-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?

THEAETETUS: Precisely.

SOCRATES: And you allow and maintain that true opinion, combined with
definition or rational explanation, is knowledge?

THEAETETUS: Exactly.

SOCRATES: Then may we assume, Theaetetus, that to-day, and in this
casual manner, we have found a truth which in former times many wise men
have grown old and have not found?

THEAETETUS: At any rate, Socrates, I am satisfied with the present
statement.

SOCRATES: Which is probably correct--for how can there be knowledge
apart from definition and true opinion? And yet there is one point in
what has been said which does not quite satisfy me.

THEAETETUS: What was it?

SOCRATES: What might seem to be the most ingenious notion of all:--That
the elements or letters are unknown, but the combination or syllables
known.

THEAETETUS: And was that wrong?

SOCRATES: We shall soon know; for we have as hostages the instances
which the author of the argument himself used.

THEAETETUS: What hostages?

SOCRATES: The letters, which are the clements; and the syllables, which
are the combinations;--he reasoned, did he not, from the letters of the
alpha