Page:Catholic Encyclopedia, volume 8.djvu/81

 INSTINCT

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INSTINCT

implies a theory of origin for instinct which is not universally accepted. Again, the Schoolmen and many competent observers, among whom E. Was- mann, S.J., is prominent, find the characteristic differ- ence between instinctive and intelligent activities in the fact that one is governed exclusi^'ely liv sensation, or by sensory associative processes, while the other is governed by intellect and free will. They accordingly attribute all the conscious activities of the animal to instinct, since, as they claim, none of these activities can be traced to intellect in the strict sense of the worth St. Thomas nowhere treats in detail of animal instinct, but his position on the subject is rendered none the less clear from a great many passages in the "Summa Theologica". He is in full agreement with the best modern authorities in lajdng chief emphasis on the absence of consciousness of the end as the essential characteristic of instinct. He says (op. cit., I-H, Q. xi, a. 2,C.): "Although beings devoid of con- sciousness (cognitio) attain their end, nevertheless they do not attain a fruition of their end, as beings do who are endowed with consciousness. Consciousness of one's end, however, is of two kinds, perfect and im- perfect. Perfect consciousness is that by which one is conscious not only of the end, and that it is good, but also of the general nature of purpose and goodness. This kind of consciousness is peculiar to rational na- tures. Imperfect consciousness is t hat bj- which a being knows the piu-pose and goodness in particular, and this kind of consciousness is found in brute animals, which are not governed by free will but are moved by natural instinct towards those things which they apprehend. Thus the rational creature attains com- plete enjoyment (friiitio); the brute attains imperfect enjoyment, and other creatures do not attain enjoy- ment at all." Wasmann's concept of instinct is in strict agreement with that of St. Thomas, while it is more explicit. He divides the instinctive activities of animals into two groups: "Instinctive actions in the strict, and instinctive actions in the wider acceptation of the term. As instances of the former class we have to regard those which immediately spring from the inherited dispositions of the powers of sensile cog- nition and appetite; and as instances of the latter those which indeed proceed from the same inherited dis- positions but through the medium of sense expe- rience. " (Instinct and Intelligence in the Animal Kingdom, p. 35.)

There is a growing tendency in biology and com- parative psychology to restrict the term instinct to inherited purposive adaptations. Many WTiters add to this two other characteristics: they insist that an instinct must be definitely fixed or rigid in character, and that it must be common to a large group of indi- viduals. Baldwin regards instinct as "a definitely biological, not a psychological conception" (Diction- ary of Philosophy and Psychology). He adds that "no adequate psychological definition of in.stiuct is possible, since the psychological state involved is exhausted by the terms sensation (and also percep- tion), instinct-feeling, and impulse." (Ibid.) The di- vergent views entertained by ■^Titers on the subject concerning the nature and origin of instinct naturally find expression in the currently accepted definitions of the term, a few of which are here appended : —

"Instinct, natural inward impulse; unconscious, involuntary or unreasoning prompting to any mode of action, whether bodily or mental. Instinct, in its more technical use, denotes any inherited tendency to perform a specific action in a specific way when the appropriate situation occurs; furthermore, an instinct is characteristic of a group or race of related animals." (Xew International Dictionary.)

" Instinct, a special innate propensity, in any organ- ized being, but more especially in the lower ani- mals, producing effects which appear to be those of reason and knowledge, but which transcend the gen-

eral intelligence or experience of the creature; the sagacity of the brute." (Century Dictionary.)

"Instinct, an inherited reaction of the sensory- motor type, relatively complex and markedly adap- tive in character, and common to a group of indi- viduals." (Baldwin, " Dictionary of Philosophy and Psychology ".)

" Instinct is the hereditary, suitable (adaptive) dis- position of the powers of sensitive cognition and appe- tite in the animal." (Wasmann, op. cit., 36.)

" Habit differs from instinct, not in its nature, but in its origin; the last being natural, the first acquired." (Reid.) _

"Instinct is a purposive action without conscious- ness of the purpose." (E. von Hartmann, " Philosophy of the Unconscious", tr. Coupland.)

" Instinct is reflex action into which there is im- ported the element of consciousness. The term is therefore a generic one, comprising all those faculties of mind which are concerned in conscious and adaptive action, antecedent to individual experience, without necessary knowledge of the relation to individual experience, without necessary knowledge of the rela- tion between means emploj'ed anil ends attained, but similarly performed under similar and frecjuently recurring circumstances by all the individuals of the same species." (Romanes, "Animal Intelligence", New York, 1S92, p. 17.)

" Movements which originally followed upon simple or compound voluntary acts, but which have become wholly or partially mechanized in the course of indi- vidual life and of generic evolution, we term instinc- tive actions." (Wundt, "Human and Animal Psy- chology", London, 1894, p. 388.)

Origin. — A great many theories have been ad- vanced to account for the origin of instinct. These theories may be grouped under three heads: (a) reflex theories, (b) theories of lapsed intelligence, and (c) the theory of organic selection. The name of Charles Darwin has been prominently associated with the reflex theory, sometimes called the theory of natural selection. This assumes that in.stincts, hke anatom- ical structiu-es, tend to vary from the specific type, and these variations, when advantageous to the species, are gradually accumulated through natural selection. In his chapter on instinct in the "Origin of Species", Darwin says: "It will be universally ad- mitted that instincts are as important as corporal structures for the welfare of each species under its present conditions of life. Under changed conditions of life, it is at least possible that slight modifications of instinct might be profitable to a species; and if it can be sho'mi that instincts do vary ever so little, then I can see no difficulty in natural selection pre- serving and continually accumulating variations of instinct to any extent that was profitable. It is thus, as I believe, that all the most complex and wonderful instincts have originated." (Op. cit.. New York, 1892, vol. I. p. 321.) The difficulty with this theory is that it fails to account for the survival of the early begin- nings of an instinct before it is of utility. It has also been urged against it that it does not accoimt for the co-ordination of the muscular groups which are fre- quently involved in instinct. Similar objections, of course, have been urged against natural selection as the origin of many complex anatomical structures. The adaptive character, in the one case as in the other, points to the operation of an intelligence that alto- gether transcends the scope of the mental powers of the creatures in question.

The second theory, that of lapsed intelligence, has assumed many forms, and has found many defenders among comparative psychologists and biologists dur- ing the last half century. Among the best-known authors espousing this theory may be mentioned Wundt, Eimer, and Cope. The two main difficulties in the way of the acceptance of this theory are, first.