68 INTRODUCTION 



a principle of pure self-identity which asserts permanence 

 to the exclusion of change or, in general, unity to the 

 exclusion of difference. In other words, it insists on 

 the reality of Terms, making relations subordinate or 

 fictitious. Consequently a philosophy whose dominant 

 principle is that of contradiction, in this sense, must 

 (consciously or unconsciously) treat whole and parts as 

 exclusive of one another, asserting the reality of the one 

 as against that of the other. For if the whole be real 

 it must be simple, it must exclude as unreal all relations 

 or differences. Otherwise it will not be purely self- 

 identical, but may receive a variety of real predicates. 

 And as it is simple it can have no real parts. Since A 

 cannot be not- A, and since not-A includes B, C, &c., 

 it cannot be true that some A is B or C. Some A can 

 only be A without further distinction,, On the other 

 hand, if the parts be real and purely self-identical, if the 

 reality of each is self-centred and is determined without 

 regard to its relations to the others, then there is no 

 real whole, but only a numerical collection of individuals 

 which may even be contradictory of one another. The 

 principle of contradiction, considered as meaning merely 

 that the real is that which is not self-contradictory, yields 

 either a whole, which has no real parts or determinations 

 because it is equally indifferent to all possible determina- 

 tions, or a bare collection of severally possible, but jointly 

 ' incompossible ' parts. 



Now, it is the influence of the principle of contra- 

 diction, thus abstractly interpreted, that leads Leibniz 

 to the conception of real substance as simple, i. e. as 

 without parts, indecomposable. And it is the same 

 principle that accounts for the infinite plurality of simple 

 substances and their complete isolation from one another. 

 For Leibniz, in order to give due value to the differences 

 in the universe, holds the principle of contradiction as 

 ensuring reality to the parts, leaving the whole to be 

 otherwise accounted for. And, on the other hand, the 



