LAWS CONTROLLING HUMAN SOCIAL HEREDITY 311 



complexly built masses of muscles, bones, and nerves. 

 The last quarter of a century has shown that to 

 develop these there are needed those laws which are 

 acting in nature, which have produced a rigid selec- 

 tion resulting in the breeding together only of indi- 

 viduals well fitted to continue to fight for existence. 

 But the development of mankind has a new aim, 

 which doubtless as yet we only dimly appreciate and 

 of which, possibly, we have as yet no conception at 

 all. Whatever this new aim may be, one thing is 

 certain: the new goal inevitably involves a higher 

 activity of the mental powers of mankind. It is not 

 simply the possession of mental powers that consti- 

 tutes humanity ; it is, rather, the use of these powers. 

 Now, while the possession of mental powers is 

 clearly a function of the brain, and while this, again, 

 has likely been produced in man by the same forces 

 that produced his other bodily features, we are sure 

 that the activities of his mental powers are controlled 

 by the environment in which he lives. That which 

 the mind of man is capable of doing is dependent not 

 wholly upon the inherited mental power, but largely 

 upon the condition in which it works, upon the train- 

 ing it can receive, and upon the tools with which it 

 has to work. This is dependent upon social life 

 almost wholly. From all of this it follows that the 

 aim of human evolution, instead of being to produce 

 a better animal, is to produce a better society, and 

 for this purpose, for reasons already pointed out, 

 other laws than those of natural selection are most 

 significant. 



Through the influence of social inheritance man- 

 kind thus comes to be more or less independent of 

 the laws of natural selection. Through its influence 



