Chapter 26 Imagination William James

Sensations, once experienced, modify the nervous organism, so that copies of them arise Again in the mind after the original outward stimulus is gone. No mental copy, however, can arise in the mind, of any kind of sensation which has never been directly excited from without.

The blind may dream of sights, the deaf of sounds, for years after they have lost their vision or hearing;¹ but the man bom deaf can never be made to imagine what sound is like, nor can the man bom blind ever have a mental vision. In Locke's words, already quoted, "the mind can frame unto itself no one new simple idea." The originals of them all must have been given from without. Fantasy, or Imagination, are the names given to the faculty of reproducing copies of originals once felt. The imagination is called 'repro­ductive' when the copies are literal; 'productive' when elements from different originals are recombined so as to make new wholes.

After-images belong to sensation rather than to imagination; so that the most imme­diate phenomena of imagination would seem to be those tardier images (due to what the Germans all Sinnesgedachtniss)—coercive hauntings of the mind by echoes of un­usual experiences for hours after the latter have taken place. The phenomena ordinarily ascribed to imagination, however, are those mental pictures of possible sensible experi­ences, to which the ordinary processes of associative thought give rise.

When represented with surroundings concrete enough to constitute a date, these pictures, when they revive, form recollections. When the mental pictures are of data freely combined, and reproducing no past combination exactly, we have acts of imagi­nation properly so called.

Our Images Are Usually Vague

For the ordinary 'analytic' psychology, each sensibly discernible element of the object imagined is represented by its own separate idea, and the total object is imagined by a 'clustef or 'gang' of ideas.

Hume was the hero of the atomistic theory. Not only were ideas copies of original impressions made on the sense-organs, but they were, according to him, completely adequate copies, and were all so separate from each other as to possess no manner of connection. Hume proves ideas in the imagination to be completely adequate copies, not by appeal to observation, but by a priori reasoning, as follows:

The mind cannot form any notion of quantity or quality, without forming a precise notion of the degrees of each, [for] 'tis confessed that no object can appear to the senses; or in other words, that no impression² can become present to the mind, without being determined in its degrees both of quantity and quality. The confusion in which impressions are sometimes involved proceeds only from then- faintness and unsteadiness, not from any capacity in the mind to receive any impression, which in its real existence has no particular degree nor proportion. That is a contradiction in terms; and even implies the flattest of all contradictions, viz., that 'tis possible for the same thing both to be and not to be. Now since all ideas are derived from impressions, and are nothing but copies and representa­tions of them, whatever is true of the one must be acknowledged concerning the other. Impressions and ideas differ only in their strength and vivacity. The fore­going conclusion is not founded on any particular degree of vivacity. It cannot therefore be affected by any variation in that particular. An idea is a weaker impression; and as a strong impression must necessarily have a determinate quan­tity and quality, the case must be the same with its copy or representative?

The slightest introspective glance will show to anyone the falsity of this opinion.

When complex impressions or complex ideas are reproduced as memories, it is probable that the copies never give all the details of the originals with perfect accuracy, and it is certain that they rarely do so. No one possesses a memory so good, that if he has only once observed a natural object, a second inspection does not show him something that he has forgotten. Almost all, if not all, our memories are therefore sketches, rather than portraits, of the originals—the salient features are obvious, while the subordinate characters are obscure or unrepresented.

Now, when several complex impressions which are more or less different from one another—let us say that out of ten impressions in each, six are the same in all, and four are different from all the rest—are successively presented to the mind, it is easy to see what must be the nature of the result. The repetition of the six similar impressions will strengthen the six corresponding elements of the complex idea, which will therefore acquire greater vividness; while the four differing im­pressions of each will not only acquire no greater strength than they had at first, but, in accordance with the law of association, they will all tend to appear at once, and will thus neutralize one another.

This mental operation may be rendered comprehensible by considering what takes place in the formation of compound photographs—when the images of the faces of six sitters, for example, are each received on the same photographic plate, for a sixth of the time requisite to take one portrait. The final result is that all those points in which the six faces agree are brought out strongly, while all those in which they differ are left vague; and thus what may be termed a generic portrait of the six, in contradistinction to a specific portrait of any one, is produced.

Thus our ideas of single complex impressions are incomplete in one way, and those of numerous, more or less similar, complex impressions are incomplete in another way; that is to say, they are generic, not specific. And hence it follows that our ideas of the impressions in question are not, in the strict sense of the word, copies of those impressions; while, at the same time, they may exist in the mind independently of language.

