70 INTRODUCTION 



reality even though they are not all perfectly clear and 

 distinct. Thus Spinoza, under the guidance of the prin- 

 ciple of contradiction, rejected merely empirical know- 

 ledge, the contingent sequence of ideas that comes ab 

 experientia vaga, as confused and therefore unreal and 

 illusory, a work of imagination. On the other hand, 

 Leibniz (for whom this empirical sequence is the series 

 of perceptions in Monads that have not reached the self- 

 conscious stage) attributes to this sequence a relative 

 reality, inasmuch as it is potentially, though not actually, 

 clear and distinct. 



Further, we see the influence of the principle of suffi- 

 cient reason in the conception of the Monads as each 

 representative of the whole universe from its particular 

 point of view. The Monads are indeed Terms or absolute 

 points, centres exclusive of one another ; but they are 

 not Terms exclusive of relations. It is a part of their 

 essential reality to contain within themselves a multi- 

 plicity of relations. The Monad may be likened to ' a 

 centre or point in which, quite simple though it is, there 

 exists an infinite number of angles, formed by the lines 

 which meet in it 1 .' The principle of contradiction 

 requires nothing but a pure simplicity in the individual 

 substance ; any kind of simple substance would satisfy 

 it. But the principle of sufficient reason imposes the 

 further condition that the simple substance must have 

 relations to other simple substances and to the whole, 

 and that only those simple (self-consistent) substances 

 are real which are also consistent with the real unity 

 of the whole. For otherwise every real substance would 

 have its ground or reason wholly in se, and those things 

 for which we must be content with a ground or reason 

 in olio would be entirely illusory. Thus the combination 

 of self-consistency with consistency in relation to the 



1 Principles of Nature and of Grace, 2. Of. Extrait du Dictionnaire de 

 Bayk, &c. (1702) (G. iv. 542) : 'God has put in each soul a concentra- 

 tion of the world.' 



