# The Philosophical Review/Volume 1/The Origin of Pleasure and Pain - Part 2

This is the second part of a two-part article; the first part is The Origin of Pleasure and Pain - Part 1
THE ORIGIN OF PLEASURE AND PAIN.
II.
IN the last number of the Review we gave evidence for specific pain nerves distributed throughout the body, for the probability of pleasure nerves in certain places, and for the possibility of such in all our sense-organs. We concluded that most of our æsthetic feelings are not sensations, but are associative central occurrences. It is this major part of aesthetics which we have now to account for. At once we say that the present distribution of pain and pleasure nerves in our body does not seem sufficient for this purpose. Holding fast to a common mode of origin for all our senses, we must, then, look further into biological development for our desired explanations.
Human anatomy and physiology were closed secrets till study of a long line of embryonic and morphologic modifications revealed them. It should be evident that human psychology can never be understood except by a like tracing out of present from past conditions. Since Darwin, 'the first sense' has been frequently discussed, but, on the whole, in a manner bringing the subject little credit. The first organs of sense, however, have long been the objects of sober biological research. As it is our task only to discover how pleasure and pain came to do what they now do, we may escape discussion of early amorphous creatures. We need not go outside of our line of ancestry, nor back of its first organized sensory system.
​It is not easy to tell, for the animal kingdom at large, what sense-organs came first. Many coelenterates have eyes, while certain annelids, standing far higher in the line of morphologic development, have no eyes. But it is fortunate for our present purpose that, though the exact line of human ancestry is not known, biological opinion now speaks conclusively for an annelid type at one stage, having a simple nervous system. The earthworm, though probably not our identical ancestor, may show us what that creature would be like.
This worm has a well-defined and relatively complex nervous system. This system comprises a lot of nerves running to and from segmental ganglia which are connected by bilateral cords. The forward ganglion is the largest, and may be called the brain. The peripheral ends of its sensory nerves terminate, so far as can be discovered, in simple cells of like nature throughout. There is no evidence of other specific sense energies than those which may be mediated by this apparently homogeneous sense system. By means of this, the creature digs, eats, procreates, is a respectable traveller, and leads a complicated life. It does not see, hear, or smell. To say it does not experience touch, taste, heat, cold, pain, or pleasure would raise criticism respectively from the champions of each of these as the primary sense. We will only assume, then, what all seem inclined to agree to, that the worm does all that it does in terms of some one sense. And for our ancestral worm, we will leave the kind, or psychic quality, of its single sense for the present unnamed.
Our worm being provided with this kind of a nervous system, we may note that from the outset its neuro-muscular functions would divide into two contrasting classes: those which would tend to continue or to promote beneficial experiences, and those which would tend to discontinue or to inhibit baneful ones. At
​once the parallel is obvious between these and the functions commonly assigned to pleasure and to pain. But, though our creature should physically experience these contrasting functions, could it mentally experience any corresponding contrasts in terms of a single sense? I answer, "Yes"; and my grounds for this answer have, as I believe, close relationship with those facts which underlie the mental experiences commonly termed desire and aversion, — experiences by no means so coincident with pleasures and pains as is commonly conceived. It will prove of importance to our subject to clear up this matter.
I desire a horse. Here the mental image of the horse is not alone the object of the desire. This concept-object also contains ideas, more or less abstract, of somewhat that might be experienced in connection with the horse. Precisely what the somewhat is that must be added to constitute my desire would be differently stated by various authors. Some contend that this mere unobstructed dwelling-in-the-mind of any pleasant concept constitutes desire; others, that an unobstructed idea of 'mine' must be added. Others would hold that an unobstructed idea, however abstract, of 'exerting myself to realize, or to continue the concept,' or of 'making it mine,' must be contained in desire. By "unobstructed" in all these cases I mean "uninterrupted by the idea of my resisting this realization."
