The Philosophical Review/Volume 1/Pleasure-Pain and Sensation

by Henry Rutgers Marshall

PLEASURE-PAIN AND SENSATION.

THE direction in which the Psychology of our day has made its most striking advances is that of the development of psycho-physics. A very large proportion of the complex and absorbing investigations which are undertaken by those who devote themselves to this relatively new science deal with phenomena of Sensation, and therefore we should not be unprepared to find, as we clearly do find, those who become absorbed in this and kindred studies emphasizing the function of Sensation and to some extent exaggerating its importance in the mental field. This tendency is often manifest in the writings of scientific men who are not psychologists, but who deal directly or indirectly with neural anatomy and pathology, in which writings it is common to find casual statements which imply a classification of Pain with Sensation, although one finds no similar classification of Pleasure.

Incidental statements like those just referred to are difficult to treat seriously, and psychologists owe acknowledgment to Dr. Herbert Nichols for having brought into the field of argument, in clear form, the theory that Pleasure and Pain are Sensations, as he has done in the articles published in the July and September numbers of this Review. I wish here to make a statement as concise as possible of the arguments for and against this view and to show the grounds upon which I base my conclusion that the position is untenable.

I.

Let us first examine the arguments presented in favor of the hypothesis that Pleasures and Pains are to be classified with Sensations.

1. It is held that Pain is just as distinct, just as 'disparate,' as any of those mental states which we all agree to call sensations. This fact, if granted, is of course suggestive of the position maintained, but that it furnishes an argument of negative rather than positive force is apparent when one notes, first, that it is not claimed to relate to pleasure at all, but only to pain, and furthermore, that it can be asserted of only a very limited proportion of our pains.^[1]

I think it will be granted that the great mass of our pains are not of this distinct and 'disparate' nature: 'floating pains,' as they are sometimes called, are certainly not distinct.^[2] What is more, those which are markedly 'disparate' are in my observation, not pains pure and simple. There is always a something else than the pain by which we are likely to describe it. It is a cutting pain or a pricking pain or a crushing pain. One can always discern some differential where the pain is distinct, although the pain itself appears to me to be the same in all cases.

But even granting to pains this occasional 'disparateness' — this distinctness which enables them at times to usurp consciousness, — this fact seems to argue little for a sensational classification; for there are other states which appear to me to be equally distinct and which in moments of intensity equally usurp sway over the whole mental field, which, however, we should never think of classifying thus: e.g. the psychic phase which fixes our conviction that an object of revival is real and not a pure imagination, — that which makes the difference between a memory or an expectation, and a mere revival; which latter may have very clear time relations without being thought real in that time. It is to be noted also that the argument which we here examine is of little value unless we agree to relegate to the vague region of 'representation' a large proportion of our pains and almost all of our pleasures, — a proceeding to which there are many objections which I shall touch upon later.

2. In the experiments which are commonly made in the laboratory, it is found that electrical and direct mechanical stimulations of nerve trunks, or of their terminals in certain spots, give pain, but that no sort of manipulation of these stimulations which has been tried has brought pleasure. From this it is argued that, as pleasure cannot be obtained by the activities of the nerves in question and as pain can be, there must be specific nerves for pain. But it seems to me that we may argue from the facts to a quite different conclusion, viz.: that the nature of the electrical or mechanical stimulus applied is such that it is always productive of the conditions of pain and that therefore pleasure cannot be reached through the activity of these particular nerve trunks or terminals unless they be stimulated by other less abnormal methods than those thus far adopted by the ordinary experimenter. This view is strengthened by evidence which we have that certain nerves have a very limited capacity for action under the conditions which make pleasure production possible. In certain directions we must have a summation of gentle stimulations if pleasure is to be noticed. The delicious softness of down and the agreeable smoothness of satin cannot be appreciated unless broad surfaces are affected at one time. It is even possible, indeed, that certain sensational nerves may be practically incapable of reacting under the conditions which pleasure implies. Surely from these facts we gain no convincing argument in favor of specific pain nerves.

Under the view that I have above suggested there is no difficulty in accounting for the fact that the inner organs, of which we are nearly or entirely unconscious in normal health, are productive of pain under the abnormal conditions of disease or under the artificial stimulations of the investigator; and the argument^[3] from these facts also loses its force.

3. It is held that certain nerve trunks, when excessively stimulated by the methods open to the experimenter, do not give pain. This, it is claimed, shows that there is no capacity to produce pain in the organs which have been stimulated. The claim is too wide, however; for, granting the facts, all that is really shown is that nerves which would give pain under the experimental conditions are separate from the trunks which the stimulation reaches. It is not clear, however, that the facts are to be conceded. Evidence cannot be felt to be decisive by the advocates of the view which it is supposed to corroborate, if they think it is necessary to state it as doubtfully as Dr. Nichols does in his articles.^[4] I think the argument cannot, on any ground, be considered a very satisfactory one when we consider the great difficulties attending the production of the artificial and delicate stimulations relied upon, and the greater difficulty of obtaining these results in subjects whose tale of absence of pain can be considered scientifically conclusive.

