that our notions of force and +of a causal nexus in the physical world imply the idea of conscious +energy as known through our muscular sensations, and so have a +suspicious resemblance to those anthropomorphic illusions of which I +have spoken under Illusions of Insight. Once more, the consciousness of +freedom may, as I have suggested, be viewed as analogous in its form and +its mode of origin to illusions of introspection. As a last example, it +may be said that the mind's certain conviction of the innateness of some +of its ideas resembles those illusions of memory which arise through an +inability to think ourselves back into a remote past having a type of +consciousness widely unlike that of the present. + +But now, mark the difference. In our scientific analysis of popularly +known illusions, we had something by which to determine the illusory +character of the presentation or belief. We had a popularly or +scientifically accepted standard of certainty, by a reference to which +we might test the particular _soi-disant_ cognition. But in the case of +these fundamental beliefs we have no such criterion, except we adopt +some particular philosophic theory, say that of the associationist +himself. Hence this similarity in structure and origin cannot in itself +be said to amount to a proof of equality of logical or objective value. +Here again it must be remarked that origin, does not carry validity or +invalidity with it.[159] + +We thus come back to our starting-point. While there are close +relations, psychological and logical, between the scientific study of +the ascertained facts of illusion and the philosophic determination of +what is illusory in knowledge as a whole, the two domains must be +clearly distinguished. On purely scientific ground we cannot answer the +question, "How far does illusion extend?" The solution of this question +must be handed over to the philosopher, as one aspect of his problem of +cognition. + +One or two remarks may, perhaps, be hazarded in concluding this account +of the relation of the scientific to the philosophic problem of +illusion. Science, as we have seen, takes its stand on a stable +consensus, a body of commonly accepted belief. And this being so, it +would seem to follow, that so far as she is allowed to interest herself +in philosophic questions, she will naturally be disposed to ask, What +beliefs are shared in by all minds, so far as normal and developed? In +other words, she will be inclined to look at universality as the main +thing to be determined in the region of philosophic inquiry. The +metaphysical sceptic, fond of daring exploits, may break up as many +accepted ideas as he likes into illusory _débris_, provided only he has +some bit of reality left to take his stand on. Meanwhile, the scientific +mind, here agreeing with the practical mind, will ask, "Will the beliefs +thus said to be capable of being shown to be illusory ever cease to +exercise their hold on men's minds, including that of the iconoclast +himself? Is the mode of demonstration of such a kind as to be likely +ever to materially weaken the common-sense 'intuition'?" + +This question would seem to be most directly answerable by an appeal to +individual testimony. Viewed in this light, it is a question for the +present, for some few already allege that in their case philosophic +reasonings exercise an appreciable effect on these beliefs. And so far +as this is so, the man of scientific temper will feel that there is a +question for him. + +It is evident, however, that the question of the persistence of these +fundamental beliefs is much more one for the future than for the +present. The correction of a clearly detected illusion is, as I have +more than once remarked, a slow process. An illusion such as the +apparent movement of the sun will persist as a partially developed error +long after it has been convicted. And it may be that the fundamental +beliefs here referred to, even if presumably illusory, are destined to +exercise their spell for long ages yet. + +Whether this will be the case or not, whether these intuitive beliefs +are destined slowly to decay and be dissolved as time rolls on, or +whether they will retain an eternal youth, is a question which we of +to-day seem, on a first view of the matter, to have no way of answering +which does not assume the very point in question--the truth or falsity +of the belief. This much may, however, be said. The associationist who +resolves these erroneous intuitions into the play of association, admits +that the forces at work generating and consolidating the illusory belief +are constant and permanent forces, and such as are not likely to be less +effective in the future than they have been in the past. Thus, he +teaches that the intuition of the single object in the act of perception +owes its strength to "inseparable association," according to which law +the ideas of the separate "possibilities of sensation," which are all we +know of the object, coalesce in the shape of an idea of a single uniting +substance. He adds, perhaps, that heredity has tended, and will still +tend, to fix the habit of thus transforming an actual multiplicity into +an imaginary unity. And in thus arguing, he is allowing that the +illusion is one which, to say the least of it, it will always be +exceedingly difficult for reason to dislodge. + +In view of this uncertainty, and of the possibility, if not the +probability, of these beliefs remaining as they have remained, at least +approximately universal, the man of science will probably be disposed to +hold himself indifferently to the question. He will be inclined to say, +"What does it matter whether you call such an apparently permanent +belief the correlative of a reality or an illusion? Does it make any +practical difference whether a universal 'intuition,' of which we cannot +rid ourselves, be described as a uniformly recurring fiction of the +imagination, or an integral constitutive factor of intelligence? And, in +considering the historical aspect of the question, does it not come to +much the same thing whether such permanent mental products be spoken of +as the attenuated forms or ghostly survivals of more substantial +primitive illusions (for example, anthropomorphic representations of +material objects, 'animistic' representations of mind and personality), +or as the slowly perfected results of intellectual evolution?" + +This attitude of the scientific mind towards philosophic problems will +be confirmed when it is seen that those who seek to resolve stable +common convictions into illusions are forced, by their very mode of +demonstration, to allow these intuitions a measure of validity. Thus, +the ideas of the unity and externality attributed to the object in the +act of perception are said by the associationist to answer to a matter +of fact, namely, the permanent coexistence of certain possibilities of +sensation, and the dependence of the single sensations of the individual +on the presence of the most permanent of these possibilities, namely, +those of the active or muscular and passive sensations of touch, which +are, moreover, by far the most constant for all minds. Similarly, the +idea of a necessary connection between cause and effect, even if +illusory in so far as it expresses an _objective_ necessity, is allowed +to be true as an expression of that uniformity of our experience which +all scientific progress tends to illustrate more and more distinctly. +And even the idea of a permanent self, as distinct from particular +fugitive feelings, is admitted by the associationist to be correct in so +far as it expresses the fact that mind is "a series of feelings which +is aware of itself as past and future." In short, these "illusory +intuitions," by the showing of those who affirm them to be illusory, are +by no means hallucinations having no real object as their correlative, +but merely illusions in the narrow sense, and illusions, moreover, in +which the ratio of truth to error seems to be a large one. + +It would thus appear that philosophy tends, after all, to unsettle what +appear to be permanent convictions of the common mind and the +presuppositions of science much less than is sometimes imagined. Our +intuitions of external realities, our indestructible belief in the +uniformity of nature, in the nexus of cause and effect, and so on, are, +by the admission of all philosophers, at least partially and +_relatively_ true; that is to say, true in relation to certain features +of our common experience. At the worst, they can only be called illusory +as slightly misrepresenting the exact results of this experience. And +even so, the misrepresentation must, by the very nature of the case, be +practically insignificant. And so in full view of the subtleties of +philosophic speculation, the man of science may still feel justified in +regarding his standard of truth, a stable consensus of belief, as above +suspicion. + + ++----------------------------------------------------------------------+ +|Transcribers note: In the original some footnotes read 'note[1]'and | +|'note[2]'. They have been renumbered to allow readers to refer directly| +|to the correct footnote. | ++----------------------------------------------------------------------+ + + +INDEX. + + + A. + + Abercrombie, Dr. J, 141, note[82], 278. + + Abnormal life, relation of, + to normal, 1, 120, 121, 124, 182, 277, 284, note[132], 336; + effects of amputation, 62; + modification of sensibility in, 65; + gross sense-illusions of, 111, hallucinations of, 118; + sense of personal identity in, 289. + + Active, stage in perception, 27; + illusion distinguished from passive, 45, 332-334. + + Actor. _See_ Theatre. + + Adaptation, illusion as want of, 124, 188, 339. + + Æsthetic intuition, 213; + illusions of, 214. + + After-dreams, 144, 183. + + After-sensation, after-impression, 55, 115. + + Anæsthesia, 65. + + Ancestral experience, results of, 281. + + Animals, recognition of portraits by, 105; + expectation of, 298. + + Anthropomorphism, 225, 360. + + Anticipation. _See_ Expectation. + + Apparitions. _See_ Hallucination. + + Aristotle, 130. + + Art, illusions of, 77, 104. + + Artemidoros, 129. + + Association, laws of, in perception, 22; + in dreams, 153, 156; + link of resemblance in dreams, 159; + associative dispositions in dreams, 169; + effect of, in insight, 221; + inseparable, 359. + + Associationist, views of, 349, 352, 355. + + Attention, involved in perception 21; + absence of, in sense-illusion, 39, 87; + relation of, to recognition of objects, 90; + expectant, 93; + attitude of, in dreaming, 137, 172; + to internal mental states, 194; + absence of, in errors of insight, 228. + + Authority, influence of, in introspection, 210; + in belief, 325. + + Autobiography, errors connected with, 276, 280. + + Automatic activity of centres, in hallucinations, 113; + in dreams, 136, 151; + automatic intellectual processes, 300, 335, 352. + + + B. + + Baillarger, J., 13, note[1], 113, note[57], 119, + notes[64] and [65], 120, note[66]. + + Bain, Dr. A., 32, note[12], 117, note[60], 190. + + Beattie, J., 141, note[82]. + + Beauty, sentiment of, 206, 213. + + Belief, immediate, 14, 15, 294; + simple and compound, 296; + illusory forms of, 297; + simple expectation, 297; + expectation, of extra-personal experiences, 307; + retrospective, 309; + in persistent objects and persons, 312; + self-esteem, 315; + representation of classes of things, 322; + representations of mankind, 322; + representation of life and the world as a whole, 322; + as predisposition to error, 324; + amount of divergence in, 325; + tendency towards convergence in, 326. + + Beneficial, correct knowledge as, 340; + illusion as, 342. + + Berkeley, Bishop, 218, 349, note[154]. + + Binet, A., 53, note[20]. + + Boismont, Brierre de, 11, note[1]. + + Börner, J., 146. + + Braid, James, 186, 187. + + Brewster, Sir D., 42, 73, 81, 116. + + Brücke, E., 77, note[38]. + + Byron, Lord, 116. + + + C. + + Carpenter, Dr. W.B., 32, note[12], 108, 110, note[56], 186, 231, + note[111], 265, note[125], 276. + + Castle-building, as illusory perception, 3, 99. + + Cause, idea of, in science, 344; + reality of relation of, 347, 349, 356, 360. + + Change, a condition of conscious life, 252, 287, note[133]. + + Childhood, our recollections of, 263, 269. + + Children, curiosity of, 175, 180; + estimate of time by, 256; + confusion of dream and waking life by, 276; + imagination of, 279; + self-assertion of, 319; + intellectual condition of, 357, note[159]. + + Clarke, Dr. E.H., 117. + + Classification, in recognition of sensation, 21; + in recognition, of object, 24; + in introspective recognition, 193. + + Clifford, Professor W.K., 56, note[24]. + + Coalescence, of sensations, 43, 52; + of dream-images, 162; + of internal feelings, 196; + of mnemonic images, 265. + + Coenæsthesis, 41, 99, 145, 286, 288. + + Cognition, immediate or intuitive, 5, 14-16, 294; + presentative and representative, 9, 13, 217, 330; + nature of, in dreams, 168, 172; + nature of, generally, 295, 331; + philosophic problems of, 346. + + Colour, external reality of, 8, 37; + illusory perception of, 37, 88; + subjective complementary colours (colour-contrast), 67, 83. + + Coloured media, objects seen through, 82. + + Common cognition, and truth, 337; + genesis and validity of, 353. + + Common experience distinguished from + individual, 26, 27, 137, 209, 214, 336, 351; + illusion as, 47,325, 337. + + Common sense, intuitions of, 346, 349, 352, 357. + + Complementary colours, 67, 83. + + Concave, apparent conversion of, into convex, 84. + + Conjuror, tricks of, 56, 106. + + Consciousness, veracity of, 192, 205; + inspection of phenomena of, 196; + of self, 283, 285. + + Consensus, the standard of truth, 7, 8, 211, 325, 338, 357. + + Conservation of energy, 343. + + Construction, rational, in dreams, 170. + + Continuum, the perception of the world as, 52, 56, note[24]. + + Correction of illusion, in sense-illusion, 38, 124, 137; + dreams, 182; + introspection, 210; + insight, 229; + memory, 291; + historical correction 338; + intellectual processes involved in, 351. + + Criterion of illusion, 337. + + Cudworth, R., 161 + + + D. + + Deception of the senses, 19; + self-deception, 200; + conscious deception of others, 222. + + Delboeuf, J., 175, note[97], 235, note[113]. + + _Delirium tremens_, 118, note[62]. + + Democritus, 130. + + De Quincey, 253, 280. + + Descartes, R., 116, 350. + + Dickens, Charles, 277. + + Direction, illusory sense of, in vision, 66, 71, 73; + in hearing, 72, 75. + + Disease. _See_ Abnormal life. + + Dissolution. _See_ Evolution. + + Doubt, starting-point in philosophy, 350. + + Dreams, relation of, to illusions of sense, 18, 130; + and waking experience, 127; + theories of, 128; + physiology of, 131; + extent of, in sleep, 132; + psychological conditions of, 136; + excitants of, 139, 143; + exaggeration in, 147; + symbolism of, 149; + as results of automatic activity of centres, 151; + as results of association, 153; + structure of, 156; + incoherent, 156; + coherent, 161; + action of feeling in, 164; + play of associative dispositions in, 168; + co-operation of attention and intelligence in, 172; + limits of intelligence in, 180; + after-dreams, 183, 274; + relation of, to hypnotic condition, 185; + experience of, in relation to errors of memory, 273. + + + E. + + Eccentricity, law of, 59. + + Ego. _See_ Self. + + Emotion, and illusion of perception, 103; + and hallucination, 115; + and bodily sensations, 150; + control of dreams by, 164; + introspection of, 199; + and illusion of introspection, 203; + and æsthetic intuition, 213; + and illusion of memory, 270; + and illusion of belief, 306, 324; + and cognition generally, 357, note[159]. + + Empiricism, philosophic, 348. + + _Ennui_, and sense of time, 250. + + Environment, sources of sense-illusion in, 47, 48, 70; + view of, in mental disease, 290, 326; + view of, in normal life, 323; + action of, in assimilating belief, 339. + + Error, immediate and mediate, 6, 334. + + Esquirol, J.E.D., 12, note[2]. + + Evolution, relation of, to dissolution, 122; + of power of introspection, 209; + of power of insight, 230; + and self-assertion, 320; + evolutionist's view of error, 339; + doctrine of, as science, 346. + + Exaggeration, in interpretation of sensations, 65; + in dream-interpretation, 147; + in memory, 269. + + Expectation, preliminary to perception, 30; + and illusory perception, 93, 102, 106; + nature of, 295; + and memory, 298; + of new experience, 301; + of remote events, 302; + measurement of duration in, 302; + action of imagination in, 305; + extension of meaning of, 307, 308. + + Experience, effect of, in perception, 22, 68, 85, 86, 91; + external and internal, 194, 210; + revivals of waking, in dreams, 152; + effects of present, on retrospection, 267; + anticipation of new, 301. + + External world. _See_ World. + + + F. + + Fallacy and illusion 6, 335; + of testimony, 265. + + Familiarity, sense of, in new objects, 272, 281. + + Fechner, G.T., 51. + + Ferrier, Dr., 32, note[12], 58, note[26]. + + Fiction, as producing illusion, 278, 279, 311. + + Fitness. _See_ Adaptation. + + Flattery, _rationale_ of, 200, 222. + + Forgetfulness and illusion, 278, 279, 311. + + Free-will, doctrine of, 207, 342, 356. + + Future. _See_ Expectation. + + + G. + + Galton, F., 117. + + Ghosts. _See_ Hallucination. + + Goethe, 116, 117, 280 and note[131]. + + Griesinger, W., 13, note[2], 63, note[31], 66, note[32], 115, 118, + note[62], 119, note[64], 120, note[66], 290, note[135], 327, + note[146]. + + Gruithuisen, 143, 144. + + Gurney, E., 224, note[109]. + + + H. + + Hall, G.S., 186, note[102]. + + Hallucination, and illusion, 11, 109, 111, 112, 121; + and subjective sensation, 63, 109, 121; + sensory and motor, 66; + nervous conditions of, 112-114; + incomplete and complete, 113; + as having either central or peripheral origin, 113; + causes of, classified, 115; + in sane condition, 116; + in insanity, 118; + visual and auditory, 119; + dreams regarded as, 139, 151; + hypnagogic, 143; + after-dreams and ghosts, 183; + of memory, 271; + relation of, to errors of belief, 322; + intuition of external world regarded as, 355. + + Happiness, feeling of, 200. + + Harmful, illusion as, 188, 229, 292, 339. + + Harmless, illusions as, 124, 292, 341. + + Hartley, D., 139, 256, note[124], 279. + + Hearing, as mode of perception, 34, 48; + localization of impression in, 60; + sense of direction in, 72; + activity of, in sleep, 140; + and muscular sense, 171. + + Heidenhain, Dr., 186-188. + + Helmholtz, H., 22, 23, note[7], 44, 51, 54 and note[22], 55, note[23], + 57, 67, note[33], 78, note[39], 80, 85, note[43], 88, 90, 207, + note[105]. + + Heraclitus, 137. + + Heredity, and illusion of memory, 280; + action of, in perpetuating intuition, 359. + + Hering, E., 67, note[33]. + + Hodgson, Shadworth H., 347, note[153]. + + Holland, Sir H., 277. + + Hood, Thomas, 146. + + Hope, illusory. _See_ Expectation. + + Hoppe, Dr. J.I., 51, 58, note[26]. + + Horwicz, A., 145, note[85]. + + Hume, D., 355. + + Huxley, Professor T., 119, note[1]. + + Hyperæsthesia, 65. + + Hypnotism, 185. + + Hypochondria, 65. + + Hypothesis, as illusory, 310, 311. + + + I. + + Idealism, 348. + + Identity, cases of mistaken, 267. + + Identity, personal, confusion of, in dreams, 163; + consciousness of, 241, 267, 282, 285; + illusory forms of, 283; + gross disturbances of, in normal life, 287; + in abnormal life, 289; + momentary confusions of, 293. + + Illusion, definition of, 1; + varieties of, 9; + extent of, 328; + _rationale_ of, 331, 337. + + Image (physical). _See_ Reflection. + + Image (mental), in perception, 22; + seat of, 32; + in dreams, 138; + mnemonic, 236. + + Imagination, play of, in perception, 95, 99; + and sense-illusion, 106; + nature of, in dreaming, 136, 161; + as antecedent of dream, 152, 158; + as poetic interpretation of nature, 224; + memory corrupted by effect of past, 264, 273, 277; + present, creating the semblance of recollection, 267, 271; + play of, in expectation, 305; + as element of illusion generally, 333. + + Immediate. _See_ Cognition. + + Individual, and common experience, 26, 27, 137, 209, 214, 336; + dream-experience as, 44, 68; + internal experience as, 209; + memory as, 232; + belief and truth, 338. + + Inference, and immediate knowledge, 6, 334; + in perception, 22, 26, 68; + in belief, 295. + + Innate, recollection as, 280; + principles, 295, 356. + + Insane, sense-illusions of, 63, 65, 111; + hallucinations of, 118; + dreaming and state of, 182; + mnemonic illusions of, 278, 289; + beliefs of, 327. + + Insight, nature of, 217; + illusions of, defined, 220; + passive illusions of, 220; + histrionic illusion, 222; + active illusions of, 223; + poetic interpretation of nature, 224; + value of faculty of, 228. + + Interpretation, in correct perception, 22; + of impression and experience, 70; + and volition, 95; + and fixed habits of mind, 101; + and temporary attitude of mind, 102; + of sensations in dreams, 137, 147; + of internal feelings, 203; + of others' feelings, 217; + of nature by poet, 225; + recollection as, 242. + + Introspection, nature of, 14, 189; + illusory forms of, 190; + confusion of inner and outer experiences, 194; + inaccurate inspection of feelings, 196; + presentation and representation confused, 199; + feelings and inferences from these, 203; + moral self-scrutiny, 204; + philosophic, 205; + value of, 208. + + Intuition. _See_ Cognition. + + Intuitivism, 348. + + + J. + + Jackson, Dr. J. Hughlings, 27, note[9], 33, 123, note[67]. + + Johnson, Dr., 116. + + + K. + + _Klang_, as compound sensation, 53. + + Knowledge. _See_ Cognition. + + + L. + + Language, function of, 195. + + Leibnitz, 133. + + Lélut, L.F., 120, note[66]. + + Lessing, G. E., 133, note[73]. + + Leuret, 290, note[135]. + + Lewes, G.H., 28, 32, note[12], 52, note[30], 62, note[1], 68, + note[35], 89, note[45], 115, note[58], 150. + + Life, our estimate of, 323, 326, 327. + + Light, sensation and perception of, 59; + effects of reflection and refraction, of, 73; + representation, of, in painting, 88, 91; + action of, in sleep, 140. + + Localization, as local discrimination of sensations, 52; + as localizing of sensations, 59, 60; + illusory, 61, 82; + in hallucination, 118, 119; + in dreaming, 148; + of events in time, in memory, 238, 245; + in expectation, 304. + + Locke, 133, note[73]. + + Lotze, H., 60, note[29]. + + Lover, illusion of, 224, 227, 342. + + Luminosity of painting, 88, 91. + + Lustre, as compound sensation, 54. + + Lyell, Sir Charles, 311. + + + M. + + Magic, arts of, 73. + + Magnitude, apparent, in vision, 75, note[37]; + perception of, in pictorial art, 88, 91; + of time-intervals, 245, 249; + recollection of, 268. + + Malebranche, 116. + + Mankind, our views of, 322. + + Matter. _See_ World (material). + + Maudsley, Dr. H., 32, note[12]. + + Maury, A., 140, 143, 153, note[92], 159, 163, note[94], 173. + + Mayer, Dr. A., 66, note[32]. + + Measurement, subjective, of time, 245. + + Media, coloured, illusions connected with presence of, 82. + + Memory, nature of, 9, 13, 231; + veracity of, 232, 290; + defined, 234; + psychology of, 236; + physiology of, 237; + localization of events in, 238; + and sense of personal identity, 241, 283; + illusions of, 241; + illusory localization, 245, 256; + distortions of, 261; + hallucinations of, 271; + illusions respecting personal identity, 283; + relation of, to belief, 295; + compared with expectation, 297; + and inference, 335. + + Metempsychosis, 294. + + Meyer, H., 83, 144. + + Mill, J.S., 298, note[138], 309. + + Mirrors, as means of delusion, 73. + + Misanthropist, 2, 323. + + Mitchell, Dr. Weir, 62. + + Monomania, 111. + + Moral, intuition, 216; + self-inspection, 204. + + Motor illusions. _See_ Muscular sense. + + Movement, apparent, 50, 57, 73, 81, 95, 107; + in dreams, 142, 154. + + Müller, Johannes, 58, note[27], 100, 117, 143. + + _Muscæ volitantes_, 118, note[62]. + + Muscular sense, in perception, 23; + illusions connected with, 50, 57, 62, 66; + co-operation, of, in dreams, 142, 154. + + Music, subjective interpretation of, 223. + + + N. + + Natural selection, effect of, in eliminating error, 340. + + Nature, personification of, 224; + uniformity of, 344, 360. + + Necessity, idea of, 349, 360. + + Nervous system, and conditions of perception, 31; + connections of, 32, 169; + function of, and force of stimulus, 47, 50; + prolonged activity of, 55; + specific energy of, 58; + variations in state of, 64; + fatigue of, 65, 115; + disease of, _ibid._; + nervous conditions of hallucination, 112, 115; + nervous dissolution and evolution, 122; + condition of, in sleep, 131; + in hypnotic condition, 186; + nervous conditions of memory, 237; + nervous conditions of illusion in general, 334. + + Normal life, relation of, + to abnormal, 1, 121, 124, 182, 277, 284, note[132]; + hallucinations of, 116. + + + O. + + Object, nature of, 36, 353. + + Objective and subjective experience, 26, 27, 137, 214. + + Old age, dreams how regarded in, 276. + + Oneirocritics, 129. + + Opera, illusion connected with, 104. + + Optimism, 323, 327, 342. + + Organic sensations, discrimination of, 41; + interpretation of, 99; + in sleep, 145, 148. + + Organism, conditions of illusion in, 47, 50; + relation of our conception of the universe to sensibilities of, 343. + + Orientation, 125, 138. + + + P. + + Pain, recollection of, 264, 270. + + Painting, representation of third dimension by, 77; + apparent movement of eye in portrait, 81; + discrepancies between, and object in magnitude and luminosity, 88; + realization of, and mental preparation, 105; + realization of, by animals, 105. + + Paræsthesia, 68. + + Paralysis of ocular muscles, 66. + + Passive, and active factor in perception, 27; + and active illusion, 45. + + Percept, 22; + and sense-impression, 59. + + Perception, a form of immediate knowledge, 10, 13, 17, 18; + external and internal, 14; + philosophy of, 14, 20, 22, 36, 346, 348, 353, 355, 359; + illusions of, 19, 35; + psychology of, 20; + and inference, 22, 26, 76; + physiological conditions of, 31. + + Persistent objects, representation of, 312. + + Persistent self. _See_ Personal identity. + + Personal equation, in perception, 101; + in æsthetic intuition, 214; + in memory, 292; + in belief, 324. + + Personal identity, consciousness of, 241, 282, 285; + illusions connected with, 283; + disturbances in sense of, 287; + sense of, in insanity, 289; + momentary confusions of, 293; + philosophic problem of, 285, 354, 360. + + Personification of nature, 224. + + Perspective, linear, 79, 97, 98; + aerial, 80; + of memory, 245. + + Pessimism, 323, 327. + + Phenomenalism, 348. + + Philosophy, conception of illusion by, 7, 36, 205, 285, 349; + of mind, 132, 285, 344, 348; + as theory of knowledge, 295, 346; + and science, 346, 348; + and common sense, 347, 349; + problems of, 347. + + Phosphenes, 58. + + Physical science. _See_ Science. + + Plato, 281. + + Platonists, 349. + + Pleasure, feeling of, 200; + recollection of, 264, 270. + + Plutarch, 133, note[73]. + + Poetry, lyrical and dreams, 164; + misinterpretation of, 223; + personification, 224. + + Points, discrimination of, 52. + + Poisons, action of, 115. + + Pollock, F., 184, note[101]. + + Pollock, W.H., 184. + + Predisposition, action of, in perception, 44, 101, 102; + in æsthetic intuition, 215; + in insight, 223; + in recollection, 268; + in belief, 305, 319; + belief as, 324. + + Prejudice. _See_ Predisposition. + + Prenatal experience, recollection of, 281. + + Preperception, 27; + illusions connected with, 44, 93; + voluntary, 95; + result of habit of mind, 101; + result of temporary conditions, 102; + as sub-expectation, 102; + as definite expectation, 106. + + Presentation and representation, 9, 10, 13, 14, 192, 234, 329, 330. + + Projection, outward, of sensations, 63; + of mental image, 111, 112; + of solid form on flat, 79, 81, 96. + + Prophetic, dreams as, 129, 147, note[88]; + enthusiast, 307. + + Psychology, popular and scientific, 9, 10; + distinguished from philosophy, 14, 36, 345, 352; + introspective method of, 208; + as a kind of philosophy, 305. + + Public events, localization, of, by memory, 258. + + + R. + + Radestock, P., 130, note[71], 132, note[72], 134, note[75], 140, 141, + 149, note[90], 162, 182, 275. + + Rationalism, philosophic, 348. + + Realism, 348. + + Reality, nature of, 36, 346. + + Recognition, and perception, 24, 25; + illusions of, 87; + and memory, 234. + + Reflection (of light), illusions connected with, 73, 83. + + Refraction and optical illusion, 73. + + Relative, sensation as, 64; + attention to magnitude and brightness as, 91; + estimate of duration as, 249. + + Relief, illusory perception of, 75, 96. + + Representation and presentation, 9, 10, 13, 14, 192. + + Retrospection. _See_ Memory. + + Ribot, T., 238, note[114], 290, note[135]. + + Richter, J.P., 143. + + Robertson, Professor G.C., 35, note[14]. + + Romanes, G.J., 105, note[2], 250, note[122]. + + Rousseau, 280. + + + S. + + Savage, dream theory of, 128; + idea of nature of, 225. + + Scherner, C.A., 140, 149. + + Schopenhauer, A., 145, 342. + + Schroeder, H., 85. + + Science, philosophy and, 8, 36, 285, 344; + conception of the material world in physical, 36, 343, 346, 347; + and common cognition, 338, 357. + + Scott, Sir W., 116, 125. + + Secondary qualities, 36, 344. + + Selection, process of, in perception, 95; + in dreams, 174; + in memory, 257, 263. + + Self, confusion of, in dreams, 163; + introspective knowledge of, 192; + self-deception, 200; + identity of, 241, 282, 285; + confusion of present and past, 267, 284; + disturbances in recognition of, 287, 289; + momentary confusions of, 295; + confusion of present and future, 305. + + Self-esteem, illusion of, 315; + origin of, 319; + utility of, 342. + + Self-preservation, 320. + + Sensation, element in perception, 20; + discrimination and classification of, 21; + interpretation of, 22; + inattention to, 39, 87; + modified by central reaction, 39, 87, 89, 91; + confusion of novel, 40; + indistinct, 41; + misinterpretation of, 44; + relation of, to stimulus, 46, 50; + limits to discrimination of, 52; + after-impression, 