[47] See the connecting words between the first and second demonstration, pp. 142 A, 159. Οὐκοῦν ταῦτα μὲν ἤδη ἐῶμεν ὡς φανερά, ἐπισκοπῶμεν δὲ πάλιν, ἓν εἰ ἔστιν, ἆρα καὶ οὐχ οὕτως ἔχει τἄλλα τοῦ ἑνὸς ἢ οὕτω μόνον; Also p. 163 B.
[48] Plato, Parmenid. ad fin. Εἰρήσθω τοίνυν τοῦτό τε καὶ ὅτι, ὡς ἔοικεν, ἓν εἴτ’ ἔστιν εἴτε μὴ ἔστιν, αὐτό τε καὶ τἄλλα καὶ πρὸς αὑτὰ καὶ πρὸς ἄλληλα πάντα πάντως ἐστί τε καὶ οὐκ ἐστι καὶ φαίνεταί τε καὶ οὐ φαίνεται.
Different judgments of Platonic critics respecting the Antinomies and the dialogue generally.
The demonstrations or Antinomies in the last half of the Parmenides are characterised by K. F. Hermann and others as a masterpiece of speculative acuteness. Yet if these same demonstrations, constructed with care and labour for the purpose of proving that the same premisses will conduct to double and contradictory conclusions, had come down to us from antiquity under the name either of the Megaric Eukleides, or Protagoras, or Gorgias — many of the Platonic critics would probably have said of them (what is now said of the sceptical treatise remaining to us under the name of Gorgias) that they were poor productions worthy of such Sophists, who are declared to have made a trade of perverting truth. Certainly the conclusions of the demonstrations are specimens of that “Both and Neither,” which Plato (in the Euthydemus[49]) puts into the mouth of the Sophist Dionysodorus as an answer of slashing defiance — and of that intentional evolution of contradictions which Plato occasionally discountenances, both in the Euthydemus and elsewhere.[50] And we know from Proklus[51] that there were critics in ancient times, who depreciated various parts of the Parmenides as sophistical. Proklus himself denies the charge with some warmth. He as well as the principal Neo-Platonists between 200-530 A.D. (especially his predecessors and instructors at Athens, Jamblichus, Syrianus, and Plutarchus) admired the Parmenides as a splendid effort of philosophical genius in its most exalted range, inspired so as to become cognizant of superhuman persons and agencies. They all agreed so far as to discover in the dialogue a sublime vein of mystic theology and symbolism: but along with this general agreement, there was much discrepancy in their interpretation of particular parts and passages. The commentary of Proklus attests the existence of such debates, reporting his own dissent from the interpretations sanctioned by his venerated masters, Plutarchus and Syrianus. That commentary, in spite of its prolixity, is curious to read as a specimen of the fifth century, A.D., in one of its most eminent representatives. Proklus discovers a string of theological symbols and a mystical meaning throughout the whole dialogue: not merely in the acute argumentation which characterises its middle part, but also in the perplexing antinomies of its close, and even in the dramatic details of places, persons, and incidents, with which it begins.[52]
[49] Plato, Euthydem. p. 300 C. Ἀλλ’ οὐ τοῦτο ἐρωτῶ, ἀλλὰ τὰ πάντα σιγᾷ ἢ λέγει; Οὐδέτερα καὶ ἀμφότερα, ἔφη ὑφαρπάσας ὁ Διονυσόδωρος· εὖ γὰρ οἶδα ὅτι τῇ ἀποκρίσει οὐχ ἕξεις ὅ, τι χρῇ.
[50] Plato, Sophist. p. 259 B. εἴτε ὡς τι χαλεπὸν κατανενοηκὼς χαίρει, τοτὲ μὲν ἐπὶ θάτερα τοτὲ δ’ ἐπὶ θάτερα τοὺς λόγους ἕλκων, οὐκ ἄξια πολλῆς σπουδῆς ἐσπούδακεν, ὡς οἱ νῦν λόγοι φασίν. — Also p. 259 D. Τὸ δὲ ταὐτὸν ἕτερον ἀποφαίνειν ἁμῇ γέ πῃ, καὶ τὸ θάτερον ταὐτόν, καὶ τὸ μέγα σμικρόν, καὶ τὸ ὅμοιον ἀνόμοιον, καὶ χαίρειν οὕτω τἀναντία ἀεὶ προφέροντα ἐν τοῖς λόγοις, οὔ τέ τις ἔλεγχος οὗτος ἀληθινός, ἄρτι τε τῶν ὄντων τινὸς ἐφαπτομένου δῆλος νεογενὴς ὤν.
[51] Proklus, ad Platon. Parmen. p. 953, ed. Stallb.; compare p. 976 in the last book of the commentary, probably composed by Damaskius. K. F. Hermann, Geschichte und System der Platon. Philos. p. 507.
[52] This commentary is annexed to Stallbaum’s edition of the Parmenides. Compare also the opinion of Marinus (disciple and biographer of Proklus) about the Parmenidês — Suidas v. Μαρῖνος. Jamblichus declared that Plato’s entire theory of philosophy was embodied in the two dialogues, Parmenides and Timæus: in the Parmenides, all the intelligible or universal Entia were deduced from τὸ ἕν: in the Timæus, all cosmical realities were deduced from the Demiurgus. Proklus ad Timæeum, p. 5 A, p. 10 Schneider.
Alkinous, in his Introduction to the Platonic Dialogues (c. 6, p. 159, in the Appendix Platonica attached to K. F. Hermann’s edition of Plato) quotes several examples of syllogistic reasoning from the Parmenides, and affirms that the ten categories of Aristotle are exhibited therein.
Plotinus (Ennead. v. 1, 8) gives a brief summary of what he understood to be contained in the Antinomies of the Platonic Parmenides; but the interpretation departs widely from the original.