No one common characteristic pervading all Plato’s works.
It is in truth scarcely possible to resolve all the diverse manifestations of the Platonic mind into one higher unity; or to predicate, about Plato as an intellectual person, anything which shall be applicable at once to the Protagoras, Gorgias, Parmenidês, Phædrus, Symposion, Philêbus, Phædon, Republic, Timæus, and Leges. Plato was sceptic, dogmatist, religious mystic and inquisitor, mathematician, philosopher, poet (erotic as well as satirical), rhetor, artist — all in one:[4] or at least, all in succession, throughout the fifty years of his philosophical life. At one time his exuberant dialectical impulse claims satisfaction, manifesting itself in a string of ingenious doubts and unsolved contradictions: at another time, he is full of theological antipathy against those who libel Helios and Selênê, or who deny the universal providence of the Gods: here, we have unqualified confessions of ignorance, and protestations against the false persuasion of knowledge, as alike widespread and deplorable — there, we find a description of the process of building up the Kosmos from the beginning, as if the author had been privy to the inmost purposes of the Demiurgus. In one dialogue the erotic fever is in the ascendant, distributed between beautiful youths and philosophical concepts, and confounded with a religious inspiration and furor which supersedes and transcends human sobriety (Phædrus): in another, all vehement impulses of the soul are stigmatised and repudiated, no honourable scope being left for anything but the calm and passionless Nous (Philêbus, Phædon). Satire is exchanged for dithyramb, and mythe, and one ethical point of view for another (Protagoras, Gorgias). The all-sufficient dramatising power of the master gives full effect to each of these multifarious tendencies. On the whole — to use a comparison of Plato himself[5] — the Platonic sum total somewhat resembles those fanciful combinations of animals imagined in the Hellenic mythology — an aggregate of distinct and disparate individualities, which look like one because they are packed in the same external wrapper.
[4] Dikæarchus affirmed that Plato was a compound of Sokrates with Pythagoras. Plutarch calls him also a compound of Sokrates with Lykurgus. (Plutarch, Symposiac. viii. 2, p. 718 B.)
Nemesius the Platonist (Eusebius, Præp. Evang. xiv. 5-7-8) repeats the saying of Dikæarchus, and describes Plato as midway between Pythagoras and Sokrates; μεσεύων Πυθαγόρου καὶ Σωκράτους. No three persons could be more disparate than Lykurgus, Pythagoras, and Sokrates. But there are besides various other attributes of Plato, which are not included under either of the heads of this tripartite character.
The Stoic philosopher Sphærus composed a work in three books — Περὶ Λυκούργου καὶ Σωκράτους — (Diog. La. vii. 178). He probably compared therein the Platonic Republic with the Spartan constitution and discipline.
[5] Plato, Republ. ix. 588 C. Οἷαι μυθολογοῦνται παλαιαὶ γενέσθαι φύσεις, ἥ τε Χιμαίρας καὶ ἡ Σκύλλης καὶ Κερβέρου, καὶ ἄλλαι τινὲς συχναὶ λέγονται ξυμπεφυκυῖαι ἰδέαι πολλαὶ εἰς ἓν γενέσθαι … Περίπλασον δὴ αὐτοῖς ἔξωθεν ἑνὸς εἰκόνα, τὴν τοῦ ἀνθρώπου, ὥστε τῷ μὴ δυναμένῳ τὰ ἐντὸς ὁρᾷν, ἀλλὰ τὸ ἔξω μόνον ἔλυτρον ὁρῶντι, ἓν ζῶον φαίνεσθαι — ἄνθρωπον.
The real Plato was not merely a writer of dialogues, but also lecturer and president of a school. In this last important function he is scarcely at all known to us. Notes of his lectures taken by Aristotle.
Furthermore, if we intend to affirm anything about Plato as a whole, there is another fact which ought to be taken into account.[6] We know him only from his dialogues, and from a few scraps of information. But Plato was not merely a composer of dialogues. He was lecturer, and chief of a school, besides. The presidency of that school, commencing about 386 B.C., and continued by him with great celebrity for the last half (nearly forty years) of his life, was his most important function. Among his contemporaries he must have exercised greater influence through his school than through his writings.[7] Yet in this character of school-teacher and lecturer, he is almost unknown to us: for the few incidental allusions which have descended to us, through the Aristotelian commentators, only raise curiosity without satisfying it. The little information which we possess respecting Plato’s lectures, relates altogether to those which he delivered upon the Ipsum Bonum or Summum Bonum at some time after Aristotle became his pupil — that is, during the last eighteen years of Plato’s life. Aristotle and other hearers took notes of these lectures: Aristotle even composed an express work now lost (De Bono or De Philosophiâ), reporting with comments of his own these oral doctrines of Plato, together with the analogous doctrines of the Pythagoreans. We learn that Plato gave continuous lectures, dealing with the highest and most transcendental concepts (with the constituent elements or factors of the Platonic Ideas or Ideal Numbers: the first of these factors being The One — the second, The Indeterminate Dyad, or The Great and Little, the essentially indefinite), and that they were mystic and enigmatical, difficult to understand.[8]
[6] Trendelenburg not only adopts Schleiermacher’s theory of a preconceived and systematic purpose connecting together all Plato’s dialogues, but even extends this purpose to Plato’s oral lectures: “Id pro certo habendum est. sicut prioribus dialogis quasi præeparat (Plato) posteriores, posterioribus evolvit priores — ita et in scholis continuasse dialogos; quæ reliquerit, absolvisse; atque omnibus ad summa principia perductis, intima quasi semina aperuisse”. (Trendelenburg, De Ideis et Numeris Platonis, p. 6.)
This opinion is surely not borne out — it seems even contradicted — by all the information which we possess (very scanty indeed) about the Platonic lectures. Plato delivered therein his Pythagorean doctrines, merging his Ideas in the Pythagorean numerical symbols: and Aristotle, far from considering this as a systematic and intended evolution of doctrine at first imperfectly unfolded, treats it as an additional perversion and confusion, introduced into a doctrine originally erroneous. In regard to the transition of Plato from the doctrine of Ideas to that of Ideal Numbers, see Aristotel. Metaphys. M. 1078, b. 9, 1080, a. 12 (with the commentary of Bonitz, pp. 539-541), A. 987, b. 20.