4. It is shown that where one operation brings both touch (e.g.) and pain, in many cases the pain arises distinctly after the touch, etc. This lateness of perception is probably exaggerated by the tendency ingrained in us to consider with promptness those elements in our experience which enter into the make-up of objects; pleasure and pain are notably not of this nature. But so far as the statement is true for normal subjects, the facts certainly here argue that separate sets of organs have been stimulated successively. The possibility is not precluded, however, of there being in such cases a certain sensation other than the pain, to which this pain belongs, which sensation follows the sensation of touch, etc. In other words, it is quite possible to argue from the observed facts that touch is followed by sensation X in a painful phase. When one presses a needle into the skin, the touch sensation may precede the pricking pain; but this may result from the fact that certain other nerve elements than those of touch are affected after the needle has pierced the skin, namely, those which bring about the pricking sensation. I am perfectly willing to believe, indeed, that a set of nerves and nerve terminals other than those affected by action upon the surface organs of pressure, heat, and cold, may be discovered, and that we shall find them to be brought into action by rupture of the surface, by laceration, by cutting, by piercing; and I think it will be allowed as possible that the action of these nerves under the conditions involved in the usual experiment must always be painful; but there is here surely no crucial argument to show that specific pain nerves have been discovered. In those morbid cases where several seconds elapse after the sensations of touch and cold are felt before the pricking pain arises, we may surmise that some disturbance has occurred which has delayed the action of the nerves affected by the laceration or cutting or pricking of painful degree. Such restrictions of activities we find in the other recognized sensations. The facts of analgesia which have been held to tell in favor of the existence of special pain nerves may also be found to be explicable in some similar manner. We may interpret the observed results to mean that the capacity to experience one form of sensation (e.g. cutting, pricking) in a certain part of the body may be cut off, together with the capacity for pain-giving which goes with it, without cutting off in the same parts the capacity to experience other sensations (e.g. those of pressure, heat, cold) with their capacity for pain-giving.

5. Schiff and his followers have been led to argue for special pain paths in the spinal cord, by the observation that under certain morbid pathological conditions or by the use of anæsthetics all the generally recognized senses may be lost to the lower extremities, whilst the pains produced by pricking or cutting remain. But, as in the case preceding this, it certainly is possible to argue from these observations that the other sensations are cut off, leaving only the sensation of pricking-cutting, which is always stimulated painfully under the methods adopted by the experimenters.^[5]

6. Finally we have the argument from the important experiments made by Goldscheider, in which it is claimed that he has isolated pain nerves and terminals. This argument rests thus far upon the observation of one man; and in no field of science is it more likely than in that of neural anatomy that subsequent observers will find ground for modification of a first investigator's results. Goldscheider's early experiments led him to the important discovery of pressure spots, cold spots, heat spots, in the skin surfaces, but did not lead him to believe that his observations told of pain spots; later, led doubtless by his interest in the theory of specific energies, he came to the conclusion that the evidence did speak in favor of pain spots also.^[6] The article declaring for this latter position was published in 1885. Since then he has made many investigations, but principally in relation to the pressure, heat, and cold spots. His words have often implicitly denied the theory of specific pain nerves; but this may be passed over.^[7] In the same year, 1885, Blix published in the Zeitschrift für Biologie a series of observations and a discussion covering the same general ground, and his conclusion is that "there are three specific kinds of nerve apparatus in the skin, one for heat, one for cold, and one for pressure. For the sense of pain there are no specific organs proven in the skin" (Vol. XXI. p. 160). It appears to me that there is little ground to hold that Goldscheider's results are to be taken as conclusive. Wundt, in rewriting his Physiologische Psychologie for the third edition, has recognized Goldscheider's discoveries in relation to the heat, cold, and pressure spots, but he does not agree that he has proven his case with reference to pain.^[8] Professor Ladd, in his late Elements of Physiological Psychology, seems more inclined to take Goldscheider's word for it; but even he does not think the case proven.^[9] Even if we accept, for the sake of argument, the correctness of the facts as stated by Goldscheider, it seems to me highly probable that it will be necessary to reinterpret them, perhaps in accordance with the hypothesis I have above suggested in reference to argument 4, in terms of which they are, in my opinion, readily statable as follows: that the nerves in question and their terminal organs are those of the cutting-pricking sensation which always occurs in painful phase under the conditions involved in the methods adopted by experimenters.

So much for the direct favorable arguments. Dr. Nichols has brought forward two indirect arguments in favor of this view which must receive attention.

7. He shows that the sensational hypothesis enables us to understand the distribution of pains and pleasures by the additional hypothesis that there are few or no pain nerves where pleasure usually occurs and few or no pleasure nerves where pains are usual, this latter hypothesis being certainly warranted by our knowledge of the distribution of other nerve terminals. It is apparent, however, that this argument is not effective unless it can be shown that pleasure-pain distribution cannot be made comprehensible under any other hypothesis than the one he defends. That such is not the case I think I shall be able to show below.

