386 EVOLUTION OF MENTAL CHARACTEKS 



difficulty and apart from the influence of disease, it is not probable 

 that other factors in the environment have any marked direct 

 effect upon either disposition or intellect. 



There is a far more serious difficulty to which allusion has 

 already been made. It arises from the fact that mental faculties 

 as exhibited in daily life are overlaid by tradition and shaped 

 by habit. There is no difficulty in getting down to any physical 

 character. It is always possible to separate the limb from the 

 tool which it uses. It is frequently very difficult to effect the 

 corresponding separation between the faculty and the tool in 

 the case of mental characters. Human mental characteristics, 

 as manifested in daily life, represent the combination of acquire- 

 ments with a certain basis. By the basis is meant that which 

 develops as the result of environmental stimuli acting upon the 

 predispositions. The basis of all mental faculties is, therefore, 

 that which strictly speaking is comparable with physical characters. | 

 Mental characters as manifested in daily life represent this basis 

 combined with tradition. This applies not only to the intellectual 

 but also to the instinctive faculties. The manifestation of instinct 

 is dependent upon the channels into which it has been led by ^ 

 tradition and upon the outlets which tradition provides for it. 



In attempting to estimate the stage of evolution of mental 

 characters reached at any one time, we must, as far as we can, 

 allow for all that obscures their manifestation. There are several 

 different ways in which this may be attempted and it will be 

 found possible to reach a fairly definite conclusion with regard 

 to the degree of development of mental characters as exhibited 

 by two races as different as the white and black. But the inquiry 

 into the differences between the more nearly related varieties, 

 such as the different branches of the white race, present far more 

 difficult problems, and by these methods we shall not be able to 

 approach them with much hope of success. Further, these 

 difficulties will be more strongly felt when we go on to inquire 

 into the causes of the changes which have led to the evolution 

 of the different types. Therefore, though in this chapter we 

 shall reach certain conclusions as to the nature, causes, and 

 results of mental changes in the earlier periods, we shall find 

 that, owing to the difficulties mentioned, we are unable to reach 

 any conclusion as to the later periods until we have inquired 

 into the importance of tradition. It will thus be necessary to 