55; + subjective, 59, 62, 107, 143; + localization of, 59. + + Sensibility, limits of, 50; + variations of, 64. + + Sensualism, philosophic, 348. + + Shadow, cast, 77. + + Shakespeare, 3. + + Sight, mode of perception, 19, 33, 34, 48, 49; + local discrimination in, 52; + single vision, 54; + localization of impression in, 60; + in sleep, 139; + images of, in sleep, 150, 154. + + Single, vision, 54; + touch, 72. + + Sleep, mystery of, 127; + physiology of, 131. + + Sleight of hand. _See_ Conjuror. + + Smell, as mode of perception, 34, note[14]; + localization of impression in, 60; + subjective sensations of, 108; + in sleep, 141; + and taste, 171. + + Solidity, illusory perception of, 75, 96. + + Space, representation of, 207. + + Specific energy of nerves, 58. + + Spectra, ocular, etc. _See_ Subjective sensation. + + Spencer, Herbert, 32, note[12], 128, note[69], 323, 340. + + Spinoza, 143, 184. + + Spiritualist _séances_, 103, 107, 123, 265. + + Stereoscope, 75. + + Stewart, Dugald, 172, 306. + + Stimulus, qualitative relation of, to sensations, 46, 58, 67; + quantitative relation of, to sensation, 50, 64; + after-effect of, 55; + prolonged action of, 56; + subjective or internal, 62; + exceptional relation of, to organ, 70; + action of, in sleep, 135, 139, 143; + in hypnotic condition, 186. + + Strümpell, L., 144, 147, note[89]. + + Subjective, experience, 26, 27, 137, 214; + movement, 51, 57; + sensation, 59, 62, 107, 113, 121, 143. + + Suggestion, by external circumstances, 30, 44, 89, 91, 267; + verbal, 30, 106, 188, 215, 268, 301, 310. + + Symbol, dream as, 129, 149. + + Sympathy, basis of knowledge, 223; + and illusion of insight, 223; + and illusion of memory, 277; + and momentary illusion, 293. + + + T. + + Taine, H., 60, note[29], 108, note[54], 117, note[59], 137, + 298, note[137], 356, note[158]. + + Taste, æsthetic. _See_ Æsthetic intuition. + + Taste, localization of impression in, 60; + subjective sensations of, 63; + variations in sensibility, 68; + activity of, in sleep, 141; + and smell, 171. + + Temperament, a factor in sense-illusion, 101; + in dreams, 137; + in illusory belief, 325; + in illusion generally, 334, note[149]. + + Temperature, sense of, 65. + + Tennyson, A., 226. + + Testa, A.J., 131. + + Testimony, of consciousness, 205; + fallacies of, 265; + to identity, 267. + + Thaumatrope, 56. + + Theatre, illusion of the, 104, 222; + self-deception of the actor, 200. + + Thompson, Professor S.P., 51, note[17]. + + Thought, in relation to belief, 326. + + Time, retrospective idea of, 239, 246, 250; + constant error in estimate of, 245; + subjective estimate of, 249; + contemporaneous estimate of, 250; + sense of, in insanity, 290; + prospective estimate of, 303. + + Touch, as form of perception, 33, 34, 49; + local discrimination in, 52; + subjective sensations of, 62; + variations in sensibility of, 65; + in sleep, 141. + + Transformation, in perception, 94; + of images in dreams, 163; + in memory, 262, 267; + in expectation, 305. + + Trick. _See_ Conjuror. + + Tuke, Dr., 110. + + Tylor, E.B., 128, note[69]. + + + U. + + Unconscious, inference, 22, 68, 269, 335, note[150]; + mental activity, 133, 235; + impressions, 41, 152. + + Useful. _See_ Beneficial. + + + V. + + Vanity. _See_ Self-esteem. + + Venn, J., 299, note[139]. + + Ventriloquism, 82. + + Verification, of sense-impression, 38, 351; + of self-inspection, 210; + of memory, 291. + + Verisimilitude, in art, 80, 88; + in theatrical representation, 104; + in dreams, 168. + + Vierordt, 245. + + Vision. _See_ Sight. + + Visions, 1, 110; + dreams regarded as, 128, 131. + + Vital sense. _See_ Coenæsthesis. + + Voice, internal, 119, 194; + activity of, in dreams, 155. + + Volition, and perception, 95; + absence of, during sleep, 137,172; + co-operation of, in correction, of illusion, 352. + + Volkelt, J., 172. + + + W. + + Weber, E.H., 43. + + Weinhold, Professor, 186. + + Wetness, perception of, 53. + + Wheatstone, Sir C, 75. + + Wheel of life, 56. + + Will. _See_ Volition. + + Wordsworth, W., 281. + + World, our estimate of, 323, 326, 327; + scientific conception of material, 8, 36, 343, 344; + reality of external, 344-346, 349, 353, 355, 360. + + Wundt, Professor, W. 13, note[2], 31, note[11], 32, note[12], 58, + note[27], 67, note[34], 75, 93, note[47], 118, note[63], 136, + note[77], 139, 143, 177, 246, 247, note[119], 251, 252, 254. + + +THE END + + +FOOTNOTES: + +[1] A history of the distinction is given by Brierre de Boismont, in his +work _On Illusions_ (translated by R. T. Hulme, 1859). He says that +Arnold (1806) first defined hallucination, and distinguished it from +illusion. Esquirol, in his work, _Des Maladies Mentales_ (1838), may be +said to have fixed the distinction. (See Hunt's translation, 1845, p. +111.) + +[2] This fact has been fully recognized by writers on the pathology of +the subject; for example, Griesinger, _Mental Pathology and +Therapeutics_ (London, 1867), p. 84; Baillarger, article, "Des +Hallucinations," in the _Mémoires de l'Académie Royale de Médecine_, +tom. xii. p. 273, etc; Wundt, _Physiologische Psychologie_, p. 653. + +[3] I here touch on the distinction between the psychological and the +philosophical view of perception, to be brought out more fully +by-and-by. + +[4] It might even be urged that the order here adopted is scientifically +the best, since sense-perception is the earliest form of knowledge, +introspected facts being known only in relation to perceived facts. But +if the mind's knowledge of its own states is thus later in time, it is +earlier in the logical order, that is to say, it is the most strictly +presentative form of knowledge. + +[5] Here and elsewhere I use the word "impression" for the whole complex +of sensation which is present at the moment. It may, perhaps, not be +unnecessary to add that, in employing this term, I am making no +assumption about the independent existence of external objects. + +[6] Psychological usage has now pretty well substituted the term "image" +for "idea," in order to indicate an individual (as distinguished from a +general) representation of a sensation or percept. It might, perhaps, be +desirable to go further in this process of differentiating language, and +to distinguish between a sensational image, _e.g._ the representation of +a colour, and a perceptional image, as the representation of a coloured +object. It may be well to add that, in speaking of a fusion of an image +and a sensation, I do not mean that the former exists apart for a single +instant. The term "fusion" is used figuratively to describe the union of +the two sides or aspects of a complete percept. + +[7] This impulse to fill in visual elements not actually present is +strikingly illustrated in people's difficulty in recognizing the gap in +the field of vision answering to the insensitive "blind" spot on the +retina. (See Helmholtz, _Physiologische Optik_, p. 573, _et seq._) + +[8] This relation will be more fully discussed under the head of +"Memory." + +[9] I adopt this distinction from Dr. J. Hughlings Jackson. See his +articles, "On Affections of Speech from Diseases of the Brain," in +_Brain_, Nos. iii. and vii. The second stage might conveniently be named +apperception, but for the special philosophical associations of the +term: _Problems of Life and Mind_, third series, p. 107. This writer +employs the word "preperception" to denote this effect of previous +perception. + +[10] Such verbal suggestion, moreover, acting through a +sense-impression, has something of that vividness of effect which +belongs to all excitation of mental images by external stimuli. + +[11] See Wundt, _Physiologische Psychologie_, p. 723. + +[12] For a confirmation of the view adopted in the text, see Professor +Bain, _The Senses and the Intellect_, Part II. ch. i. sec. 8; Herbert +Spencer, _Principles of Psychology_, vol. i. p. 234, _et passim_; Dr. +Ferrier, _The Functions of the Brain_, p. 258, _et seq._; Professor +Wundt, _op. cit._, pp. 644, 645; G. H. Lowes, _Problems of Life and +Mind_, vol. v. p. 445, _et seq._ For an opposite view, see Dr. +Carpenter, _Mental Physiology_, fourth edit., p. 220, etc.; Dr. +Maudsley, _The Physiology of Mind_, ch. v. p. 259, etc. + +[13] See note, p. 22. + +[14] Touch gives much by way of interpretation only when an individual +object, for example a man's hat, is recognized by aid of this sense +alone, in which case the perception distinctly involves the reproduction +of a complete visual percept. I may add that the organ of smell comes +next to that of hearing, with respect both to the range and definiteness +of its simultaneous sensations, and to the amount of information +furnished by these. A rough sense of distance as well as of direction is +clearly obtainable by means of this organ. There seems to me no reason +why an animal endowed with fine olfactory sensibility, and capable of an +analytic separation of sense elements, should not gain a rough +perception of an external order much more complete than our auditory +perception, which is necessarily so fragmentary. This supposition +appears, indeed, to be the necessary complement to the idea first +broached, so far as I am aware, by Professor Croom Robertson, that to +such animals, visual perception consists in a reference to a system of +muscular feelings defined and bounded by strong olfactory sensations, +rather than by tactual sensations as in our case. + +[15] It may be said, perhaps, that the exceptional direction of +attention, by giving an unusual intensity to the impression, causes us +to exaggerate it just as in the case of a novel sensation. An effort of +attention directed to any of our vague bodily sensations easily leads us +to magnify its cause. A similar confusion may arise even in direct +vision, when the objects are looked at in a dim light, through a want of +proper accommodation. (See Sir D. Brewster, _op. cit._, letter i) + +[16] They might also be distinguished as objective and subjective +illusions, or as illusions _a posteriori_ and illusions _a priori_. + +[17] _Die Schein-Bewegungen_, von Professor