400 ANTIENT METAPHYSICS. Book V. 



rightly inferred, then there is a defe^ft in the form of the fyllogifm ; 

 and it is what Ariftoile calls unJyllogifiicaL 



But, what is this form of the fyllogifm, of fuch univerfal ufe, and 

 the touch-ftone, as it fccms, of all kind of reafoning I This queftioa 

 is anfwered by ArirtoMc> in his Fir/i Analytics, which are fo called, be- 

 caufe they analyfe human reafon into its elemental parts, fhowi ng, at 

 the fame time, how thofe parts are to he put up again, as it were, and 

 combined, fo as to produce certain conclufions ; the work therefore is 

 fynthetical as well as analytical though it be denominated from that 

 part of it which muft neceflarily precede the other, and may, liiere- 

 fore, be confidered as principal. The book of Categories, and that of 

 Interpretation, the one treating of fimple terms, the other of the com- 

 pofition of thcfe into propofitions, are only preliminaries to this 7nag- 

 nwn opus ; yet are they, confidered by themfelves, works of great 

 fcience, and particularly the laft, which contains fpeculat'ons c^xceed- 

 ingly fubtile and intricate. And the whole, taken together., is lo won- 

 derful a fyftem of fcience, that, if Arifl:otle be trulv the author of it, 

 it is the greatefl difcovery in fcience that ever was made by a fingle 

 man, fince the beginning of the world. But 1 have fome reafons, 

 which I fliall give in a more proper place, for thinking that Ariftotle 

 took the dodirine of the fyllogifm from the Pythagorean School, as 

 well as the dodrine of Categories *. 



But, though the fyllogifm be perfect as to its form, the conclufion 

 may not be true ; for, if either of the premises be falfe, probable, or 

 doubtful, the conclufion will be of the fame kind ; whereas, if the 

 premifles be neceflarily true, the conclufion will likewife be fo. And 



this 



* See, upon t>iis fubjea, the laft book of this volume, where I give an account of 

 Ariftolle's philofophy, and where there is a great deal more faid concerning the fyllo- 

 gyfm. 