8. The same objection may be made to the effectiveness of Dr. Nichols's argument from biology. He shows very cleverly that it is possible to sketch out a theory of biological development compatible with the sensational theory of Pleasure and Pain; but this does not establish his main thesis unless he can show that it is impossible to bring opposed Pleasure-Pain theories into line with our modern biological conceptions. I shall presently attempt to show that one counter-theory at least is compatible with our general notions of biological development.

With reference to Dr. Nichols's carefully elaborated theory I have little to say, except to note the danger of trusting overmuch to results obtained from such combinations of hypotheses as one must make use of in biological retrospect. The danger is illustrated in the fact that the very number of this Review which contains the first part of Dr. Nichols's article contains also an argument by Mr. Stanley showing grounds for a position exactly opposite in one respect to that taken by the former. Dr. Nichols holds pleasure to have been the primal sense. Mr. Stanley, on the other hand, holds pain to have been the primal sense. There is a difficulty in reference to both of these theories, viz.: that if Pain and then Pleasure, or Pleasure and then Pain, be supposed to be the originally differentiated sensations from which all others have been developed, we should certainly look for their disappearance in the process of development or else for a distinct common-sense division of all sensational phenomena on lines of pleasure and pain; and this we nowhere find. Dr. Nichols does not make clear to me what may be the mechanism by which the hypothetical pleasure nerves bring about "the neural activities whose function is to continue certain beneficial processes," or that by which the pain nerves bring about the "neural activities whose function is discontinuance." Apparently the continuance and discontinuance must refer to the organ which is functioning in direct connection with the pain and pleasure activities, and as we must postulate, I presume, one brain centre for pain and one for pleasure to regulate this discontinuance and continuance in an indefinite number of directions, it would appear to be necessarily by means of some direct return motor (?) activity to the functioning organ; but how it is to act upon the organic function which is to be discontinued or continued, I do not understand. Can it be inhibitively in the case of pain and in manner to duplicate the stimulus in the case of pleasure?

I have above presented all arguments of moment which to my knowledge have been brought forward to substantiate the view that Pleasure and Pain are to be classified with Sensation. It seems to me that any unbiassed observer must grant that the utmost that can be claimed for these arguments is that they furnish ground for the provisional acceptance of the view in question as a working hypothesis unless objections to the acceptance of the hypothesis appear in other directions. But it seems to me that very formidable objections do appear as soon as the matter is taken into full consideration. Some of these I wish now to lay before the reader.

II.

9. Pleasure and Pain have been treated in relation by masters of thought from the earliest times. By one we find them called opposites; another speaks of them as related as heat is to cold. Now, pain is looked upon as normal and pleasure as its mere absence; again, pleasure is held to be normal and pain its mere negation: but the bond of relation between the two is rarely questioned and is usually conceded. It appears to me that this weight of authority cannot properly be ignored: such a full expression of the observation of mental states by thoughtful men is clearly a datum of Psychology which cannot be passed over by scientific psychologists in their consideration of this subject. Sufficient ground for these statements of relation appears in the fact that Pleasure and Pain arise in consciousness as disparate parts of a continuum. One fades into the other, when there is no other observed change in the nature of the mental elements presented at the same time. Strong stimuli, if continuous, gradually fail in the production of pleasure and as gradually become pain producers. One displaces the other. Apparently no element of consciousness can be both pleasurable and painful at the same time: the one appears to exclude the other, although it seems equally certain that psychoses composed of diverse elements may have in their make-up coexistent elements both pleasurable and painful. It is the judgment of common sense that Pleasure and Pain are two states, too disparate to be commonly known by any one word, but so inseparably connected that they must be mentioned in one breath. I have dwelt upon this matter a little at length, because there seems to be nowadays a tendency to ignore this relation.

Since the sensations of heat and cold, which are held in relation, have been found to have specific nerves and corresponding terminals, the fact of the relation between Pleasure and Pain would be no objection to the Sensational view were it not for the fact that while the discovery of pain nerves has been claimed, there is not the slightest indication of the existence of pleasure nerves. This failure casts further doubt upon the claim of Goldscheider as to pain nerves, the existence of which is already denied by other authoritative observers; for surely if the pain nerves are isolated, we should expect to find some evidence of these related pleasure nerves. Dr. Nichols attempts to overcome this objection by the somewhat summary process of referring almost all pleasures to the region of representation, which he considers may have a coincident of organic activity, although the original pleasure sensations and their organic basis be no longer traceable. I think there is little warrant for this supposition. Pleasures are just as clear, just as 'presentative,' to me as pains are, in reference to the vast majority of my sensuous activities; and, furthermore, there are grave objections to the treatment of pleasure-pain representations in the manner above referred to: of this I speak below more at length.

