Chap. IX. ANTIENT M ETAP^HY SICS. 453 



And this fyftem, I think, has the merit of being as fimple as the na- 

 ture of things will permit ; for it fuppofes only two things in Na- 

 ture, that which ads, and that which is aded upon ; and it is not 

 only fimple in itfelf, hut, as I have endeavoured to fhow, fimplifies 

 exceedingly the Aftronomy of Sir Ifaac, hy difincumhering it of 

 Axioms and Poftulates, which cannot be admitted, or, if they could 

 are entirely unneceflary for the purpofe of Aftronomy. That the 

 Laws of the Planetary Motion, upon this hypothefis, would be fuch 

 as Sir Ifaac has demonftrated them to he, and that all the Phaeno- 

 mena vfould correfpond with thefc Laws, I think it is impoffible to 

 deny; and, if fo, every Newtonian muft admit that it is a very- 

 great improvement, if not of the Syftem, at leaft of the Manner of 

 teaching it. 



This fecond Hypothefis, however, will admit of fome variety; 

 for there are, who, unwilling to part with Sir Ifaac's Firfl: Law of 

 Motion, and being refolved, in fome way or another, to make a 

 Machine of the Heavens, are difpofed to think that the Planet may 

 have been at firft fet in Motion by Mind ; but that it aftervv'ards 

 goes on for ever, without the agency of either Body or Mind ; 

 whereas I maintain that it cannot go on without the unceafing ener- 

 gy of Mind. And there is another difference of opinion upon this 

 Hypothefis : For I maintain that the Planetary Motion by Mind is 

 perfectly fimple ; whereas thofe, who believe that there can be 

 no Motion, even by Mind, but in a Straight Line, muft employ 

 another Mind to urge the Body towards the Centre : And thus the 

 Planetary Motion, according to them, though produced by Mind 

 onlv, is compounded. 



This is all the variety, which, I think, the fecond Hypotliefis ad- 

 mits of But the third, which makes Body (by whidi, I mean, 

 Body, other than the Planet itfelf) the only moving Power, admits 

 of much greater; So that, out of it, there grow fevei-al hypothefes, 

 which it requires fome tiine and patience to confider diftindly; 



and 



