Popular Science Monthly/Volume 60/March 1902/Were the Earliest Organic Movements Conscious or Unconscious?

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By Professor E. B. TITCHENER,


THERE are now current two general theories of the place of mind in nature. The one of these, and the one which it is easier to state in precise terms, regards the processes of the material universe (including those of the physical organism) as a closed chain of cause and effect, which is altogether removed from any psychical influence. Mental process is a concomitant of certain highly complex material processes, but not anything that affects these processes themselves. Whether or not it is a constant concomitant, and thus a valid index or symptom of the nature of the underlying material processes, is a question which science must settle by appeal to the facts. Modern psychology answers it in the affirmative, though she offers no explanation—cannot, in the nature of the case, offer an explanation—of the 'why' of the connection. Mind exists; mental processes run their course in constant parallelism to bodily processes; they never interfere with these processes. This is the first view, and the view which I myself, at the present time, consider to be the more tenable.

The alternative theory regards mind as capable of causal interaction with body. Mind and body have developed together, and it stands to reason that they mutually influence each other. This is a common sense point of view; it seems, at first sight, to have everything in its favor, and to be just as intelligible as the other.

We must, however, go a little deeper. And, in order to keep things clear, let us give the theory of interaction a more concrete form. One of the strongest arguments in support of the theory, or perhaps we might rather say one of its necessary implications, which appears to many psychologists to be borne out by the facts, is that 'consciousness' has a 'survival value,' that mind is a factor in organic evolution. Now we must sharply distinguish between two different uses of the term 'consciousness,' which are oftentimes confused by the advocates of interaction. Consciousness may mean knowledge or awareness, our acquaintance with the world about us, or it may mean simply (as on the first theory it always must mean) a complex of mental processes. In the former meaning, it covers the great functions of cognition, memory, reasoning, imagination, etc. And this is the point at which confusion enters. Cognition, memory, and the rest, are not purely mental functions, but functions of the mind-brain union, of the total psychophysical organism. It is not a detached mind that knows and remembers, but the living organism, embodied soul and ensouled body. We never find reasoning where there is no mind; but neither do we find it where there is no body. If, then, I am allowed to interpret 'consciousness' in this way, I can, although I hold the theory of concomitance, subscribe to everything that the interactionist says of the survival value of consciousness. An organism that remembers will certainly, other things equal, get the better, in the struggle for existence, of an organism that cannot remember. Only, the real question remains: does the remembering animal survive because it consciously remembers, or because its brain is capable of those complicated processes which form the substrate of conscious memory? Parallelism maintains that the concomitant mental processes make no difference to the result. Interactionism has to maintain, in this concrete form of the 'survival theory,' that the mental process as such is an aid to evolution; that the function which is psychophysical helps the organism onwards, on that account, more than the function which is physical; that consciousness, just because it is mental process, furthers life and progress. On any other formulation than this parallelism and interaction join hands,—for any other formulation begs the whole question. And in this formulation, as asserting that a mental process may be interpolated as a causal link between two physical processes, the theory of interaction seems to me to be weaker than its rival.

The foregoing paragraphs are not intended to convert or convince the reader; each theory has its peculiar difficulties, the discussion of which here would lead me too far afield.[1] They are merely a brief expression of a scientific creed. Such an expression is, I think, a necessary prolegomenon to the special problem of this paper.

One other prefatory remark must be made. I shall often speak, in what follows, as if the problem of the origin and development of organic movements were identical with that of the origin and development of mind at large. In many contexts this identification holds. For it is an universally admitted fact—sometimes raised to the dignity of a law, as the 'law of dynamogenesis'—that there can be no intake on the organism's part without corresponding output; the action of any appreciable stimulus has its reaction of motor discharge. The simpler the organism, the clearer is this correlation; but it holds throughout.[2] It follows, then, that there can be no consciousness without movement, though there may, of course, be movement without consciousness.