10. But the difficulty here presented becomes more marked when we consider the matter of brain locus. There is some ground for the notion that a locus has been found in the cortex for the pains of cutting-pricking-laceration, although this can scarcely be said to have been established.^[10] On the other hand, there is not the faintest indication, to my knowledge, of the existence of a pleasure centre in the brain. This, again, evidently casts much doubt upon the claim that a pain centre has been discovered and seems to indicate that the centre, if its existence be verified, will probably be found to be the centre for the sensations involved in cutting and pricking, which, under the experimenter's methods, have been stimulated in painful phase. Surely, if Pleasure and Pain are Sensations, developed probably early, perhaps earlier than any others, in the history of our race, we ought to be able to identify in the cortex the centres of their coincident activities, as we have done those of many of the other senses, or else some adequate explanation should be forthcoming for their non-appearance.

Pleasure and Pain show characteristics which are not noticeable in the generally recognized sensations.

11. Each of the typical sensations has a very special means of production by which it, and it only, is brought into consciousness. None of them have the characteristic which is observable in Pleasure-Pain, that they are aroused by the widest range of psychic occurrences.

Sensations are pleasurable and painful. Pains, indeed, as we see, are so closely related to sensations that an attempt is made to bring them together in classification.

But Emotions also are pre-eminently pleasure-pain colored. Pleasure is, in common parlance, spoken of as an emotion; and emotions are usually treated by English psychologists together with pleasure and pain.

Intellectual pleasures and intellectual pains, again, are well known to all thoughtful people.

Certainly we have here phenomena very different from anything noticeable with the recognized sensations. We never, for instance, have a cold thought as we have a painful thought or a sonorous emotion as we have a pleasurable emotion.

12. Under continuation of stimulative conditions, the typical sensations do not habitually change from one form to another. A definite stimulus does not habitually alter from a pressure into a sound, nor from a sound into a brightness. To be sure, water which feels hot when the hand is first plunged in, may soon seem none too warm, but it does not become cold unless there is a real change of the conditions of stimulation.

But under continuation of stimulative conditions, pleasure habitually fades into pain, although there are some relatively few exceptions, probably traceable, as I have elsewhere argued, to alterations in the system which really bring about a change in what appear to be continuous stimulative conditions.

13. Again, in the case of ordinary sensations, within the limits of normal activity, increasing or diminishing intensity of physical stimulation brings corresponding alterations of psychic activity, although the relation is complex and not simple. But with Pleasure-Pain the case is quite different. An increase of intensity of stimulus often at first increases a pleasure, then decreases it, then produces an increasing painfulness, — a series of which we have no counterpart in sensational experience.

14. The differentiation of the typical sensations seems to be related to differences of environmental action upon us. The eye mediates ethereal vibrations. The ear tells of air waves. Heat and cold terminals react to molecular vibrations. Taste probably deals with chemical reactions. But pleasure and pain are not determined by any such special relation to our environment. Heat may be painful or pleasurable; so may cold, so may taste, so may touch, to go no further.

15. The alterations of pleasure-pain phase which are observed in connection with identical stimuli at different times are apparently incompatible with the sensational hypothesis. Hypernormal activity in any special direction often produces pleasure at one moment and pain at another, the change occurring often within narrow time limits. Are we to suppose that under certain conditions the pain-sense organs are affected by a given stimulus and the pleasure organs not, while under some mysterious altered conditions with the same stimulus the pain organs become quiescent and those for pleasure become active? We surely are in a position to ask for some explanation of this mode of stimulation so different from that found with other senses. Again, activities which are uniformly disagreeable when first experienced, if not too extreme or too long continued or too often stimulated, habitually become gradually less disagreeable and finally may be productive of pleasures. This process is commonly described as the 'acquisition of tastes.' The only explanation of these phenomena in terms of the sensational theory would seem to be that pain nerves become separated from activities or cease to act when the latter function, and that pleasure nerves begin to become connected with the same activities. But what has kept these pleasure nerves from atrophy during the long periods they have been inactive? And after the new connection of the activities with pleasure why do not the pain nerves suffer atrophy, as they certainly do not? For we find that a man who has learned to enjoy the taste of olives, at first disagreeable to him, may eat a few with his dinner every day for years and always with enjoyment; but if he double his allowance some day, he will find the last one disagreeable. The man who walks little may find the action of his muscles on a five-mile walk very painful, but if he persevere he may come to find that definite amount of action in those muscles enjoyable and regularly required for his comfort. If, some day, however, he use these muscles in a twenty-mile walk, he will find that his capacity for pain in them has not disappeared. The hypothetical pain nerves have not become in the least disabled by disuse. How does it happen that for year after year we live on with practically no consciousness whatever of the existence of our intestines, until some day an irritant gives us excruciating pain? Have these supposititious pain nerves been lying dormant for so long, and yet actually gaining capacity to act with vigor, instead of becoming atrophied as other organs do?

Cases like this and the one immediately preceding it have led to the suggestion that a certain width of stimulation may be necessary to bring the pain nerves into action. If we accept this notion, we are confronted with the further difficulty that those of our activities which occur after rest are most vivid and widely effective, and yet are our most pleasurable experiences. The very same conditions which are held to bring about the stimulation of pain nerves here seem to be productive of pleasure. How is it that the man who is well-rested and vigorous in health finds it difficult to experience pain, although he is more active than the average man? How is it, on the other hand, that the gentlest stimulus is painful to one who is exhausted by illness or who is thoroughly weary?

