300 APPENDIX. Chap. I. 



Body in the way Sir Ifaac fuppofes, but the Motion towards the 

 centre by Mind. 



Here there is this obvious inconfiftency, that the two Powers pro- 

 ducing the Motion are of natures quite different, the one being Bo- 

 dy, and the other Mind ; an inconfiftency which Sir Ifaac has a- 

 voided. And it is a queftion which will naturally be afked by every 

 one, but which, I think, is difficult to be anfwered, If Mind pro- 

 duce the one Motion, why {hould it not alfo produce the other ? 



It is this difficulty, and to reconcile their fyftem, as much as pof- 

 fible, to the philofophy of Mind, that inclines fome of the Newto- 

 nians with whom I have converfed, to adopt the third method of 

 die compofition of Motion, and to afcribe both Motions to Mind. 

 According to this hypothefis, therefore, the Motion muft be pro- 

 duced by two Minds ; for it is abfolutely impoffible that one Mind, 

 or one Power of any kind, (hould at the fame inftant move the Bo- 

 dy both to and from the centre. 



If I {hould allow this opinion to be the truth, I think the Newto- 

 nians, who maintain it, muft admit that they give up Sir Ifaac's firft 

 law of Motion and his vis i?ijita^ by which he accounted for the 

 compofition of the Motion ; and, indeed, upon the fuppofitlon of 

 the Motion being begun diredly in the elliptical line, they muft 

 give up one half of their fyftem, I mean projection ; and, if they 

 will continue ftill to maintain that the Motion is compounded, they 

 muft fay that it is otherwife compounded than of projedion and gra- 

 vitation : And, accordingly, thefe gentlemen fay that the Motion is 

 compounded, by one Mind tending to move the Body in a ftraight 

 line, and by another bending it into a curve. 



That, upon the hypothefis of the Motion being compounded, it is 

 poffible,by the nature of things, that it fhould be fo compounded, I do 

 not deny; but I will endeavour to fhow that the hypothefis of the com- 

 pofition, 



