PAPERS OX PSYCHOLOGY AND EDUCATION 491 



interested in measnriilg individual differences in per- 

 sonal traits have, like the intelligence testers, worked 

 on an almost purely empirical basis. The differential 

 psychologist, in enumerating character traits, for in- 

 stance, is bound to pick out the measurable rather than 

 the fundamentally important. 



A final question occurs to me in this attempt to inter- 

 pret the appearance of a new chapter in psychology. 

 Does this chapter contain, or is it likely to contain, any 

 forms or principles of mental activity comparable in im- 

 portance for psychology as a whole to the reaction arc, 

 perception, image, idea, and habit? There are those 

 who believe that the science of psychology will have 

 largely to be rewritten as a result of modern studies of 

 personality. Although time forbids an adequate defense 

 of my position, I should like to say that I am extremely 

 doubtful as to the truth of this statement. Most of the 

 so-called new principles which have come into psychology 

 with the recent studies in personality are after all not 

 so very new. The notion of causal relationships between 

 mental phenomena, the importance of unconscious activi- 

 ties, and the conception of conflict put forth so vividly 

 by ■ the psychoanalysts harken back to many historic 

 systems and debates. I should not for a moment deny 

 the paramount importance of the many neglected prob- 

 lems which recent studies of personality by the psycho- 

 analysts and others have pointed out, but what is needed 

 at the present time is not a proclamation that these 

 mechanisms of personality are newly discovered phe- 

 nomena, unrelated to any psychology heretofore thought 

 of. Eather, there is a need, and I believe it is being 

 increasingly acknowledged, for these personal mechan- 

 isms to be set in their proper relationships to that host 

 of psychological principles which have been accumulat- 

 ing since Aristotle. 



