i68 ANTIENT METAPHYSICS. Book IIT. 



in?de thefe univerfal ideas, upon which he has written his book of 

 Categories, the foundation of his whole fyftem of Logic, yet he has 

 not told us what the nature of an idea is, nor how it is formed; nei- 

 ther has Porphyry, in the Introdudion which he has written to 

 Ariftoile's Logic, faid a word upon the fubje£t. I will therefore en- 

 deavour to fupply this defe<ft, which I think there is in Ariflotle's 

 philofophy, the beft way I can : And I hope to be able to give a 

 better account of ideas than is to be found in any modern book, at 

 leaft better than what Mr Locke has given of them. 



I muft begin with a di.^indlon of them, which Mr Locke has not 

 made, but which, I think, is abfolutely necefTary to be made, in or- 

 der to account for the origin of them, into Particular and General ; 

 of which the particular muft, in the order of nature, be firft ; for it 

 is impoflible to conceive general ideas without particular, of which 

 they are compofed.. 



As our fenfes, in this ftate of our exiftence, are the firft inlets to 

 our knowledge, our firft ideas muft neceffarily be of particular ob- 

 jects of fenfe, of v/hich we perceive by our fenfes feveral different 

 qualities. But thefe we muft not take altogether and in a lump, as 

 the brute does, but we muft feparate a quality, one or more, which is 

 predominant in the object and peculiar to it, from other qualities that 

 are accidental and common to it with other objedts ; and of thefe 

 qualities we form the Idea of the thing. Of this I have given an 

 example in the cafe of a Horje * ; in which the reader will obferve, 

 that if we did not feparate thofe diftinguijfhing qualities, which I 

 have mentioned, from that of colour^ of having four feet^ and from 

 other qualities that a Horfe may have in common with other animals, 

 we ftiould not have any idea of a Horfe, And this may be illuftrat- 

 ed by the ideas we form of the Figures of geometry. Of thefe 



figures 



* P?.gc 1 6. of vol. 4- of this work.. 



