Plato's episodic use of logical distinctions is frequent. His recourse to such logical analysis as would meet the requirements of the problem in hand2 is not rare. In the “dialectical ” dialogues the question of method and of the justification of its postulates attains at lf~, ast a like prominence with the ostensible subject matter. ThCIf' is even formal recognition of the fact that to advance in diale “fc is a greater thing than to bring any special inquiry to a successful issue? But to the end there is a lack of interest in, and therefore a relative immaturity of, technique as such. In the forcing atmosphere, however, of that age of controversy, seed such as that sown in the master's treatment of the uttered }'yos 4 quickly germinated. Plato's successors in the Academy must have developed a system of grammaticological categories which Aristotle could make his own. Else much of his criticism of Platonic doctrine5 does, indeed, miss fire. The gulf too, which the Philebuss apparently left unbridged between the sensuous apprehension of particulars and the knowledge of universals of even minimum generality led with Speusippus to a formula of knowledge in perception (é1ncr1"r7}LOVLK'tj a.'icr01;¢ns). These and like developments, which are to be divined from references in the Aristotelian writings, jejune, and, for the most part, of probable interpretation only, complete the material which Aristotle could utilize when he seceded from the Platonic school and embarked upon his own course of logical inquiry.

This is embodied in the group of treatises later known as the Orgononl and culminates in the theory of' syllogism and of syuogism demonstrative knowledge in the Analytics. All else is finally subsidiary. In the well-known sentences with which the Organon closes” Aristotle has been supposed to lay claim to the discovery of the principle of syllogism. He at least claims to have been the first to dissect the procedure of the debate-game, and the larger claim may be and Aristotle who was inferior as a meta physician to neither. No other dialogue adds anything to the logical content of these. Granted their genuineness, the relative dating of three of them is iven, viz. Theaetetus, Sophistes and Politicus in the order named. The Philebus seems to presuppose Politicus, 283-284, but if this be an error, it will affect the logical theory not at all. There remains the Pafmenides. It can scarcely be later than the Sophistes. The antinomies with which it concludes are more naturally taken as a prelude to the discussion of the Sophistes than as an unnecessary re treatment of the doctrine of the one and the many in a more negative form. It may well be earlier than the Theactetus in its resent form. The stylistic ar ument shows the T/zeaetetus rclhtively early. The maturity 0? its philosophic outlook tends to give it a place relatively advanced in the Platonic canon. To meet the problem here raised, the theory has been devised of an earlier and a later version. The first may have linked on to the series of Plato's dialogues of search, and to put the Parmenides before it is impossible. The second, though it might still have preceded the Parmenides might equally well have followed the negative criticism of that dialogue, as the beginning of reconstruction. For Plato's logic this question only has interest on account of the introduction of an 'Apurav-é)s in a non-speaking part in the Parmenidcs. If this be pressed as suggesting that the philosopher Aristotle was already in full activity at the date of writing, it is of importance to know what Platonic dialogues were later than the début of his critical pupil.

On the stylistic argument as applied to Platonic controversies ]anell's Quaestiones Platonicae (1901) is important. On the whole question of genuineness and dates of the dialogues, li. Raedcr, Pla/ons philosophische Entwickelung (1905), gives an excellent conspectus ot the views held and the grounds alleged. See also PL ro.

Eg. that of essence and accident, Republic, 454. 2 Eg. the discussion of correlation, ib. 437 sqq. 1 Politicus, 28511. 4 Sophistes, 2611: sqq.

E.g. in Nic. Eth. i. 6. 5 Philebus, 16d.

7 Principal edition still that of Waitz, with Latin commentary, (2 vols., 1844-1846). Among the innumerable writers who have thrown light upon Aristotle's logical doctrine, St Hilaire, Trendelenburg, Ueberweg, Hamilton, Mansel, G. Grote may be named. There are, however, others of equal distinction. Reference to Prantl, op. cit., is indispensable. Zeller, Die Philosophie der Griechen, ii. 2, “ Aristoteles " (3rd ed., 1879), pp. 185'257 (there is an Eng. trans), and Maier, Die Syllo istik des Aristotetes (2 vols., 1896, 1900) (some 900 pp.), are also of first-rate importance.

