Chap, IV. AN TIEN T METAPHYSICS. 341 



lars. Thus, the fpecies, maity cannot exlft without the genus, an'ujial ; 

 but animal may be without man : And this holds univerfally of all 

 genufes and fpeciefes. The fubje6t, therefore, of metaphyfics, is w4iat 

 is principal in nature, and firft, if not In priority of time, in dignity 

 and excellence, and in order likewife, as being the caufes of every 

 thing in the univerfe. Leaving, therefore, particular fubjed:s, and their 

 feveral properties, to particular fciences, this univerfal fcience compares 

 thefe fubjeds together; confiders wherein they differ, and wherein they 

 agree : And that which they have in common, but belongs not, in 

 particular, to any one Icience, is the proper fubjed of metaphyfics. 



In this manner, it confiders the fubjef^s of mathematics above men- 

 tioned, viz. number i the dlmenjions of body y and motion. The two firft 

 are the fubjeds, as I have faid, the one of arithmetic-, the other of geo-- 

 metry ; and it finds this difference betwixt the tVv'o, that the fubjedt of 

 geometry is continuous ; that is, the parts of it are contiguous, touch- 

 ing one another, and having one common boundary ; whereas the 

 parts of the fubjed of arithmetic are, by their nature, disjoined and fe- 

 parated from one another, each Handing by itfelf. Another difference 

 which it difcoverSj is, that the parts of the one have place or pofition, 

 whereas the parts of the other have none * ; and a third is, that the 

 one is dlvifible into an infinite number of parts, whereas the divillon 

 of the other can be carried no farther than the monad, w^hich, by its 

 nature, is one indivifible thing. According to thefe differences, 

 therefore, metaphyfics diflinguifhes the fubjeds of thefe two parti- 

 cular fciences, calling the one 'magnitude "I'j and the other number. 



But 



* Sec thofe two difTerences fully explained by Ariflotlc, in the 6th chapter of his 

 book of Categories. 



t Euclid ufes this word {fttyih',^ or magnitude^) very frequently, but nowhere defines 

 it, referring it, as well as other things, to common fenfe and obfervation ; and this 

 1 think wife in him ; fo'r the definition of it muft neceffarily have carried him beyond 

 the bounds of his fcience, and into metaphyfics. 



