[122] Plato, Theætêt. p. 201 D. τὴν μὲν μετὰ λόγου ἀληθῆ δόξαν ἐπιστήμην εἶναι· τὴν δὲ ἄλογον, ἐκτὸς ἐπιστήμης· καὶ ὧν μὲν μή ἐστι λόγος, οὐκ ἐπιστητὰ εἶναι, οὑτωσὶ καὶ ὀνομάζων, ἂ δ’ ἔχει, ἐπιστητά.
The words οὑτωσὶ καὶ ὀνομάζων are intended, according to Heindorf and Schleiermacher, to justify the use of the word ἐπιστητά, which was then a neologism. Both this definition, and the elucidation of it which Sokrates proceeds to furnish, are announced as borrowed from other persons not named.
Criticism on the answer by Sokrates. Analogy of letters and words, primordial elements and compounds. Elements cannot be explained: compounds alone can be explained.
Taking up this definition, and elucidating it farther, Sokrates refers to the analogy of words and letters. Letters answer to the primordial elements of things; which are not matters either of knowledge, or of true opinion, or of rational explanation — but simply of sensible perception. A letter, or a primordial element, can only be perceived and called by its name. You cannot affirm of it any predicate or any epithet: you cannot call it existing, or this, or that, or each, or single, or by any other name than its own:[123] for if you do, you attach to it something extraneous to itself, and then it ceases to be an element. But syllables, words, propositions — i. e., the compounds made up by putting together various letters or elements — admit of being known, explained, and described, by enumerating the component elements. You may indeed conceive them correctly, without being able to explain them or to enumerate their component elements: but then you do not know them. You can only be said to know them, when besides conceiving them correctly, you can also specify their component elements[124] — or give explanation.
[123] Plato, Theæt. pp. 201 E — 202 A. αὐτὸ γὰρ καθ’ αὑτὸ ἕκαστον ὀνομάσαι μόνον εἴη, προσειπεῖν δὲ οὐδὲν ἄλλο δυνατόν, οὔθ’ ὡς ἔστιν, οὔθ’ ὡς οὐκ ἔστιν’ ἤδη γὰρ ἂν οὐσίαν ἢ μὴ οὐσίαν αὐτῷ προστίθεσθαι, δεῖν δὲ οὐδὲν προσφέρειν, εἴπερ αὐτὸ ἐκεῖνο μόνον τις ἐρεῖ· ἐπεὶ οὐδὲ τὸ αὐτό, οὐδέ τὸ ἐκεῖνο, οὐδὲ το ἕκαστον, οὐδὲ το μόνον, οὐδὲ τὸ τοῦτο, προσοιστέον, οὐδ’ ἄλλα πολλὰ τοιαῦτα· ταῦτα μὲν γὰρ περιτρέχοντα πᾶσι προσφέρεσθαι, ἕτερα ὄντα ἑκείνων οἷς προστίθεται. Also p. 205 C.
[124] Plato, Theæt. p. 202.
Sokrates refutes this criticism. If the elements are unknowable, the compound must be unknowable also.
Having enunciated this definition, as one learnt from another person not named, Sokrates proceeds to examine and confute it. It rests on the assumption (he says), that the primordial elements are themselves unknowable; and that it is only the aggregates compounded of them which are knowable. Such an assumption cannot be granted. The result is either a real sum total, including both the two component elements: or it is a new form, indivisible and uncompounded, generated by the two elements, but not identical with them nor including them in itself. If the former, it is not knowable, because if neither of the elements are knowable, both together are not knowable: when you know neither A nor B you cannot know either the sum or the product of A and B. If the latter, then the result, being indivisible and uncompounded, is unknowable for the same reason as the elements are so: it can only be named by its own substantive name, but nothing can be predicated respecting it.[125]
[125] Plato, Theæt. pp. 203-206.
Nor can it indeed be admitted as true — That the elements are unknowable, and the compound alone knowable. On the contrary, the elements are more knowable than the compound.[126]