THE
INTRODUCTION OF PORPHYRY.[1]
Chap. I.—Object of the writer, in the present Introduction.
1. Knowledge of the predicables requisite as preliminary to that of the Aristotelian Categories, and the Platonic dialectic.Since it is necessary, Chrysaorius, both to the doctrine of Aristotle's Categories, to know what genus, difference, species, property, and accident are, and also to the assignments of definitions, in short, since the investigation of these is useful for those things which belong to division and demonstration,[2] will endeavour by a summary briefly to discuss to you. as in the form of introduction, what on this subject has been delivered by the ancients, abstaining, indeed, from more profound questions, yet directing attention in a fitting manner, to such as are more simple. For instance, I shall
- ↑ At the request of Chrysaorius, his pupil, who had recently met with the Categories of Aristotle, Porphyry wrote this introduction, in order to his comprehension of that treatise: nearly the whole of it is composed from the writings, and often almost in the very words of Plato. As philosophers reduced all things under ten common natures, as grammarians also, with respect to eight words, so Porphyry has comprehended every significant word, except such as are significant of individuals, under five terms. The five heads of predicables therefore, taken from this Isagoge, which was written in the third century, are an addition to the Aristotelian Logic, in part of which, (the Topics,) the doctrine laid down differs from that enunciated here, in several points, as Porphyry's view also differs from that of Aldrich. Upon the subject generally, the reader may compare Albertus Magnus de Praedieab. Aquinas. Occam Logica. Abelard de. Gen. et Spec, ed Cousin. Trendelenb. Elem. Crakanthorpe's, Whately's, Hill's, and Wallis' Logics, also Boethius de Divisione.
- ↑ Dialectic, according to Plato, consists of four parts, division, definition, demonstration, and analysis ; hence a treatise adapted to the formation of these, will be evidently useful to the dialectic of Plato. The difference between the dialectic of Plato and that of Aristotle, is noticed in the subsequent notes upon the Organon, and the reader will find the subject ably discussed in the introduction to Mansel's Logic; here we need only observe that Aristotle in the Topics, looks to opinion (in his treatment of dialectic), while Plato disregards it, and the former delivers many arguments about one problem, but the latter, the same method about many problems. Cf. Proclus. MSS. commentary on the Parmenides, Philip., Schol. p. 143, ch. 4; Waitz, vol. ii. p. 437.
