46 Darwinism and Other Essays. 



in the universe that is isolated or sui generis in 

 being incapable of scientific explanation. Im 

 mense as the fabric of human speech has grown 

 to be, it is undoubtedly based on sundry acts of 

 discovery or invention not necessarily very 

 conspicuous at the outset among primeval semi- 

 human savages. The inventive acts which led to 

 the systematic use of vocal sounds for the inter 

 change of ideas, like the inventive acts which re 

 sulted in bows and arrows and in cookery, are to 

 be regarded simply as instances of the general 

 increase in psychical plasticity which has been 

 the fundamental fact in the genesis of man in 

 tellectually. In other words, the existence of 

 language is a fact no more wonderful than the 

 general superiority of human over simian intelli 

 gence ; and when it shall have been shown how 

 the rigid mind of an ape might acquire plasticity, 

 the problem of the origin of language, along with 

 many other problems, will have been, ipso facto, 

 more than half solved. 



A great step in this direction was taken by 

 Mr. Wallace, when he pointed out that when 

 variations in intelligence have become, on the 

 whole, more useful to a race of animals than 

 variations in physical constitution, then natural 

 selection must seize upon the former to the rela- 



