47^ A N T I E N T METAPHYSICS. Book V. 



two, would be a work of time and difficulty, and would carry hirn too- 

 far from the fubjecl on hand. I wifh, however, that, if not there, in 

 fome other place, he had exphiined this matter. But this he has not 

 done, as far as I know. Neither has Ariftotle done it in hi& Logic, 

 where he has talked fo much of one term of a propofition' being a part 

 of another, and has made it, as 1 have fhown, the toundation of hia 

 whole fyfteni. 1 can aifign no other reafon for this omiffion, ex- 

 cept the fame which I affign for his giving no account, in his E- 

 thics, of the//zV and the handfome^ which> however, he has made 

 the principle of all virtuous adions, namely, that fuch inquiries be- 

 long to the firft philofophy, not to particular fciences, fuch as logic or 

 morals, which, like other fubordmate fciences, alTume their principles, 

 and refer you to \htjitjl fcience, or Icienee of fciences, for the demon- 

 ftration and explanation of them. But, neither in his Metaphyfics 

 have I found any folution of this difficulty concerning the principle 

 of his Logic ; nor have any of his commentators, as far as I know, 

 fupplied this defe£L We muft, therefore, try what we can do, without 

 their affiftance, to folve it. 



In ihefrjl place, it Is impoffible, by the nature of things, that the 

 genus (hould contain the fpecies as a part of it, and the fpecies fhould 

 likewife contain the genus, in the fame refped. But, in different re* 

 fpeds, it is poffible that each of them may contain the other, and be 

 contained by it. We muft, therefore, try to diftmguifh the different 

 manners of coiita'ming^ and being contained. And there is a diltinc- 

 tion that runs through the whole of antient philofophy, folving many 

 difficulties that are otherwife infurmountable, and which, 1 hope, will 

 like ife folve this difficulty. The diftin£tion 1 mean is the diitindion 

 betwixt what exifts h;xuti, or potentially only, and that which exiils 

 jngv««, or atlually. In the tirft fenie, every thing exifts in its caufes ; 

 and, in the other ienfe, nothing exifts but what is adually produced* 

 "Now, in this firft fenle, the whole Ipecies exifts in the genus ; for the 



genus 



