LAWS CONTROLLING HUMAN SOCIAL HEREDITY 329 



monkeys Garner claims to have found the highest 

 trace of language yet reported among animals. 



In short, the nondevelopment of language among 

 animals is due fully as much to the low condition of 

 their social customs as to their inferior intelligence. 

 Such a complicated phenomenon as speech could 

 develop in a community of associated men only after 

 many generations of experimenting, and it could be 

 transmitted to each generation only by social hered- 

 ity. The universal habit of forming lasting associa- 

 tions among men, and the lack of social customs of 

 similar duration among animals, furnishes a sufficient 

 explanation for the development of langTiage in one 

 case and its absence in the other. Language, like 

 civilization, is based primarily upon social habits 

 rather than upon intelligence. 



Social Heredity Leads to Altruism 



We have noticed that there are two fundamental 

 instincts innate in human nature. The egoistic 

 instinct impels each individual to seek his own inter- 

 ests, and is found throughout the human race. The 

 altruistic instinct is in some respects in conflict with 

 the egoistic, and impels each individual to cherish 

 the interests of others. The first of these two is the 

 primitive instinct, and is shared by all other animals. 

 The latter is a secondary one, is in general weaker 

 than the former, and is almost distinctly confined to 

 the human race, although slight traces of it may be 

 found among other animals. The fundamental law 

 of nature, based upon the struggle for existence with 

 the resulting natural selection, is founded upon the 

 instinct of egoism. It is very significant now to find 

 that the force of social heredity emphatically leads 



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