SCIENCE AND PHILOSOPHY 155 



a problem; we know that ?t is different from the 

 experimenting of a burglar who tries which key 

 in a bunch will open a particular door; we know 

 that it is different from the experimenting of a 

 dog trying to take a stick with a hooked handle 

 through the close-set upright bars of a fence; we 

 know that it is different from the behaviour of 

 earthworms trying various ways of transporting 

 leaves to their burrows; but is it not the beginning 

 of the "trial by error" method, common to all 

 these instances? 



(6) In the second place, the "genetic psycholo- 

 gist" has much to tell us of the individual develop- 

 ment of behaviour, of the gradual emergence of 

 capacities of action whether instinctive (involv- 

 ing apparently no inference), intelligent (involv- 

 ing apparently perceptual inference), or rational 

 (involving conceptual inference). Comparative 

 child-study in the wide sense, zoological as well 

 as anthropological, has surely some bearing on 

 the general question. 



(c) In the third place, Science has much to 

 say in regard to the actual correlation between 

 the static and the dynamic aspects, between 

 structure and function. Complexity of brain 

 structure is associated with very intelligent 

 behaviour; increase in the complexity of brain 

 structure from year to year in the individual is 

 associated with increased capacity of intelligent 



