Chap. XV. ANT IE NT METAPHYSICS. 195 



fore I have called it a proof a pojlerion ; yet It appears to me to be as 

 convincing as the proof a priori contained in the preceding chapter ; 

 for the amount of it is this, That, whatever is moved, muft be moved 

 either by body or mind. It is not moved by body ; therefore It muft 

 be moved bv mind. This is a demonftration of the fame kind with 

 thofe demonftrations of the mathematicians, which prove, that one 

 line, or one figure, is equal to another, by proving, ly?, That it is not 

 greater ; 2^/y, That it is not lefs. The neceff.-.ry confequence of which 

 is, that it is equal. Nor do 1 think, that the demonllration here can 

 be evaded, otherways than by fuppofing, either that body may be 

 moved in fome third way of moving bodies, never heard nor thought 

 of, or, that body may move body oth.rways than by impulfe. Now, if, 

 m order to evade any argument, it be allowed to make^ fuppofitions of 

 things, the exiftence of which is not only not proved, nor probable, 

 but of which 1 deny that any man can have fo much as a conception, 

 I afk, What can be proved in phyfics, or in any thing elfe ? 



The next thing to be confidered, is. Whether this immaterial prin- 

 ciple of motion exifts in body only, or leparated from body, and by 

 itfelf ? a fubjcd of very great importance, both in religion and phi- 

 lofophy ; and which, thererore, very well deierves a chapter by itfelf. 



Bbs CHAP. 



