CHAPTER III 



THE DIRECTION OF EVOLUTION 



I. Genetic Determination: Congenital and Acquired 



Characters 



THE problem of determination, in its varied aspects, is 

 no more than the problem of the method of evolution; hence 

 the attention given in the following pages to this topic in both 

 its phases, that of evolution and also that of development. 1 

 As an intergenetic conception it takes form as follows: 

 first, what determines the development of the individual, 

 both bodily and mentally, or in a word, psychophysically ? 

 second, what determines the evolution of the species, in 

 both the same two phases, that is, psychophysically ? and 

 third, how can these two forms of determination work 

 together so that race determination is ' concurrent ' with 

 individual determination ? It is only when all three phases 

 of the problem are held together that the extraordinary 

 complexity of the data comes fairly out. The data of fact 

 and of principle resting upon formulations of fact, as 

 they appear in the present state of knowledge, may be pre- 

 sented somewhat as follows, while the later chapters may 

 be looked to for treatment of various of the subordinate 

 topics which fall under the larger heading. 



First, individual development seems to take place by 

 gradual accommodation to environment on the basis of 



1 See especially Chaps. X. and XVII. below, on 'Determinate Evolu- 

 tion ' and ' Selective Thinking.' 



34 