If we turn, now, to the question of the character of the earliest organic movements, we find, again, that two views are current. It is maintained, on the one hand, that mind is as old as life. The first movement of the first organism must, then, if it exceeded a certain liminal extent, have been attended by some sort of consciousness. Let us say, in round terms, that the first locomotion of the first vagrant organism must have been accompanied by mental process. It is maintained, on the other hand, that the first movements are more akin to the movements that physiologists term 'reflexes,' direct and unconscious responses to stimulation; and that mental process appeared at some relatively high stage of organic development, when the conflicting demands upon the organism could no longer be met by such direct response, but led to tensions and inhibitions, in a word, to 'hesitancy' of movement. The parallelist will naturally incline to accept the first hypothesis; the interactionist, to accept the second. What are the arguments?

Let us look, first of all, at some of the arguments for an unconscious first movement. (1) One of the most insistent is the appeal to the law of parsimony. If we can start organic movement with something like the reflex, it is urged, is it not our bounden duty to do so, and thus to work out our problem with the fewest possible terms? If life is conceivable without consciousness, ought we not so to conceive it, instead of dragging in a superfluous 'mind'? As a purely formal argument, the appeal to parsimony may be met by the counter-appeal to the law of continuity. It is no more impressive to say, in the abstract, 'Entia non sunt multiplicanda præter necessitatem,' than it is to say 'Natura non facit saltum.' But the argument is, of course, more than purely formal. It suggests, as adequate and as the simplest possible, a certain definite interpretation of the facts. It throws upon parallelism the burden of proving the necessity of mind at the first appearance of life.

The parallelist might meet this challenge by raising the previous question. The facts to be interpreted are natural phenomena, and nature is not bound by any law of parsimony. Indeed, the prodigality of nature is fully as evident as her frugality: witness the prolongation of life beyond the period of reproductiveness, the enormous range of our sensations of tone, the genius lavished on pure mathematics. It is at least possible that, in the present instance, nature is less economical in action than we strive to be in thought; that, in giving us life, she has given us mind into the bargain. It is, I say, at least possible. We know too little of the facts cited as analogical to be able to say more.

But there is another and a stronger objection. We know nothing of mind, at first hand, except as it exists in man. Elsewhere, we are forced to rely upon the 'objective criteria,' of which more presently. What right, now, has the interactionist to bring mind into the organic series at any point lower than man? Why is he not bound, under the law of parsimony, to keep mind out until its presence can be positively demonstrated? I think that the answer is plain; he is so bound, unless he can show cause for believing that mind, were it present, would be of service to the organism in the struggle for existence. As he has called upon his opponent to 'prove the necessity of mind at the first appearance of life,' so we might retort that he is himself bound to show the indispensableness of mind to the struggling organism. But we will let the more modest phrasing stand, and proceed to an examination of the arguments.

The locus classicus for the survival value of consciousness is Chapter V. of James' 'Principles of Psychology.' The arguments are three.

(a) "The brain is an instrument of possibilities, but of no certainties. . . . Its hair-trigger organization makes of it a happy-go-lucky, hit-or-miss affair. It is as likely to do the crazy as the sane thing at any given moment. . . . But the consciousness, with its own ends present to it, and knowing also well which possibilities lead thereto and which away, will, if endowed with causal efficacy, reinforce the favorable possibilities, and repress the unfavorable and indifferent ones."

The facts bear out this 'a priori analysis'; for

'consciousness is only intense when nerve-processes are hesitant.' (b) The phenomena of vicarious function 'seem to form another bit of circumstantial evidence.' "Nothing seems at first sight more unnatural than that [the remaining parts of the brain] should vicariously take up the duties of a part now lost without those duties as such exerting any persuasive or coercive force." (c) "If pleasures and pains have no efficacy, one does not see. . . why the most noxious acts, such as burning, might not give thrills of delight, and the most necessary ones, such as breathing, cause agony."

