64 INTRODUCTION 



event or contingent truth is possible in this sense : it does 

 not necessarily imply a self-contradiction. The opposite 

 of the axiom, ' Things that are equal to the same thing- 

 are equal to one another,' is not possible, for it involves 

 an immediate self-contradiction. The opposite of the 

 truth, ' I am sitting here at this moment,' is possible, for it 

 does not involve a direct self-contradiction. Accordingly, 

 the truth of contingent things is not grounded in their 

 possibility \ It is not in virtue of their very essence or 

 idea that they, and not their opposites, are true or real. 

 Their sufficient reason lies beyond themselves, in their 

 relation to other things. In themselves, the contingent 

 truths and their opposites are alike possible : considered 

 in relation to other things, the truths alone are possible. 

 For instance, if we consider the truth that 1 1 am sitting 

 here at this moment/ not in itself alone, but in relation 

 to an indefinite number of other truths regarding (say) 

 my habits, character, work, the hour of the day, &c., we 

 shall see that the truth alone is possible, that in this 

 connexion its opposite is impossible. The opposites of 

 contingent truths, though not self-contradictory, are in 

 contradiction with the general system. Each is possible, 

 but 'they are not jointly possible, mutually compatible, 

 or, in Leibniz's phrase, ' compossible.' Accordingly, 

 ' compossibility,' or conformity with the actual system of 

 .things, is the true test of reality, the sufficient reason. 

 /Everything which is possible has an essence or meaning, 

 | but only that which is also compossible has existence 2 . 



1 Descartes did not admit that everything which is possible is 

 realized, but assigned the choice among possible things to the mere 

 will of God. But this is practically to make the choice arbitrary 

 and consequently to make the contingent (which is the result of 

 choice) fortuitous. Spinoza, on the other hand, by holding that 

 everything possible is realized, made the contingent necessary. 

 Leibniz, however, points out that Descartes in one passage ( Principia, 

 iii. 47) says that ' Matter must successively take all the forms of 

 which it is capable/ an approach to Spinoza's view. Reponse aux 

 Reflexions, &c. (1697) (E. 144 a ; G. iv. 340). 



2 Cf. Lettre a Bourguet (1714) (E. 719 b; G. iii. 572): 'I do not 

 admit that, in order to know whether the romance of Astraea is 



