The bearing of our studies on a theory of the conditions of pleasure-pain is obvious. If we consider pure feeling as the primary, fundamental, and conditioning mentality, it stands before all other mentality, and cannot be interpreted as conditioned. Pain as primum mobile is not intrinsically dependent on any other psychosis. Hence we run counter to the Herbartian School, which maintains that psychism exists from the first for itself as intellectual ideational activity, and that pleasure-pain is but reflex of the efficiency and ease, or the inefficiency and difficulty of this activity. The checking of the current of ideas may give a pain, but our exposition has been that pain arose before ideas or presentations of any kind, and long before any interference could be felt as pain.

Again, if we say “all pain comes from tension” (Mind, xii. p. 6), we have to ask, Tension of what? If we say tension of sensation or ideation, this is Herbartianism merely. How also can tension be felt as painful, except through sensation of tension, which is a feeling of intense sensation—obviously a late psychosis? And certainly pain is more than a general consciousness fatigue. And further stress and strain result in pain, because we imply these as painful activities by the very notion of the words. A stress or strain is assumedly painful activity, but this is not explanation. But apart from this, if the organism felt pain merely as direct result of struggling and straining, it would cease activity; activity and evolution would stop. It may be that by tension is not meant a mode of consciousness, but of nervous or muscular activity; but as we are now considering psychosis only as conditioning pure feeling, we leave this aspect for discussion till a little later. But on the psychical side, that all pain is a by-product of over-intense consciousness, intellectual or volitional, that the origin and development of pain is in a mental intensity which has gone beyond a certain point, this seems, on general evolutionary grounds, unlikely. Here, indeed, is merely a very particular and rather late mode of pain. And may not pains themselves attain an intensity which is itself painful? It must be acknowledged, however, that the whole doctrine as to consciousness intensity, its nature, reactions, laws, and measurements is very obscure.

Again, as to the theory that pleasure-pain is reflex of quantity of consciousness, that pleasure results from mental expansion, pain from mental contraction, this must, like the intensity theory, be considered as putting a late and special form as covering all forms. Mentality here exists for itself, and conscious self-development—a very late mode—is presupposed. The promotion of large complete free consciousness, the sense of progress and of unimpeded mental activity, certainly conveys high joys to certain choice natures, but they do not touch the vast majority of even human minds, much less animal. With the stolid an expanding consciousness is painful. Consciousness only as conscious of itself, and as self-developing, reaches a pleasure or pain as a felt furtherance or hindrance of its own expansion.

All reflex theories take us above the realm of simple consciousness acting directly for life, and this is the very form which seems commonest, and which appears to be full of passing pleasures and pains. That consciousness does react on itself in late phases is plain, but if consciousness, like other functions, has developed from the extremely simple to the extremely complex, this self-reaction cannot be regarded as primitive. Not till consciousness becomes integrated as a manifold organism do pleasure and pain become prominent as reflexes. We are not now looking for the functional value of pleasure and pain in mind itself as an independent whole; but regarding its functional quality and that of all mentality in life values, and here the functional meaning of such reflexes is secondary. In mind, as organic continuous whole, pleasure-pain is both resultant and excitant; it stands related to an antecedent state and it is stimulant to following states. Its function is excitant and it is the starting point of all other mentality, both originally and in the later manifestation. The having pleasure-pain is what starts both motor and cognitive volition.

It has, indeed, been maintained that while pleasure-pain is not a product or concomitant of some psychosis, as sensation, it is itself a sensation, a definite mode of sensibility. I have a pain sense just as I have a temperature sense, I feel pain in the same way as I feel warm, and by the analogous sensory nerves. With reference to this theory we must ask, since sensation is correspondent to modes of objects, to what mode is pain correspondent? Sense responds to modes of object, as light, and sonorous vibrations; but pain is not based on any such mode of objects. If pain were, there would have been long since a department of physics, which would have treated that basis just as it treats light, heat, sound, etc. But we all know that an object is not painful or pleasing in the same way that it is warm or cold, heavy or light. I do not say the stone feels heavy and painful, but I do say the stone feels painfully heavy, that is feeling pain is not a state of awareness. Further, having pain or pleasure is not by any sensing effort. I do not try to feel pain as I try to see the light of a star or feel the warm spot in a bar of iron. To be sure, the doctor asks his patient, “do you feel any pain?” and after a moment’s delay the answer may be, “yes,” but this is not in the nature of a sensing effort, but merely an attentiveness to bodily conditions as affecting mental state, not an objective attention but an analytical self-attention. Still further, a neural basis for pleasure-pain is altogether likely, but even if these nerves were found to be generally distributed over the body, this would not prove sensation, but merely that pleasure-pain is functional throughout the organism, diffusive organic consciousness. If pleasure-pain is primitive, and neurality and mentality correlate, the earliest nerve structure—ganglion—was a pleasure-pain organ. However, the sensory motor predominance is so early and complete that the current theory, as the more objective, is the natural physiologic interpretation.