The generic ideas which are formed from several similar, but not identical complex experiences are what are called abstract or general ideas; and Berkeley endeavored to prove that all general ideas are nothing but particular ideas an­nexed to a certain term, which gives them a more extensive signification, and makes them recall, upon occasion, other individuals which are similar to them. Hume says that he regards this as 'one of the greatest and the most valuable discoveries that has been made of late years in the republic of letters,' and en­deavors to confinn it in such a manner that it shall be 'put beyond all doubt and controversy.'

I may venture to express a doubt whether he has succeeded in his object; but the subject is an abstruse one; and I must content myself with the remark, that though Berkeley's view appears to be largely applicable to such general ideas as are formed after language has been acquired, and to all the more abstract sort of conceptions, yet that general ideas of sensible objects may nevertheless be pro­duced in the way indicated, and may exist independently of language.

Are Vague Images 'Abstract Ideas'?

The only point which I am tempted to criticise in this account is Prof. Huxley's identifi­cation of these generic images with 'abstract or general ideas' in the sense of universal concep­tions. Taine gives the truer view. He writes:

Some years ago I saw in England, in Kew Gardens, for the first time, araucarias, and I walked along the beds looking at these strange plants, with their rigid bark and compact, short, scaly leaves, of a sombre green, whose abrupt, rough, bristling form cut in upon the fine softly-lighted turf of the fresh grass-plat. If I now inquire what this experience has left in me, I find, first, the sensible representation of an araucaria; in fact, I have been able to describe almost exactly the form and color of the plant. But there is a difference between this representation and the former sensations, of which it is the present echo.

In other words, a blurred picture is just as much a single mental fact as a sharp picture is; and the use of either picture by the mind to symbolize a whole class of individuals is a new mental function, requiring some other modification of consciousness than the mere per­ception that the picture is distinct or not. I may bewail the indistinctness of my mental image of my absent friend. That does not prevent my thought from meaning him alone, however. And I may mean all mankind, with perhaps a very sharp image of one man in my mind's eye. The meaning is a function of the more 'transitive' parts of conscious­ness, the 'fringe' of relations which we feel surrounding the image, be the latter sharp or dim.

Our ideas or images of past sensible experience may then be either distinct and adequate or dim, blurred, and incomplete. It is likely that the different degrees in which different men are able to make them sharp and complete has had something to do with keeping up such philosophic disputes as that of Berkeley with Locke over abstract ideas. Locke had spoken of our possessing 'the general idea of a triangle' which "must be neither oblique nor rectangle, neither equilateral, equicrural, nor scalenon, but all and none of these at once." Berkeley says:

If any man has the faculty of framing in his mind such an idea of a triangle as is here described, it is in vain to pretend to dispute him out of it, nor would I go about it. All I desire is that the reader would fully and certainly inform himself whether he has such an idea or no.⁶

Until very recent years it was supposed by all philosophers that there was a typical human mind which all individual minds were like, and that propositions of universal validity could be laid down about such faculties as 'the Imagination.' Lately, however, a mass of revelations have poured in, which make us see how false a view this is. There are imaginations, not 'the Imagination,' and they must be studied in detail.

The Neural Process which Underlies Imagination?

The commonly-received idea is that it is only a milder degree of the same process which took place when the thing now imagined was sensibly perceived. Professor Bain writes:

Since a sensation in the first instance diffuses nerve-currents through the interior of the brain outwards to the organs of expression and movement,—the persis­tence of that sensation, after the outward exciting cause is withdrawn, can ܸ but a continuance of the same diffusive currents, perhaps less intense, but not otherwise different. The shock remaining in the ear and brain, after the sound of thunder, must pass through the same circles, and operate in the same way as during the actual soιmd. We can have no reason for believing that, in this self-sustaining condition, the impression changes its seat, or passes into some new circles that have the special property of retaining it. Every part actuated after the shock must have been actuated by the shock, only more powerfully. With this single differ­ence of intensity, the mode of existence of a sensation existing after the fact is essentially the same as its mode of existence during the fact.... Now if this be the case with impressions persisting when the cause has ceased, what view are we to adopt concerning impressions reproduced by mental causes alone, or without the aid of the original, as in ordinary recollection? What is the manner of occupation of the brain with a resuscitated feeling of resistance, a smell or a sound? There is only one answer that seems admissable. The renewed feeling occupies the very same parts, and in the same manner, as the original feeling, and no other parts, nor in any other assignable manner. I imagine that if our present knowledge of the brain had been present to the earliest speculators, this is the only hypothesis that would have occurred to them. For where should a past feeling be embodied, if not in the same organs as the feeling when present? It is only in this way that its identity can be preserved; a feeling differently embodied would be a different feeling.⁷

