714 PHILOSOPHICAL THOUGHT. 



and connected by the idea of causality or its reverse, 

 finality, accordingly as we connect the sequent with its 

 antecedent, or the latter with the former. As dis- 

 tinguished from this, causality in the outer physical 

 world is merely the rearrangement in space of something 

 which in quantity is supposed to be unalterable ; which 

 we call Substance, and picture to ourselves in some form 

 or other such as matter, its ultimate particles, or in more 

 recent times Energy. This rearrangement we assume 

 to be continuous, and it is subject to the principle of 

 conservation or equivalence. 



These modern theories of conservation of matter or 



energy, or, in general, of Substance, are not applicable to 



mental processes, which are, on the other side, subject to 



the principle of the growth or increase of mental energy. 



78. From this point of view Wundt denies the usefulness 



Rejection 



of the term and validity of the conception of Substance as applied 



Substance 



ton?ind ied ^ men tal phenomena. The traditional notion of a soul 

 as a spiritual thing has thus no place in his philosophy, 

 which, as such, stands in marked opposition to the 

 philosophy of Lotze, for whom the conception of the 

 universal substance is identical with that of the under- 

 lying reality, of the spiritual ground of everything. 



Wundt is, next to Spencer, the most recent thinker 

 who has ventured upon a systematic comprehension of 

 his philosophical ideas. His definition of philosophy as 

 expressive of the inherent tendency of thought towards 

 unity falls in with the general drift of modern specula- 

 tion, but nevertheless it differs both from the definition 

 of Herbart and Lotze on one side and from that of 

 Spencer on the other. Further, he recognises, as did 