The first of these arguments is little less than amazing. It asserts that the brain, the central and ruling organ of the whole body, has been so far exempt from the influence of natural selection that it is 'indeterminate,' 'an instrument of possibilities,' 'as likely to do the crazy as the sane thing' I 'The natural law of an organ constituted after this fashion can be nothing but a law of caprice.' Does such 'a priori analysis' commend itself to the neurologist? I should rather say that the brain, combining as it does an immense structural complexity with great architectural simplicity, has been stably and determinately molded for the part which it plays in the economy of the organism; that it is a marvelously reliable organ, definitely disposed for definite functions. I think that anatomy and physiology bear me out. And as for consciousness being intense only when 'nerve processes are hesitant': what of the plunge into cool water on a hot day? what of the enjoyment of music after a long æsthetic starvation? what of our grief at the loss of a dear friend?

The second argument I take to be misleading. Vicarious function has its limits. We can never see by aid of the auditory center, or hear by aid of the visual. But the brain is bilaterally symmetrical; its centers are arranged in a hierarchy, one above another; the connections of center with center, direct and indirect, are multitudinous. Vicarious function is thus, within wide limits, possible and natural; the excitation whose 'principal path' is blocked finds several 'secondary paths' still open. Let all the paths for a given form of excitation be blocked, however, and what happens? Here is the supreme occasion when consciousness might be useful; and consciousness does nothing.

The third argument requires a somewhat more detailed examination. It is an empirical law, a rule of average, that pleasant things are good for the organism, and unpleasant things bad. Pleasant things, things that we like, are things which, presented as stimuli, evoke movements of extension or approach; unpleasant things, things which we do not like, repel us,—we shrink from them. The usual explanation of the law is that organisms which (as psychical) liked and (as physical) reached out after things that were bad for them would, in the long run, be killed off. It is a condition of living that the things sought after shall, on the whole, be good for the seeker. The argument alleges that this explanation is insufficient. 'If pleasures and pains' as such 'have no efficacy,' there is no reason why their relation should not be reversed; why the things that are bad for us should not be pleasant, and the good things unpleasant.

I think that the argument, by its very formulation, assumes the causal efficacy which it is meant to prove. It assumes that a change of mental process must necessarily condition a corresponding change of motor reaction. Now there is good biological reason—psychology apart—why the things that are bad for us should not be sought after, and the things that are good for us neglected or repelled. But what mental process colors the 'sought after' and the 'repelled' is simply a question of fact. If it is the peculiar quality of pleasure and pain that we are asked to account for, I reply that we can no more explain this than we can explain why ether waves of a certain frequency correspond to the sensation quality 'red' and not to that of 'blue.' If it is the constancy of the mental accompaniment that is at issue—and this is suggested by the reference to an 'a priori rational harmony'—I reply that the constancy is a given fact, accepted by parallelist and interactionist alike, just as it is in the case of the colors. The argument, so far as I have understood it, does not 'make sense' except from the standpoint which it is supposed to recommend. And the instances do not help us. Breathing is not a source of such extreme pleasure, as things are, that a reversal of relations should make it an agony, and the nervous processes in burning are by no means hesitant, and ought, therefore, to yield nothing so intensive as delight.[3]

So far, then, the argument from parsimony seems to have little positive content. It simply asserts that the onus probandi lies with those who make mind and life coeval. Whether the parallelist can shoulder the burden we shall see later on. In the meantime, let me insist upon the limitation that attaches to both theories alike. The parallelist can never explain why life should be attended by mind. He thinks that there is evidence of the connection, but he cannot further account for it. The interactionist is apt to suppose that, by his appeal to parsimony, he has furnished an explanation of the appearance of consciousness; mind came upon the scene, when and because it was useful to the organism. The fallacy is obvious. The development of mind under the rule of natural selection is one thing; the question of the origin of mind is another, and is something that lies wholly beyond the ken of science.

