USELESS IMPULSES 75 



approval or disapproval, respect or contempt. 

 Clapping and hissing are purely conventional. We 

 salute a friend by offering him vestiges of homage : 

 the Tibetans salute him by protruding the tongue. 



Our instinctive impulses are so numerous and 

 so varied that it is exceedingly difficult to group 

 them into general classes. And the difficulty is 

 increased by our desire to find a useful purpose in 

 everything. Those who hold that evolution has 

 been directed by the struggle for life are generally 

 as persuaded that all things have evolved for 

 good as the most convinced believer in Provi- 

 dential intervention. Yet a dispassionate survey 

 of Life's activities will hardly find justification for 

 so comforting a belief. What, for instance, is 

 the use of lust that is not limited by the require- 

 ments of reproduction, of appetite that outruns 

 digestion, of gratuitous cruelty, of kindness that 

 disregards merit, of the impulses to dance, and 

 to practise asceticism ? Many, perhaps most, 

 of our instincts are of practical utility more, no 

 doubt, than may appear to possess it at first sight. 

 But there are many that are out of all connection 

 with the stern conditions of the struggle for life. 

 From its point of view they are superfluities. If 

 harmful to their possessors they will be eliminated ; 

 but when we reflect upon the vast number of 

 species that have become extinct in the past, a 

 suspicion arises that injurious impulses may have 

 survived until they brought a race to destruction. 

 Did not the giant lizards of the Mesozoic age, the 

 giant mammals of a period less remote, outgrow 

 their food supply ? Does it not appear that there 

 may be glands and outgrowths in the human 

 body (such as the appendix) which are not merely 

 useless but injurious ? If superfluous impulses 