So much for pain. What can be the special conditions which determine the stimulation of the supposititious pleasure nerves has not yet, I believe, been even suggested.

16. It would seem that if pain nerves are so widely distributed as is implied by the sensational theory, there should be a more distinct localization of pains than is experienced; this localization, in general, however, is so very indistinct that the fact has been used to argue for that theory which makes Pleasure and Pain a special mode of conscious life distinctly removed from all other mental activity.

17. In bringing this list of objections to a close, I must mention one difficulty which relates to the special form of this sensational theory defended by Dr. Nichols in the article above referred to. Dr. Nichols's theory, especially as it relates to pleasure, necessitates the existence of images of pleasure and of pain, similar to the images of sensations and objects which are grasped in revival. I think there is no ground in experience for supposing that pleasure and pain are 'represented' in this way. It seems to me to be an error to hold that there are images of pain or of pleasure, as it would be an error to speak of there being images of intensity, for example. The intensity of an image of a sensation, is not an image of the intensity of the sensation. The intensity in both cases is a psychosis of relation; and it seems to me that the case is similar with pleasure and pain. Sensations and their images, indeed, however closely they may be bound together, are always markedly distinct. It seems probable to me that the image is present with the sensation, but swamped, as it were, by the force of the sensation, somewhat as represented by the symbols below.

	Sensational Object.
	Image.

Thus when the image arises it is grasped in its relations as familiar, but with a sense of the loss of its emphatic part. Be this true or no, it is certain that sensational images are definitely distinct from their sensational "presentations" and I cannot find any corresponding distinction in my experience of pleasure-pain. A pleasant sensation may be revived pleasurably (or at times painfully), a painful sensation may be revived painfully (or at times pleasurably), in manner similar to that by which a special relation of. intensity is revived. The word 'pleasure' and the word 'pain' are also revived with objective connotations in pleasurable and painful phases respectively; but I cannot bring myself to believe that I have images of pleasures or pains similar to the images I have of sensations, or that pleasures or pains can be revived apart from any content to which they are attached.

III.

I have attempted in Section I. to show that the arguments suggested as favorable to the sensational theory of Pleasure and Pain are not conclusive, and in Section II. to show further that there are many positive objections to be raised to the acceptance of this theory. In what follows I shall attempt to show that there is a hypothesis relative to Pleasure and Pain, which is not in disaccord with the observations that have been used as arguments supporting the sensational view, and which explains with seeming adequacy the facts I have raised in objection to that view.

The hypothesis which I wish to present is this: that pleasure and pain are qualities of relation one of which must, and, given the proper conditions, either of which may belong to any element of consciousness.^[11] That, psychologically considered, the condition of pleasure is psychic effectiveness of the element of consciousness to which the pleasure is attached, or, in other words, of which it is a quality; and the condition of pain, psychic ineffectiveness of the element to which the pain is attached. That, physiologically considered, we may suppose pleasure to be experienced whenever the physical activity coincident with the psychic state to which the pleasure is attached involves the use of surplus stored force, — the resolution of surplus potential into actual energy, — or, in other words, whenever the energy involved in the reaction to the stimulus is greater in amount than the energy which the stimulus habitually calls forth. Pain, on the other hand, may be supposed to be experienced whenever the physical activity coincident with the psychic state to which the pain is attached is so related to the supply of nutriment to its organ that the energy involved in the reaction to the stimulus is less in amount than the energy which the stimulus habitually calls forth. Further, that pleasures of rest are systemic and apart from the psychic activity which had been emphatic before the moment of rest, and that pains of obstruction are also systemic and apart from the psychic activity which is inhibited. That, therefore, there is ground to believe that both the pleasures of rest and pains of obstruction will be found to be statable in terms of activity in accordance with the laws above formulated.^[12]

This view serves to account for the diversity of opinion expressed by different thinkers as to the nature and classification of pleasure and pain, by referring the divergence to differences of personal equation, to varied mental emphasis in the conscious life of the opposed thinkers, and by a corresponding difference of pleasure and pain distribution. It serves also to explain the persistency, referred to by Dr. Nichols, with which thinkers "from Plato and Aristotle down through Descartes, Leibniz, Hobbes, Sulzer, Kant, Herbart, Bain, Spencer, Dumont, and Allen" . . . have held to the doctrine "that pleasure and pain are in some way complementary expressions of the general welfare of the individual," notwithstanding the logical difficulties and contradictions of experience which have made their statements unsatisfactory. For it appears under this view that the relation between pleasure and pain and the welfare of the individual is not direct but indirect; while the relation is direct with the welfare of the organ the activity of which is coincident with the psychic state to which the pleasure or pain is attached. I must refer my reader to the articles in Mind, Nos. 56, 63, and 64, already referred to, for a more detailed argument in support of this view; here I shall merely consider the hypothesis as related to the sensational theory which we have under discussion.