(2) But we may leave the sphere of formal argument. The theory of originally unconscious movement finds factual support, it may be said, and support of the strongest kind, in recent experimental investigations. The movements of the lowest animals are not random and variable, but simple and stereotyped; they are, in many cases, even simpler than the reflex, as we ordinarily conceive of the physiological reflex; they may be referred to mere 'tropisms,' direct physico-chemical responses to physico-chemical changes in the environment. Nay more, the complicated activities of such highly developed organisms as ants and bees may be subsumed, with surprising completeness, under some such heading as the 'chemoreflex.'[4] Here is proof positive. What more can we ask?

We may ask, first, for a clearer recognition of the point of view from which these investigations have been made. The psychologist has no choice but to begin at the upper end of the organic scale—to begin with himself, and his own mind—and to work downwards, interpreting as he goes. The road is full of pitfalls; there is constant temptation to exaggerate the mental endowments of the lowest creatures, to make their minds miniature copies of the human. Romanes' books, for instance, show over and over again how a psychologist, working in the interests of mental evolution, may overestimate the range and complexity of the animal consciousness. Still, this is the one path that psychology can follow. The biologist, on the other hand, thinks his world, when he thinks consistently, in terms of physics and chemistry. He is also accustomed to think from below upwards. His natural tendency, then, is to carry physical and chemical principles as high in the scale of life as they will go. He has his inconsequences, as the psychologist has his exaggerations; and his besetting inconsequence is to admit the presence of mind in animals higher than those which he has himself examined. But science is not inconsistent because her representatives may sometimes nod. It is a postulate of mechanistic biology that physical and chemical principles will carry the biological student all the way, from the algæ to man. Consciousness does not fall within his horizon. Until, then, the interactionist has converted his biological colleagues to vitalism, and thence to the admission of mental process as an equivalent of physical energy, we must conclude that the two fields of enquiry, the psychological and the biological, do not overlap. There is no reason why the biologist, granted a steady increase of natural knowledge, should not some day reduce all the movements, say, of the monkeys, to physico-chemical terms, to a system of simple or complex 'reflexes.' That is what he is on the way to do. On the other hand, the reduction of all the movements of Paramecium to a single 'reflex' type does not prove to the psychologist that the creature has not (or has not had) a mind. Biology and psychology, if I may change the metaphor, meet and pass on a double track. They do not collide, but neither do they turn out to be two halves of a single train of thought.

We may ask, secondly, for a clearer understanding of what has been called the 'objective criterion of mind.' The phrase is open to the objection that it contains a contradictio in adjectivo; how can there be an objective criterion of the subjective? But we may waive this, and assume that an empirical correlation is possible. Let us suppose, then, that biology and psychology agree to ask the question: How are we to tell, by watching a lower animal's movements, whether or not it has a mind? And let us suppose, further, that they are agreed upon their answer. The answer must be of this kind: If you see so and so, then you may infer the presence of consciousness. Beyond that, no answer has gone, and no answer can possibly go. Because this animal does this thing, it has a mind; this other animal does not do this thing, therefore—what? Therefore, we do not know whether it has a mind. It may not, of course, but then again, it may. The biologist, 1 repeat, may multiply his tropisms till they cover the whole field of organic movement; he is only consistent in so doing, just as he is consistent in refusing to speak of 'visual perception' and in martyrising his linguistic consciousness to the term 'photo-reception,' But, though it rain tropisms, the psychologist may go without his umbrella.

However, when all is said, is there not at least a presumption in favor of the unconscious-movement theory? That is the theory adopted by the men who made the investigations; and, surely, they ought to know, if anybody knows. Would it not be good common sense to take their conclusions, instead of speculating about what may be? I have no great objection; save on that single score of scientific methodology, I have no objection. For it is one of the cardinal points of the theory which I hold, that a movement which at first was conscious may presently lose its conscious character; that the physical may in course of time replace the psychophysical. The fact, then, if it be a fact, that ants and bees are nowadays mere reflex machines will mean that they started out, so to say, with a certain endowment of mind, which they have lost in the process of adaptation to their special environment; and the similar fact that paramecium has its one stereotyped form of motor reaction to stimulus will mean that it, too, had at first its modicum of mind, which it has lost* on its journey through the ages. The evidence for this view I have yet to give. If it be sound, then the automatism of the lower animals does not in the least degree affect the theory that mind is as old as life.

