THE KINSHIP OF LIFE. 



47 



The theory of evolution, in brief, is this : There ex- 

 ists in all things a tendency to become specialized and 

 differentiated. In accordance with this tendency nebu- 

 lous masses have been concentrated into planets and the 

 generalized creatures of early time have been special- 

 ized into distinct forms. The formula of the process of 

 evolution as stated by Mr. Spencer resolves itself into 

 this: "Evolution is a change from an indefinite, inco- 

 herent homogeneity to a definite, coherent heterogeneity 

 through successive differentiations and integrations." 



That this is true in the world of life is beyond ques- 

 tion, and we have reason to believe that something of 

 the sort is true in the world outside of life, whether the 

 laws and forces in question be in essential respects com- 

 parable or not. 



The influence of the theory of descent on all forms 

 of modern mental activity has been great beyond com- 

 parison. The thoughts of every student 

 Influence of i , , ,.^ , , 



have been more or less modified by it. 

 theory of .^ i •, • 



descent ^^ philosophy as in science the publica- 



tion of the Origin of Species has been 

 the great event of the nineteenth century. Not only 

 have all the strictly biological sciences undergone a 

 complete transformation since the year 1859, but such 

 allied sciences as psychology, philology, sociology, and 

 ethics have felt the same impulse and have fallen under 

 the same influences. Even the organization of charities 

 in every well-ordered community is avowedly based on 

 the principles of Darwinism. 



The various attacks on the theory of descent have 



been nearly all based on the question of the origin of 



„ . . . man. For the human race is likewise a 



Origin of man. 



species of animals, and from its physical 

 side it must be discussed with other species. If we sup- 

 pose that the various forms of the lower animals and 



5 



