view, supporting the Alexandrine canon of Thrasyllus, a grammarian of the Augustan age, cited by Diogenes of Laerta. This canon rejected ten dialogues, which Diogenes enumerates; and these have since then been universally treated as spurious. Some of them did not survive: seven are printed at the close of the Tauchnitz edition and by Bekker, along with the 13 Epistles (which Grote, differing from most scholars, accepts as genuine) and the Definitions (őpoi). Thrasyllus distributed the dialogues of Plato into two classes; (1) d. of Investigation (TηTIKO); (2) d. of Exposition (nynтikoi). These he also subdivided (ύφηγητικοί). variously but his subdivisions have little interest. The chronological order of the dialogues, like the genuineness of many, is a much disputed question on some points: strikingly so respecting the date of the Phaedrus, which Schleiermacher, as an essential feature in his system, deems the earliest; while others, as Stallbaum and Steinhart, place it among the latest.

Generally it may be said that the shorter and slighter dialogues, when accepted as genuine, are ascribed to Plato's youth; the Republic, Timaeus and Leges are universally admitted to be the latest: while the Theaetetus, Sophista and Politicus (usually too the Parmenides and Cratylus) are supposed to have been written by Plato during his travels or on his return at all events before his 40th year.

The following arrangement is that of a critic who had evidently given much time and thought, with great zeal, to the elucidation of these questions; I mean K. F. Hermann. He, in common with most

writers on this subject, distributes the works which he accepts into three groups: (1) the earlier, composed partly before the death of Socrates B. C. 399, partly after it, before Plato quitted Megara: (2) those written under the influence of the Megarian dialectic, during or immediately after the years of travel: (3) the later, commencing with the Phaedrus, and going on during the second half of Plato's career, while he was scholarch of the Academy, from 386 (probably) till his

Those to which e is appended are classed by Grote as dialogues of exposition; the rest are of investigation (zetetic) except the two with asterisks, which are of neither kind. Grote accepts seven others which Hermann disallows.

It is satisfactory to gather from these notices that the Theaetetus is admitted on all hands to be a genuine work of Plato. It is almost universally ascribed to his age of manhood, and to a time when (having imbibed before his 27th year the lore and didactic skill of Socrates, having in the subtle discussions of Megara had full opportunity of practising the dialectic method) he had enlarged his learning and experience by intercourse with the mathematicians of Cyrene and the Pythagorean schoolmen of Italy. The dialogues called Sophistes and Politicus are connected with the Theaetetus, and their genuineness is generally admitted, though the Sophistes is disallowed by Ueberweg.

III. A preface to the Theaetetus would be incomplete without some account of antecedent Hellenic philosophy. But in a preface, even to Plato's works, much more to single dialogue, such an account must be brief and eclectic. Some topics must be placed in stronger light, and more fully considered than others. What are these?

(1) In the first place, Socrates is an interlocutor in all Plato's dialogues, excepting 'the Laws': and in most of them (though not in the Sophistes) we find him discussing, more or less, some principle or practice of those who are called Sophists. With Socrates himself therefore, with his method, and with the Sophists and their doctrines, a young student will do well to make acquaintance, before he enters upon any of Plato's writings.

(2) In several of Plato's works (as in the Theaete

tus) appears the contrast between (1) the physical teaching of the Eleatic School (Melissus, Parmenides, Zeno), the forerunner of pantheism, in which the universe is one Being (Ens) at rest, and (2) that of Heracleitus of Ephesus, who taught Becoming in the place of Being, Many rather than One, Motion and Change instead of Rest, ascribing such motion to the flow of a prevailing fiery element (máνта рeî). Distinct again from these were (1) the teaching of Empedocles of Agrigentum, who took the concord of four elements (fire, air, earth, water) as the base of existence; (2) that of the Atomists, Leucippus and Democritus, who ascribed the origin of things to the fortuitous concurrence in space of small indivisible particles (äтoμa); (3) that of Anaxagoras, who assigned the arrangement of his oμoloμépeial to supreme Intelligence (voûs). All these philosophers had been preceded by two other famous schools in the 6th century B.C.: (1) the Ionian (Thales, Anaximander, Anaximenes), who imagined the primary substance of things to be-the first, Water, the second, Indeterminate Matter (Tò aπeipov), the third, Air: (2) the Italic sect of Pythagoras, which lasted long, and formed a powerful order. This school ascribed marvellous organic properties to Number, and believed in the transmigration of souls. All the philosophers above-named, from Thales to Anaxagoras, flourished during the century and a half anterior to the age of Socrates (600-440 B.C.), though their exact dates are uncertain.

Zeller, whose views are welcomed by Professor

Jowett, maintains that all these various schools were engaged in teaching purely physical doctrines; for that even the seeming abstractions, assumed as primal by the Pythagoreans the Eleatics and Anaxagoras (Number, Being, Intellect), were not understood by them as absolutely incorporeal. See Zeller's Presocratic Philosophy (translated by Alleyne); also Preller's Historia Philosophiae (for citation of passages), Schwegler's History of Philosophy (translated by Stirling), and the fuller work of Ueberweg (published by Messrs Hodder and Stoughton).

IV. Socrates is said by Cicero to have called down philosophy from heaven; by which is meant that Socrates was the first to change the direction of philosophical studies in Hellas; to divert them from the universe to man himself, from cosmogony to anthropology. But this credit belongs rather to that school of thinkers with whom Socrates was most at war, to those who are called Sophists: especially to Protagoras the eldest and most influential of their number-the author of the famous dogma 'man is the measure of all things,' in other words, 'what seems to each is to each.' Protagoras was born at Abdera in Thrace, and flourished B.C. 450-430. Gorgias of Leontini was contemporary, but lived to a great age, dying 380. Prodicus of Ceos flourished 435. Others of note were Hippias of Elis, Polus, Thrasymachus, and the brothers Euthydemus and Dionysodorus. They professed to teach all subjects of liberal education; philosophy, rhetoric, language, logical eristic, &c.: and they travelled from city to