72 ESSAYS OF A BIOLOGIST 



must have something important and indeed funda- 

 mental in common, something which if we could but 

 unravel would help us in the study of both. 



The correlation of biology with sociology is im- 

 portant not only in itself, but also as part of a moie 

 general correlation of all the sciences. The correla- 

 tion of the sciences is of particular importance to-day 

 for a double set of reasons. The rise of evolution- 

 ary biology and of modern psychology have not 

 only changed our outlook on specially human prob- 

 lems, but have altered the whole balance, if I may 

 so put it, of science. There was a time when the 

 basic studies of physics and chemistry seemed not 

 only basic but somehow more essentially scientific 

 than the sciences dealing with life. Distinctions 

 were drawn between the experimental and the obser- 

 vational sciences — often half-consciously implying a 

 distinction between accurate, scientific, self-respecting 

 sciences and blundering, hit-or-miss, tolerated bodies 

 of knowledge. Biological phenomena are now, how- 

 ever, seen to be every whit as susceptible of accurate 

 and experimental analysis; and indeed to present so 

 many problems to the physicist and chemist that in 

 fifty years or so, I venture to prophesy, the wise 

 virgins in those basic sciences will be those who have 

 laid in a store of biological oil. 



But the main point is this — the study of evolu- 

 tion, of animal behaviour and of human psychology 

 makes it clear that in the higher forms of animals at 

 least we are dealing with a category not touched on 



