MATHEMATICS VERSUS PSYCHOLOGY 15 



the significance of introspection as a method of analysis finds 

 scant recognition. Consider for a moment the central feature 

 of his psychological theory, the conception of subconscious sen- 

 sations (or petites perceptions, as he called them). By what 

 manner of argument is the assumption of their existence sup- 

 ported? We hear the sound of the waves beating upon the shore. 

 The waves are made of tiny drops, the separate sounds of which 

 we cannot distinguish. But yet we may be assured that each 

 drop makes some sound; for if the drops were silent the whole 

 ocean would be dumb. What would Berkeley have thought of 

 that? Leibniz's followers endeavored to make room for the new 

 psychology by giving it a place alongside of the old, distinguishing 

 thus between empirical and rational psychology. This was as 

 far as appreciation of it went. 



In insisting thus upon the contrasting characteristics of ration- 

 alism and empiricism, we have had an ulterior object in view; 

 namely, to prepare the way for an exposition of their common 

 presuppositions. To have attempted this latter task without 

 such preparation would have been doubly dangerous; first, by 

 exposing us to the criticism, that we were losing sight of dif- 

 ferences and endeavoring to confound well-established distinc- 

 tions; and, secondly, by putting us in the position of one who is 

 arguing for a thesis and hence is involuntarily led to suppress or 

 distort the facts which tend to weaken his contention. Whereas 

 now we can at least pretend to candor, and can prosecute our 

 discussion without fearing that we shall be accused of a par- 

 tisan interest in its outcome. 



