sophist   

Str. With those who make being to consist in ideas, there will be
less difficulty, for they are civil people enough; but there will be
very great difficulty, or rather an absolute impossibility,
in getting
an opinion out of those who drag everything down to matter. Shall I
tell you what we must do?
Theaet. What?
Str. Let us, if we can, really improve them; but if this is not
possible, let us imagine them to be better than they are, and more
willing to answer in accordance with the rules of argument, and then
their opinion will be more worth having; for that which better men
acknowledge has more weight than that which is acknowledged by
inferior men. Moreover we are no respecters of persons, but seekers
after time.
Theaet. Very good.
Str. Then now, on the supposition that they are improved,
let us ask
them to state their views, and do you interpret them.
Theaet. Agreed.
Str. Let them say whether they would admit that there is such a
thing as a mortal animal.
Theaet. Of course they would.
Str. And do they not acknowledge this to be a body having a soul?
Theaet. Certainly they do.
Str. Meaning to say the soul is something which exists?
Theaet. True.
Str. And do they not say that one soul is just, and another
unjust, and that one soul is wise, and another foolish?
Theaet. Certainly.
Str. And that the just and wise soul becomes just and wise by the
possession of justice and wisdom, and the opposite under opposite
circumstances?
Theaet. Yes, they do.
Str. But surely that which may be present or may be absent will be
admitted by them to exist?
Theaet. Certainly.
Str. And, allowing that justice, wisdom, the other virtues, and
their opposites exist, as well as a soul in which they
inhere, do they
affirm any of them to be visible and tangible, or are they all
invisible?
Theaet. They would say that hardly any of them are visible.
Str. And would they say that they are corporeal?
Theaet. They would distinguish: the soul would be said by them to
have a body; but as to the other qualities of justice,
wisdom, and the
like, about which you asked, they would not venture either to deny
their existence, or to maintain that they were all corporeal.
Str. Verily, Theaetetus, I perceive a great improvement in
them; the
real aborigines, children of the dragon's teeth, would have been
deterred by no shame at all, but would have obstinately asserted
that nothing is which they are not able to squeeze in their hands.
Theaet. That is pretty much their notion.
Str. Let us push the question; for if they will admit that
any, even
the smallest particle of being, is incorporeal, it is enough; they
must then say what that nature is which is common to both the
corporeal and incorporeal, and which they have in their mind's eye
when they say of both of them that they "are." Perhaps they may be
in a difficulty; and if this is the case, there is a possibility
that they may accept a notion of ours respecting the nature of
being, having nothing of their own to offer.
Theaet. What is the notion? Tell me, and we shall soon see.