ABSTRACT
THE specific definiteness of behaviour of the type to which I apply the term instinctive, is an organic heritage. It is dependent upon the inherited structure of the nervous system. According to the interpretation suggested in the last chapter, it is determined by the hereditary disposition of the neurones in the lower or sub-cortical brain-centres. But the accompanying experience is correlated with functional activities within the cortex. And when such experience has been gained it may be the condition of intelligent modification of behaviour. This interpretation is, however, open to criticism." Dr. Myers regards 1 "the separation of instinct and intelligence as a purely artificial abstraction." Instinct and intelligence are, he urges, the same process regarded from different standpoints. "So far as instinctive behaviour can be regarded from the standpoint of the individual experience of the organism it appears, however imperfectly, as intelligent—characterized by finalism. So far as intelligent behaviour can be regarded from the standpoint of observing the conduct of other organisms, it appears, however imperfectly, as instinctive—characterized by mechanism." "Thus the psychology and physiology of instinct are inseparable from the psychology and physiology of intelligence. There is not one nervous apparatus for instinct and another for intelligence. .. . Throughout the psychical world there is but one physiological mechanism; there is but one psychological function—instinct-intelligence." I suppose the divergence of opinion between us partly rests upon differences in the definition of terms. In any case this double-aspect doctrine is interesting and suggestive. I cannot discuss it now; nor can I here follow Dr. Myers into the difficult regions of finalism and mechanism. Somewhat will be said concerning them in due course. At present I am only concerned to emphasize the fact that, so far as the consciousness of instinctive performance is under consideration, I too believe that there is one and only one " physiological mechanism," within which, as I have indicated above, neural processes have experience-correlates. This, in my interpretation, is the cerebral cortex. Just now, however, I have nothing to do with the cortex. I must ask to be allowed to develop my thesis on the assumption that the specific nature of the instinctive performance is biologically and physiologically determined by the inherited disposition of the neurones in the lower sub-cortical brain-centres.
