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?