[126] Plato, Theæt. p. 206.
Rational explanation may have one of three different meanings. 1. Description in appropriate language. 2. Enumeration of all the component elements in the compound. In neither of these meanings will the definition of Cognition hold.
When you say (continues Sokrates) that knowledge is true opinion coupled with rational explanation, you may mean by rational explanation one of three things. 1. The power of enunciating the opinion in clear and appropriate words. This every one learns to do, who is not dumb or an idiot: so that in this sense true opinion will always carry with it rational explanation. — 2. The power of describing the thing in question by its component elements. Thus Hesiod says that there are a hundred distinct wooden pieces in a waggon: you and I do not know nor can we describe them all: we can distinguish only the more obvious fractions — the wheels, the axle, the body, the yoke, &c. Accordingly, we cannot be said to know a waggon: we have only a true opinion about it. Such is the second sense of λόγος or rational explanation. But neither in this sense will the proposition hold — That knowledge is right opinion coupled with rational explanation. For suppose that a man can enumerate, spell, and write correctly, all the syllables of the name Theætêtus — which would fulfil the conditions of this definition: yet, if he mistakes and spells wrongly in any other name, such as Theodôrus, you will not give him credit for knowledge. You will say that he writes Theætêtus correctly, by virtue of right opinion simply. It is therefore possible to have right opinion coupled with rational explanation, in this second sense also, — yet without possessing knowledge.[127]
[127] Plato, Theæt. p. 207-208 B. ἔστιν ἄρα μετὰ λόγου ὀρθὴ δόξα, ἣν οὔπω δεῖ ἐπιστήμην καλεῖν.
Third meaning. To assign some mark, whereby the thing to be explained differs from everything else. The definition will not hold. For rational explanation, in this sense, is already included in true opinion.
3. A third meaning of this same word λόγος or rational explanation, is, that in which it is most commonly understood — To be able to assign some mark whereby the thing to be explained differs from every thing else — to differentiate the thing.[128] Persons, who understand the word in this way, affirm, that so long as you only seize what the thing has in common with other things, you have only a true opinion concerning it: but when you seize what it has peculiar and characteristic, you then possess knowledge of it. Such is their view: but though it seems plausible at first sight (says Sokrates), it will not bear close scrutiny. For in order to have a true opinion about any thing, I must have in my mind not only what it possesses in common with other things, but what it possesses peculiar to itself also. Thus if I have a true opinion about Theætêtus, I must have in my mind not only the attributes which belong to him in common with other men, but also those which belong to him specially and exclusively. Rational explanation (λόγος) in this sense is already comprehended in true opinion, and is an essential ingredient in it — not any new element superadded. It will not serve therefore as a distinction between true opinion and knowledge.[129]
[128] Plato, Theætêt. p. 208 C. Ὅπερ ἂν οἱ πολλοὶ εἴποιεν, τὸ ἔχειν τι σημεῖον εἰπεῖν ᾧ τῶν ἁπάντων διαφέρει τὸ ἐρωτηθέν.
[129] Plato, Theætêt. p. 209.
Conclusion of the dialogue — Summing up by Sokrates — Value of the result, although purely negative.
Such is the result (continues Sokrates) of our researches concerning knowledge. We have found that it is neither sensible perception — nor true opinion — nor true opinion along with rational explanation. But what it is, we have not found. Are we still pregnant with any other answer, Theætêtus, or have we brought forth all that is to come? — I have brought forth (replies Theætêtus) more than I had within me, through your furtherance. Well (rejoins Sokrates) — and my obstetric science has pronounced all your offspring to be mere wind, unworthy of being preserved![130] If hereafter you should again become pregnant, your offspring will be all the better for our recent investigation. If on the other hand you should always remain barren, you will be more amiable and less vexatious to your companions — by having a just estimate of yourself and by not believing yourself to know what you really do not know.[131]