so ANTIENT METAPHYSICS. Book II. 



idea was, though he has written a whole book upon the fubjed ; and 

 has given us a fydeni of the philofophy of mind, without making the 

 diftindion, which is the foundation of that whole philofophy, betwixt 

 the mind operating by itfelf, and operating by the afliflance of the 

 fenfes: And, becaufe the mind muft of neceflity at firft operate by the 

 means of the fenfes only, he has from thence raihly concluded, that it 

 can never operate in any other way *. 



But, whether Mr Locke had any idea of fubflance, or not, it is evi- 

 dent, that there muft be fomething in which the feveral qualities of 

 fubftance are inherent ; for we can very well conceive, abftraded from 

 any fubftances, fuch qualities as hoty colJ, jnoijl^ dry^ hitter^ fiveet^ 

 rounds Square^ and the like, and dill there will remain fomething, 

 which we call xki^fith fiance of the thing, that is, xh^fubfiratiim for all 

 thefe qualities. Now, it is only carrying abftradion further, and fepa- 

 rating from this fubftance even extenfion and figure of every kind, 

 and then we have remaining this matter of the antient philofophers. 



I will give another illuftration from mathematics, which, perhaps, 

 will be better underftood, as all our natural philofophers profefs to be 

 mathematicians, and fome of them are really learned in that fcience. No 

 man, who is not a profefTed fceptic, and does not fet himfelf up, out of 

 wantonnefs or vain oftentation of fuperior parts, to difpute the clcareft 

 truths, will deny that we have clear ideas of the fubjeift of geometry ; for, 

 otherwife, there could be no certainty in that fcience. Now, the fubjeds 

 of geometry are the boundaries of bodies, viz. points^ lines^ Surfaces^ 

 ?ind folids : For a point is the termination of a liney a line is the boun- 

 dary of 2i fur/ace, and ajurjace of a /olid. Therefore, a /olid is defi- 

 ned to be that which has three dimenfions, viz. lengthy breadth^ and 

 depth ; dijiirface what has two, viz. length and breadth] a line Vv^hat 



has 



• See TV'bat I have further faid on this fubjccfl in the Origin and Progrefs of Lan- 

 guage, vol. I. book I. chap. 4. in the beginning. 



