CHAPTER XXIV

SENSATION AND EXTERNAL REALITY

         We must not omit to point out another fundamental difference between sensory and representative elements. Sensations have the significance, or possess the attribute of external reality, while images, ideas, or representations entirely lack it. Put in Baldwin's terminology―sensations have the coefficient of external reality, the sensory coefficient of reality. No matter whether the sensation was produced by an external stimulus, or by a pathological process going on in the sense-organ, or brought about indirectly through the action of another sense-organ by means of indirect association-paths; no matter whether the sensation is primary or secondary, as long as it is a sensation at all, it possesses the sensory coefficient of reality. A sensation whether 'true or false' possesses rightfully the coefficient of reality as its necessary and inherent attribute. The percept, true or hallucinatory, consisting of sensory elements, has therefore the sensory coefficient of reality. Psychologically regarded, the 'true' percept and the hallucination have the same sensory constitution with the same attributes. The difference between the true and false percept may be regarded from a biological standpoint as a matter of adjustment. The percepts with successful adjustments are true, while those with unsuccessful motor reactions are false and hallucinatory. Psychologically, the difference between the 'true' percept and hallucination is in the shifting of the primary and secondary sensory elements. Where the secondary sensory elements can be shifted and become primary, the percept is regarded as true, where the secondary sensory elements do not admit of being shifted and becoming primary, the percept is regarded as hallucinatory.

        If we turn now to the representative elements, we find that they lack the sensory coefficient of reality. This lack of sensory coefficient is on the negative side of the image. There is also a positive side to it. The image is not felt as image, because it is not sensation or lacks the sensory coefficient, but because it possesses a qualitative character of its own. A sensation is not felt as such, simply because it lacks the character of another sensation. Thus sensation green is not experienced as the particular color sensation, because it has not the quale of sound or of pressure, but because the sensation green has a positive experience of its own. The same holds good of the representation―it possesses its own characteristic quale. As an experience sui generis we claim for the representation a special psychic mark, an 'ideational or representative' coefficient. The image has its own qualitative character just as the sensation possesses its own. In contrast to the sensation which possesses the coefficient of external reality, the image or representation has the coefficient of internal reality. Both sensation and image have reality, each one has its own kind of reality―the sensation has external objective reality, the image has internal subjective reality. It is on account of the ideational or representative coefficient that every image is placed unhesitatingly into its own world of reality, into its own series of images with which it easily associates and fuses.

        Writers on psychology in trying to define further the coefficient of reality refer it to the will. Some maintain that the coefficient of reality is the 'independence of the will,' while others claim that the coefficient of reality is 'subjection to the will.' Baldwin in his paper 'The Perception of External Reality,' offers an extremely interesting solution which reconciles both views. He points out that there is a difference between the 'memory coefficient' of reality and 'sensational coefficient' of reality. The two coefficients are opposite as far as control of will is concerned. The sensational coefficient is independence of the will, while the memory coefficient is control by the will. A sensation, in short, is not under the control of the will, while an image is subject to the will.

        Baldwin makes a further distinction between a simple image or 'memory image' and a 'memory image of external reality.' The memory image can be brought up voluntarily by its proper associates, but it has no sensational coefficient as a result, while the memory image of external reality can be followed by sensational coefficients, that is, sensations can be brought about in the train of such an image. To quote Baldwin: "Certainly a present sensible reality is not under the control of my will; it is independent, and if my coefficient is to be discovered in the relation of the presentation to my voluntary life, this must be its expression and I go over to the class of writers who find the psychological basis of external reality in sensations of resistance. But when we come to inquire into the 'memory' coefficient-asking the question what character is in a memory-image which testifies to its memory of reality, the tables seemed to be turned. Without stopping to examine other views, I hold that that image is a true memory which we are able to get again as a sensation (Baldwin's italics) by voluntarily repeating the series of muscular sensations which were associated with it in its first experience. The memory coefficient therefore is subjection to the will in the sense indicated.  .  .  .  A true memory in short an image which I can get at will by a train of memory i associates, and which, when got, is further subject to my will; a memory of external reality, on the contrary, is an image which I can get at will by a train of sensa- tional associates and which, when got, is not subject to my will."