5 Sophist. Elench. 184, espec. b 1-3, but see Maier, loc. cit. i. I. thought to follow. In the course of inquiry into the formal consequences from probable premises, the principle of mediation or linking was so laid bare that the advance to the analytic determination of the species and varieties of syllogism was natural. Once embarked upon such an analysis, where valid process from assured principles gave truth, Aristotle could find little difnculty in determining the formula of demonstrative knowledge or science. It must be grounded in principles of assured certainty and must demonstrate its conclusions with the use of such middle or linking terms only as it is possible to equate with the real ground or cause in the object of knowledge. Hence the account of axioms and of definitions, both of substances and of derivative attributes. Hence the importance of determining how first principles are established. It is, then, a fair working hypothesis as to the structure of the Organon to place the Topics, which deal with dialectical reasoning, before the Analytics? Of the remaining treatises nothing of fundamental import depends on their order. One, however, the Categories, may be regarded with an ancient commentator, ” as preliminary to the dialectical inquiry in the T opics. The other, on thought as expressed in language (Hepl ép, u1j1/eias) is possibly spurious, though in any case a compilation of the Aristotelian school. If genuine, its naive theory that thought copies things and other features of its contents would tend to place it among the earliest works of the philosopher.

Production in the form of a series of relatively self-contained treatises accounts for the absence of a name and general definition of their common field of inquiry. A more important lack which results is that of any clear intimation as xzézffl to the relation in which Aristotle supposed it to stand to other disciplines. In his definite classification of the sciences, ” into First Philosophy, Mathematics and Physics, it has no place. Its axioms, such as the law of contradiction, belong to first philosophy, but the doctrine as a whole falls neither under this head nor yet, though the thought has been entertained, under that of mathematics, since logic orders mathematical reasoning as well as all other. The speculative sciences, indeed, are classified according to their relation to form, pure, abstract or concrete, i.e. according to their objects. The logical inquiry seems to be conceived as dealing with the thought of which the objects are objects. It is to be regarded as a propaedeuticfz which, although it is in contact with reality in and through the metaphysical import of the axioms, or again in the fact that the categories, though primarily taken as forms of predication, must also be regarded as kinds of being, is not directly concerned with object-reality, but with the determination for the thinking subject of what constitutes the knowledge correlative to being. Logic, therefore, is not classed as one, still less as a branch of one, among the 'ologies, ontology not excepted. The way in which logical doctrine is developed in the Aristotelian treatises fits in with this view. Doubtless what we have is in the main a refiex of the heuristic character of Aristotle's own work as pioneer. But it at least satisfies the requirement that the inquiry shall carry the plain man along with it. Actual modes of expression are shown to embody distinctions which average intelligence can easily recognize and will readily acknowledge, though they may tend by progressive rectification fundamentally to modify the assumption natural to the level of thought from which he begins. Thus we start 13 from the point of view of a world of separate persons and things, in which thought mirrors these concrete realities, taken as ultimate subjects of predicates. It is a world of communication of thought, where persons as thinkers need to utter in language truths objectively valid for the mundus communis. In these truths predicates are accepted or rejected by subjects, and therefore depend on the reflection of fact in }'yoL (propositions). These are combinatory of parts, attaching or detaching predicates, and so involving 9 References such as 1812 12 are the result of subsequent editing and prove nothing. See, however, ARISTOTLE.

O Adrastus is said to have called them 1rpé fav rmmréiv. 1* Metaphys. E. I.

Z De Part. Animal. A. 1, 639a 1 sqq.; cf. Metaphys. 1005b 2 sqq.

13 De I nterpretatione 16a sqq.