128 Mind and Body 



ence in movements — analogous to the difference between 

 pleasure-incited and pain-incited movements, — and that 

 natural selection has operated upon variations in it. The 

 biologist may say that this is too special — this differ- 

 ence of reaction — to be fundamental ; so it may be. 

 But then so is life special, very special ! ^ 



Whatever we may say to such particular conclusions, 

 they illustrate one of the topics which should be dis- 

 cussed by any one, biologist or psychologist, who wants 

 to understand the factors in evolution. There are some 

 factors revealed in ontogenesis which do not appear in 

 the current theories of evolution. Indeed, so far beside 

 the mark are the biologists who are discussing transmis- 

 sion to-day that they generally omit — except when they hit 

 at each other — the two factors which the psychologist has 

 to recognize : Social Transmission, for the handing down 

 of socially acquired characters, and Functional Selection, 

 for the accommodations of the individual organism, with^ 

 whatever effects they may have on subsequent evolution. 



Indeed, I do not see how either theory of heredity 

 can get along without this appeal to ontogenesis. For 

 if we agree in denying the inheritance of acquired char- 

 acters, thus throwing the emphasis on variations, still it is 

 only by the interpretation of ontogenetic processes and 

 characters that any general theory of variations can be 

 reached. Either experience causes the variations, as one 

 theory of heredity holds ; or it exemplifies them, as the 

 other theory holds ; in either case, it is the only sphere 



1 See remarks made on this and other ' comparative conceptions ' above, 

 Chap. II. 



2 Yet, of course, this statement is truer of the Darwinians than of the 

 Lamarckians. 