It is not plain from Professor Bain's text whether by the 'same parts' he means only the same parts inside the brain, or the same peripheral parts also, as those occupied by the original feeling. The examples which he himself proceeds to give are almost all cases of imagination of movement, in which the peripheral organs are indeed affected, for actual movements of a weak sort are found to accompany the idea. This is what we should expect. All currents tend to run forward in the brain and discharge into the muscular system; and the idea of a movement tends to do this with peculiar facility. But the question remains: Do currents run backward, so that if the optical centres (for example) are excited by 'association' and a visual object is imagined, a current runs down to the retina also, and excites that sympathetically with the higher tracts? In other words, can peripheral sense-organs be excited from above, or only from without? Are they excited in imagination? Professor Bain's instances are almost silent as to this point. All he says is this:

We might think of a blow on the hand until the skin were actually irritated and inflamed. The attention very much directed to any part of the body, as the great toe, for instance, is apt to produce a distinct feeling in the part, which we account for only by supposing a revived nerve-current to flow there, making a sort of false sensation, an influence from within mimicking the influences from without in sensation proper.—(See the writings of Mr. Braid, of Manchester, on Hypnotism, etc.)

If I may judge from my own experience, all feelings of this sort are consecutive upon motor currents invading the skin and producing contraction of the muscles there, the muscles whose contraction gives 'goose-flesh' when it takes place on an extensive scale. I never get a feeling in the skin, however strongly I imagine it, until some actual change in the condition of the skin itself has occurred. The truth seems to be that the cases where peripheral sense-organs are directly excited in consequence of imagination are exceptional rarities, if they exist at all. In common cases of imagination it would seem more natural to suppose that the seat of the process is purely cerebral, and that the sense-organ is left out. Reasons for such a conclusion would be briefly these:

1. In imagination the starting-point of the process must be in the brain. Now we know that currents usually flow one way in the nervous system; and for the peripheral sense-organs to be excited in these cases, the current would have to flow backward.

2. There is between imagined objects and felt objects a difference of conscious quality which may be called almost absolute. It is hardly possible to confound the liveliest image of fancy with the weakest real sensation. The felt object has a plastic reality and outwardness which the imagined object wholly lacks. More­over, as Fechner says, in imagination the attention feels as if drawn backwards to the brain; in sensation (even of after-images) it is directed forward towards the sense-organ. The difference between the two processes feels like one of kind, and not like a mere 'more' or less' of the same.⁸ If a sensation of sound were only a strong imagination, and an imagination a weak sensation, there ought to be a border-line of experience where we never could tell whether we were hearing a weak sound or imagining a strong one. In comparing a present sensation felt with a past one imagined, it will be remembered that we often judge the imagined one to have been the stronger. This is inexplicable if the imagination be simply a weaker excitement of the sensational process.

To these reasons the following objections may be made:

To 1: The current demonstrably does flow backward down the optic nerve in Meyer's and Fere's negative afterimage. Therefore it can flow backward; therefore it may flow backward in some, however slight, degree, in all imagination.⁹

To 2: The difference alleged is not absolute, and sensation and imagination are hard to discriminate where the sensation is so weak as to be just perceptible. At night hearing a very faint striking of the hour by a far-off dock, our imagination reproduces both rhythm and sound, and it is often difficult to tell which was the last real stroke. So of a baby crying in a distant part of the house, we are uncertain whether we still hear it, or only imagine the sound. Certain violin-players take advantage of this in diminuendo terminations. After the pianissimo has been reached they continue to bow as if still playing, but are careful not to touch the strings. The listener hears in imagination a degree of sound fainter still than the preceding pianissimo. This phenomenon is not confined to hearing:

If we slowly approach our finger to a surface of water, we often deceive ourselves about the moment in which the wetting occurs. The apprehensive patient believes himself to feel the knife of the surgeon whilst it is still at some distance.¹⁰

Visual perception supplies numberless instances in which the same sensation of vision is perceived as one object or another according to the interpretation of the mind.