Again, it has been maintained that pleasure-pain is not a definite state of consciousness, but a quality like intensity, a modus which must belong to all states. But if we assign pleasure-pain to such a category as intensity we must define just what we mean by this category. Is intensity a mere objective quality which we as observers assign to all psychosis, just as we do to electrical or luminous phenomena? or is it inherent element, an actual constituent, of every psychosis? If a man is angry and becomes more angry, intensity is increased; but we may conceive that he simply is more angry without being aware of this change of intensity, that is without every change of intensity being noted by consciousness. As introspection avers, it often happens that a man is both unconscious of his anger and unconscious of its increase. As I have frequently had occasion to note, simple natures are wholly unconscious of their emotions and of their intensity variations. That is, as matter of fact, intensity of feeling is not feeling of intensity. If you feel warm you feel differently than when you feel warmer, but this is no more than saying that when the iron is hot it is in a different state than when it is hotter. Intensity means the same in both cases. Consciousness, primitively, at least, is not self-awareness of its own changes in intensity. The feeling warm and the feeling warmer occur simply as facts which are subjectively unrelated and unmeasured by the consciousness which has the varying intensities. I strike a cow hard—result, intense pain; harder, more intense pain; this is correlative with, I strike iron, intense tremor; harder, more intense tremor. The cow experiences more intense pain, but does not consciously measure it off as such. I can say, “I feel hotter than I did,” but the cow does not appreciate and express its own sense of its experience. The language fallacy leads us astray. By our very use of terms, warm and warmer, and by our discussion of the matter, we imply a consciousness of intensity which is far from being primitive or general. It would probably be an overestimate to say that the intensity of one in a thousand psychoses makes itself felt as such in consciousness.

That consciousness is not always conscious of its own intensity is then shown by direct introspection. And in general we must observe that every psychosis has its own intensity, which intensity may or may not be noted by a consciousness of intensity. If there come a consciousness of intensity, this consciousness has its own intensity, which may be noted by a new consciousness, whose intensity may in like manner be noted by a new consciousness, etc., ad infinitum. That is, a consciousness is never its own intensity, and intensity is never a consciousness, such as pain or pleasure, but is mere comparative objective quality.

Again, consciousness has almost from the first different degrees of activity, but it would be most unlikely that so complex an act as consciousness conscious of its own intensity should be primitive and early. Also, if consciousness develops as life factor it must be immediate utility which determines its early forms. Hence on this general principle of biologic evolution it is most unlikely that primitive organisms will both have consciousnesses and consciousness of their intensity, for of what direct and vital value is this intensity-consciousness as psychic mode? On the other hand it is obviously desirable that psychoses should early differentiate intensity as objective quality, i.e., without self-awareness of it, should have different degrees of a psychosis to meet different degrees of requirement; thus to fear strongly or weakly according to necessity of the case. To have fear set at one pitch for all cases is perhaps absolutely primitive, but differentiation is early. But to fear more or less, i.e., at different intensities, is not to have intensity as subjective element, an actual psychosis constituent appreciated as such, which is very late evolution since the demand for it is late. In thus defining the category of intensity we have plainly isolated it from the pleasure-pain category. We know pleasure or pain as act of consciousness just as we know volition or sensation. Pain and pleasure are definite facts like seeing or touching or willing, and are so recognised by common consciousness. One or the other may be involved in all experience, but this does not make them general qualities like intensity. Pain is a consciousness, intensity is not a consciousness. This is the immediate value of the terms, the very names convey distinctness of category. I have a pain, I do not have an intensity; I am in pain, I am not in intensity. My pain is intense, but I cannot say my intensity is painful. We experience pain and pleasure, but we never experience intensity.