Dr. J.I. Hoppe (1879); _cf._ +an ingenious article on "Optical Illusions of Motion," by Professor +Silvanus P. Thompson, in _Brain_, October, 1880. These illusions +frequently involve the co-operation of some preconception or +expectation. For example, the apparent movement of a train when we are +watching it and expecting it to move, involves both an element of +sense-impression and of imagination. It is possible that the illusion of +table-turning rests on the same basis, the table-turner being unaware of +the fact of exerting a certain amount of muscular force, and vividly +expecting a movement of the object. + +[18] _Physiologische Optik_, p. 316. + +[19] It is plain that this supposed error could only be brought under +our definition of illusion by extending the latter, so as to include +sense-perceptions which are contradicted by reason employing idealized +elements of sense-impression, which, as Lewes has shown (_Problems of +Life and Mind_, i. p. 260), make up the "extra-sensible world" of +science. + +[20] An ingenious writer, M. Binet, has tried to prove that the fusion +of homogeneous sensations, having little difference of local colour, is +an illustration of this principle. (See the _Revue Philosophique_, +September, 1880.) + +[21] Even the fusion of elementary sensations of colour, on the +hypothesis of Young and Helmholtz, in a seemingly simple sensation may +be explained to some extent by these circumstances, more especially the +identity of local interpretation. + +[22] The perception of lustre as a single quality seems to illustrate a +like error. There is good reason to suppose that this impression arises +through, a difference of brightness in the two retinal images due to the +regularly reflected light. And so when this inequality of retinal +impression is imitated, as it may easily be by combining a black and a +white surface in a stereoscope, we imagine that we are looking at one +lustrous surface. (See Helmholtz, _Physiologische Optik_, p. 782, etc., +and _Populäre wissenschaftliche Vorträge_, 2tes Heft, p. 80.) + +[23] The conditions of the production of these double images have been +accurately determined by Helmholtz, who shows that the coalescence of +impressions takes place whenever the object is so situated in the field +of vision as to make it practically necessary that it should be +recognized as one. + +[24] These illusions are, of course, due in part to inattention, since +close critical scrutiny is often sufficient to dispel them. They are +also largely promoted by a preconception that the event is going to +happen in a particular way. But of this more further on. I may add that +the late Professor Clifford has argued ingeniously against the idea of +the world being a continuum, by extending this idea of the wheel of +life. (See _Lectures and Essays_, i. p. 112, _et seq._) + +[25] It is supposed that in the case of every sense-organ there is +always some minimum forces of stimulus at work, the effect of which on +our consciousness is _nil_. + +[26] See Helmholtz, _Physiologische Optik_, p. 603. Helmholtz's +explanation is criticised by Dr. Hoppe, in the work already referred to +(sec. vii), though I cannot see that his own theory of these movements +is essentially different. The apparent movement of objects in vertigo, +or giddiness, is probably due to the loss, through a physical cause, of +the impressions made by the pressure of the fluid contents of the ear on +the auditory fibres, by which the sense of equilibrium and of rotation +is usually received. (See Ferrier, _Functions of the Brain_, pp. 60, +61.) + +[27] I do not need here to go into the question whether, as Johannes +Müller assumed, this is an original attribute of nerve-structure, or +whether, as Wundt suggests, it is due simply to the fact that certain +kinds of nervous fibre have, in the course of evolution, been slowly +adapted to one kind of stimulus. + +[28] I here refer to what is commonly supposed to be the vague innate +difference of sensation according to the local origin, before this is +rendered precise, and added to by experience and association. + +[29] The illusory character of this simple mode of perception is seen +best, perhaps, in the curious habit into which we fall of referring a +sensation of contact or discomfort to the edge of the teeth, the hair, +and the other insentient structures, and even to anything customarily +attached to the sentient surface, as dress, a pen, graving tool, etc. On +these curious illusions, see Lotze, _Mikrokosmus_, third edit., vol. ii. +p. 202, etc.; Taine, _De l'Intelligence_, tom. ii. p. 83, _et seq._ + +[30] Quoted by G.H. Lewes, _Problems of Life and Mind_, third series, p. +335. These illusions are supposed to involve an excitation of the +nerve-fibres (whether sensory or motor) which run to the muscles and +yield the so-called muscular sensations. + +[31] It is brought out by Griesinger (_loc. cit._) and the other writers +on the pathology of illusion already quoted, that in the case of +subjective sensations of touch, taste, and smell, no sharp line can be +drawn between illusion and hallucination. + +[32] For a fuller account of these pathological disturbances of +sensibility, see Griesinger; also Dr. A. Mayer, _Die Sinnestäuschungen_. + +[33] Helmholtz, _op. cit._, p. 600, _et seq._ These facts seem to point +to the conclusion that at least some of the feelings by which we know +that we are expending muscular energy are connected with the initial +stage of the outgoing nervous process in the motor centres. In other +pathological conditions the sense of weight by the muscles of the arms +is similarly confused. + +[34] Wundt (_Physiologische Psychologie_, p. 653) would exclude from +illusions all those errors of sense-perception which have their +foundation in the normal structure and function of the organs of sense. +Thus, he would exclude the effects of colour-contrast, _e.g._ the +apparent modification of two colours in, juxtaposition towards their +common boundary, which probably arises (according to E. Hering) from +some mutual influence of the temporary state of activity of adjacent +retinal elements. To me, however, these appear to be illusions, since +they may be brought under the head of wrong _interpretations_ of +sense-impressions. When we see a grey patch as rose-red, as though it +were so independently of the action of the complementary light +previously or simultaneously, that is to say, as though it would appear +rose-red to an eye independently of this action, we surely misinterpret. + +[35] Quoted by G.H. Lewes, _loc. cit._, p. 257. + +[36] The subject of the perception of movement is too intricate to be +dealt with fully here. I have only touched on it so far as necessary to +illustrate our general principle. For a fuller treatment of the subject, +see the work of Dr. Hoppe, already referred to. + +[37] The perception of magnitude is closely connected with that of +distance, and is similarly apt to take an illusory form. I need only +refer to the well-known simple optical contrivances for increasing the +apparent magnitude of objects. I ought, perhaps, to add that I do not +profess to give a complete account of optical illusions here, but only +to select a few prominent varieties, with a view to illustrate general +principles of illusion. For a fuller account of the various mechanical +arrangements for producing optical illusion, I must refer the reader to +the writings of Sir D. Brewster and Helmholtz. + +[38] Painters are well aware that the colours at the red end of the +spectrum are apt to appear as advancing, while those of the violet end +are known as retiring. The appearance of relief given by a gilded +pattern on a dark blue as ground, is in part referable to the principle +just referred to. In addition, it appears to involve a difference in the +action of the muscles of accommodation in the successive adaptations of +the eye to the most refrangible and the least refrangible rays. (See +Brücke, _Die Physiologie der Farben_, sec. 17.) + +[39] Helmholtz tells us (_Populäre wissenschaftliche Vorträge_, 3tes +Heft, p. 64) that even in a stereoscopic arrangement the presence of a +wrong cast shadow sufficed to disturb the illusion. + +[40] Among the means of giving a vivid sense of depth to a picture, +emphasized by Helmholtz, is diminishing magnitude. It is obvious that +the perceptions of real magnitude and distance are mutually involved. +When, for example, a picture represents a receding series of objects, as +animals, trees, or buildings, the sense of the third dimension, is +rendered much more clear. + +[41] A striking example of this was given in a painting, by Andsell, of +a sportsman in the act of shooting, exhibited in the Royal Academy in +1879. + +[42] This is at least true of all near objects. + +[43] Helmholtz remarks _(op. cit._, p. 628) that the difficulty of +seeing the convex cast as concave is probably due to the presence of the +cast shadow. This has, no doubt, some effect: yet the consideration +urged in the text appears to me to be the most important one. + +[44] _Populäre wissenschaftliche Vorträge_, 3tes Heft, pp. 71, 72. + +[45] See, on this point, some excellent remarks by G.H. Lewes, _Problems +of Life and Mind_, third series, vol. ii. p. 275. + +[46] To some extent this applies to the changes of apparent magnitude +due to altered position. Thus, we do not attend to the reduction of the +height of a small object which we are wont to handle, when it is placed +far below the level of the eye. And hence the error people make in +judging of the point in the wall or skirting which a hat will reach when +placed on the ground. + +[47] I refer to the experiments made by Exner, Wundt, and others, in +determining the time elapsing between the giving of a signal to a person +and the execution of a movement in response. "It is found," says Wundt, +"by these experiments that the exact moment at which a sense-impression +is perceived depends on the amount of preparatory self-accommodation of +attention." (See Wundt, _Physiologische Psychologie_, ch. xix., +especially