Now, I maintain of any mental state that it is its tendency toward an act calculated to reproduce its object, that constitutes its essential characteristic as a desire, if it be such. As we shall show, ideas of pleasant experiences, from reasons lying within the conditions of their biological development, usually do tend strongly toward acts that should reproduce their object. Here the proper tendency is emphatically innate within the idea of the pleasure alone. This is why the first class of authors are led to contend that the mere dwelling-in-the-mind of pleasure concepts is desiring. Some ideas of past experiences do not possess this tendency within themselves; therefore, concepts containing such ideas must, in order to constitute desires, also contain somewhat further that does possess such a tendency. My ​desire for a horse was an example. Authors of our second and third classes are those who hit upon this kind of a desire. Yet a large number of mental states other than states of pleasure do tend innately to acts that should reproduce their objects. The impulses of children to mimic and to imitate are marked examples of such. Since it is the fundamental function of every mental event to tend to some act, since such a tendency is its own reason-to-be, biologically, we may surmise that a much larger proportion of our ideas than commonly we take note of do, during the moment of their occurrence, fall fundamentally under the category of desire; rightfully so fall, though their distinguishing tendency, being swamped in the subsequent trend of our thoughts, may consequently be lost sight of. Ideas of pain usually tend to acts that should discontinue pains like those thought of; hence, usually, ideas of pain are not desires. Yet ideas of pain may be so joined with other ideas that the whole concept shall be a genuine desire.
Our worm, then, could desire ; for on his brain could be made impressions, which, when revived in memory, would tend to acts that should bring about experiences like those from which such impressions sprung. He could also hate; for from the foregoing it will plainly follow that aversions, or hates, are mental states that tend toward acts that should discontinue their objects.
It may still be contended that our worm would not itself know any difference between such desires and such aversions, transacted in terms of a single sense ; that, as psychic experiences to be judged of themselves, they would not be different. But we further point out that even under this aspect the desires and aversions of the worm would display characteristics of makeup markedly contrasting with each other. Even the muscular activities executed in pursuance of these desires and aversions would betray corresponding characteristics. Our lips act differently when pressing a luscious cherry than when, accidentally, we have bitten a bitter one. We do not shake hands as we strike. The whole muscular deportment of a child actively at play is far different from one flying in fright from a dog. If all our conscious states should drop out except those of our muscle ​sense, these would yet bear to us as complete significance of the various contrasting vicissitudes of life, as do our muscular activities to the common observer. As there are distinctive earmarks common to all healthy organs, and others common to all unhealthy organs, whatever their particular functions, or whatever the animal, so there are ear-marks common to those neural activities whose function is to continue certain beneficial processes, and contrasting ear-marks for other neural activities whose function is discontinuance. And these traits hold good for all kinds of sense, and for most creatures. To follow these out and to note them would throw much light on the common mistake of identifying all desires with pleasure, and all aversions with pains. But we content ourselves here with making plain that, from the first, the desires of our worm would be of different make-up from its aversions, and that, in so far as these contrasting states were representative of like contrasts in outer events, to that degree they would constitute for the worm a knowledge of these outer differences, and would constitute its love or hate of them.
But, if the nervous organism of our creature should now be changed so that most of these occurrences which I have defined as desires should be transacted in terms of one specific sense, and those of aversion in terms of a different sense, we see at once that new and important characteristics would thus be introduced mentally distinguishing desire from aversion. In this case, we should bear in mind, however, that the essential features by which we should still test desires and hates would not lie in the facts that most desires were of one particular kind of sense, and aversions of another kind, but, as described above, in certain peculiar relations based on the corresponding physical functions which such mental states bore to other mental states.
Our worm had one sense; we have several. In light of what we know of specialization, we should now inquire whether something like what we discussed in our last paragraph did not really take place in the development of the worm to man.
