1 62 THE EVOLUTION OF MAN 



and it is generally assumed that in each of these lines we may 

 look forward to endless progress. The infinite perfectability 

 of man is a fundamental article of faith with many people, 

 and yet all biological evidence indicates that it is not supported 

 by fact. Not only the history of other organisms but also that 

 of man himself indicates that progress in any particular line 

 is limited. 



In bodily evolution man has made no very marked progress 

 during the last twenty thousand years at least. Undoubtedly 

 there have been minor changes in the human body, probably an 

 increasing resistance to certain diseases due to the elimination 

 of those persons who were more susceptible, as well as certain 

 degenerative changes in sense organs, hair, teeth, and toes; 

 but such changes are insignificant when compared with those 

 which marked the transition from pre-human ancestors to man, 

 or even tho-se changes which brought about the differentiation 

 of the primary races of mankind. The physical evolution of 

 man has slowed down almost to a standstill, and if it is to go 

 forward again it will probably be in new lines and in response 

 to new and very different environmental conditions. 



The opinion is widely held that intellectual evolution is 

 advancing rapidly and in justification of this belief is instanced 

 our increasing knowledge of the world and of man. But it 

 is necessary to distinguish between intellect and knowledge, 

 between the capacity for knowing and things known. Un- 

 doubtedly we know many more things than the ancients or 

 even than our own parents, but has there been any increase in 

 intellect comparable with the increase in knowledge which has 

 marked the last few centuries? On the contrary, those who 

 have devoted much attention to this subject are of the opinion 

 that no modern race is intellectually equal to the ancient Greek 

 race. Not only did this race produce a larger number of illus- 

 trious men than has any other race during an equal period of 



