124 INTRODUCTION 



certain ideas or impressions ; each is a kind of atomism. 

 The eternal and necessary truths (or clear and distinct 

 ideas) of Descartes are unconditionally valid ; they are 

 a priori atoms, forming the totality of knowledge. The 

 * simple ideas ' of Locke are equally unconditional in their 

 validity ; they are a posteriori atoms or data of knowledge *. 

 But, here as elsewhere, Leibniz would rather reconcile 

 than overthrow. While the mechanical view of things is 

 not the truest, it nevertheless has value in its own sphere. 

 Thus he regards the errors of Descartes and Locke as due 

 in each case to the over-emphasis of one of the two com- 

 plementary elements in knowledge, the necessary and the 

 'contingent. Descartes's view might hold if knowledge 



1 Locke's opposition to Descartes, great though it was, ought not 

 ~V^ to be emphasized to such an extent as to hide the fact that they 

 have much in common. For instance, we know that Locke's first 

 attraction to philosophy came from a reading of Descartes, and he 

 may perhaps owe the suggestion of some of his leading ideas to 

 such passages as the following extract from an unfinished dialogue 

 of Descartes, in which the method of doubt is wittily set in con- 

 trast with the Scholastic metaphysics. The question is : ' What 

 is man's first knowledge ? In what part of the soul does it dwell ? 

 And why is it so imperfect at the beginning?' Epistemon, the 

 representative of Scholastic learning, says : ' That appears to me 

 to be very clearly explained, if we liken the imagination of infants 

 to a tabula rasa on which our ideas, which are as it were the living 

 image of objects, are to be painted. Our senses, the dispositions of 

 our mind, our teachers and our intelligence are the different painters 

 who can execute this work, and those among them which are least 

 fitted to succeed, begin it ; namely imperfect senses, blind instinct 

 and foolish nurses. At last comes the best of all, intelligence ; and 

 yet is it still necessary that it should serve an apprenticeship of 

 several years and for some time follow the example of its teachers, 

 before it dare rectify one of their errors. . . . It is like a clever 

 artist, called to put the finishing touches to a picture sketched by 

 learners. Though he use all his art, correcting gradually now one 

 feature, now another, and putting in all that has been omitted, 

 there must still remain great defects in it, because the picture was 

 badly drawn at first, the figures were ill- arranged and little atten- 

 tion was given to proportion.' Recherche de la Verite par les lumieres 

 natureVes, (Euvres de Descartes (ed. Cousin), vol. xi. p. 345 ; cf. ibid. 

 P- 375 : ' All truths follow from one another and are united by 

 a common bond ; the whole secret consists in beginning with the 

 first and most simple, and rising gradually to the most remote and 

 most complex.' See also Eraser's ed. of Locke's Essay, vol. i. 

 Prolegomena, p. ao. 



