b) After once associating the various parts of a problem, adult rats make only the movements necessary to attain the desired end, while young rats-owing to their superabundant physical activity and lack of muscular control-continue to make useless movements long after adult rats have discarded them entirely. c) There is a gradation in the number of useless movements made by rats at different ages. At thirty-five days of age, when physical activity appears to have reached its highest stage, the percentage of useless movements is largest. As the rats grow older this superabundant activity disappears, and in its place comes direction of activity. Concerning the stages of memory the author writes: 1. Until the rat has reached the age of twelve days, life to it is simply a matter of pure instinct. Certain movements are made, but these movements are dependent upon the ready-made adjustments of neural and motor elements with which the rat begins life; intelligence plays little or no part. 2. At twelve days of age memory is present in a simple form. 3. From the twelfth to the twenty third day there is a gradual but rapid increase in the complexity of the memory processes until at the latter age psychical maturity is reached. Development after this age is analogous to the development that takes place in a child of ten years as he gradually becomes more and more mature. Parts II and III. Having investigated the capacity of rats to learn simple associations, at different stages of development, the author proceeded to make a careful histological study of the changes which occur in the nervous system from birth to maturity in order that he might be able to correlate the psychical and neural conditions and definitely determine whether associations are dependent upon the medullation of nerve fibers. As a result of this work Dr. WATSON concludes: (1) that the "medullated fibers in the cortex of the rat are not a conditio sine qua non of the rat's forming and retaining definite associations, and (2) that the complexity of the psychical life increases much more rapidly than does the medullation process in the cortex, psychical maturity being reached when approximately only one-fifth of the total number of fibers in the cortex are medullated." Instead of speculating about the general significance of medullation the author very wisely confines himself to the discussion of his own particular facts. The experimental work is clear cut and decisive, and if one sometimes feels that fewer words might have sufficed and and space been saved by the condensation of results into tables, the excellent summaries more than compensate for the lengthiness of the descriptions. Dr. WATSON has done a valuable piece of work in a field which has been open thus far for the theorizing of neurologists and psychologists. ROBERT YERKES. Metaphysics in Comparative Psychology.' The first of these articles is a defence of the comparative method in psychology in general, but more particularly when based upon an identity theory of the relation of brain and consciousness. He criticizes that school of comparative psychologists which attempts to reduce all forms of animal reactions to the type of mechanical tropisms, asserting that this tendency toward a mechanical interpretation is the direct product of false metaphysical assumption-that of psychophysical parallelism. Instead of this, the author upholds a theory of identity which makes it possible for him to put "Seele" in parenthesis after "Gehirn." The arguments with which he attacks the parallelistic doctrine are familiar enough and will perhaps pass muster; at least they are the usual arguments wielded in current controversy. On a parallelistic hypothesis, when the one series is complex, the other should be complex, and vice versa: but this is not the case. The psychical sequence, which, on the parallelistic theory, ought to form a continuous whole is arbitrarily broken without any assignable cause, or the psychological causes which are assigned prove, on closer inspection, to be inadequate. Both of these arguments, in the opinion of the reviewer, can be met by the parallelist. But let it pass. More important for criticism are the positive arguments brought forward in support of the identity doctrine. The author points out that there are important brain centers which are inaccessible to present physiological experimentation and which seem to bear no direct relation to our ordinary consciousness. Consciousness corresponds to a comparatively limited phase of cerebral activity. Indirectly, however, the content of consciousness is influenced to a high degree by the activities of these centers. It is not astonishing, therefore, that the psychophysical law does not hold. (He does not say so, but presumably this is because of the inhibitory effect of competing stimuli originating in these centers.) Instead of regarding this as evidence simply of an unsuspected complexity in the conditions of that shifting area of tension which con A. FOREL. Die Berechtigung der vergleichenden Psychologie und ihre Objekte. Journal für Psychologie und Neurologie, Band I, Heft und 2, pp. 3-10 (1902); Beispiele phylogenetischer Wirkungen und Rückwirkungen bei den Instinkten und dem Körperbau der Ameisen als Belege für die Evolutionslehre und die psychophysiologische Identitätslehre. Ibid., Band I, Heft 3, pp. 99110 (1902); Ants and Some Other Insects, Monist, Vol. XIV, No. 1. Oct. 1903; Jan. 1904. Tr. by W. M. WHEELER. stitutes consciousness he, however, regards it rather as evidence of an infra-consciousness corresponding to, or rather he would say, constituting these inaccessible cerebral activities. What more natural than to assume, he says, that every cerebral activity has its introspective or inner counterpart, if not in our ordinary upper consciousness, then in this lower consciousness. Here is the key to the author's point of view and to his identity theory, and the reader who has already threshed out the problems here involved will doubtless turn to more instructive reading. There is no fallacy which to a greater extent vitiates the arguments ordinarily brought forward in support of this theory than the doctrine of subconscious mental states. Under cover of this concept of a lower consciousness, the author finds it possible to attribute, not only consciousness but in some cases a high degree of consciousness to the lowest types of animals, e. g., to the Arcellae described by ENGELMANN. He finds evidences of memory, perception, association, feeling, choice in ants and bees. He says that the domestication of certain insects proves their plasticity, and finds evidence of this trait even in worms and echinoderms. Obviously, the significance