THE NEWTONIAN PHILOSOPHY. ^03 



niufl: fieeds be, which does not mention the moving power. This de-r 

 fe6l In his fyflem he has never fupplied with refpedt to the projedile 

 motion. His followers, indeed, fay, that the projedion of the planets 

 is the immediate operation of Deity ; but this Sir Ifaac has nowhere 

 faid ; though, I am perfuaded, he believed that the Deity was medi- 

 ately, or by the intervention of other bodies, the caufe- of the projec- 

 tile motion, as w^ell as of every other motion in the univerfe. And, 

 indeed, as he fays that both the projedile motion and gravitation are 

 produced by an impulfe, or impreired force, as he calls it, in the fame 

 manner as body is moved by body, it is impoffible it could be produ*. 

 ced immediately by Mind, as 1 fhail, in the fequel, demonflrate. I 

 fhall, however, in the prefent argument, fuppoie, with his followers, 

 that the projedile motion is the immediate operation of the Supreme, 

 Mind. But, even upon that fuppofition, it is flill true, that the fyfterrift 

 of the heavens is a machine, according to the definition above given of. 

 a machine, fince it goes on without the conftant and immediate agency, 

 of Mind. As to gravitation, he has, in the Queries fubjoined to his 

 Optics, endeavoured to account for it by a fubtile fluid, which moves 

 the bodies that gravitate towards each other. But this is an occult, 

 cauje^ if ever there was one ; for, in iht Jirji place, there is no evi- 

 dence that any fuch fluid exifts ; Tindi^fecondly^ if it did exiil, he has 

 not fhown how it could produce fuch wonderful effeds *. And, fur- 

 ther, I fay, that it is abfolutely inconceivable how a fluid, with which 

 'he fills the celeftial fpace, (hould be able to impel fuch vaft bodies, 

 and yet, at the fame time, not refift their motions, and fo, by degrees, 

 def^roy the projedile force : For what can impel can refifi, and what 



can- 



*"See what I have faid further upon this fubjed,. page 197. It is only this caufe af- 

 figned to gravitation, which can be called an occult CdUie, in the Newtonian philofo- 

 phy ; for thofe who fpcak 01 gravitation itfeif as an occult caufe, do not appear to me 

 to underftand what they fay ; for gravitation is the motion itfeif, which undoubtedly 

 has an exillence, at leaft, here on earth ; but the queflion is concerning the caufe of. 

 that motion. 



