Theaet. That is a distinction, Socrates, which I have heard made by some one else, but I had forgotten it. He said that true opinion, combined with reason, was knowledge, but that the opinion which had no reason was out of the sphere of knowledge ; and that things of which there is no rational account are not knowable — such was the singular expression which he used — and that things which have a reason or explanation are knowable.
Soc. Excellent ; but then, how did he distinguish between things which are and are not “knowable” ? I wish that you would repeat to me what he said, and then I shall know whether you and I have heard the same tale.
Theaet. I do not know whether I can recall it ; but if another person would tell me, I think that I could follow him.
Soc. Let me give you, then, a dream in return for a dream : — Methought that I too had a dream, and I heard in my dream that the primeval letters or elements out of which you and I and all other things are compounded, have no reason or explanation ; you can only name them, but no predicate can be either affirmed or denied of them, for in the one case existence, in the other non-existence is already implied, neither of which must be added, if you mean to speak of this or that thing by itself alone. It should not be called itself, or that, or each, or alone, or this, or the like ; for these go about everywhere and are applied to all things, but are distinct from them ; whereas, if the first elements could be described, and had a definition of their own, they would be spoken of apart from all else. But none of these primeval elements can be defined ; they can only be named, for they have nothing but a name, and the things which are compounded of them, as they are complex, are expressed by a combination of names, for the combination of names is the essence of a definition. Thus, then, the elements or letters are only objects of perception, and cannot be defined or known ; but the syllables or combinations of them are known and expressed, and are apprehended by true opinion. When, therefore, any one forms the true opinion of anything without rational explanation, you may say that his mind is truly exercised, but has no knowledge ; for he who cannot give and receive a reason for a thing, has no knowledge of that thing ; but when he adds rational explanation, then, he is perfected in knowledge and may be all that I have been denying of him. Was that the form in which the dream appeared to you ?
Theaet. Precisely.