Chap. II. ANTIENT METAPHYSICS. 7 



gans of our^enfes : nor do we know that even our ovv-n Mind 

 exifis, c -ccpt by its adtions and energies ; for Des Cartes ar- 

 gued well when he faid, ' / think, therefore I am.'' Neither are 

 thefetwo propofitions identic, as fome believe, but diaerent : And the 

 argument is a fair conclufion from this general topic. That whatever 

 a<3;s, or energizes, exifis. Nov/, if there be actions and operations, 

 there muft of neceflity be fomething that ads or operates ; and this 

 fomething is what I call Suhjlance. This is the definition of Sub- 

 fiance in general ; but, as to particular Subftances, they can only be 

 known by their particular operations, and qualities, of one kind or 

 another. 



In this way Mind and Body are to be defined ; and, as Mind and 

 Body compofe the whole of things, and are fo conneded and related 

 to one another, that, without them, the material world could not ex- 

 ift, I have chofen to give a definition of them, or defcription, as the 

 mathematician and accurate logician would rather choofe to call it, 

 by v hich I have expreffed that neceflary connexion and relation ; 

 for I fay that Mind is that which moves. Body that which is moved, 

 it being abfolutely neceflary, that, when a thing is moved, there fhould 

 be fomething that moves it ; or, vice verfa, that, when a thing moves,. 

 there fhould be fomething that is moved. This definition has ano- 

 ther advantage, that it is taken from a quality of each of the two 

 n things, as evident as any thing can be to us in this ftate of our ex- 

 iflence ; the evidence of them being immediately derived from the 

 two fources of all human knowledge, viz. the perceptions of fenfe 

 and confcioufnefs : For, that Body is moved, is a perception of fenfe ; 

 and, that there is fomething within us which moves our bodies, we 

 know from confcioufnefs. Now, that principle of motion ib what I 

 call Mind. 



When 1 fay that Mind moves, and Body is moved, I would not 

 be underflood to mean that Mind always moves, or that Body is al- 



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