GENERAL INTRODUCTION. 



The investigation of which this thesis is the outcome, 

 had its origin in a desire to reach a conclusion with regard to 

 the value of the method followed by the great evolutionists in 

 biology when they approached psychological or ethical 

 questions. 



It is evident that what is at stake in such an investigation 

 is not, in the first instance, the great ethical concepts, for every 

 one would recognize a place for 'duty', 'obligation', 'virtue', etc. 

 The ethical schools differ in their interpretation of these terms 

 by reason of the conceptions of motive, moral criterion, etc. 

 It was very soon recognized that the aspect of the subject 

 which was really vital was the method of approaching these 

 questions rather than, in the first instance, the solutions reached. 

 For this reason it was felt that in order to appreciate the 

 position of the modern evolutionist, it was necessary to under- 

 stand the theories, both psychological and biological, with 

 which he approached the ethical problem. It is the attempt 

 to understand the evolutionist in a sympathetic way which led 

 to the somewhat extensive exposition of Part I. For clearness 

 we have confined the discussion of this part almost altogether 

 to the broad question of the use of the evolutionary method in 

 psychology. Very naturally, then, Part II. had to be taken 

 up with a discussion of the ethical content, for which, under 

 some form, all moralists have to provide a theory. In Part 

 III. the conclusions reached in Parts Land 1 1. have been briefly 

 summarized. 