We have already discovered that it is the particular function ​of pains to prompt to acts that should discontinue those pains. Hardly a word more is needed in favor of the postulate that we have here a separate sensory system introduced and developed, at some time since our first or primary sense, for the special function of physical aversion or neural discontinuance. We have yet more to offer on this subject. But we will only remark here that any sense so specialized to avoidance of baneful events, would necessarily become specially 'made up' into the particular characteristics and associated with the peculiar mental experiences coming to us when baneful events occur, and would, therefore, be specially wrought up into our ideas of baneful events, and into our ideas of detriment and of aversion in the abstract. This would be the case although the pain and the pain processes would, of themselves, be as truly beneficial in essential nature as any other sense or bodily function. Indeed, our pains must be essentially beneficial, in order to have been so fundamentally and widely wrought up into our developed organism. Had their general function been detrimental, it would have become eliminated.
The origin of pleasure is not at first so clear. For it we shall have to follow the destiny of our ancestral worm more closely. At the outset we may note that whatever sense it was in terms of which our worm transacted its primary neural functions, this sense would become from the first wrought up into peculiar mental representation of beneficial occurrences. Necessarily so. For one reason: because organization adapted to beneficial occurrences is at first the only organization that is taken up and perpetuated. The more simple a creature is, the more preponderatingly must its possible experiences be beneficial, in order to survive. As the number of its possible experiences increase, the greater may the absolute number of its detrimental experiences be, and the species yet prosper. The more fundamental a function is, the more nearly invariably must it work beneficially. Primary functions must be fundamental functions. We see, then, how any primary sense, which was the mental correspondent of these functions, must be wrought up into special representation of beneficial experiences, ​— how pre-eminently so above other senses subsequently added to the nervous organism for the purpose of mediating other less fundamental functions.
This, however, is but the beginning of the story. If, as we have postulated, another sense, as pain, should presently be introduced, specially to perform the functions significant of danger and of detriment, not only by this specialization would the new sense become representative of detriment, but also, in proportion, would the old sense be relieved of this class of functions. And in proportion as it would cease to perform functions significant of detriment, the less then would it be woven into detrimental experiences, and the less would it be mentally representative of detriment and of aversion. And as this occurred the more specifically, therefore, would the primary sense be representative of beneficial occurrences and of desire.
But more follows with the addition of still other senses in the development of our worm toward man. Every new sense taken up into the organism is certain to perform some function less fundamental to that organism than that performed by the primary sense. Though, on the whole, each new sense must be representative of more benefit than detriment, yet it will be far less specially representative of benefit than we have seen the first sense become after being relieved of mediating experiences peculiarly representative of detriment. Thus, sight, though enormously beneficial on the whole, continually pours in upon us a flood of experiences of no benefit whatever. We have already compared the primary sense of our worm with pleasure as developed in us. Our abstract notions, being residuary impressions of past experiences of a particular kind, are in a way fair tests of these experiences. The common notion of pleasure since philosophy began is that essentially it is the expression of our well-being. No such notion has ever arisen regarding sight. The notion is a competent indication, we think, of how much more fundamentally and representatively our first sense has been woven into our beneficial experiences, both biological and psychological, than have any of our other senses.
​But we must understand this matter yet more clearly. In our ancestral worm was developed a pretty complex nervous organism, for the mediation of a pretty complex life of physical activities and of mental experiences. We must now examine how new sense systems would join in upon the old, and, in consequence, what relationships the mental experiences mediated by the new would bear to those mediated by the old. Suppose a pair of eyes should develop in the worm's head. They would be of no use biologically unless joined in some way with the motor apparatus of the creature. Either a new set of motor nerves must be developed correspondent to the new optic fibres, or the new fibres must be grafted upon the old nervous centres. We do not fear contradiction when we say that, in general, the latter was the method of rise of our different senses.
