42 PHILOSOPHICAL THOUGHT. 



former almost exclusively the development which psy- 

 chology underwent during the first half of the century ; 

 to the latter almost all the important constructive 

 efforts in modern philosophy. These two quite in- 

 dependent movements met on common ground when 

 they approached, from different sides, the theories 

 of logic and philosophical method. To this common 

 task British psychologists were led, mainly under the 

 guidance of John Stuart Mill, when they desired to 

 extend their methods and theories so as to deal with 

 economic and social phenomena : German metaphysicians 

 were led to similar investigations through a criticism of 

 the dialectic (or metaphysical logic) of Hegel, the leader 

 in this movement being the Aristotelian scholar, Adolf 

 Trendelenburg. From these two independent modes of 

 approach, which met over a discussion of Hume's and 

 Kant's criticisms, the modern theory of Knowledge 

 (Erkentniss-theorie) arose. On this ground British and 

 German philosophy met again after a separation of more 

 than half a century. 



One would have thought that the great achievements 

 of the exact methods in France at the end of the 

 eighteenth century, resulting as we saw in many in- 

 stances in a creation of new sciences or a complete 

 remodelling of older ones, would have led on to a similar 

 revolution in mental and moral science. Such a process 

 indeed seemed to make a beginning in the school of 

 De Tracy and the ' Ideologues ' ; but for reasons which 

 have been explained in an earlier section of this work, 

 this development was stifled in its inception. 1 



1 See this History, vol. i. p. 149. 



