104 HEREDITY AND SEX 



and honesty with which objections to the theory are 

 considered. 



I will let no one admire Darwin more than I admire 

 Darwin. But while affection and respect and honor 

 are the finest fruits of our relation to each other, we 

 cannot let our admiration for the man and an ever 

 ready recognition of what he has done for you and for 

 me prejudice us one whit in favor of any scientific 

 theory that he proposes. For in Science there is no 

 authority ! We should of course give serious considera- 

 tion to any theory proposed by a man of such wide expe- 

 rience and trained judgment as Darwin ; but he himself, 

 who broke all the traditions of his race, would be the 

 first to disclaim the value of evidence accepted on 

 authority. 



From the definition of sexual selection with which 

 we started it may be said that Competition and Courtship 

 stand for the two ways in which Darwin supposes 

 the secondary sexual characters to have arisen. 



Competition amongst the males is only a form of nat- 

 ural selection, as Darwin himself recognized (if we leave 

 out of account the further assumption that the victor 

 chooses his spoils). We may dismiss this side of the 

 problem as belonging to the larger field of natural selec- 

 tion, and give our attention mainly to those secondary 

 sexual characters that Darwin supposes to have arisen 

 by the female choosing the more ornamented suitor. 



I shall first bring forward some of the more striking 

 examples of secondary sexual characters in the animal 

 kingdom. These characters are confined almost ex- 

 clusively to three great groups of animals — Insects, 