p. 735. _et seq._) + +[48] Quoted by Helmholtz, _op. cit._, p. 626. + +[49] When the drawing, by its adherence to the laws of perspective, does +not powerfully determine the eye to see it in one way rather than in the +other (as in Figs. 5 to 7), the disposition to see the one form rather +than the other points to differences in the frequency of the original +forms in our daily experience. At the same time, it is to be observed +that, after looking at the drawing for a time under each aspect, the +suggestion now of the one and now of the other forces itself on the mind +in a curious and unaccountable way. + +[50] _Ueber die phantastischen Gesichsterscheinungen_, p. 45. + +[51] Another side of histrionic illusion, the reading of the imitated +feelings into the actors' minds, will be dealt with in a later chapter. + +[52] In a finished painting of any size this preparation is hardly +necessary. In these cases, in spite of the great deviations from truth +in pictorial representation already touched on, the amount of essential +agreement is so large and so powerful in its effect that even an +intelligent animal will experience an illusion. Mr. Romanes sends me an +interesting account of a dog, that had never been accustomed to +pictures, having been put into a state of great excitement by the +introduction of a portrait into a room, on a level with his eye. It is +not at all improbable that the lower animals, even when sane, are +frequently the subjects of slight illusion. That animals dream is a fact +which is observed as long ago as the age of Lucretius. + +[53] This kind of illusion is probably facilitated by the fact that the +eye is often performing slight movements without any clear consciousness +of them. See what was said about the limits of sensibility, p. 50. + +[54] _Mental Physiology_, fourth edit., p. 158. + +[55] In persons of very lively imagination the mere representation of an +object or event may suffice to bring about such a semblance of +sensation. Thus, M. Taine (_op. cit._, vol. i. p. 94) vouches for the +assertion that "one of the most exact and lucid of modern novelists," +when working out in his imagination the poisoning of one of his +fictitious characters, had so vivid a gustatory sensation of arsenic +that he was attacked by a violent fit of indigestion. + +[56] Mentioned by Dr. Carpenter (_Mental Physiology_, p. 207), where +other curious examples are to be found. + +[57] See _Annales Médico-Psychologiques_, tom. vi. p. 168, etc.; tom. +vii. p. 1. etc. + +[58] I have already touched on the resonance of a sense-impression when +the stimulus has ceased to act (see p. 55). The remarks in the text hold +good of all such after-impressions, in so far as they take the form of +fully developed percepts. A good example is the recurrence of the images +of microscopic preparations, to which the anatomist is liable. (See +Lewes, _Problems of Life and Mind_, third series, vol. ii. p. 299.) +Since a complete hallucination is supposed to involve the peripheral +regions of the nerve, the mere fact of shutting the eye would not, it is +clear, serve as a test of the origin of the illusion. + +[59] That subjective sensation may become the starting-point in complete +hallucination is shown in a curious instance given by Lazarus, and +quoted by Taine, _op. cit._, vol. i. p. 122, _et seq._ The German +psychologist relates that, on one occasion in Switzerland, after gazing +for some time on a chain of snow-peaks, he saw an apparition of an +absent friend, looking like a corpse. He goes on to explain that this +phantom was the product of an image of recollection which somehow +managed to combine itself with the (positive) after-image left by the +impression of the snow-surface. + +[60] For an account of Mr. Galton's researches, see _Mind_, No. xix. +Compare, however, Professor Bain's judicious observations on these +results in the next number of _Mind_. The liability of children to take +images for percepts, is illustrated by the experiences related in a +curious little work, _Visions_, by E.H. Clarke, M.D. (Boston, U.S., +1878), pp. 17, 46, and 212. + +[61] A common way of describing the relation of the hallucinatory to +real objects, is to say that the former appear partly to cover and hide +the latter. + +[62] Griesinger remarks that the forms of the hallucinations of the +insane rarely depend on sense-disturbances alone. Though these are often +the starting-point, it is the whole mental complexion of the time which +gives the direction to the imagination. The common experience of seeing +rats and mice running about during a fit of _delirium tremens_ very well +illustrates the co-operation of peripheral impressions not usually +attended to, and possibly magnified by the morbid state of sensibility +of the time (in this case flying spots, _muscæ volitantes_), with +emotional conditions. (See Griesinger, _loc. cit._, p. 96.) + +[63] Wundt (_Physiologische Psychologie_, p. 652) tells us of an insane +woodman who saw logs of wood on all hands in front of the real objects. + +[64] It is stated by Baillarger (Mémoires de l'Académie Royale de +Médicine, tom. xii. p. 273, etc.) that while visual hallucinations are +more frequent than auditory in healthy life, the reverse relation holds +in disease. At the same time, Griesinger remarks (_loc. cit._, p. 98) +that visual hallucinations are rather more common than auditory in +disease also. This is what we should expect from the number of +subjective sensations connected with the peripheral organ of vision. The +greater relative frequency of auditory hallucinations in disease, if +made out, would seem to depend on the close connection between +articulate sounds and the higher centres of intelligence, which centres +are naturally the first to be thrown out of working order. It is +possible, moreover, that auditory hallucinations are quite as common as +visual in states of comparative health, though more easily overlooked. +Professor Huxley relates that he is liable to auditory though not to +visual hallucinations. (See _Elementary Lessons in Physiology_, p. 267.) + +[65] See Baillarger, _Mémoires de l'Académie Royale de Médicine_, tom. +xii. p. 273, _et seq._ + +[66] See Baillarger, _Annales Médico-Psychologiques_, tom. vi. p. 168 +_et seq._; also tom. xii. p. 273, _et seq._ Compare Griesinger, _op. +cit._ In a curious work entitled _Du Démon de Socrate_ (Paris, 1856), M. +Lélut seeks to prove that the philosopher's admonitory voice was an +incipient auditory hallucination symptomic of a nascent stage of mental +alienation. + +[67] This is well brought out by Dr. J. Hughlings Jackson, in the papers +in _Brain_, already referred to. + +[68] _Friend_, vol. i. p. 248. The story is referred to by Sir W. Scott +in his _Demonology and Witchcraft_. + +[69] See E.B. Tylor, _Primitive Culture_, ch. xi.; _cf._ Herbert +Spencer, _Principles of Sociology_, ch. x. + +[70] For a fuller account of the different modes of +dream-interpretation, see my article "Dream," in the ninth edition of +the _Encyclopædia Britannica_. + +[71] For a fuller account of the reaction of dreams on waking +consciousness, see Paul Radestock, _Schlaf und Traum_. The subject is +touched on later, under the Illusions of Memory. + +[72] For an account of the latest physiological hypotheses as to the +proximate cause of sleep, see Radestock, _op. cit._, appendix. + +[73] Plutarch, Locke, and others give instances of people who never +dreamt. Lessing asserted of himself that he never knew what it was to +dream. + +[74] The error touched on here will be fully dealt with under Illusions +of Memory. + +[75] For a very full, fair, and thoughtful discussion of this whole +question, see Radestock, _op. cit._, ch. iv. + +[76] This may be technically expressed by saying that the liminal +intensity (Schwelle) is raised during sleep. + +[77] See Wundt, _Physiologische Psychologie_, pp. 188-191. + +[78] There is, indeed, sometimes an undertone of critical reflection, +which is sufficient to produce a feeling of uncertainty and +bewilderment, and in very rare cases to amount to a vague consciousness +that the mental experience is a dream. + +[79] _Observations on Man_, Part I. ch. iii, sec. 5. + +[80] Quoted by Radestock, _op. cit._, p. 110. + +[81] _Le Sommeil et les Rêves_, p. 132, _et seq._ + +[82] _Das Leben des Traumes_, p. 369. Other instances are related by +Beattie and Abercrombie. + +[83] _Le Sommeil et les Rêves_, p. 42, _et seq._ + +[84] _Beiträge sur Physiognosie und Heautognosie_, p. 256. For other +cases see H. Meyer, _Physiologie der Nervenfaser_, p. 309; and +Strümpell, _Die Natur und Entstehung der Träume_, p. 125. + +[85] A very clear and full account of these organic sensations, or +common sensations, has recently appeared from the pen of A. Horwicz in +the _Vierteljahrsschrift für wissenschaftliche Philosophie_, iv. +Jahrgang 3tes Heft. + +[86] Schopenhauer uses this hypothesis in order to account for the +apparent reality of dream-illusions. He thinks these internal sensations +may be transformed by the "intuitive function" of the brain (by means of +the "forms" of space, time, etc.) into quasi-realities, just as well as +the subjective sensations of light, sound, etc., which arise in the +organs of sense in the absence of external stimuli. (See _Versuch über +das Geisterschen: Werke_, vol. v. p. 244, _et seq._) + +[87] _Das Alpdrücken_, pp. 8, 9, 27. + +[88] It is this fact which justifies writers in assigning a prognostic +character to dreams. + +[89] A part of the apparent exaggeration in our dream-experiences may be +retrospective, and due to the effect of the impression of wonder which +they leave behind them. (See Strümpell, _Die Natur und Entstehung der +Träume_.) + +[90] _Cf._ Radestock, _op. cit._, pp. 131, 132. + +[91] I was on one occasion able to observe this process going on in the +transition from waking to sleeping. I partly fell asleep when suffering +from toothache. Instantly the successive throbs of pain transformed +themselves into a sequence of visible movements, which I can only +vaguely describe