This being so, it is to be noted that, excepting those of the new organs of sight, no new acts are made possible to the body by reason of its new sensations. Its old acts, however, are stimulated to far more numerous and complicated occurrence. In so far, therefore, as formerly these acts were in turn incitive to mental states, so the kind of states formerly incited and their peculiar characteristics would now be multiplied to far more numerous occurrence. The like would occur with the birth of each new sense system. Whatever the peculiar characteristics of our worm's primary sense, therefore, we should expect to discover them preserved to it and multiplied over and over again into the increased mental life of the developing creature.
It is probable, also, that the nerves of the primary system would, to some degree, extend themselves into the new organs of the new senses. And, to the degree that this happened and its nerves were stimulated by the same occurrences as worked upon the new sense, would the developed characteristics of the primary sense be revived and multiplied, both directly and by association, in the new mental experiences, and would thus become woven still more widely into the increasing mental life of the developing creature.
Having identified our primary sense with that of pleasure, it may now be suspected that we have accounted for far too much. ​Pleasure does not play any such quantitative part in our mental experiences as the aforesaid multiplications would at first indicate. Another genetic neural process accounting for this matter must now be noted.
Our worm had a sensory nervous system of a particular kind, ramifying throughout its body. Pleasure nerves do not ramify through our body to a like extent. "If the worm's nerves were pleasure nerves," you ask, "what has become of these in us?" As well you might ask what has become of the particular muscles that controlled the worm's various segments, or the segments themselves. They have been lost in morphologic modifications. Each sensory nerve of the worm may, so far as I know, now have its representation in us. But, if so, it could by no means play the same part in mediating our sensory life as it did in that of the worm. In the worm most if not all of these nerves terminated peripherally. If they were pleasure nerves, we must conceive that they there in some vague way mediated pleasure in response to the kinds of influence to which pleasure now responds in us; that is, to most of those kinds of influence which in us cause sight, sound, smell, taste, touch, heat, and cold. But as new sense systems came in, and new sense-organs were developed specially to mediate these separate kinds of influences, the old systems became pushed aside or down, or were left behind in growth, and buried from where their former influences would commonly reach them. In view of consequent disuse, therefore, we might say they would atrophy; only, 'inherited atrophy' is not a happy biological postulate at present. It seems better to conceive that as new organs developed, — organs of all kinds, sensory and muscular, legs, arms, eyes, ears, tongue, — as the organism as a whole grew, and developed to special forms and functions, each new sense system grew along with and into its appropriate organs, while the old sense did not grow, at least did not grow to anything like the extent that the other special sense systems did.
In the last Review we pointed out that 'in us' pleasure sensations seem to be developed in those sensory functions which are most fundamental, and in due proportion to their being ​fundamental. In witness of this are the pleasure functions of sex and of nutrition. We may now say, rather, that pleasure was duly preserved to the performance of these sensory functions. We intimated, also, the possibility of pleasure nerves yet preserved in all our special sense-organs, and of the kinds of general occurrence that are likely there to reach and to stimulate these submerged fibres. The morphologic bearing of all these matters will now, I think, be sufficiently obvious for our present sketch, without further comment on them.
We now are able to understand why our pleasure sense, if it be our primary sense, does not occupy that quantitative share of our present mental life which, under our postulate, its various multiplications by newly rising sense associations at first seemed to promise. The surface and even the interior of our body has been usurped by a varied set of new sense systems, which now mediate the majority of our efferent experiences. Our primary sense now mediates but few original sensations. The lack of positive demonstration that it mediates any at all, with the fact that so many fundamental functions of the primary sense have been usurped from it, leads us to inquire more closely as to those functions which have been preserved to it, and for what reasons they have been preserved.
