EVOLUTION OF MENTAL CHAKACTEKS 405 



outwardly manifested has been clearly favoured. But how far 

 we should see in this process a favouring of certain innate types 

 of disposition and of temperament must be left for consideration 

 until later. These reservations regarding the passing at present of 

 any judgement apply with the greatest force to the results of the 

 differential fertility between the social classes in many countries 

 at the present day. But we may say that, as in the case of 

 physical characters, there has now ceased to be any strong 

 tendency towards the preservation of a mean type. Conditions 

 allow of the existence of variations away from the mean 

 but, as regards intellect, unfavourable equally with favourable 

 variations. 



10. We have seen that the evidence derived both from a study 

 of fossil remains and from a study of primitive races leads to 

 the conclusion that the evolution of human intellectual capacity 

 early reached a relatively advanced stage. An inquiry into the 

 forces which we must assume to have been at work shows that 

 intellectual capacity was more favoured in the intermediate stage 

 than after primitive society had come into being. It was favoured 

 at first as the character which enabled man to obtain his dominating 

 position in the world and afterwards again as the necessary trait 

 which enabled him to enjoy the benefits of co-operation. When 

 dwelling on the fact that the advance since the setting-up of 

 primitive society has been relatively small, it must not be forgotten 

 that the latter period has been far shorter than the former. The 

 period of time which has elapsed since the ancestors of man set 

 out, so to speak, to conquer the world, must at a minimum 

 estimate be five to ten times as long as the period sinee the 

 establishment of primitive society to the present day. 



The general conclusion to which we are led is that of the whole 

 degree of mental evolution which has taken place by far the 

 greater part was achieved at a time when only a beginning had 

 been made with progress in skill. To the question whether the 

 historical process outlined in the fifth chapter is comparable with 

 progress among wild species is based, in other words, upon 

 changes in the germinal constitution these conclusions suggest 

 the answer that the happenings in the intermediate period are 

 very largely in any case to be accounted for in this manner. 

 There can be little doubt that the increasing domination of man 

 was largely proportional to the growth of his innate intellectual 