as the forward strides of some menacing adversary. + +[92] Even the "unconscious impressions" of waking hours, that is to say, +those impressions which are so fugitive as to leave no psychical trace +behind, may thus rise into the clear light of consciousness during +sleep. Maury relates a curious dream of his own, in which there appeared +a figure that seemed quite strange to him, though he afterwards found +that he must have been in the habit of meeting the original in a street +through which he was accustomed to walk (_loc. cit._, p. 124). + +[93] See p. 53. + +[94] See Maury, _loc. cit._, p. 146. + +[95] See what was said respecting the influence of a dominant emotional +agitation on the interpretation of actual sense-impressions. + +[96] It is proved experimentally that the ear has a much closer organic +connection with the vocal organ than the eye has. Donders found that the +period required for responding vocally to a sound-signal is less than +that required for responding in the same way to a light-signal. + +[97] On the nature of this impulse, as illustrated in waking and in +sleep, see the article by Delboeuf, "Le Sommeil et les Rêves," in +the _Revue Philosophique_, June, 1880, p. 636. + +[98] _Physiologische Psychologie_, p. 660. + +[99] I may, perhaps, observe, after giving two dreams which have to do +with mathematical operations, that, though I was very fond of them in my +college days, I have long ceased to occupy myself with these processes. +I would add, by way of redeeming my dream-intelligence from a deserved +charge of silliness, that I once performed a respectable intellectual +feat when asleep. I put together the riddle, "What might a wooden ship +say when her side was stove in? Tremendous!" (Tree-mend-us). I was aware +of having tried to improve on the form of this pun. I am happy to say I +am not given to punning during waking life, though I had a fit of it +once. It strikes me that punning, consisting as it does essentially of +overlooking sense and attending to sound, is just such a debased kind of +intellectual activity as one might look for in sleep. + +[100] See Radestock, _op. cit._, ch. ix.; _Vergleichung des Traumes mit +dem Wahnsinn_. + +[101] For Spinoza's experience, given in his own words, see Mr. F. +Pollock's _Spinoza_, p. 57; _cf._ what Wundt says on his experience, +_Physiologische Psychologie_, p. 648, footnote 2. + +[102] See an interesting account of "Recent Researches on Hypnotism," by +G. Stanley Hall, in _Mind_, January, 1881. + +[103] I need hardly observe that physiology shows that there is no +separation of different elementary colour-sensations which are locally +identical. + +[104] This kind of error is, of course, common to all kinds of +cognition, in so far as they involve comparison. Thus, the presence of +the excitement of the emotion of wonder at the sight of an unusually +large object, say a mountain, disposes the mind to look on it as the +largest of its class. Such illusions come midway between presentative +and representative illusions. They might, perhaps, be specially marked +off as illusions of "judgment." + +[105] So far as any mental state, though originating in a fusion of +elements, is now unanalyzable by the best effort of attention, we must +of course regard it in its present form as simple. This distinction +between what is simple or complex in its present nature, and what is +originally so, is sometimes overlooked by psychologists. Whether the +feelings and ideas here referred to are now simple or complex, cannot, I +think, yet be very certainly determined. To take the idea of space, I +find that after practice I recognize the ingredient of muscular feeling +much better than I did at first. And this exactly answers to Helmholtz's +contention that elementary sensations as partial tones can be detected +after practice. Such separate recognition may be said to depend on +correct representation. On the other hand, it must be allowed that there +is room for the intuitionist to say that the associationist is here +reading something into the idea which does not belong to it. It is to be +added that the illusion which the associationist commonly seeks to +fasten on his opponent is that of confusing final with original +simplicity. Thus, he says that, though the idea of space may now to all +intents and purposes be simple, it was really built up out of many +distinct elements. More will be said on the relation of questions of +nature and genesis further on. + +[106] I may as well be frank and say that I myself, assuming free-will +to be an illusion, have tried to trace the various threads of influence +which have contributed to its remarkable vitality. (See _Sensation and +Intuition_, ch. v., "The Genesis of the Free-Will Doctrine.") + +[107] I purposely leave aside here the philosophical question, whether +the knowledge of others' feelings is intuitive in the sense of being +altogether independent of experience, and the manifestation of a +fundamental belief. The inherited power referred to in the text might, +of course, be viewed as a transmitted result of ancestral experience. + +[108] I here assume, along with G.H. Lewes and other competent dramatic +critics, that the actor does not and dares not feel what he expresses, +at least not in the perfectly spontaneous way, and in the same measure +in which he appears to feel it. + +[109] The illusory nature of much of this emotional interpretation of +music has been ably exposed by Mr. Gurney. (See _The Power of Sound_, p. +345, _et seq._) + +[110] The reader will note that this impulse is complementary to the +other impulse to view all mental states as analogous to impressions +produced by external things, on which I touched in the last chapter. + +[111] Errors of memory have sometimes been called "fallacies," as, for +example, by Dr. Carpenter (_Human Physiology_, ch. x.). While preferring +the term "illusion," I would not forget to acknowledge my indebtedness +to Dr. Carpenter, who first set me seriously to consider the subject of +mnemonic error. + +[112] From this it would appear to follow that, so far as a percept is +representative, recollection must be re-representative. + +[113] The relation of memory to recognition is very well discussed by M. +Delboeuf, in connection with a definition of memory given by +Descartes. (See the article "Le Sommeil et les Rêves," in the _Revue +Philosophique_, April, 1880, p. 428, _et seq._) + +[114] A very interesting account of the most recent physiological theory +of memory is to be found in a series of articles, bearing the title, "La +Mémoire comme fait biologique," published in the _Revue Philosophique_, +from the pen of the editor, M. Th. Ribot. (See especially the _Revue_ of +May, 1880, pp. 516, _et seq._) M. Ribot speaks of the modification of +particular nerve-elements as "the static base" of memory, and of the +formation of nerve-connections by means of which the modified element +may be re-excited to activity as "the dynamic base of memory" (p. 535). + +[115] What constitutes the difference between such a progressive and a +retrogressive movement is a point that will be considered by-and-by. + +[116] It is not easy to say how far exceptional conditions may serve to +reinstate the seemingly forgotten past. Yet the experiences of dreamers +and of those who have been recalled to consciousness after partial +drowning, whatever they may prove with respect to the revivability of +remote experiences, do not lead us to imagine that the range of our +definitely localizing memory is a wide one. + +[117] _Der Zeitsinn nach Versuchen_, p. 36, _et seq._ + +[118] _Physiologische Psychologie_, p. 782. + +[119] Wundt refers these errors to variations in the state of +preadjustment of the attention to impressions and representations, +according as they succeed one another slowly or rapidly. There is little +doubt that the effects of the state of tension of the apparatus of +attention, are involved here, though I am disposed to think that Wundt +makes too much of this circumstance. (See _Physiologische Psychologie_, +pp. 782, 783. I have given a fuller account of Wundt's theory in _Mind_, +No. i.) + +[120] Strictly speaking, it would occupy more time, since the effort of +recalling each successive link in the chain would involve a greater +interval between any two images than that between the corresponding +experiences. + +[121] I need hardly say that there is no sharp distinction between these +two modes of subjective appreciation. Our estimate of an interval as it +passes is really made up of a number of renewed anticipations and +recollections of the successive experiences. Yet we can say broadly that +this is a prospective estimate, while that which is formed when the +period has quite expired must be altogether retrospective. + +[122] See an interesting paper on "Consciousness of Time," by Mr. G. J. +Romanes, in _Mind_ (July, 1878). + +[123] It is well known that there is, from the first, a gradual falling +off in the strength of a sensation of light when a moderately bright +object is looked at. + +[124] _Cf._ Hartley, _Observations on Man_, Part I. ch. iii. sec. 4 +(fifth edit., p. 391). + +[125] See Dr. Carpenter's _Mental Physiology_, fourth edit, p. 456. + +[126] This is, perhaps, what is meant by saying that people recall their +past enjoyments more readily than their sufferings. Yet much seems to +turn on temperament and emotional peculiarities. (For a fuller +discussion of the point, see my _Pessimism_, p. 344.) + +[127] The only exception to this that I can think of is to be found in +the power which I, at least, possess, after looking at a new object, of +representing it as a familiar one. Yet this may be explained by saying +that in the case of every object which is clearly apprehended there must +be vague revivals of _similar_ objects perceived before. Oases in which +recent experiences tend, owing to their peculiar nature, very rapidly to +assume the appearance of old events, will be considered presently. + +[128] _Mental Physiology_, p. 456. + +[129] _Mental Physiology_, second