FACTORS OF ORGANIC EVOLUTION 



both to Darwin and Wallace, by consideration of a 

 special case. This is the case discussed by Malthus 

 in his famous essay on population, published in 

 1798. Malthus discussed the consequences of an 

 increase of population in geometrical progression 

 while the necessaries of life increased only in 

 arithmetical progression. In other words, he dis- 

 cussed the case of what Wallace calls the "strug- 

 gle for existence." If the means of subsistence 

 be superabundant, natural selection can scarcely 

 operate. It depends for any considerable sphere 

 of action upon the occurrence of a struggle for 

 existence. Given such a struggle, it stands to 

 reason that the fittest must survive. That there 

 be no struggle may perhaps be conceived as the 

 happiest, the ideal, state of affairs; but given a 

 struggle, it follows that the law of natural selec- 

 tion is a beneficent one, as Darwin clearly showed. 

 Unfortunately, these considerations, very imper- 

 fectly thought out and uncorrected by any others, 

 have led such writers as Nietzsche and his follow- 

 ers to assume that might is right, and that science 

 has demonstrated the uprightness and expedien- 

 cy of the doctrine " Each man for himself, and the 

 devil take the hindmost." In a subsequent chapter 

 it will be shown how imperfectly and rudely the 

 Nietzschean doctrine is in correspondence with the 

 facts. 



On that factor of organic evolution which Dar- 

 win discerned and named sexual selection we need 

 129 