This quale hypothesis as presented by Marshall in Pain, Pleasure and Aesthetics, is set upon the dangerous foundation of ignorance, viz.[viz.], of the neural basis of pleasure-pain, and of causes of its variability. It is as yet disputed whether a nerve organ for pleasure-pain has been found; but if one is generally acknowledged, the theory would be overthrown. Greater intensity in any psychosis, as sensation of warmth, means simply greater nervous activity in the particular nerves subserving the psychosis, in this case the temperature nerves. So also pleasure-pain as general concomitant like intensity must mean merely some general mode of nervous activity as yet unknown, if we allow it any nervous basis at all. Again, the variability of pleasure-pain for a given content, the fact that the taste of olives is at one time pleasant, at another, unpleasant, suggests that pleasure-pain is like intensity merely a general quality, which must in one form or another attach to all psychoses. But this does not explain anything. What we want to know is why in any given case we have pleasure and not pain; we do not wish to be put off with a general statement that the nature of pleasure-pain is such that we may have either, which is akin to the old metaphysical method of abstract explanation; making the rationale of the lion leoninity is not unlike the hypothesis that explains pleasure-pain in all its variations by variability as its nature. We have a scientific faith that variability is not a general unexplainable quality, but that there is for every case of pleasure-pain a definite rationale based in the facts of life demand and life history. That olives now give pleasure, and now give pain, is based upon definite conditions of physical state which are very complex, but which can be revealed by patient research alone.

Any theory of pleasure-pain then from the point of view of pure psychology, as explaining it by reference to other modes of consciousness, is, we think, unsatisfactory. But perhaps the physiological point of view will be more satisfactory. It is generally considered that the function and origin of pain is in what is unfavourable to physiological function, of pleasure, in what is favourable. I cut my finger, and the pain says, stop the injurious action. However, there are exceptions. I taste sugar of lead; it is pleasant, and I keep on tasting, and am poisoned. Lotze explains that this sweetness is immediately soothing and advantageous. “We must not regard pleasure,” says Grant Allen, as “prophetic.” But what has been the evolution of taste as sensing act except to be “prophetic,” to give at the opening of the alimentary canal a monitor to the stomach and other digestive organs? That it tastes sweet, that this taste is pleasant, and so the substance is swallowed, or that it tastes bitter and unpleasant, and the substance is rejected; this surely is anticipatory and “prophetic.” The taste for sweetness is not evolved for itself; but for its life value; and hence Lotze’s explanation fails from the point of view of evolutionary psychology. The organic sweet is the nutritious and beneficial, and the sensing this quality in connection with these favourable and pleasant effects on the stomach and organism as a whole has led to a taste and liking for sweetness. “Sweet and wholesome” is the common and just conception. But if mineral sweets injurious to life, like sugar of lead, had been a common environment, and the only sweet known, this sweetness would have been as unpleasant as the sour or acid now is. We see even now that sweets that have several times caused nausea, though at first highly agreeable, come to be distasteful and disgustful. We now find that sour and bitter substances are disliked by animals in general as painful, for the sour and bitter is general sign of the unwholesome; but those animals which live almost exclusively on bitter herbs undoubtedly appreciate this quality as we do a bon bon. Men lost in a desert by pertinaciously tasting bitter herbs and becoming dependent upon them for support would soon realize their bitterness as pleasant, and a race might originate to whom sweetness would be unpleasant. Hence the value of a sensation does not—in natural evolution—lie in itself, it is merely a guide and index; and the sensation quality will be pleasant or unpleasant according to its relation to the demands of life. A sensation is inherently either pleasurable or painful, but not essentially one and not the other, hence the proverb, de gustibus non disputandum. The sensing act in itself is indifferent, i.e., sweetness and bitterness, purely as tastes, as sensing acts, are indifferent; but as matter of fact having grown up with and for pleasure-pain tones as indicative of life values, they are either one or the other according to their relation to life. Where sense serves not life but itself, as with the epicure, a new order of pleasures and pains is determined which is not within our present scope of discussion.