442 Mental Factors in Evolution 



There are diversities of opinion, as Darwin showed, with regard 

 to the range of instinct in man and the higher animals as contrasted 

 with lower types. Darwin himself said 1 that "Man, perhaps, has 

 somewhat fewer instincts than those possessed by the animals which 

 come next to him in the series." On the other hand, Prof. Wm. James 

 says 2 that man is probably the animal with most instincts. The true 

 position is that man and the higher animals have fewer complete and 

 self-sufficing instincts than those which stand lower in the scale of 

 mental evolution, but that they have an equally large or perhaps 

 larger mass of instinctive raw material which may furnish the stuff 

 to be elaborated by intelligent processes. There is, perhaps, a greater 

 abundance of the primary tissue of experience to be refashioned and 

 integrated by secondary modification ; there is probably the same 

 differentiation in relation to the determining biological ends, but 

 there is at the outset less differentiation of the particular and specific 

 modes of behaviour. The specialised instinctive performances and 

 their concomitant experience-complexes are at the outset more 

 indefinite. Only through acquired connections, correlated with 

 experience, do they become definitely organised. 



The full working-out of the delicate and subtle relationship of 

 instinct and educability — that is, of the hereditary and the acquired 

 factors in the mental life — is the task which lies before genetic and 

 comparative psychology. They interact throughout the whole of 

 life, and their interactions are very complex. No one can read the 

 chapters of The Descent of Man which Darwin devotes to a con- 

 sideration of the mental characters of man and animals without 

 noticing, on the one hand, how sedulous he is in his search for 

 hereditary foundations, and, on the other hand, how fully he realises 

 the importance of acquired habits of mind. The fact that educability 

 itself has innate tendencies — is in fact a partially differentiated 

 educability — renders the unravelling of the factors of mental progress 

 all the more difficult. 



In his comparison of the mental powers of men and animals it 

 was essential that Darwin should lay stress on points of similarity 

 rather than on points of difference. Seeking to establish a doctrine 

 of evolution, with its basal concept of continuity of process and 

 community of character, he was bound to render clear and to em- 

 phasise the contention that the difference in mind between man and 

 the higher animals, great as it is, is one of degree and not of kind. 

 To this end Darwin not only recorded a large number of valuable 

 observations of his own, and collected a considerable body of informa- 

 tion from reliable sources, he presented the whole subject in a new 

 light and showed that a natural history of mind might be written 



1 Descent of Man, Vol. i. p. 100. 2 Principles of Psychology, Vol. n. p. 289. 



