468 ANTIENT METAPHYSICS. Book V. 



Let me further fuppofe, that this artift executes many works, fome 

 of the fame kind, fame of a different kind ; cannot I form a notion, 

 not only of each particular work by itfelf, but of what they have 

 in common, Hkewife of that in which they differ, and alfo of their 

 feveral quaHties and properties ? 



Now, to apply this to the fovereign artifl:, the author of this uni- 

 verfe, and of all the wonderful things in it ;. — or, let me fuppofe that 

 there is no artift in the cafe, no plan, no defign, no previous idea of 

 the work that was to be executed, but all the effe6t of chance or ma- 

 terial neceffity; ftill I can find out the frame or conftitution of the feveral 

 produdions of nature ; I can likewife difcover what they have in com- 

 mon, and alfo wherein they differ from one another. Further, I can 

 rccognife in them certain qualities which 2ire peculiar to fome of them,, 

 and never are feparated from them ; ethers, again, which are accident 

 taU and may be in them, or not, jufl as it happens. And thus we 

 have all thofe five clalTes of ideas, of which Porphyry treats ^, viz. ge- 

 nus, fpecies, difference, peculiar, and accidental. 



The only doubt, therefore, that can pofTibly be, with refped to the 

 cxiflence of ideas in our mind, is, whether or not we have in fad the 

 power of thus abflrading and generalizing ? or, in other words, whe- 

 ther we have the faculty of intelk^, or only the faculties of fenfe and 

 imagination ? for thofe who deny that we have ideas muft neceffarily 

 maintain that we have no more intelled than the brutes, and only, like 

 them, fenfes, imagination, and memory. Now, that we have the fa- 

 culty of abflrading and generalizing, is a fad that, I think, I have 

 made evident, by what I have faid above t> where I have fhown, that 

 even our children pofTefs this faculty, when they can operate upon 

 that mof\ abftrad idea of number^ without applying it to any parti- 

 cular thing. At the fame time, 1 do not deny that it is very difficult 

 in many cafes, and a great work of fcience, to form a perfed idea of 



a 



* Porphyry's Introdu£lion to Ariftode's Categories, 

 t beep. 324. 



