GENERAL PRINCIPLES 63 



absence of self-contradiction is one test of the sufficiency 

 of the reason. But, on the other hand, the principle of 

 contradiction has ail independent and, in some sense, 

 superior position, for in the case of necessary truths the 

 reason can always be given, that is, can be made explicit, 

 while in the case of contingent truths we often can only 

 say that there must be a sufficient reason, without know- 

 ing fully what the reason is. 



/The Possible and the Compossible. The lest of all 

 possible Worlds. 



The value and importance of the principle of sufficient 

 reason become more manifest when we inquire further 

 'In what does the sufficiency of the reason consist?' 

 We have seen that the grounds of any contingent truth 

 or fact are to be sought in other contingent truths or 

 facts, and that an attempt to analyze a contingent truth 

 or fact into its grounds thus leads to an infinite process. 

 Accordingly it seems to Leibniz that the final reason of I 

 contingent truths must be sought in something outside 1 

 of the system of contingent things, viz. in an eternal and I 

 necessary Substance or God, who is their source. But \ 

 this requires some further explanation. In the case of 

 the principle of contradiction, what may be called the 

 sufficiency of the reason consisted in the absence of 

 self-contradiction in the thing or proposition. But to 

 say that a thing is in itself free from contradiction is the 

 same as to say that, by itself and without reference to 

 other things, it is possible *. Accordingly, to say that 

 everything which is not self-contradictory is true or real 

 is to say that everything possible is true or real. ' I call 

 possible everything which is perfectly conceivable and 

 which has consequently an essence, an idea, without 

 considering whether the remainder of things allows it to 

 become existent V But the opposite of every particular 



1 Cf. Meditationes de Cognitione, &c. (1684) (E. 80 b ; G. iv. 425 ; 

 Baynes, Port-Royal Logic, 428). 



a Lettre a Bourguet (1714) (E. 720 a ; G. iii. 573). 



