122 INTRODUCTION 



knowledge which is not clear and distinct, knowledge of 

 contingent things which it cannot reduce to eternal and 

 necessary truth. This must be so, for otherwise the 

 human soul would be perfectly clear and distinct in its 

 perceptions, complete and unrestrained in its activity, 

 actus purus. But this characteristic of perfect intuitive 

 knowledge and absolute activity belongs to God alone ; 

 the perceptions of man are always at best only relatively 

 clear and distinct. Accordingly it is impossible for 

 Leibniz to assent to the Cartesian theory of knowledge, 

 which gave worth only to the absolutely clear and distinct, 

 drawing a hard and fast line between self-conscious 

 thinking and all else. Descartes's use of the principle of 

 contradiction was inconsistent with the possibility of 

 relative truth. It explains the universal and necessary, 

 but only by setting aside the contingent as ultimately 

 inexplicable. 



On the other hand, the theory of Leibniz is equally 

 opposed to the opposite view, expounded in Locke's Essay 

 on the Human Understanding. If distinctively human 

 knowledge does not consist solely in the perception of 

 universal and necessary truths, neither is the human mind 

 altogether destitute of such knowledge and dependent for 

 its ideas entirely upon the contingency of the senses. As 

 the human soul is a Monad, its knowledge does not come 

 to it from outside itself, for it cannot be really influenced 

 by any other substance. It is not originally a tabula rasa 

 on which externally-produced impressions are made ; for 

 no Monad can ever be purely passive or absolutely without 

 perception. The human mind, being spontaneous in all 

 its activities, must produce its knowledge entirely from 

 within itself. It is not a vacuum, gradually filled ab extra 

 with independent ideas ; it is a force or life transforming 

 itself, a growth, a self-revelation \ 



1 Cf. Nouveaux Essais, bk. ii. ch. i, 2 (E. 222 b ; G. v. 99) : 'This 

 tabula rasa, of which so much is said, is in my opinion nothing but 

 a fiction, which nature does not allow and which has its grounds 