And now for the alternative theory,—which must, I suppose, always strike the biologist, more especially if he be physiologist, as fanciful and far-fetched; the theory that the first animal movements were conscious, and that all our present movements, the reflexes included, are the direct descendants of conscious movements. What is the evidence in its favor?

If we consider the facts of organic movement as they are presented in our own experience; if, following the rule of psychological enquiry, we set out from an examination of our own action and conduct; we find that the phenomena cannot be brought at once under the head of any single principle, but that they rather result from the joint operation of two different tendencies. On the one hand, we are continually enlarging our sphere of action; conduct grows more complex; new motives are formed, new adaptations made; there is a tendency towards more and more complicated or specific coordinations of movements. The realization of this tendency is always accompanied by consciousness, by the mental formations that are known, both in popular speech and in psychology, as choice, resolve, deliberation, judgment, doubt, etc. On the other hand, there is a tendency towards the simplification of movement; coordinations that at first involved corti cal activity are presently, as a 'habit' is formed, relegated to lower centers. And the realization of this tendency is accompanied by lapse or loss of consciousness. We learn to walk, to swim, to bicycle, to typewrite, to play a musical instrument, with conscious pains and effort. Later, if we practise enough, we do these things 'automatically,' unconsciously. We may typewrite correctly while our attention is wholly directed upon the meaning of our paragraph; we may play a musical composition correctly while we are engaged in an absorbing conversation. The original impulsive or selective or volitional action has become automatic. We can, of course, bring its terms back to consciousness; we can stop and 'think' that we are typewriting or playing the piano or bicycling; but if we do this, the movements become hesitating and may be seriously deranged. If the natural tendency takes its course, we finally reach a form of movement which (except that we know its course of development) is not distinguishable from the physiological reflex.

Here is a bit of positive and unmistakable evidence. It is possible, in the life history of the individual, for conscious movements to pass -over into unconscious. Not only is it possible: it is a regular occurrence. From the biological point of view, it is eminently useful; the simplification of response to stimulus, its relegation to lower nervous centers leaves the organism free for further adaptations. Is there not some ground, then, for generalizing the facts, and saying that, probably, all unconscious movements have developed from conscious? This is what Wundt has done, in his statement that 'the reflexes are voluntary actions that have become mechanical.[5] Only, his terminology is at fault, for the antithesis of the voluntary is not the mechanical (all actions, biologically regarded, are mechanical), but the unconscious action; and the antithesis of the reflex is not the voluntary but the complex, coordinated action. So difficult is it, even when one's thought is scientifically clean, to avoid the language of 'common sense'!

I think that the reader who has recognized the weakness of the opposing theory will take great comfort in this piece of undisputed fact, and will be willing to generalize it farther than the logical canons warrant. To myself, brought up in the faith that mind developed somehow and appeared somewhere after the birth of life, and always unsuccessful in my attempts to reconcile this faith with reason, Wundt's counter-statement came as a real illumination. Nevertheless, as it stands, it is nothing more than an argument from analogy; we argue from the individual to the race. Is there no evidence from the race itself?

