94 THE RIDDLE OF THE UNIVERSE. 



formerly isolated, that has elevated them in this 

 manner. 



The first task of every science is the clear definition 

 of the object it has to investigate. In no science, 

 however, is this preliminary task so difficult as in 

 psychology ; and this circumstance is the more 

 remarkable since logic, the science of defining, is 

 itself a part of psychology. When we compare all 

 that has been said by the most distinguished philo- 

 sophers and scientists of all ages on the fundamental 

 idea of psychology, we find ourselves in a perfect 

 chaos of contradictory notions. What, really, is the 

 "soul"? What is its relation to the "mind"? 

 What is the inner meaning of "consciousness"? 

 What is the difference between " sensation " and 

 "sentiment"? What is instinct"? What is the 

 meaning of " free will " ? What is " presentation " ? 

 What is the difference between "intellect" and 

 " reason " ? What is the true nature of " emotion " ? 

 What is the relation between all these "psychic 

 phenomena" and the "body"? The answers to 

 these and many other cognate questions are infinitely 

 varied ; not only are the views of the most eminent 

 thinkers on these questions widely divergent, but even 

 the same scientific authority has often completely 

 changed his views in the course of his psychological 

 development. Indeed, this " psychological metamor- 

 phosis "of so many thinkers has contributed not a 

 little to the colossal confusion of ideas which prevails 

 in psychology more than in any other branch of 

 knowledge. 



The most interesting example of such an entire 

 change of objective and subjective psychological 

 opinions is found in the case of the most influential 



