Again, Plato tells us that the Sophist is a person who disputes about all matters, and pretends to know all matters: respecting the invisible Gods, respecting the visible Gods, Sun, Moon, Stars, Earth, &c., respecting transcendental philosophy, generation and essence — and respecting all civil, social, and political questions — and respecting special arts. On all these miscellaneous topics, according to Plato, the Sophists pretended to be themselves instructed, and to qualify their disciples for arguing on all of them.
Now it is possible that the Sophists of that day may have pretended to this species of universal knowledge; but most certainly Plato and Aristotle did the same. The dialogues of Plato embrace all that wide range of topics which he tells us that the Sophists argued about, and pretended to teach. In an age when the amount of positive knowledge was so slender, it was natural for a clever talker or writer to fancy that he knew every thing. In reference to every subject then discussed, an ingenious mind could readily supply deductions from both hypotheses — generalities ratiocinative or imaginative — strung together into an apparent order sufficient for the exigencies of hearers. There was no large range of books to be studied; no stock of facts or experience to be mastered. Every philosopher wove his own tissue of theory for himself, without any restraint upon his intellectual impulse, in regard to all the problems then afloat. What the theories of the Sophists were, we do not know: but Plato, author of the Timæus, Republic, Leges, Kratylus, Menon — who affirmed the pre-existence as well as post-existence of the mind, and the eternal self-existence of Ideas — has no fair ground for reproaching them with blamable rashness in the extent and diversity of topics which they presumed to discuss. They obtained indeed (he says justly) no truth or knowledge, but merely a fanciful semblance of knowledge — an equivocal show or imitation of reality.[98] But Plato himself obtains nothing more in the Timæus: and we shall find Aristotle pronouncing the like condemnation on the Platonic self-existent Ideas. If the Sophists professed to be encyclopedists, this was an error natural to the age; and was the character of Grecian philosophy generally, even in its most illustrious manifestations.
[98] Plato, Sophistês, p. 233 C. δοξαστικὴν ἄρα τινὰ περὶ πάντων ἐπιστήμην ὁ σοφιστὴς ἡμῖν, ἀλλ’ οὐκ ἀληθείαν ἔχων ἀναπέφανται. 234 B: μιμήματα καὶ ὁμώνυμα τῶν ὄντων.
When the Eleate here says about the Sophists (p. 233 B), δοκοῦσι πρὸς ταῦτα ἐπιστημόνως ἔχειν αὐτοὶ πρὸς ἅπερ ἀντιλέγουσιν, this is exactly what Sokrates, in the Platonic Apology, tells us about the impression made by his own dialectics or refutative conversation, Plato, Apolog. p. 23 A.
ἐκ ταύτησι δὴ τῆς ἐξετάσεως πολλαὶ μὲν ἀπέχθειαί μοι γεγόνασι καὶ οἷαι χαλεπώταται καὶ βαρύταται, ὥστε πολλὰς διαβολὰς ἀπ’ αὐτῶν γεγονέναι, ὄνομά τε τοῦτο λέγεσθαι, σοφὸς εἶναι· οἶονται γάρ με ἑκάστοθ’ οἱ παρόντες ταῦτ’ εἶναι σοφὸν ἃ ἂν ἄλλον ἐξελέγξω.
Inconsistency of Plato’s argument in the Sophistês. He says that the Sophist is a disputatious man who challenges every one for speaking falsehood. He says also that the Sophist is one who maintains false propositions to be impossible.
Having traced the Sophist down to the character of a man of delusion and imposture, passing off appearance as if it were reality, and falsehood as if it were truth — Plato (as we have seen) suddenly turns round upon himself, and asks how such a character is possible. He represents the Sophist as maintaining that no man could speak falsely[99] — that a false proposition was self-contradictory, inasmuch as Non-Ens was inconceivable and unutterable. I do not see how the argument which Plato here ascribes to the Sophist, can be reconciled with the character which he had before given of the Sophist — as a man who passed his life in disputation and controversy; which involves the perpetual arraigning of other men’s opinions as false. A professed disputant may perhaps be accused of admitting nothing to be true: but he cannot well be charged with maintaining that nothing is false.
[99] Plato, Sophist. pp. 240-241. Compare 260 E.
Reasoning of Plato about Non-Ens — No predications except identical.
To pass over this inconsistency, however — the reasoning of Plato himself on the subject of Non-Ens is an interesting relic of ancient speculation. He has made for himself an opportunity of canvassing, not only the doctrine of Parmenides, who emphatically denied Non-Ens — but also the opposite doctrine of other schools. He farther comments upon a different opinion, advanced by other philosophers — That no proposition can be admitted, in which the predicate is different from the subject: That no proposition is true or valid, except an identical proposition. You cannot say, Man is good: you can only say, Man is Man, or Good is good. You cannot say — Sokrates is good, brave, old, stout, flat-nosed, &c., because you thereby multiply the one Sokrates into many. One thing cannot be many, nor many things one.[100]