        Now if I understand Baldwin aright, a sensation does not fall under the control of the will, while a simple 'memory image' and a 'memory image of external reality' are both under the control of the will, the difference being that the former does not terminate in a sensation, whereas the latter does. This I take to mean that a sensation does not depend on the subject (will), but on the external objects; in other words, a sensation cannot be produced from center to periphery (not internally initiated by the will), but is initiated by an external excitation peripherally stimulating the sense-organ and giving rise to sensation. An image, on the other hand, does not depend for its initiation on the external object or excitation, but is essentially an internal event which can be brought about from within by the process of associative activity, so highly characteristic of the image. Thus far my analysis seems to me to be in full accord with Baldwin's view. Similarly, Baldwin's views in regard to 'memory images' and 'memory images of external reality,' the former not ending in sensory experience, the latter terminating in experience with sensory coefficient, seem to me to be closely related to the views expressed by me in this work and in my other works on the subject.

        In spite of the agreement on so many points there are other points which do not appear to me acceptable. We may agree that kinaesthetic and muscular sensations or sensations of resistance are at the core of things, but are they the be-all of external reality? Have not sensations of pain, of hearing, of color, or of smell as much reality as our sensations coming from muscle, joint, synovial membrane and articular surfaces? The acute, shooting, twinging pains of rheumatism, gout, tabes-dorsalis, the burning pains of meningitis, the excruciating throbs of megrim, the fine stabbing pains of toothache, the agony of angina, the sharp tormenting pains of facial neuralgia, and many other pains coming from different organs and tissues, are not they real and external? In fact, do they not bear on them more the mark of grim, pitiless, external necessity than any of the sensations coming from active muscle and joint? What about light, color, sound, smell, are not they sensations of external reality, even if sensations of resistance do not enter into their make-up?

        Muscular and kinaesthetic sensations may be granted to play an important role in our knowledge of things, but psychologically regarded, all sensations bear on them unmistakably the mark of external reality. It is not the particular form or kind of sensation, but it is the sensory quale as such, that gives the coefficient of reality. As far as resistance is concerned Baldwin is right, if it be applied to each and every sensation. For each and every sensation possesses this mark of stubbornness about it; it shows opposition, resistance, and floods the mind. We may say that the stimulus forces i open the gates of the sense-organs and invades the mind with an overwhelming power. Still, on the whole, Baldwin is right in laying special stress on sensations of activity and resistance, since, biologically regarded, they are the ones that give the smack of life and the kernel of things and help to bring about adjustments to the external environment.

        Thus far the difference between Baldwin and myself seems to be rather insignificant.¹ When, however, we reach what Baldwin terms the 'memory image of external reality' the difference stands out somewhat more strongly. He contrasts the two, image and sensation, on the basis of dependence or independence of the will. The sensation is independent of the will, while the memory image of external reality is subject to the will which can bring about the sensation originally experienced. Now it seems to me that we are just as sure of the external reality of a sensation if referred to by the memory image, even if we cannot bring about the original experience. We may perceive sensations which cannot possibly be repeated, and still they are regarded in memory as events that have taken place in the world of external reality. We may have the perception of a comet which may never again come into our experience, and even if it should come, its coming is not due to our voluntary control; it is not we that can make the comet-experience come into our perceptual or sensory world with its sensory coefficient of external reality. We may be in the position of Plato's cave-dwellers and have no control over reality, the reflection of which is displayed before us, and still we may agree with Plato that for the cave-dwellers the memory images of external reality, the recurrence of which is not under control, will still be discriminated from a general memory image, from an image of fancy. The sensation or percept may be unique, its reproduction may not be possible, and still its memory image will be that of external reality.

        On the other hand, we meet in psychopathology with a vast domain of phenomena, such as recurrent mental states, insistent ideas which force themselves on the patient's mind against his will. The recurrent mental states or the insistent ideas are far more stubborn and uncontrollable than any resistant sensory object. The idea may come like attacks which overcome the patient more than any sensory reality, or the idea may be persistent gnawing at the very vitals of his mental life. No external object is so stubbornly, so painfully resistant as just such an idea; and still the insistent idea is not regarded as a sensory reality. The insistent idea possesses the coefficient of external reality, independence of the will, painfully so, and still it is not regarded by the patient as external reality; in spite of its being independent of the will, it is still regarded as an idea.

