276 ANTIENT METAPHYSICS. Book I U 



than any mentioned by Arlftotle ; for Arlftotle, when he fpeaks of 

 ocadt caufesy does not fay what they are ; nor does he mean, as I have 

 faid, to conceal his ignorance, but to confefs it ; whereas, Sir Ifaac 

 mentions the caufe particularly, by calling it a moji Juhtile fpirit. 



Now, in i\vQfrJi place, I deny that any fuch fpirit exifls, or that we 

 can even conceive it to exift. And, indeed, I. wonder that a philofo- 

 phy, which profefles to be founded upon the phaenomena of nature, 

 and what falls under fenfe and obfervalion, fhould fuppofe a material 

 thing, which does not, like other matter, only occupy empty fpace, 

 but pervades folid bodies, or (hould fuppofe bodies that could be pe- 

 netrated in that way, that is, bodies without impenetrability or re- 

 fiftence. And, idly. Sir Ifaac has not lliown, nor attempted to fhow> 

 how this fpirit, fuppofing it to exift, could perform the v/onderful ef- 

 fects he afcribes to it, direding the motions of the bodies it pervades 

 regularly and uniformly, and to a certain end and purpofe. If mere 

 matter, however fubtlle, can do this, I fhould defire to know the di- 

 ftindion betwixt matter and rnind. 



Sir Ifaac, in this refped, puts me in mind of an antient philofo* 

 pher, Anaxagoras, who maintained, as Sir Ifaac does, that mind was 

 the caufe of all things ; but, when he came to explain the particular 

 phaenomena of nature, inftead of having recourfe to mind, employed 

 airs and aethers, fubtile fpirits and fluids, and I know not what ; in 

 fhort, any thing rather than mind — a caufe which he admitted to ex- 

 ift in the univerfe — but, rather than employ it, had recourfe to ima- 

 ginary caufes, of the exiftence of which he could give no proof *. 



The 



• It was for this reafon that Socrates, in the Phaedo, fays he was fo much difap- 

 pointed in his hopes of being inftrufted by the philofophy of Anaxagoras : * For,' fays 

 he, * I was told that he made mind or intelle^ the caufe of every thing in the uni- 



' verfe ; 



