62 INTRODUCTION 



contingent truths, however (if they are to be truths at 

 all, and not merely false or doubtful statements), must 

 have some ground or reason \ If the truth is such that 

 it is impossible to find for it an absolute and eternal 

 reason in the first principles of things, there must at 

 least be some satisfactory or sufficient reason why it 

 should be so and not otherwise. 



Logical Principles of the Philosophy of Leibniz. (fc) Principle 



of Sufficient Eeason. 



Thus Leibniz supplements the principle of contra- 

 diction by the addition of the principle of sufficient 

 reason. The name has a makeshift sound as if one 

 should say, ' We must be content with a sufficient reason 

 in cases where a perfect reason is not to be found.' But 

 in the philosophy of Leibniz it is much more than a 

 makeshift. This principle is essential to his system and, 

 indeed, gives it the greater part of its value. In the 

 Monadology, Leibniz defines this principle as that ' in 

 virtue of which we hold that no fact can be found real or 

 existing, no statement true, unless there be a sufficient 

 reason why it should be so and not otherwise, although 

 these reasons very often cannot be known by us 2 .' As 

 thus defined, the principle of sufficient reason might 

 almost be regarded as including the principle of contra- 

 diction, inasmuch as the self-consistency of necessary 

 truths is their sufficient reason. Self-consistency or. 



analysis, which God alone can accomplish. Accordingly it is by 

 Him alone that these truths are known a priori and with certainty. 

 For, although the reason of any succeeding state might be found in 

 that which precedes it, yet a reason for this preceding state can 

 again be given, and so we never come to the final reason in the 

 series. But this infinite process itself takes the place of a reason, 

 because in its own special way it might from the beginning have 

 been immediately understood outside of the series, in God, the 

 Author of things, on whom both antecedent and consequent states 

 are dependent, even more than they are dependent upon one 

 another.' 



1 Monadology, 36, 37. 



2 Ibid. 32. In the Theodicee, 44 (E. 515 ; G. vi. 127), he calls 

 it 'Determining [deciding] Reason.' 



