LIFE AND WOKKS 13 



The 'Nouveaux JEssais' and the l Tfieodicee.' 



Having thus definitely fixed his philosophical system- 1 , 

 and having published its leading principles, Leibniz 

 gradually expounded it in detail, for the most part by 

 means of correspondence and criticism. Hitherto he 

 had given most attention to ontological or purely meta- 

 physical problems. But now he began to consider more 

 carefully the theory of knowledge and the psychological 

 questions that are connected with it. Locke's Essay was 

 published in 1690, and a few years afterwards Leibniz 

 read it, writing (as was his custom) notes and comments 

 as he read. Some of these criticisms were in 1697 sen ^ 

 to Locke, who treated them with contempt, and made no 

 reply 2 . In 1703 Leibniz wrote the Nouveaux Essais sur 

 I'Entendement humain, a long dialogue, in which the views 

 of Locke and of himself are set in contrast throughout 

 a discussion dealing with the subjects of Locke's Essay 

 chapter by chapter. This book was evidently intended 

 to call forth a rejoinder from Locke. But before it was 

 ready for publication Locke died (in 1704) ; and Leibniz, 

 saying that he ' greatly disliked publishing refutations of 

 dead authors,' and that he now 'preferred to publish his 

 thoughts independently of another person's,' allowed the 

 Nouveaux Essais to remain in manuscript, so that the 

 book was first published by Kaspe in 1765, nearly fifty 

 years after Leibniz's death. 



After writing some other papers on psychological and 



1 In 1697 he writes to Thomas Burnet of Kemnay : ' I have 

 changed and changed again, according as new light came to me ; 

 and it is only about twelve years since I found what satisfies me, and 

 arrived at demonstrations regarding matters which did not seem 

 capable of demonstration/ (G-. iii. 205.) 



* Leibniz (in 1714) says that he was not surprised at Locke's 

 disdain. 'The difference between our principles was somewhat 

 too great, and what I maintained seemed to him to be paradox.' 

 He adds that Locke ' had subtlety and dexterity, and he had 

 a kind of superficial metaphysics which he knew how to make the 

 most of; but he did not know the method of mathematicians.' 

 Ltttre a Eemond (E. 703 b ; G. iii. 612). 