of such statements must be interpreted in terms of his theory of unconscious mind. His second article treats more in detail of the habits of various species of South American ants—which, again, he makes corroboratory of his identity doctrine. That there is truth in some form of the identity theory is extremely probable. One will perhaps agree with the author when he says that logically there is no more direct connection between my individual psychology and your individual psychology than there is between my individual psychology and the physiology of my brain. Hence actions, gestures, movements, attitudes, are as significant for psychology as sense-impressions. Human psychology is, and must be, comparative psychology. But when he says that environment influences brain (soul) through the sensory nerves, and brain (soul) influences the muscles, glands, etc. (and thus the environment) through the motor nerves, one begins to feel that the meanings of words are becoming confused. And this feeling is increased when he adds that the soul is the brain-activity reflected in consciousness. One suspects that the concept of a lower consciousness is simply a screen behind which the author may slip unnoticed from one meaning of a word to the other according to the exigencies of the argument. But quite apart from this, it must be remembered that the brainactivity, which the author identifies with the soul-activity, cannot be isolated from the activities of the whole organism. It is probably true that the brain activity and the so-called mental activity are ultimately one, but it certainly is neither good biology nor good psychology to attempt to identify the latter with the former in any sense which opposes these to non-nervous organic or to the extra-organic processes. The author unquestionably has hold here of an important truth, but it is a truth still in solution-still fluid, not yet precipitated in a form that is quite consistent. In truth, this is just the desideratum in the current controversy as to the nature of the relation existing between the physical and the psychical—a statement of the law of the conditions of consciousness which will not violate the principle of continuity in nature. The article in the Monist on "Ants and Some Other Insects,” traslated from the German by Professor WILLIAM MORTON Wheeler, is an "inquiry into the psychic powers of these animals with an appendix on the peculiarities of their olfactory sense.". This is an account of some very interesting experiments upon ants and bees, prefaced, as in the case of the other two papers, by a metaphysical introduction. As in the former articles, he finds evidence of the possession in these insects of memory, association, will, etc. The experiments are certainly instructive even though one is inclined to regard the interpretation of results as infected detrimentally by the metaphysical standpoint. The standpoint here again, while suggestive, seems untenable. One is pleased with the statement that "we can therefore compare attention to a functional macula lutea wandering in the brain, or with a wandering maximal intensity of neurocymic activity' (p. 36). But we are astonished then to be told that "if this assumption is correct. . . we are not further concerned with consciousness. It does not at all exist as such, but only through the brain-activity of which it is the inner reflex. . . . Consciousness is only an abstract concept, which loses all its substance with the falling away of 'conscious' brainactivity" (37). In other words, the author adopts the identity theory and wholly rejects the parallelism. And the criticism, in a word, is this, that he has thus cast aside the very element that makes the identity intelligible. Claparède on Animal Consciousness.' H. HEATH BAWDEN. The present article is in large measure a revision, or restatement, of the author's contribution to the subject in the Revue Philosophi 1 EDOUARD CLAPARÈDE. The Consciousness of Animals. The International Quarterly, Vol. VIII, pp. 296-315. Dec., 1903. Translated by WILLIAM HARPER DAVIS, Columbia University. que, worked over for the benefit of English readers. After a brief glance at the history of the problem, the present reaction of biologists against the anthropomorphic tendencies of the Darwinian period, and the attempts of LOEB, BETHE and others, to reduce the activities of lower organisms to simple physico-chemical tropisms are discussed in detail. The question is pointedly asked, why are tropisms necessarily unconscious? In all probability they are a great deal more complex than they are assumed to be by these investigators, and in any case it is difficult to discover any difference in kind between tropisms, reflexes and voluntary acts. Any such objective tests of consciousness as LOEB's "associative memory", or WATKINS' "spontaneity" are quite beside the mark, for they overlook the fact that consciousness is and can be only subjective. The only legitimate point of view for approaching the problem is that of pyscho-physical parallelism, the principle which assumes that for every change in consciousness there is a parallel and corresponding change in the nervous system. Just what the relation is that subsists between the two is as yet undetermined, but at any rate we must look upon them as two distinct series, and therefore it does not make a particle of difference, so far as the external series of acts is concerned, whether a biological process is conscious or not. If biologists would realize this fact, and cease trying to bring in the mind as a biological factor which exerts an influence on the body, much confusion would be avoided. So far as physical acts are concerned, consciousness is an epiphenomenon. BETHE and his associates have gone to the other extreme in their efforts to get a perfectly objective nomenclature for all reactions to stimuli. They deny the possibility of psychic states in animals, or at least the possibility of gaining such knowledge of them as will furnish material for science, and hence they demand the suppression of comparative psychology. But any such argument would apply to human psychology as well. Comparative psychology is here and cannot be suppressed. From the standpoint of psycho-physical parallelism there are two parallel methods of studying life activity: (1) the ascending, or physiological, beginning with the lowest organisms and going on to the highest, explaining everything on purely physico-chemical principles; (2) the descending, or psychological, going down from man, and reasoning by analogy as to the mental life of animals. Both of these 1 EDOUARD CLAPARÈDE. sophique, tome LI, pp. 481-498. Les animaux sont-ils conscients? Revue Philo |