MENTAL EVOLUTION OF MAN 199 



history of transformation to become what it is and what 

 it was not. 



Many who would be ready to accept the evolution of 

 physical characteristics find it impossible to treat the 

 history of human mentality as a subject for dispassion- 

 ate consideration, because above all else the intellectual 

 powers of mankind seem to be truly distinctive. It is 

 only after constant use of the methods of science that 

 we can bring ourselves to see how closely we resemble 

 lower forms in physical make-up ; still greater reluc- 

 tance must be overcome before we can view our mental 

 processes as counterparts of those of inferior animals, 

 so essential to our very humanity do they seem. But 

 our duty to undertake the task is plain, and its dis- 

 charge will be greatly facilitated by a clear realization 

 that mental evolution is but a part of human transfor- 

 mation in times past, as the latter is only a small frac- 

 tion of the universal process of organic evolution in 

 general. While our own nature and inquisitiveness 

 give us so intense an interest in the teachings of science 

 that relate to the constitution and history of human 

 faculty, wherefore these matters gain an undue promi- 

 nence in perspective, it must never be forgotten that 

 these teachings do not stand by themselves, for they are 

 built upon the sure foundations already laid in physical 

 evolution ; and these foundations cannot be disturbed 

 by our failure to use them as a basis when we construct 

 our own conceptions of human intellect and its history. 



Before passing to the systematic review of the facts 

 and principles of comparative psychology which demon- 