We find a little—as much, perhaps, as we have a right to expect. There is a class of movements, familiar to every one who has read Darwin's 'Expression of the Emotions in Man and Animals' which are known in psychology as 'expressive' movements. Such are the opening of mouth and eyes in surprise, the frown and clenched fist of anger, the play of the facial muscles in joy and sorrow. These movements belong to various psychological classes, volitional, selective, impulsive, reflex. But there are among them certain reflexes—primary reflexes, not automatic actions or 'secondary' reflexes of the kind just described—that can only be explained as the unconscious descendants of earlier impulsive actions. The face of proud contempt reflexly 'curves a contumelious lip.' What does the movement mean? Why, it lays bare the canine teeth; it is the human counterpart of the snarl of dog or wolf; it is the last reflex or unconscious remnant of a coordinated or impulsive action which, somewhere or other in our not remote ancestry, preceded the movements of actual attack. The deer bounds away when it hears the hounds, and we 'jump' when we are startled; the sitting bird crouches on its nest when danger approaches, and we wince or shrink when we are frightened or censured. The connection is obvious; the activities are related; but the action which formerly was conscious has become, in us, a mere 'automatism.' Instances of this sort might easily be multiplied.[6] The facts are admitted, and their explanation accepted, by psychologists of all schools. But here is evidence of the derivation of unconscious from conscious movement, not in the life history of the individual, but in that of the race.

In both of the cases which we have discussed, consciousness has shown itself to be chronologically prior to unconsciousness. Are there any known cases to the contrary? Have we any instance of an action which, unconscious in the lower animals or early in our own lives, later becomes conscious? Have we any hint of a tendency in this direction? On the former count, as regards the animals, the appeal must lie to the 'objective criterion' of mind, and therefore to biology as well as to psychology. I can only say that the psychological evidence is negative, and that I have not myself—speaking, however, as a layman in biology—come across any positive indications in-biological literature. On the latter, as regards ourselves, I find no evidence either in psychological literature or in my own experience. Omne consciens e conscienti is the law of conduct known to the psychologist. It may be retorted that the negative evidence is worth very little, since, e. g., we believe that life evolved from inorganic matter, and yet no one has seen the not-living pass over into the living. I reply that the evidence is at least negative, that is, is not positive; and that, although we have not built up living protoplasm from dead matter, we have at least gone a good way towards it.

There is another point. The automatic actions that take shape in the course of the individual life have upon them the marks of appropriateness, of 'purposive' response to stimulus. They are relatively precise and clean-cut; they subserve some one end, or some set of interrelated ends. Appropriateness and precision are also, notoriously, characteristic of the physiological reflexes. They are similarly characteristic, we are told, of the tropisms and stereotyped reactions of the lowest forms of life, so that these are often spoken of as 'reflexive.' Is not this item of internal evidence worth something? Is it not probable that things which are so much alike have had a similar history? For it must be remembered that, however simple the organism which we are examining, it is still not a primitive organism; its history is, presumably, at least as long as the history of man. Not until we see the organism take shape from its inorganic constituents, and note the first reactions of the living mass, shall we have direct evidence of the nature of primitive movement; but by all analogy, that movement will not be precise and clean-cut, but vague and clumsy, indefinite and irregular. It is surely reasonable to suggest that the two tendencies which we find in ourselves, and which (on the testimony of expressive movements) are also operative in the race—the tendency towards new coordination and progressive adaptation, with consciousness, and towards specialized and stationary adaptation, without consciousness—were present from the very beginning; that the rudimentary organism might, as circumstances dictated, follow either of two paths, the downward path to static adjustment, by reflexes, or the upward path to dynamic adjustment, by conscious and coordinated action; and that in following the first path, it forever lost the power of higher development, while, in following the second, it still retained the power of fixing stably the reactions whose modification was unnecessary. Paramecium would then have lost the faint flicker of mind with which its original ancestor was endowed, and, losing therewith the possibility of coordinated movement, would have remained paramecium. But a primitive organism of like endowment, living under different conditions, and retaining both mind and the correlated physical adaptability, would have become man.

Still the opposing arguments will not down. If consciousness disappears as soon as adjustment to surroundings has become easy, why may it not have appeared as soon as adjustment became difficult? Why may it not have developed late, when the difficulties of living called for a new aid to life? Why may we not return to the belief that mind has a survival value?