At the start I must say a word to show that the theory of 'specific energies,' so far as it is verified, is not in disaccord with the view I support. Sensations are psychoses of limitation — they are due to an emphasis of certain parts of consciousness and an obscuration of certain other parts; and on their physical side, so far as we can judge, they are determined by exclusive differentiation in the physical activities coincident with consciousness, — by the activities of definite parts of the nervous substance or organs. It seems highly probable that all complex fixed contents and also all images simple or complex are also determined by the action of specific organs. But it must not be forgotten that there are also relations between these activities which leave an impress corresponding thereto upon consciousness from moment to moment. The mind acts as a totality, and the relations between its special partial activities must be embodied in consciousness even though the functioning of no special distinct organ be coincident with the grasp by us of these relations. Intensity is such a psychosis of relation, for instance; and it is in this general category that Pleasure and Pain, under my theory, are conceived to belong.

Let us now consider the arguments and objections of Sections I. and II. as they appear in the light of the theory I defend. I shall treat them seriatim with numbers corresponding to those already used. First, then, is it possible to show that the arguments adduced in favor of the sensational theory do not militate against the hypothesis we defend?

1. That a few pains are very distinct, are 'disparate,' while it may indicate a likeness to sensation, as is claimed, certainly does not present evidence against the view that we are here examining; for there appears to be every reason why, under extreme conditions of excess of activity as related to nourishment, the psychosis of relation should be vivid.

2. Under the physical theory, as I have elsewhere argued, we should expect to find that organs which are regular in their rhythm of action and are not called upon at intervals to act powerfully would come to be supplied with just enough nutrition to enable them to function properly and would have little capacity to store or to use stored force, and little ability, therefore, to function pleasurably. For such organs, practically any hypernormal stimulus would produce the conditions of painfulness. This may account for the fact that certain organs appear to be incapable of pleasurable stimulations, although in such cases the lack may be connected with the nature of the stimulus, as above suggested; it certainly accounts, without too great a stretch of the hypothesis, for the common observation that the functioning of certain internal organs scarcely appears in consciousness unless in the painful phase.

3. If it could be shown that an organ, when stimulated with such excess that it resulted in its deterioration, produced its specific sensation and yet no pain in connection with the stimulation, a valid argument would certainly be had against the theory I defend; but as I have already shown, the evidence is not decisive and the observed facts may be accounted for on other grounds; and when we consider, as I hope to show, that the preponderance of evidence favors my view, it makes it highly probable that a reinterpretation of the facts will some day be presented.

In my consideration of arguments 4 and 5 in themselves, I have shown how it is possible to explain the observed facts in a manner other than that adopted by those holding the sensational theory, and the reader will readily perceive that the explanation there given is in accord with the theory now before us.

4. The fact that the pain of pricking arises after the sensation of touch, when one operation produces both, is explicable if we suppose that a second set of nerves, viz. those producing the sense differentiation known as pricking or cutting, are brought into action after those of touch, and that they do not appear in pleasurable form under the method of experiment, and, maybe, that they have practically little storage capacity and are therefore little liable to appear in pleasurable phase at all. Analgesia in terms of this hypothesis becomes a very commonplace phenomenon; for it is very frequent in morbid cases, whether produced artificially or by disease, to find one sense obliterated (e.g. that of heat or cold) whilst another is not cut off (e.g. that of touch or pressure): the only marked characteristic in this case is this, that the sense which is cut off is not clearly differentiated in consciousness until it appears under the conditions which make its phase painful.

5. The facts which lead to the conclusion as to there being a separate pain path in the spinal cord are explicable in a manner so similar that repetition of the counter-argument seems unnecessary.

6. The argument based upon the claim of the discovery of specific pain nerves deals with evidence so distinctly in dispute that I do not feel that it needs reply here. I have already shown the direction in which I think it probable the reinterpretation of observations will be made, and if my surmise be correct these observations would not be in opposition to my theory.

7. Is it possible under our theory to explain the distribution of pleasures and pains as we find them? I think it is as simple as under the sensational theory.

Pleasure, under our hypothesis, involves a tendency to continuance of the activity which is producing the pleasure; and pain, a tendency to discontinuance of the activity which is producing the pain.

It is evident that, under the laws of elimination of the unfit and of survival, those individuals would prevail whose capacity to use stored force in reaction to a stimulus (or, in other words, whose pleasure-getting) was confined to organs producing activities the continuance of which would be advantageous to the individual.

Again, those would have the advantage whose tendencies to discontinuance of special activities (or, in other words, whose pain-gettings) were limited to organs producing activities which would be disadvantageous to the individual if continued. In general, then, we should expect to find pleasure capacity emphasized in directions in which continuance of the activity will be advantageous to the individual and pain production prompt (pleasure capacity practically absent) where the continuance of the activity will be disadvantageous. These are the conditions which in a general way are found to hold.