Taken together, all these facts would force us to admit that the subjective difference between imagined and felt objects is less absolute than has been claimed, and that the cortical processes which underlie imagination and sensation are not quite as discrete as one at first is tempted to suppose. That peripheral sensory processes are ordinarily involved in imagination seems improbable; that they may sometimes be aroused from the cortex downwards cannot, however, be dogmatically denied.

The imagination-process can then pass over into the sensation-process. In other words, genuine sensations can be centrally originated. When we come to study hallucinations in the chapter on Outer Perception, we shall see that this is by no means a thing of rare occurrence. At present, however, we must admit that normally the two processes do not pass over into each other; and we must inquire why. One of two things must be the reason. Either

1. Sensation-processes occupy a different locality from imagination-processes; or

2. Occupying the same locality, they have an intensity which under normal cir­cumstances currents from other cortical regions are incapable of arousing, and to produce which currents from the periphery are required.

It seems almost certain that the imagination-process differs from the sensation-process by its intensity rather than by its locality. However it may be with lower animals, the assump­tion that ideational and sensorial centres are locally distinct appears to be supported by no facts drawn from the observation of human beings. After occipital destruction, the hemianopsia which results in man is sensorial blindness, not mere loss of optical ideas. Were there centres for crude optical sensation below the cortex, the patients in these cases would still feel light and darkness. Since they do not preserve even this impres­sion on the lost half of the field, we must suppose that there are no centres for vision of any sort whatever below the cortex, and that the corpora quadrigemina and other lower optical ganglia are organs for reflex movement of eye-muscles and not for con­scious sight. Moreover there are no facts which oblige us to think that, within the occipital cortex, one part is connected with sensation and another with mere ideation or imagination. The pathological cases assumed to prove this are all better explained by disturbances of conduction between the optical and other centres. In bad cases of hemianopsia the patient's images depart from him together with his sensibility to light. They depart so completely that he does not even know what is the matter with him. To perceive that one is blind to the right half of the field of view one must have an idea of that part of the field's possible existence. But the defect in these patients has to be revealed to them by the doctor, they themselves only knowing that there is 'something wrong' with their eyes. What you have no idea of you cannot miss; and their not definitely missing this great region out of their sight seems due to the fact that their very idea and memory of it is lost along with the sensation. A man blind of his eyes merely, sees darkness. A man blind of his visual brain-centers can no more see darkness out of the parts of his retina which are connected with the brain-lesion than he can see it out of the skin of his back. He cannot see at all in that part of the field; and he cannot think of the light which he ought to be feeling there, for the very notion of the existence of that particular 'there' is cut out of his mind.¹¹

Now if we admit that sensation and imagination are due to the activity of the same centres in the cortex, we can see a very good teleological reason why they should correspond to discrete kinds of process in these centres, and why the process which gives the sense that the object is really there ought normally to be arousable only by currents entering from the periphery and not by currents from the neighboring cortical parts. We can see, in short, why the sensational process ought to be discontinuous with all normal ideational processes, however intense. For, as Dr. Miinsterberg justly observes:

Were there not this peculiar arrangement we should not distinguish reality and fantasy, our conduct would not be accommodated to the facts about us, but would be inappropriate and senseless, and we could not keep ourselves alive.... That our thoughts and memories should be copies of sensations with their intensity greatly reduced is thus a consequence deducible logically from the natural adaptation of the cerebral mechanism to its environment.¹²

Mechanically the discontinuity between the ideational and the sensational kinds of process must mean that when the greatest ideational intensity has been reached, an order of resistance presents itself which only a new order of force can break through. The current from the periphery is the new order of force required; and what happens after the resistance is overcome is the sensational process. We may suppose that the latter consists in some new and more violent sort of disintegration of the neural matter, which now explodes at a deeper level than at other times.

Now how shall we conceive of the 'resistance' which prevents this sort of disintegra­tion from taking place, this sort of intensity in the process from being attained, so much of the time? It must be either an intrinsic resistance, some force of cohesion in the neural molecules themselves; or an extrinsic influence, due to other cortical cells. When we come to study the process of hallucination we shall see that both factors must be taken into account. There is a degree of inward molecular cohesion in our brain-cells which it probably takes a sudden inrush of destructive energy to spring apart. Incoming periph­eral currents possess this energy from the outset. Currents from neighboring cortical regions might attain to it if they could accumulate within the centre which we are sup­posed to be considering. But since during waking hours every centre communicates with others by association-paths, no such accumulation can take place. The cortical currents which run in run right out again, awakening the next ideas; the level of tension in the cells does not rise to the higher explosion-point; and the latter must be gained by a sudden current from the periphery or not at all.