I reply, as I have replied in another connection, that the formulation of the question begs the issue. The question assumes that there is a causal connection between biological adaptation and consciousness. Since the facts can be formulated both in biological and in psychological terms, without lapse or break in the separate series of material and mental processes, the proof of survival value must be sought elsewhere. We have considered the evidence, and found it wanting. But we can, also, meet the question on its own terms. We may answer that the difficulties of adjustment were present from the outset, nay, must have been peculiarly pressing at the outset, when life was young and inexperienced; so that mind must also have been present from the first, and could not disappear until adjustment had already proceeded some little distance. Taken in the abstract, the one possibility is as likely as the other. There is, however, a direct answer which—if we bear in mind the limitations of theory at large—seems to be satisfactory. Mind appears with life. At first, there is no differentiation of functions; mind and life are uniformly coextensive. Later, with growing complexity of the organism, come differentiation of functions and the development of a central coordinating organ. If mind and life run parallel to each other, we must suppose that mind has also suffered differentiation, and that the supreme consciousness of the organism now accompanies the functions of the supreme organ. But this is what we find. There is, in strictness, no evidence of a complete 'disappearance' of mind; our own reflexes and automatic actions, though not attended by our consciousness, may have a consciousness of their own. This hypothesis has, in fact, recommended itself to many investigators.[7]

This last objection, then, does not shake our position. Have we, now, shown the 'necessity of mind at the first appearance of life?' We have at least made its presence so reasonable and probable that we need stand in no fear of the law of parsimony. But the recurrence of the counter-arguments at the very end of our enquiry is suggestive. It reminds us that we have been dealing, throughout, with inferences and probabilities, not with demonstrations and mathematical certainties. And an argument from probability is like an india-rubber ball; you hit it, and it may fly away, or it may return to you, all the more vigorously the harder you hit. So far from convincing the reader, this paper may simply prompt him to refutation and rebuttal. All the better—provided only that he adduce new arguments.

  1. A good popular account of psychophysical parallelism is given by H. Ebbinghaus, Grundzüge der Psychologie, I., i., 1897, 41-47. The strongest attack made upon the theory in recent years is that of C. Stumpf's 'Eröffnungsrede,' printed in the 'Bericht über den III. internationalen Congress für Psychologie,' 1897. I say nothing in the text of Interactionism as a static (opposed to genetic) theory. The reader must pardon this and other sins of omission, on the score of necessary brevity.
  2. Cf. J. M. Baldwin, 'Mental Development,' etc. . Methods and Processes, 1895, 166.
  3. W. James, 'The Principles of Psychology,' 1890, i., 138 ff., 67 ff.; ii., 584, 591 f.
  4. I have in mind such investigations as those of A. Bethe, Pflüger's Archiv, lxx., 1898, 15, and H. S. Jennings, Amer. Journ. of Physiol., ii., 1899, 311; cf. Amer. Journ. of Psych., X., 1899, 503. The number of these studies is steadily increasing. On the following arguments, cf. E. Claparède, Revue phil., 1901, 481 ff.
  5. W. Wundt, Grundzüge der physiologischen Psychologie, ii., 1893, 591. Cf. the historical discussion, 591-593, and Philos. Stud., i., 1883, 354 ff.; also J. Ward, art. Psychology, Encycl. Brit., 9th ed., 43, col. a.
  6. It would be especially interesting to examine from this point of view the movements of the new-born infant. The position taken in the text is, I think, supported by, e. g., the mimetic facial reflexes, and by the various atavistic reflexes (hanging from stick or finger, swimming movements, etc.)-But a full consideration of all these movements would require a separate paper. On the other hand, the fact that in the higher animals the reflexes are imperfect at birth, and take a little time to 'harden'—a fact which has been rightly emphasized in several recent studies of animal behavior—does not seem to touch the present argument one way or the other.
  7. Cf., e. g., E. F. W. Pflüger, Müller's Arch. f. Anat., 1851, 484-494.