369 



I will touch only on two subjects, which we commonly 

 think are, and which surely ought to be, most thoroughly 

 understood: I menu, the ivature of the body in genera!,, 

 and the nature of sensation. As to the first, since we 

 turn ourselves no way, but we are invironed by co.rporeal 

 substances one would think un object that so many ways 

 affects our senses, should be perfectly known to us. And 

 yet the notion of the body in general, or what it is that 

 discriminates bodies from other substances, is not by any 

 means agreed even among the modern philosophers. And 

 Indeed, no account of it, which has yet been given, wilt 

 extricate us out of the difficulties of that no less per- 

 plexed than famous dispute, " Of the Composition of 

 Bodies." But the difficulties attending this, will, till 

 they are removed, spread a thick niffht over I lie notion 

 of bodies in general. For either a corporeal substance 

 is divisible into extended parts, and each of these divisi- 

 ble into other parts smaller and smaller, ad infinitnm, or 

 this division must stop somewhere. But there are in- 

 conveniences, not to say absurdities urged against either 

 of these suppositions. The objections on both sides are 

 so strong that the most sensible and candid men, after 

 having 'tired themselves and their readers with striving 

 to solve them, have at length owned them to be inso- 

 luble. 



" But though we do not understand the nature of 

 bodies in general, must we not perfectly understand what 

 passes within ourselves, in reference to the particular 

 bodies we daily see, and hear, and smell, and taste, and 

 touch? These we know by our senses: but how little 

 do we know of the manner wherein our senses inform 

 us of any thing 7 Sensation we allow is not performed 

 by the organ, but by the mind perceiving the motion 

 produced in the organ. Ask then a philosopher how 

 the soul comes to be wrought on, and that in such vari- 

 ous manners, by those external bodies, which are the ob- 

 jects of our senses? He will tell you, that by the im- 

 pression on the organs, they variously move the nervous 

 fibres, wherewith those parts are endowed, by which the 

 oiotiwa is propagated to the brain : where these motions 



