248 SOCIAL HEREDITY AND SOCIAL EVOLUTION 



wise, an animal in the reproductive act is not influ- 

 enced by intelligence, since he has no idea of its 

 meaning. The impulse to preserve life and the 

 impulse to perform the sexual act are inborn with 

 the individual, and demand obedience with such force 

 that, without a shred of thought as to their signifi- 

 cance, thej^ are universally obeyed by animals. 

 These two instincts together have led to natural 

 selection, which has been the foundation of progress. 



The Ethical Instinct 



Mankind is under the influence of a third addi- 

 tional force which we call his ethical nature, which 

 seems likely to have had its origin in the instinct 

 present among animals that leads to a struggle for 

 the life of a species. Whatever may have been its 

 origin, there is no doubt that it has greatly developed 

 during the evolution of society. Like the instincts of 

 animals, the moral nature of man controls his 

 actions, not by reason but by impulse. The individ- 

 ual who acts because he regards a certain line of 

 actions as right does not argue the question whether 

 he should follow the right course, and, indeed, recog- 

 nizes no room for argument. He may debate the 

 question whether he will do right or wrong; he may 

 argue as to the results of the action, and may use his 

 reason to determine which of two actions is the right 

 one. But the impulse that leads him to do the right 

 is beyond argument. He does the right simply be- 

 cause he feels that it is right, and at this point every- 

 one recognizes that logic is no longer possible. Of 

 course this does not mean that all men obey this feel- 

 ing of right, but simply that the moral sense, to the 

 extent to which it is developed in different men, is 



