SOCRATES: And there might be given other proofs of this belief, if I am not mistaken. But do not let us in looking for them lose sight of the question before us, which is the meaning of the statement, that right opinion with rational definition or explanation is the most perfect form of knowledge.
THEAETETUS: We must not.
SOCRATES: Well, and what is the meaning of the term 'explanation'? I think that we have a choice of three meanings.
THEAETETUS: What are they?
SOCRATES: In the first place, the meaning may be, manifesting one's thought by the voice with verbs and nouns, imaging an opinion in the stream which flows from the lips, as in a mirror or water. Does not explanation appear to be of this nature?
THEAETETUS: Certainly; he who so manifests his thought, is said to explain himself.
SOCRATES: And every one who is not born deaf or dumb is able sooner or later to manifest what he thinks of anything; and if so, all those who have a right opinion about anything will also have right explanation; nor will right opinion be anywhere found to exist apart from knowledge.
THEAETETUS: True.
SOCRATES: Let us not, therefore, hastily charge him who gave this account of knowledge with uttering an unmeaning word; for perhaps he only intended to say, that when a person was asked what was the nature of anything, he should be able to answer his questioner by giving the elements of the thing.
THEAETETUS: As for example, Socrates...?