Notes

1. Prof. Jastrow has ascertained by statistical inquiry among the blind that if their blindness have occurred before a period embraced between the fifth and seventh yean the visual centres seem to decay, and visual dreams and images are gradually outgrown. If sight is lost after the seventh year, visual imagination seems to survive through life. See Prof. J.'s interesting artide on the Dreams of the Blind, in the New Princeton Review for January 1888.

2. ImpressionmeanssensationforHume.

3. Treatise on Human Nature, part I. § VΠ.

4. Huxley's Hume, pp. 92-94.

5. On Intelligence (N.Y∙), vol. ∏. p. 139.

6. Principles, Introd. § 18.

7. Senses and Intellect, p. 338.

8. V. Kandinsky (Kritische u. Hinische Betrachtungen in Gebiete der Sinnestauschungen (Berlin, 1885), p. 135ff.) insists that in even the liveliest pseudo-halludnations, which may be regarded as the intensest possible results of the imaginative process, there is no outward objectivity perceived in the thing represented, and that a ganzer Abgrund separates these 'ideas' from true hallucination and objective perception.

9. It seems to also flow backwards in certain hypnotic hallucinations. Suggest to a 'Subject' in the hypnotic trance that a sheet of paper has a red cross upon it, then pretend to remove the imaginary cross, whilst you tell the Subject to look fixedly at a dot upon the paper, and he will presently tell you that he sees a bluish-green' cross. The genuineness of the result has been doubted, but there seems no good reason for rejecting M. Binefs account (Le Magnitisme Animal, 1887, p. 188). M. Binet, following M. Parinaud, and on the faith of a certain experiment, at one time believeid, the optical brain-centres and not the retina to be the seat of ordinary negative after-images. The experiment is this: Look

Imagination 191 fixedly, with one eye open, at a colored spot on a white background. Then close that eye and look fixedly with the other eye at a plain surface. A negative after-image of the colored spot will presently appear. (Psychologic du Raisormemerd, 1886, p. 45.) But Mr. Delabarre has proved (American Journal of Psychology, ∏. 326) that this after-image is due, not to a higher cerebral process, but to the fact that the retinal process in the closed eye affects consciousness at certain moments, and that its object is then projected into the field seen by the eye which is open. M. Binet informs me that he is converted by the proofs given by Mr. Delabarre.

The fact remains, however, that the negative after- images of Herr Meyer, M. F6r⅛, and the hypnotic subjects, form an exception to all that we know of nerve-currents, if they are due to a refluent centrifugal current to the retina. It may be that they will hereafter be explained in some other way. Meanwhile we can only write them down as a paradox. Sig. Sergi's theory that there is always a refluent wave in perception hardly merits serious consideration (Psychologie Physiologique, pp. 99, 189). Sergi's theory has recently been reaffirmed with almost incredible crudity by Lombroso and Ottolenghi in the Reoue Philosophique, XXDC 70 (Jan. 1890).

10. Lotze, Med. Psych, p. 509.

11. See an important article by Binet in the Reoue Philosophique, XXVI. 481 (1888); also Dufour, in Reoue Mid. de la Suisse Romande, 1889, No. 8, dted in the Neurologisches Cerdralblatt, 1890, p. 48.

12. Die Willenshandlung (USS), pp. 129-40.

References

Baia Alexander. The Senses and the Intellect. London: J. W. Parker ⅛ Soa 1855. Fedmer, G. T. Elemente der Psychophyak. Leipzig: Breitkopf und HarteL 1860. F6ι⅛, Charles. Sensation et Mouoement. Paris: F. Alcoa 1887.

Galtoa Sir Frands. Inquiries into Human Faculty. London: MacMillan ⅛ Co., 1880. Huxley, Thcwnas Henry, Hume. London: MacMillan & Co., 1879.

Meyer, G. H. Untersuchungen ub. d. Physiol, d. Nervenfaser. Tubingen: H. Laupp., 1843. Taine, H. Ort Irdelligence. Vol. ∏ London: L Reeve & Co., 1871.