INTRODUCTION XV 



ceding, and surviving, for a time at least, because more 

 completely conformed to environment. If this be true, 

 and it must be true unless our theory of evolution be 

 false, higher forms are more completely conformed to 

 their environment than lower ; and man has attained 

 the most complete conformity of all. Our biological 

 history is therefore a record of the results of successive 

 efforts, each attaining a little more complete conformity 

 than the preceding. From such a history we ought to 

 be able to draw certain valid deductions concerning 

 the general character and laws of our environment, to 

 discover the direction in which its forces are urging 

 us, and how man can more completely conform to it. 



If man is a product of evolution, his mental and 

 moral, just as really as his physical, development must 

 be the result of such a conformity. The study of en- 

 vironment from this standpoint should throw some 

 light on the validity of our moral and religious creeds 

 and theories. It would seem, therefore, not only justi- 

 fiable, but imperative to attempt such a study. 



Our argument is not directly concerned with modern 

 theories of heredity, or variation, or with the " omnipo- 

 tence" or secondary importance of natural selection. 

 And yet Nageli, and especially Weismann, have had so 

 marked an influence on modern thought that w^e cannot 

 afford to neglect their theories. "We will briefly notice 

 these in the closing chapter. 



