Then another idea of greatness now comes into view over and above
absolute greatness, and the individuals which partake of it; and
then another, over and above all these, by virtue of which they will
all be great, and so each idea instead of being one will be infinitely
multiplied.

  But may not the ideas, asked Socrates, be thoughts only, and have no
proper existence except in our minds, Parmenides? For in that case
each idea may still be one, and not experience this infinite
multiplication.

  And can there be individual thoughts which are thoughts of nothing?

  Impossible, he said.

  The thought must be of something?

  Yes.

  Of something which is or which is not?

  Of something which is.

  Must it not be of a single something, which the thought recognizes
as attaching to all, being a single form or nature?

  Yes.

  And will not the something which is apprehended as one and the
same in all, be an idea?

  From that, again, there is no escape.

  Then, said Parmenides, if you say that everything else
participates in the ideas, must you not say either that everything
is made up of thoughts, and that all things think; or that they are
thoughts but have no thought?

  The latter view, Parmenides, is no more rational than the previous
one. In my opinion, the ideas are, as it were, patterns fixed in
nature, and other things are like them, and resemblances of
them-what is meant by the participation of other things in the
ideas, is really assimilation to them.

  But if, said he, the individual is like the idea, must not the
idea also be like the individual, in so far as the individual is a
resemblance of the idea? That which is like, cannot be conceived of as
other than the like of like.

  Impossible.

  And when two things are alike, must they not partake of the same
idea?

  They must.

  And will not that of which the two partake, and which makes them
alike, be the idea itself?

  Certainly.

  Then the idea cannot be like the individual, or the individual
like the idea; for if they are alike, some further idea of likeness
will always be coming to light, and if that be like anything else,
another; and new ideas will be always arising, if the idea resembles
that which partakes of it?

  Quite true.

  The theory, then that other things participate in the ideas by
resemblance, has to be given up, and some other mode of
participation devised?

  It would seem so.

  Do you see then, Socrates, how great is the difficulty of
affirming the ideas to be absolute?

  Yes, indeed.

  And, further, let me say that as yet you only understand a small
part of the difficulty which is involved if you make of each thing a
single idea, parting it off from other things.

  What difficulty? he said.

  There are many, but the greatest of all is this:-If an opponent
argues that these ideas, being such as we say they ought to be, must
remain unknown, no one can prove to him that he is wrong, unless he
who denies their existence be a man of great ability and knowledge,
and is willing to follow a long and laborious demonstration; he will
remain unconvinced, and still insist that they cannot be known.

  What do you mean, Parmenides? said Socrates.

  In the first place, I think, Socrates, that you, or any one who
maintains the existence of absolute essences, will admit that they
cannot exist in us.

  No, said Socrates; for then they would be no longer absolute.