204 INTRODUCTION 



the mind conceives relations to be applied.' (E. 768 a; G. vii. 

 400.) 



I have made some slight alterations in Clarke's translation 

 for the sake of clearness. As to other details of Leibniz's 

 doctrine of space, cf. Eraser's ed. of Locke's Essay, vol. i. 

 pp. 158 and 1 86. 



APPENDIX C. 



THE MEANING OF CAUSE. 



IN a draft of a letter to Arnauld (1686) (G. ii. 68) Leibniz 

 expounds his view of cause as follows-: 'The hypothesis of 

 concomitance is a consequence of my notion of substance. 

 For, in my view, the individual notion of a substance includes 

 all that is ever to happen to it, and it is in this respect that 

 concrete things [etres accomplis = res completae ?] differ from 

 those which are not so. Now, the soul being an individual 

 substance, its notion, idea, essence or nature must include all 

 that is ever to happen to it ; and God, who sees it perfectly, 

 sees in it all that it will ever do or suffer and all the thoughts 

 it will have. Accordingly, since our thoughts are nothing but 

 the consequences of the nature of our soul and arise in it 

 in virtue of its notion, it is useless to seek in it the influence 

 of any other particular substance, besides that such an influence 

 is absolutely inexplicable. It is true that certain thoughts come 

 to us when there are certain bodily motions, and that certain 

 bodily motions happen when we have certain thoughts ; but 

 that is because each substance expresses the entire universe 

 in its own way, and that expression of the universe which is 

 a motion in the body is perhaps a pain in relation to the soul. 

 But we attribute activity [action} to that substance whose 

 expression is the more distinct, and we call it cause. Thus 

 when a body passes through water, there is an infinity of 

 motions of the parts of the water, such as there must be in 

 order that the place which the body leaves may be filled up 

 again by the shortest way. We say that this body is the 

 cause of the motions, because by its means we can explain 

 distinctly what happens ; but if we consider what is physical 



