on this account we not only supposed what was said to be the object of this treatise, viz. to be able to assume an argument, but also that sustaining the argument, we may defend the thesis in a similar manner, through the greatest probabilities. We have besides, assigned the cause of this; since, for this reason also, Socrates questioned, but did not answer, for he confessed that he knew nothing.2 Moreover, it has been

*Problems.

+ Of assumptions.

shown in the preceding treatise, with reference to how many,* and from what number † this will be, and whence we shall be well supplied with these; further, how interrogations must be made, and how every one must be arranged, and likewise, concerning the answers and solutions of things appertaining to syllogisms. Such other particulars besides, have been developed as belong to the same method of arguments, and in addition to these, we have discussed paralogisms, as we stated before, wherefore, it is evident that what we proposed has sufficiently obtained its end. Still we ought not to be ignorant of that which occurs in this treatise; for of all discoveries, some being received formerly from others,3 elaborated partially afterwards, have been increased by those who received them; but others being discovered from the beginning, are wont to receive, at first, but small increase, becoming much more useful by the increase which they receive from others afterwards. For the beginning of every thing is perhaps, as it is said, the greatest thing, and on this account the most difficult; for that is the hardest to be perceived, which, as it is the most powerful in faculty, is by so much the smallest in size; yet when this is discovered, it is more easy to add and co-increase what re

1 He here appears to refer to what is stated in the first chapter of this treatise.

2 He who interrogates is presumed to do so for the sake of instruction, but Socrates' method (which was characterized by much of the tentative system) he resorted to, not only because he confessed his own ignorance, notwithstanding the testimony of the oracle to his being the wisest of men, (Plat. Apol., p. 21,) but because he had a mean opinion of the knowledge of the sophists, who, like written books, could discourse freely, yet if examined by questions, were unable to reply (vide Protagoras, p. 329).

Taylor and Buhle have translated this erroneously, notwithstanding the remark of Alexander, (Schol. 321, a. 14,) that the word pórepov is to be joined to ληφθέντα,

*

* 1aylor and

tical.

+ Of rhetoric.

Dialectic. 3. Peculiarity of this subject, in that, unlike received no

others, it has

mains, which also occurs in rhetorical arguments, and in almost all the other arts. For they Buhle, poliwho discovered principles, altogether made but little progress; but men who are now celebrated, receiving, as it were, by succession from many who promoted (art) by parts, have thus increased it; Tisias after the first (authors), but Thrasymachus after Tisias, Theodorus after him, and many (others) have brought together many particulars, wherefore it is no wonder that the art† has a certain multitude (of precepts).1 Of this subject, however, there has not been a part cultivated, and a part not before, but nothing of it has existed at all, for of those who employed themselves about contentious arguments for gain, there was a certain instruction, similar to the treatise of Gorgias. For some gave rhetorical, others interrogative discourses to learn, into which each thought their conversation with each other would most often fall. Hence the instruction indeed to their disciples was rapid, but without art, since they supposed they should instruct them by delivering not art, but the effects of art, just as if a person professing to deliver the science of keeping feet from injury, should afterwards not teach shoemaking, nor whence such things (as safe-guards for the feet) may be procured, but should exhibit many kinds of shoes of every form; for he would indeed afford assistance

previous eluci dation.

shoes.

the judgment.

as to use, yet not discover the art. § And indeed, § of making about rhetoric, many old discourses are extant, but about the art of syllogism we have received nothing at all from the ancients, but we have laboured for a long time by the exercise of investigation. If 4. Appeal to then, it appear to you, when you have inspected (our writings), that this method derived from such materials as existed originally, when compared with other treatises which have been increased from tradition, has || || Taylor and been (handled) sufficiently, it remains for you all, Buhle, "not."

1 Knowledge is like a town, he who builds the first walls, seldom sees the completion of the last tower. Concerning Tisias and his successors, vide Spengel, F. D. Gerlach, Hist. Studien, and Winckelmann in Plat. Euthydem. p. 34, seqq.; and upon the progress of ancient and modern knowledge, some admirable remarks may be found in Blair's Lectures on Rhetoric, Lect. 35.

or for those who have heard this work, to excuse the omissions in this method, and to be very grateful for its discoveries.1

Though hardly equal to the dexterous conclusion of the Poetics, wherein the example of the peroration is practically employed for a farewell to the reader, we cannot help drawing attention to the simplicity and candour of the philosopher's present address, at once courting the decision of his readers, yet honestly declaring to them their duty.

THE

INTRODUCTION OF PORPHYRY.

1. Knowledge

of the predica bles requisite to that of the

as preliminary

CHAP. I.-Object of the writer, in the present Introduction. 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 I 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

Aristotelian Categories, and the Platonic

dialectic.

1 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 Prædicab. 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.

2 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.

omit to speak about genera and species, as to whether they subsist (in the nature of things) or in mere conceptions only; whether also if subsistent, they are bodies or incorporeal, and whether they are separate from, or in, sensibles,1 and subsist about these,2 2* for such a treatise is most

* Kant. Sir W. Hamilton, Ed. Review, No. 115, and Reid's works; also Cat. 5, note.

1. Neither genus nor

3

profound, and requires another more extensive investigation. Nevertheless, how the ancients, and especially the Peripatetics, discussed these and the other proposed subjects, in a more logical manner, I will now endeavour to point out to you.

CHAP. II.-Of the Nature of Genus and Species.

species denominated simply;

the former is

either a collec

tion of many

NEITHER genus nor species appear to be simply denominated, for that is called genus which is a collection of certain things, subsisting in a certain respect relatively to one thing, and to each other, according to which signification the genus of the

On the metaphysical part of this question, the opinions of philosophers are as vague as (I may add) they are unprofitable, hence the term "universals," is the best to be employed, as least liable to commit the logician to any metaphysical hypothesis; since the realist may interpret it of "substances," the nominalist of "names," the conceptualist of "notions." Cf. Occam, Log. p. 1, Albertus Magnus, Abelard. The agreement between the first and last, proves that there is no real difference between nominalism and conceptualism, since they were both. Vide also Mansel, Appendix A, where the authorities upon each side will be found quoted.

2 Genus and species, in short all forms, have a triple subsistence, for they are either prior to the many, or in the many, or posterior to the many. Taylor. Philoponus, in his extracts from Ammonius, illustrates this as follows: Let a seal-ring be conceived, having the image of Achilles upon it, from which seal let there be many impressions taken in pieces of wax, afterwards let a man perceiving the pieces of wax to have all the impression of one seal, retain such impression in his mind: then the seal in the ring is said to be prior to the many; the impression in the wax to be in the many, and the image remaining in the conception of the spectator, after the many, and of posterior origin. This he applies to genus and species.

3 Viz. metaphysics; it is, in fact, psychological. Cf. Leibnitz Meditat. de Cognit. Ver. opera. ed Erdmann. and Mansel's Prolegomena Logica.

With this chapter compare ch. 5, of the Categories, and Top. i. 5 and 8, whence the discrepancies between the account of the predicables given by Arist. and this by Porphyry will appear, upon which see Mansel's comment. Log. App. A, p. 9. Cf. also Albertus Mag. de Predicab. Trac. 11, cap. 1, Metap. iv. 28,