8. It is clear from what has just been said that our theory may be stated in terms not incompatible with modern notions of biological genesis. I perhaps do not lay so much stress upon biological argument as others do; this, however, is not because I think it unimportant, but because I think it a dangerous habit to rest upon a foundation which must be laid so largely upon hypotheses. But taking the argument for what it is worth I think it not too great a strain upon our credibility to surmise that the first general undifferentiated sense, which has now disappeared in its differentiations, may have had attached to it from the very start the capacity for pain under excessive stimulations corresponding to the relation involved in the tendency to discontinuance of the coincident neural activities; in the second place to surmise, as added to this pain capacity, the capacity for pleasure whenever it became of advantage to the organism as a whole that the activities coincident with this general sense should have the capacity of continuance. As the senses became differentiated, those would appear with emphasis of their pleasure capacity where, in the long run, the continuance of the activities involved would be advantageous to the individual, and conversely, mutatis mutandis, as to pain. But evidently the pleasure and pain would be directly connected with the capacity of the organ active in producing the sensation and not directly with the welfare of the individual. An indirect connection on wide lines between pain and pleasure and disadvantage and advantage respectively to the individual would, however, soon be brought about, because the individuals that took pleasure in and continued disadvantageous actions, and that found pain in and tended to discontinue advantageous actions, would be in time eliminated. The connection would be so indirect, however, that the law could not be expected to be without numerous exceptions, and we should look to find exactly what we do find, vis. those anomalous cases, which have given so much trouble to theorists, where sweets mean death and pains mean health to the individual, while indicating, under our view, actions respectively healthful and harmful to the organs functioning. This hypothesis also makes it easy to understand why, with Pleasure-Pain so early a development as it must have been, there is no evidence of the later development of consciousness on the two great lines of Pain and of Pleasure as would seem to be necessitated by any doctrine which makes Pleasure and Pain the primal sensational elements.

Let us now turn to the objections which I have raised to the sensational view.

9. The bond between pleasure and pain so widely recognized and so inexplicable under the sensational hypothesis becomes natural under the theory here defended; for the two are really part of a continuum, both being determined by relations of the nutritive conditions to the activity of the organ which is the physical correspondent of the mental state.

10. Under our theory no special localized organs should be looked for in the brain for Pleasure and for Pain, for each differentiation of pleasure or pain, except as to degree, implies a change of organ, so to speak. The theory does not meet the demand that we shall tell what special organs are active for pleasure and for pain, because under it we are led to hold that, properly speaking, there are none such: or, to put it differently, that there are an indefinite number of such; that each organ which is capable of bringing about by its activities a definite psychosis is in that special case an organ either for pleasure or for pain.

11. This hypothesis accounts most easily for the fact that pleasures and pains are aroused by the widest range of psychic occurrences; that there are sensational, emotional, and intellectual pleasures and pains. It would be most unexpected if it were not so found in experience, when we consider that each sensation, each emotion, each intellectual act implies activity of an organic coincident, in some effective or ineffective relation.

12. That under continuation of stimulus-conditions pleasure habitually fades into pain, is to be expected under my hypothesis; for pleasure means the use of surplus stored energy, and the hypernormal stimulus which is bringing about this result, if continued, will surely, in ordinary cases, use up the surplus and then bring about the conditions which give pain. It is a notable corroboration of my theory that the process is not reversed. Pain caused by excess in activity does not go over into pleasure, with unchanged content, unless there supervenes rest, i.e., opportunity for recuperation and storage in the organ which has been active.

13. That increase of the stimulus which is giving pleasure increases the pleasure for a time, then diminishes it, and then produces an increasing pain, is quite in accordance with the notion that something is used up (with pleasure experience) before we can get the organ which is active into the condition in which it becomes capable of giving pain.

14. Under our hypothesis we do not need to look for any special environmental stimulus-differentiation corresponding with pleasure and pain, as we did under the sensational view, if the hypothetical pleasure and pain senses are to fall in line with all other sensations; for under our hypothesis pleasure and pain are determined by relations within the organism which are general and which occur with all differentiations of environmental action upon us.

15. We are not surprised, when we consider the great variations of nutritive conditions, that a mental element which at one time brings us pleasure on some other day brings us pain, or vice versa, with no change of stimulation. The capacity to bring conscious pleasure or conscious pain after very long intervals is also quite explicable without supposing any such non-activity as would imply atrophy of the organ which finally acts pleasurably or painfully.

That the phenomena of habit are found to be a corollary from the general theory, I have argued at some length in Mind, No. 64. The action which is painful to-day but not carried too far calls for an unusual supply of nutriment, and this develops a capacity for pleasure-giving at the next moment of stimulation. This pleasure capacity may increase largely by continuous repetition of this process.

The pains which first bring to our notice the existence of inner sensations are accounted for by supposing that these organs, being very regular in their action and not ordinarily called upon to react to unusual stimuli, lose practically the storage capacity; so that a strong stimulus always brings pain, as it also first brings into prominence in consciousness the psychic elements to which the pain is attached. The theory accounts for the fact that the well-rested and vigorous man finds pleasure-getting easy; for with him storage must be large and the capacity for pleasure-getting full: and also for the fact that one weakened by excessive activity or illness finds pleasure-getting impossible; his illness or overwork has drained away all his surplus stored force.

