all sides of a question; whose dulness cannot be
convinced, and who will never leave off?

THEAETETUS: But what puts you out of heart?

SOCRATES: I am not only out of heart, but in positive despair; for I do
not know what to answer if any one were to ask me:--O Socrates, have you
indeed discovered that false opinion arises neither in the comparison of
perceptions with one another nor yet in thought, but in union of thought
and perception? Yes, I shall say, with the complacence of one who thinks
that he has made a noble discovery.

THEAETETUS: I see no reason why we should be ashamed of our
demonstration, Socrates.

SOCRATES: He will say: You mean to argue that the man whom we only think
of and do not see, cannot be confused with the horse which we do not see
or touch, but only think of and do not perceive? That I believe to be my
meaning, I shall reply.

THEAETETUS: Quite right.

SOCRATES: Well, then, he will say, according to that argument, the
number eleven, which is only thought, can never be mistaken for twelve,
which is only thought: How would you answer him?

THEAETETUS: I should say that a mistake may very likely arise between
the eleven or twelve which are seen or handled, but that no similar
mistake can arise between the eleven and twelve which are in the mind.

SOCRATES: Well, but do you think that no one ever put before his own
mind five and seven,--I do not mean five or seven men or horses, but
five or seven in the abstract, which, as we say, are recorded on the
waxen block, and in which false opinion is held to be impossible; did
no man ever ask himself how many these numbers make when added together,
and answer that they are eleven, while another thinks that they are
twelve, or would all agree in thinking and saying that they are twelve?

THEAETETUS: Certainly not; many would think that they are eleven, and
in the higher numbers the chance of error is greater still; for I assume
you to be speaking of numbers in general.

SOCRATES: Exactly; and I want you to consider whether this does not
imply that the twelve in the waxen block are supposed to be eleven?

THEAETETUS: Yes, that seems to be the case.

SOCRATES: Then do we not come back to the old difficulty? For he who
makes such a mistake does think one thing which he knows to be another
thing which he knows; but this, as we said, was impossible, and afforded
an irresistible proof of the non-existence of false opinion, because
otherwise the sa