         It seems to me that we cannot express the sensational and ideational coefficients in terms of will, of control or non-control. It is not resistance to the will that makes experience sensory, nor is it subjection to the will that makes experience ideational or representative. Why not state the fact as it is? External reality is the quale of sensory experience, while internal reality is the quale of the image or representation. A sensation is experienced as sensation, no matter whether or no it depends on the will, the independence is a secondary matter; the same holds true in the case of the image, it is experienced as image, independent of the fact of its subjection to the will.

         There is another view which finds the fundamental difference between percept and image in what is and what is not common to all selves. Perceptual experience is common, while ideational experience is not common to all fellow-beings. I see the sun and other people can share it with me, while my image of the sun is experienced by myself. Thus Calkins tells us: "I perceive lowering heavens, pouring rain, bare trees and drenched sparrows, but I imagine wide horizons, brilliant sky, blossoming apple-trees and nestling orioles. The main difference is this: in the one case I assume that my experience is shared by other people and that everybody who looks out sees the same dreary landscape; but my imagination of the sunny orchard I regard as my private and unshared experience.

        The mark of being common is not the essential coefficient of external reality given by the percept. The percept is not experienced as external because it is common to other people. We do not see the tree yonder, because other people can see it too; we would see it there even if, like Robinson Crusoe, we had no fellow-being to compare notes with. A hallucination is as fully a percept and is perceived in the full garb of external reality, although it may have no currency with my fellow-men. The percept possesses the coefficient of external reality, no matter whether or no others can share in it.

        Moreover, psychologically regarded, the percept is as much of a private experience as the image is. In fact, every psychic state has the privacy ascribed to the image, and as such is unshared by other selves. It is simply the old psychological fallacy of confusing the physical with the psychic object, or with the psychic state cognizant of the physical object.² The flower as physical object, as stimulus, is r shared by all who perceive it, but the perception of the flower varies with each individual. My perception of the flower cannot be experienced by anyone else; like the image, the percept is entirely individual, unshared by other selves. I perceive the flower as having external reality, not because my perceptual experience is the same as that of other people, not because it is shared with others―as a matter of fact, it is not the same, and from its very nature cannot be the same as the experience of others, as we cannot possibly share our individual psychic experience with our fellow-men. We perceive the flower as an external reality simply and solely because it is sensory. The percept consisting of sensations, primary and secondary, bears the impress of external reality it possesses what Baldwin so aptly terms 'sensational coefficient' giving external reality. External reality is given directly and immediately by the sensation or by the sensory compound, by the percept.

        To quote from a work of mine: "Sensation carries along with it the reality of its stimulus. It i is not that the sense of reality is different from the sensation, it is given in the sensation itself. Similarly the percept and the sense of external reality are not two different things; they are given together in the same process of perception and are identical. . . . The sensory process is also the process of the sense of external reality. . . . In seeing or perceiving the chair yonder we do not perceive it as real, because of its social or common character―the reality of its existence is given directly in the sensory processes of the percept itself. . . .

        "The sense of reality of the external object is strengthened by association of the original sensory systems with other sensory systems, and the intensity rises in proportion to the number of systems of sensory elements, brought into relation with the functioning sensory systems. . . . The more systems of sensory elements are pressed into service, the stronger is the sense of external reality and the more assured is the reaction to the stimuli of the external environment.

        "In the evolutionary process of man's adaptation to his environment he becomes extended in being and grows more developed, because of his social relations. Man presses into active service the systems of sensory elements of his fellow-beings. Adaptations and hence successful reactions to the external environment are now more assured and the sense of external reality is still further emphasized and intensified. Throughout the course of intensification of the sense of reality the principle remains unchanged in nature. The sense of reality is given by and consists in nothing else but the sensory elements."

        From a philosophical and epistemological satndpoint the social aspect may perhaps be sufficient to fix the externality of the object, but from a psychological standpoint the trade-mark of "shares and common-stock" has no currency. The percept consisting, as we have shown, of sensory elements, primary and secondary, possesses, on that account, the sensory attribute of external reality.

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1. The difference is far less than I have originally thought. In a letter to me Professor Baldwin writes: "I am much interested in your views. You will find my later and fuller treatment of resistance and of the nature of memory images in my Thought and Things, or Genetic Logic, where I attempt explicitly to trace the genetic development of knowledge from sense objects to image objects in detail. being I think nearer to lour views than my earlier article brought out."

2. Royce and Münsterberg define the physical object in terms of 'sociality,' but if I understand them correctly they do not regard the definition as a psychological one.