edit., p. 172. + +[130] _Loc. cit._, p. 390. + +[131] This source of error has not escaped the notice of autobiographers +themselves. See the remarks of Goethe in the opening passages of his +_Wahrheit und Dichtung_. + +[132] One wonders whether those persons who, in consequence of an injury +to their brain, periodically pass from a normal into an abnormal +condition of mind, in each of which there is little or no memory of the +contents of the other state, complete their idea of personal continuity +in each state by the same kind of process as that described in the text. + +[133] The reader will remark that this condition of clear intellectual +consciousness, namely, a certain degree of similarity and continuity of +character in our successive mental states, is complementary to the other +condition, constant change, already referred to. It may, perhaps, be +said that all clear consciousness lies between two extremes of excessive +sameness and excessive difference. + +[134] It follows that any great transformation of our environment may +lead to a partial confusion with respect to self. For not only do great +and violent changes in our surroundings beget profound changes in our +feelings and ideas, but since the idea of self is under one of its +aspects essentially that of a relation to not-self, any great revolution +in the one term, will confuse the recognition of the other. This fact is +expressed in the common expression that we "lose ourselves" when in +unfamiliar surroundings, and the process of orientation, or "taking our +bearings," fails. + +[135] On these disturbances of memory and self-recognition in insanity, +see Griesinger, _op. cit._, pp. 49-51; also Ribot, "Des Désordres +Généraux de la Mémoire," in the _Revue Philosophique_, August, 1880. It +is related by Leuret (_Fragments Psych. sur la Folie_, p. 277) that a +patient spoke of his former self as "la personne de moi-même." + +[136] In the following account of the process of belief and its errors, +I am going over some of the ground traversed by my essay on _Belief, its +Varieties and Conditions_ ("Sensation and Intuition," ch. iv.). To this +essay I must refer the reader for a fuller analysis of the subject. + +[137] For an account of the difference of mechanism in memory and +expectation, see Taine, _De l'Intelligence_, 2ième partie, livre +premier, ch. ii. sec. 6. + +[138] J.S. Mill distinguishes expectation as a radically distinct mode +of belief from memory, but does not bring out the contrast with respect +to activity here emphasized (James Mill's _Analysis of the Human Mind_, +edited by J.S. Mill, p. 411, etc.). For a fuller statement of my view of +the relation of belief to action, as compared with that of Professor +Bain, see my earlier work. + +[139] For some good remarks on the logical aspects of future events as +matters of fact, see Mr. Venn's _Logic of Chance_, ch. x. + +[140] James Mill's _Analysis of the Human Mind_, edited by J.S. Mill, +vol. i p. 414, _et seq._ + +[141] _Principles of Geology_, ch. iii. + +[142] To make this rough analysis more complete, I ought, perhaps, to +include the effect of all the errors of introspection, memory, and +spontaneous belief, into which the person himself falls, in so far as +they communicate themselves to others. + +[143] In the case of a vain woman thinking herself much more pretty than +others think her, the error is still more obviously one connected with a +belief in objective fact. + +[144] _The Study of Sociology_, ch. ix. + +[145] As a matter of fact, the proportion of accurate knowledge to error +is far larger in the case of classes than of individuals. Propositions +with general terms for subject are less liable to be faulty than +propositions with singular terms for subject. + +[146] For a description of each of these extremes of boundless gaiety +and utter despondency, see Griesinger, _op. cit._, Bk. III. ch. i. and +ii. The relation of pessimism to pathological conditions is familiar +enough; less familiar is the relation of unrestrained optimism. Yet +Griesinger writes that among the insane "boundless hilarity," with "a +feeling of good fortune," and a general contentment with everything, is +as frequent as depression and repining (see especially p. 281, also pp. +64, 65). + +[147] It has been seen that, from a purely psychological point of view, +even what looks at first like pure presentative cognition, as, for +example, the recognition of a present feeling of the mind, involves an +ingredient of representation. + +[148] See especially what was said about the _rationale_ of illusions of +perception, pp. 37, 38. + +[149] I say "usually," because, as we have seen, there may sometimes be +a permanent and even an inherited predisposition to active illusion in +the individual temperament and nervous organization. + +[150] See what was said on the nature of passive illusions of sense (pp. +44, 68, 70, etc.) The logical character of illusion might be brought out +by saying that it resembles the fallacy which is due to reasoning from +an approximate generalization as though it were a universal truth. In +thus identifying illusion and fallacy, I must not be understood to say +that there is, strictly speaking, any such thing as an unconscious +reasoning process. On the contrary, I hold that it is a contradiction to +talk of any _mental_ operation as altogether unconscious. I simply wish +to show that, by a kind of fiction, illusion may be described as the +result of a series of steps which, if separately unfolded to +consciousness (as they no longer are), would correspond to those of a +process of inference. The fact that illusion arises by a process of +contraction out of conscious inference seems to justify this use of +language, even apart from the fact that the nervous processes in the two +cases are pretty certainly the same. + +[151] If we turn from the region of physical to that of moral ideas, we +see this historical collision between common and individual conviction +in a yet more impressive form. The teacher of a new moral truth has +again and again been set down to be an illusionist by a society which +was itself under the sway of a long-reigning error. As George Eliot +observes, "What we call illusions are often, in truth, a wider vision of +past and present realities--a willing movement of a man's soul with the +larger sweep of the world's forces." + +[152] To make this account of the philosophic problem of the +object-world complete, I ought to touch not only on the distinction +between the vulgar and the scientific view of material things, but also +on the distinction, within physical science, between the less and the +more abstract view roughly represented by molar and molecular physics. + +[153] For an excellent account of the distinction between the scientific +and the philosophic point of view, see Mr. Shadworth Hodgson's +_Philosophy of Reflection_, Bk. I. chs. i. and iii.; also Bk. III. chs. +vii. and viii. + +[154] I hold, in spite of Berkeley's endeavours to reconcile his +position with that of common sense, that the popular view does at least +tend in this direction. That is to say, the every-day habit, when +considering the external world, of abstracting from particular minds, +leads on insensibly to that complete detachment of it from mind in +general which expresses itself in the first stage of philosophic +reflection, crude realism. The physicist appears to me, both from the +first essays in Greek "nature-philosophy," as also from the not +infrequent confusion even to-day between a perfectly safe "scientific +materialism" and a highly questionable philosophic materialism, to share +in this tendency to take separate consideration for separate existence. +Each new stage of abstraction in physical science gives birth to a new +attempt to find an independent reality, a thing-in-itself, hidden +further away from sense. + +[155] See the interesting autobiographical record of the growth of +philosophic doubt in the _Première Méditation_ of Descartes. + +[156] The appeal is not, as we have seen, invariably from sight to +touch, but may be in the reverse direction, as in the recognition of the +duality of the points of a pair of compasses, which seem one to the +tactual sense. + +[157] I might further remark that this "collective experience" includes +previously detected illusions of ourselves and of others. + +[158] M. Taine frankly teaches that what is commonly called accurate +perception is a "true hallucination" (_De l'Intelligence_, 2ième partie, +Livre I. ch. i. sec. 3). + +[159] It only seems to do so, apart from philosophic assumptions, in +certain cases where experience testifies to a uniform untrustworthiness +of the origin. For example, we may, on grounds of matter of fact and +experience, be disposed to distrust any belief that we recognize as +springing from an emotional source, from the mind's feelings and wishes. + +I may add that a so-called intuitive belief may refer to a matter of +fact which can be tested by the facts of experience and by scientific +methods. Thus, for example, the old and now exploded form of the +doctrine of innate ideas, which declared that children were born with +certain ideas ready made, might be tested by observation of childhood, +and reasoning from its general intellectual condition. The same applies +to the physiological theories of space-perception, supposed to be based +on Kant's doctrine, put forward in Germany by Johannes Müller and the +"nativistic school." (See my exposition and criticism of these doctrines +in _Mind_, April, 1878, pp. 168-178 and 193-195.) + + + + + + +End of the Project Gutenberg EBook of Illusions, by James Sully + +*** END OF THIS PROJECT GUTENBERG EBOOK ILLUSIONS *** + +***** This file should be named 17815-8.txt or 17815-8.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/1/7/8/1/17815/ + +Produced by Thierry Alberto, Janet Blenkinship and the +Online Distributed Proofreaders Europe at +http://dp.rastko.net + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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