Why, under the foregoing wide-spread specialization and substitution, has not our primary sense been eliminated entirely? Our answer is that by the very order and manner of origin and development of our various sense systems the primary sense was peculiarly developed to fitness for centro-neural functions. It has, therefore, been specialized to that function. We have already noted that each new sense must be joined to old motor paths, in order to become of service. The complex nature of our higher nervous centres, which is required to bring about the proper adjustments of the infinite variety of our present sensory experiences to appropriate co-ordination with a nearly equal variety of possible muscular combinations, is too common a subject of modern knowledge to need more than mention here. This vast central co-ordination of sensory paths to motor paths has itself become a special function of our neural organism of ​major importance. Both by reason of its early start in advance of our other senses in performing this particular function, and the special fitness for mediating all kinds of neural energies which its first selection as a primary sense seems to indicate, it seems not improbable that the primary sense, under the general processes of neural specialization, became devoted to central functions, similarly as the other senses became devoted to those functions to which their fitness and date of origin destined them.
Though the peripheral fibres of our primary sense system have, therefore, been largely submerged, and their functions lost, its central parts, with their functions and their particular mental characteristics, have yet been preserved to us essentially unaltered. We cannot fail to observe that this specialization of our primary sense to central functions would make it characteristically 'associative' in comparison with the peripheral senses. For, except in so far as we grant absolute spontaneity to the cortex, our primary sense would now be chiefly dependent for stimulation upon its function of associating or connecting various in-coming impulses with proper out-going impulses. This corresponds with the 'associative' nature of our aesthetic pleasures, which we discovered in our analysis of those matters, and to that degree favors our postulate that pleasure is our primary sense.
But to substantiate our theory we must now inquire how these morphologic developments affect the present individual. Our postulate is likely to incur prejudice, in that it declares that we experience particular pleasure, without previous correspondent stimulation of any peripheral pleasure nerves. We are indebted to Professor William James for taking ground emphatically against the notion that there is nothing in the mind not let in by our sensations. This author declares that "the mind is filled with necessary and eternal relations" which "it in no way gets through experience." Yet each of these relations he holds to be a definite feeling based, as are all other feelings, upon some definite cortical action. Thus, his "fringe" feelings, his feelings of "if," "and," "but," "like," "equal," "different," "more," ​and so on, — all of these Professor James bases on cortical peculiarities which have come into the line of our inheritance by the "back door" of spontaneous biologic development. Among other of these a priori mental occurrences Professor James includes our aesthetic and moral judgments.
But in ourselves, more precisely what are these strange aesthetic feelings, based on natural genesis, but not let in by correspondent sensations of our own experience? And how do they work ? First, I answer, they are not so strange after all; and, secondly, they work on a footing with all other conscious processes. The paths of our primary or pleasure sense are not the only associative or connective paths which our cortex has inherited. At birth the cortex is braided through and through with associative paths, probably of every kind of sense. Unquestionably the arrangement inherited by every sense system has somewhat to do with the manner in which it shall be stimulated. Thus, a stimulation of the retina must, by necessity, first go to the optic centre rather than to the auditory centre. There must be a vast number of optic cells in the cortex which are not direct terminals of optic fibres. There is little doubt that the paths to these are as fixed at birth as is the route up from the retina. It is such cells and paths with which those inherited from our primary sense stand on essentially common footing.
The more we look at the matter, the more it seems probable that the number and the arrangement of all the sensory paths and cells in the body are likely to be pretty much the same in the child as in the adult, and not very different among most men. Rather, it is the manner in which these paths work and are used that determines the 'make-up' of our mental lives. Most men inherit the same number and general arrangement of legs, arms, and features, yet there is abundance of variety in individuals. I am inclined to believe that most of the neural paths, even in the cortex, and of whatever kind of sense they be, are, as paths, fixed forever congenially; that the whole is the result of an untold period of selected adaptation of inner possibilities to outer possibilities; that we must, therefore, look ​to certain characteristics inherited in every human cortex for numerous mental traits exhibited in common by all men; and that, of certain other differences more peculiar to individual lives, we should attribute some, perhaps, to congenital temperaments or 'working traits,' but more to the endless variety of education and of human experience.