16. That localization should be dim for pleasure-pain is not surprising since the organs of pleasure and those of pain are so constantly shifting.

17. The difficulty as to representation does not occur under our theory; for no such thing as a representation of a pain or pleasure is supposed, although pleasurable and painful representations are acknowledged and are covered by the general law.

Here my argument must close. There is much evidence corroborative of the general theory I have here advocated, which I cannot present within the limits of this article, and no more indeed is called for in this connection than bears especial reference to the sensational hypothesis. If any reader be interested, he will find a fuller treatment of the subject in the numbers of Mind above referred to and in a series of articles now appearing in the same journal, in which the important subject of Æsthetics is treated from the standpoint of my hypothesis. I cannot lay down my pen, however, without one word more. Introspective psychology in our day cannot take any steps without inquiring whether they are in accord with the results reached by our new-born science of psycho-physics. On the other hand, if there be any force whatever in the argument for the thorough-going coincidence of psychic and neural phenomena, investigators in psycho-physics on their part must also take into account the records of introspective psychology. The mass of observations from introspection is large in comparison with what has been obtained from the studies on the physical side, and this should lead to an emphasis of the former, in our time at least: and it seems to me clear that the balance will be always in favor of introspection; that it is the final reference to which all psycho-physical result must be made now and always. The rapid development and the brilliant and valuable results obtained from this new science of psycho-physics have, however, led, if not to a disregard of introspective evidence, at least to an over-emphasis of the data from neurology. The sensational hypothesis as to pleasure and pain under discussion appears to me to be eminently a case in point. The evidence produced in favor of this hypothesis is almost altogether physiological and anatomical, and furthermore, in my opinion, is in itself not at all of such nature as should lead a truly scientific mind to adopt the hypothesis without reserve. It does not seem to me that it would have been possible for psychologists to have maintained it had they as scientists taken into full consideration the data from subjective psychology proper which bear on the question.

Henry Rutgers Marshall.

1. Wundt, in a late study (Phil. Stud., Bd. VI., Hft. III., p. 359), states the relation thus: "Ein Unterschied freilich bleibt zwischen Gefühl und Empfindung, der auf wesentlich andere Bedingungen des ersteren hinweist. Die Empfindung ist nicht nur selbst ein einfaches, unzerlegbares Element unseres Bewusstseins, sondern auch ihre Entstehungsbedingungen sind relativ einfache, beruhend auf bestimmten psychophysischen Organisationsverhältnissen, die bei den verschiedenen Empfindungen als wesentlich übereinstimmende erscheinen. Ganz anders das Gefühl. Von dem sinnlichen Gefühl an, welches unter ähnlich einfachen Bedingungen zu stehen scheint wie die Empfindung, bis zu den höheren intellectuellen Gefühlen bietet sich hier eine Stufenreihe höchst mannigfaltiger und immer verwickelter sich gestaltender psychologischer Entstehungsbedingungen."
2. It cannot be granted, as Dr. Nichols puts it (op. cit., p. 405), that we are unable to attach a floating pain "to some other sensation as a quale": for the very fact that these pains appear to shift is evidence that they are connected with other psychic elements, which, however, we are not accustomed to discriminate. Shifting either implies distinct localizations, which we clearly have not in such cases; or else an uncertainty of judgment in reference to obscure localizations: localizations we have in any case and these imply attachments to sensations or else definite local signs in the pains themselves, neither of which suppositions can be made use of by Dr. Nichols without logical weakness.
3. Cf. Goldscheider, Archiv f. Anatomic u. Physiologie (Physio. Ab.), 1885, p. 341.
4. Cf., for instance, Nichols, Origin of Pleasure and Pain, p. 407, l. 17, l. 23; p. 417, l. 21.
5. Wundt (Phy. Psy., Ed. III., p. 114) has pointed out that the facts as we have them do not necessarily imply the existence of distinct transmissive fibres for pain, separate from those of the generally recognized sensations. Cf. also Th. Lipp's Grund. d. Seelengelebens, pp. 202, 205, 206.
6. Cf. Archiv f. Anatomie u. Physiologie (Physio. Ab.), 1885, Sup. p. 87.
7. Cf., for instance, op. cit. p. 345; also Sup. pp. 19 and 88.
8. Vol. I., pp. 395 and 409.
9. P. 512.
10. The evidence, indeed, is so contradictory that it has appeared quite possible to hold, as has been done by F. Courmont in his late work, Le Cervelet et ses Fonctions, that the cerebellum is the seat of all pleasure and pain activities, and those connected with the emotions.
11. Cf. my article on the "Psychological Classification of Pleasure and Pain," in Mind, No. 56.
12. Cf. my articles on "The Physical Basis of Pleasure and Pain," in Mind, Nos. 63 and 64.