fire, and cold is not the same with snow?

Yes.

And yet you will surely admit, that when snow, as was before said, is
under the influence of heat, they will not remain snow and heat; but at
the advance of the heat, the snow will either retire or perish?

Very true, he replied.

And the fire too at the advance of the cold will either retire or
perish; and when the fire is under the influence of the cold, they will
not remain as before, fire and cold.

That is true, he said.

And in some cases the name of the idea is not only attached to the idea
in an eternal connection, but anything else which, not being the idea,
exists only in the form of the idea, may also lay claim to it. I will
try to make this clearer by an example:--The odd number is always called
by the name of odd?

Very true.

But is this the only thing which is called odd? Are there not other
things which have their own name, and yet are called odd, because,
although not the same as oddness, they are never without oddness?--that
is what I mean to ask--whether numbers such as the number three are not
of the class of odd. And there are many other examples: would you not
say, for example, that three may be called by its proper name, and also
be called odd, which is not the same with three? and this may be said
not only of three but also of five, and of every alternate number--each
of them without being oddness is odd, and in the same way two and
four, and the other series of alternate numbers, has every number even,
without being evenness. Do you agree?

Of course.

Then now mark the point at which I am aiming:--not only do essential
opposites exclude one another, but also concrete things, which, although
not in themselves opposed, contain opposites; these, I say, likewise
reject the idea which is opposed to that which is contained in them,
and when it approaches them they either perish or withdraw. For example;
Will not the number three endure annihilation or anything sooner than be
converted into an even number, while remaining three?

Very true, said Cebes.

And yet, he said, the number two is certainly not opposed to the number
three?

It is not.

Then not only do opposite ideas repel the advance of one another, but
also there are other natures which repel the approach of opposites.

Very true, he said.

Suppose, he said, that we endeavour, if possible, to determine what
these are.

By all means.

Are they not, Cebes, such as comp