[3] Plato, Parmenid. p. 129 A. οὐ νομίζεις εἶναι αὐτὸ καθ’ αὐτὸ εἶδός τι ὁμοιότητος, καὶ τῷ τοιούτῳ αἶ ἄλλο τι ἐναντίον, ὃ ἔστιν ἀνόμοιον; τούτοιν δὲ δυοῖν ὄντοιν καὶ ἐμὲ καὶ σὲ καὶ τὰ ἄλλα ἃ δὴ πολλὰ καλοῦμεν, μεταλαμβάνειν;
[4] Plato, Parmenid. pp. 129-130.
Parmenides and Zeno admire the philosophical ardour of Sokrates. Parmenides advances objections against the Platonic theory of Ideas.
Parmenides and Zeno are represented as listening with surprise and interest to this language of Sokrates, recognising two distinct worlds: one, of invisible but intelligible Forms, — the other that of sensible objects, participating in these Forms. “Your ardour for philosophy” (observes Parmenides to Sokrates), “is admirable. Is this distinction your own?”[5]
[5] Plato, Parmenid. p. 130 A. Ὦ Σώκρατες, ὡς ἄξιος εἶ ἄγασθαι τῆς ὁρμῆς τῆς ἐπὶ τοὺς λόγους· καί μοι εἰπέ, αὐτὸς σὺ οὕτω διῄρησαι ὡς λέγεις, χωρὶς μὲν εἴδη αὐτὰ ἄττα, χωρὶς δὲ τὰ τούτων αὖ μετέχοντα;
Plato now puts into the mouth of Parmenides — the advocate of One absolute and unchangeable Ens, separated by an impassable gulf from the sensible world of transitory and variable appearances or phenomena — objections against what is called the Platonic theory of Ideas: that is, the theory of an intelligible world, comprising an indefinite number of distinct intelligible and unchangeable Forms — in partial relation and communication with another world of sensible objects, each of which participates in one or more of these Forms. We thus have the Absolute One pitted against the Absolute Many.
What Ideas does Sokrates recognise? Of the Just and Good? Yes. Of Man, Horse, &c.? Doubtful. Of Hair, Mud, &c.? No.
What number and variety of these intelligible Forms do you recognise — (asks Parmenides)? Likeness and Unlikeness — One and Many — Just, Beautiful, Good, &c. — are all these Forms absolute and existent per se? Sokr. — Certainly they are. Parm. — Do you farther recognise an absolute and self-existent Form of Man, apart from us and all other individuals? — or a Form of fire, water, and the like? Sokr. — I do not well know how to answer:— I have often been embarrassed with the question. Parm. — Farther, do there exist distinct intelligible Forms of hair, mud, dirt, and all the other mean and contemptible objects of sense which we see around? Sokr. — No — certainly — no such Forms as these exist. Such objects are as we see them, and nothing beyond: it would be too absurd to suppose Forms of such like things.[6] Nevertheless there are times when I have misgivings on the point; and when I suspect that there must be Forms of them as well as of the others. When such reflections cross my mind, I shrink from the absurdity of the doctrine, and try to confine my attention to Forms like those which you mentioned first.
[6] Plato, Parmenid. p. 130 D. Οὐδαμῶς, φάναι τὸν Σωκράτην, ἀλλὰ ταῦτα μέν γε, ἅπερ ὁρῶμεν, ταῦτα καὶ εἶναι· εἶδος δέ τι αὐτῶν οἰηθῆναι εἶναι μὴ λίαν ᾖ ἄτοπον.
Alexander, who opposes the doctrine of the Platonists about Ideas, treats it as understood that they did not recognise Ideas of worms, gnats, and such like animals. Schol. ad Aristot. Metaphys. A. 991 a. p. 575, a. 30 Brandis.