As there is nothing strange in the arrangement of our aesthetic paths, so there is nothing fundamentally peculiar in their mode of work; in the manner in which they respond to whatever stimulations their definite arrangements bring to them. We have said it is the fundamental function of every sensory state to tend to some act. Suppose a child to open his eyes for the first time, that they fall on a red blanket, and that they then close. We are not to think that his retinal stimulations would run up to the cortex and stop there at the first cells reached. They would push on to some sort of activity. The resulting activity might seem to us a merely inco-ordinate kicking of limbs and working of muscles. Yet, physiologically, the movements would be as definite as playing the piano. They would be the movements most naturally beneficial to the life of man as a whole, in response to that kind of experience in the abstract. If the glance at the blanket was brief, the resulting movement might be beyond our scrutiny. If the red blanket attracted attention for sufficient time, the kicking would, very likely, be considerable.
Now what does the child feel as the sensory side of such a first occurrence? Those who have watched babies know they appear to feel something more than the mere optic sensations. Professor James, with his peculiar notion as to emotions, would say the child feels happy because he kicks. But, according to this author's own views with reference to volition and innervation-sense, he ought rather to say, as we shall, The child feels the natural ideo-motor pleasure-state which makes him kick. It is our postulate that, frequently on such early occasions, such optic stimulations (and others of various kinds similarly) discharge to their appropriate acts through the inherited paths of primary pleasure sense, and that what the child feels, in ​addition to the peripheral sensation, is the proper pleasure feeling or emotion corresponding to such a discharge. Not that this need be all ' additionally ' that the child might feel ; for other a priori or 'fringe' feelings would also be likely to be awakened at an early date. Nor would the child always 'kick and coo' at sight of a red blanket. At another time, the same optic stimulation might come to him compounded with other stimulations, say with a pang of stomach-ache. In which case the modified discharge would be quite different; the child now might cry and kick. And the child might thus have developed, in pursuance of the laws of use and habit, an aesthetic 'prejudice' against the color red, lasting an indefinite time thereafter, in place of a 'liking' for the color, as in the first instance.
So much for first occurrences ; now for subsequent ones partially involving paths used in previous occasions. It is a primary neural law that the exercise of any inherited tendency modifies that tendency. This paper may presuppose a knowledge of psychologic association, according to the laws of which our mental events are persistently 'objectified' and grouped into the percepts and concepts which, as we say, correspond to outer events. Yet, for our subject, we must emphasize the truth that it is not the association of outer things, but the different associations of inner neural tendencies which is the immediate source of modification and of persistent grouping in these processes. No matter how the paths got into the brain, and no matter what sort of stimulations, associative or peripheral, the currents be which traverse them, the same laws of use and habit will govern all alike.
The manner in which our peripheral senses are associatively 'worked up' under the dual influences of outer events and inherited conditions is commonly thought to be pretty plain. Why then should it now be less plain how, under circumstances fundamentally of the same nature, our aesthetic feelings come to be worked up in the manner in which we know them? All our senses work under these dual conditions of inherited function and of the outer influences which these functions subject them to. All our senses are made up differently ​in accordance with these dual conditions. Thus, our joint or articulate feelings are made up differently from our auditory feelings, and our temperature feelings from those of touch. I could not in this short paper trace up each phase of our aesthetic feelings, and show precisely both to what outer and to what inner conditions they are due. I can only indicate general conditions. To this end we may first note that in so far as the conditions, outer and inner, of our aesthetic feelings correspond to those of any other sense, or class of senses, in that proportion will the make-up correspond to the make-up of the latter.
If, then, our above account of their origins be correct, pleasure, and also pain, in us ought to betray both certain characteristics resembling the make-up of our motor feelings and other characteristics more like those of our objective senses, — these which give us our ideas of outer things and objects. This ought to be so for pleasure, because pleasure has inherited characteristics of a motor make-up, and is now by its central functions intimately associated with the outer senses. And this ought to be so for pain, because pain, on account of the nearly universal distribution of its nerves in every muscle and organ of the body, is both eminently motor and eminently associative in its present functions.
