370 NEW ESSAYS 



stance cannot exist without activity [action], and indeed 

 that there never is a body without motion. Experience 

 is already in my favour as regards this, and to be per- 

 suaded of it one has only to refer to the book of the 

 illustrious Mr. Boyle 55 against an absolute rest. But 

 I think that reason also supports it, and this is one of the 

 proofs which I use to overthrow the theory of atoms 56 . 



Besides there are countless indications which lead us 

 to think that there is at every moment an infinity of 

 perceptions within us, but without apperception and 

 without reflexion ; that is to say, changes in the soul 

 itself of which we are not conscious [s'apercevoir], because 

 the impressions are either too small and too numerous 

 or too closely combined [trop unies], so that each is not 

 distinctive enough by itself, but nevertheless in com- 

 bination with others each has its effect and makes itself 

 felt, at least confusedly, in the whole. Thus it is that, 

 through being accustomed to it, we take no notice of the 

 motion of a mill or a waterfall when we have for some 

 tune lived quite near them. Not that this motion does 

 not continually affect our organs, nor that something 

 does not pass into the soul, which responds to it because 

 of the harmony of the soul and the body, but these 

 impressions which are in the soul and in the body, 



55 Robert Boyle (b. Lismore, 1627, d. London, 1691), the famous 

 chemist and physicist, who (almost contemporaneously with 

 Mariotte) discovered the law of the pressure of gases, which is 

 called the Boyle-Mariotte law. He maintained that there is no 

 such thing as absolute rest, in the book here referred to, under the 

 title Of Absolute Rest in Bodies. [Boyle's Works (London, 1744), vol. i. 

 p. 281.] It was also published in Latin in his Opera Varia (Geneva, 

 1680). Leibniz had some intercourse with Boyle during his stay 

 in London in 1673. See Introduction, Part i. p. 7. 



5(5 As rest is infinitely small motion, everything moves. Conse- 

 quently the essence of body cannot be absolutely unmoved 

 extension, but must be force, which is the source of motion. But 

 a force is a real unity, absolutely indivisible, while the atom is only 

 physically indivisible, it being ideally divisible. Hence physical 

 atoms are not the elements of things. Cf. New System, u. 



