326 ANTIENT METAPHYSICS. Book III. 



as having no permanent exlftence, nor ex'iflence properly fo called, but 

 fomething which he expreffes by a word that, like many other terms 

 of the Greek philofophy, cannot be rendered into Englifli, without 

 much circumlocution *. Such things, therefore, being perpetually 

 changing, cannot be objedts of fcience, or of eternal truth, of which 

 the objeds muft, like itfelf, be eternal. Whereas, fliould we attempt 

 to demonftrate any property of a material thing, it would not continue 

 the fame thing till the demonftration was ended. Therefore, fays A- 

 riftotle, there is no definition, demonftration, or fcience, of particular 

 or individual things. And, I will venture to fay, that no man, who is 

 a man of fcience of any kind, or who knows what fcience or demon- 

 ftration is, will maintain the contrary ; for, what is the objedt, ac- 

 cording to thofe material philofophers, of the geometrical fcience of a 

 triangle, for example ? it is an indetermined number of particular tri- 

 angles, perceived by the fenfe, with a number of indetermined qua- 

 lities, fuch as being black or white, equilateral, ifofceles, fcalenum, right- 

 angled, obtufe-angled, &c. Now, will any man, who is a geometer, 



faj, 



• The word is yinvi^ \ and every material being, he fays, is i> yuts-ei, or, as he o« 



thervvife expreffes it, ovk ts-rt, tt>^xa ymroa ; the meaning of which is, that fuch things 

 are never in any fixed or permanent flate, but are perpetually changing from one ftatc 

 to another, and becoming what they were not before. To fuch things he oppofes the 

 T« ei-Tflt, a word which occurs in almoft every page of Plato, by which he means no- 

 thing cife than the ideas of things which are permanent and immutable, while the 

 (f/^'/w^j themfclves are conflantly changing •, and therefore he fays they are, yiyv»ii.i,x, 



•ircc Ss ovS'sTTOTf ; whereas ideas are the r«. «vt«, and the ru atet y.ui'a)<rxvroiiy x«< x«t« reivrx. 



t)^»*Tci, And, in the Timaeus^ he divides all things into thefe two claffes. His 



words are, 'Eo-rt^ ovf o/j xxt' tf^n* ool»y ?rg«iiT»v 0(Ui^iTiov Tet of rt to »f ^i¥ ctni^ yii%vt¥ Si ovk 

 iX,*''- >'-"■' 1"' Ta yiyia^i^tf «6», «y 6i c<rv(it7rcTt. to j^i* oij vtric-ii f^trx Xtyov 7ri^i>.yt7rriiif ectH KXTe6 

 'Tu-jrx e>. T« S' XV ^e|« ^tir' uis-^niritjg xXoyov, 6»|<te-Ts», yiyiof^mi kxi XTioX'Kvf^.'cVov^ tirt/i J'j tvSiE. 



woij «». Timaeus, pag. 1046. edit. Ficini. It is with this diflin£lion that Plato begins 

 his Cofmogony, and Syflem of the Univerfe; and, indeed, it is a diftinftion which ap- 

 pears to me to be the foundation of the whole philofophy of Nature, though it be not 

 made in any modern book of natural philofophy thit I remember to have feen. For 

 in no other way can we conceive any thing in the univerfe to be fixed, ftable^ 

 and permanent ; but, in this way conceived, the univerfe, and every thing in it, is e- 

 ^crnal and unchangeable as its great Author. 