How, from the associative functions and characteristics of pleasure and pain, we get our more objective and 'outer' make-up of aesthetic feelings, I think has now been as clearly indicated as in this short space could be expected. From these, made up with our other senses, we have the varied prettiness of every stretch of landscape; the delights or discords of its complicated colors; the grace or ugliness of its many outlines and objects; the catching melody or unpleasant grating of its sounds; the agreeable fragrance of its winds or flowers; the unpleasant nastiness of its muddy paths and ditches. How these mosaics of aesthetic feelings correspond psychologically with the similar mosaics of other feelings in combination with which they are woven; how they vary in men of different temperaments, and how they change within ourselves with varying moods and ​from occasion to occasion; what is their present process of individual make-up, and what their biological origin in general, — all these things, I hope, will now appear somewhat more comprehensible to the student of modern science.
For our more massive aesthetic groupings, — those lying at the base of our emotions and deeper passions, — a few more words are needed. From the first we may surmise that here we have more to do with the inherited motor characteristics of our aesthetic senses. By reference to our instincts in general, we may appreciate this more clearly. Spalding has thrown light on their complicated nature. Certain complex outer influences must be brought into proper accord with inner conditions equally complex, or the instinct is forever inherited in vain. The chick may flap his wings at certain periods, and see men or hawks at others; but not unless the chick see the man at a particular post-natal period, and his wings be free to flap at that particular conjunction of events, will it execute that definite and complex set of movements which betrays his inherited fear of man.
The instinct seems to be a complex motor-idea inherited as a whole. It never goes off, unless it be fired as a whole. When it is fired, we have reason to believe that it is felt as a whole. For myself, this, in connection with the theories of this paper, seems to bring the nature of our inherited emotions more clearly home to me. In life's varied experiences, more or less of our aesthetic paths may be knit up into the more complicated associations which we have described in connection with the 'objective' senses. But on the occurrence of proper conditions of stimulation, these should not hinder us from experiencing the purer instinctive 'wholes' which we have inherited, or the as pure and even more massive wholes which may be occasioned by more diffusive stimulation of our inherited primary tracts in general. Such survived efforts and struggles, as it were, transacted by our unknown ancestors in terms of their primary motor sense, are precisely what I seem to feel when I experience these deeper passions and emotions, whether pleasant or unpleasant.
A final point remains to be considered. Though I believe ​the last chapter in Professor James's text-book is one of the most important contributions to the future of psychology ever written, yet I think grave misuse is made there of the term a priori as applied to traits of mind inherited from a like source to those treated of in this paper. Whether the origin of these traits is 'spontaneous' or 'acquired,' the result is the same; and experience plays the same part in that result in either case. It is only played in a different way according to Weismann than according to Lamarck. By rejecting the unfit and perpetuating only 'her own,' Experience as truly moulds our organic and mental functions as if for each individual she formed them wholly and anew. No traits of mind, then, are 'independent of experience,' except in the sense that all traits are so; except in so far as the first cause of all things is unknown. This is important relative to the way in which we should look at the inherited characteristics of our primary or pleasure sense. Looked at as traits of our ancestral worm, we are sceptical regarding the whole postulate. Looked upon as traits of our present neural system, of similar origin and like function with all the rest, and as mediatory and expressive of our present environment as any traits of our other senses, the postulate at once loses its strangeness. Human nature is said to be much alike in all men. That we have much in common; that we are moulded much alike; that, as 'moulds,' we are much alike; that nature and experience between them have worked through unknown periods in fashioning the moulds to be filled so differently in our individual lives, — all this ought no longer to be a difficult hypothesis of mental science.
Acknowledging the many blunders likely to be made in so broad a departure from traditions, I yet must declare this whole matter of the biological origin of mind to be one of the most promising sources of future psychological investigation. To me, also, it is a main avenue to the deeper secrets of the universe and of man's futurity.
Herbert Nichols.
HARVARD UNIVERSITY.
(Concluded.)