ch is neither good nor
evil, for nothing can be the friend of the bad.

True.

But neither can like be the friend of like, as we were just now saying.

True.

And if so, that which is neither good nor evil can have no friend which
is neither good nor evil.

Clearly not.

Then the good alone is the friend of that only which is neither good nor
evil.

That may be assumed to be certain.

And does not this seem to put us in the right way? Just remark, that the
body which is in health requires neither medical nor any other aid,
but is well enough; and the healthy man has no love of the physician,
because he is in health.

He has none.

But the sick loves him, because he is sick?

Certainly.

And sickness is an evil, and the art of medicine a good and useful
thing?

Yes.

But the human body, regarded as a body, is neither good nor evil?

True.

And the body is compelled by reason of disease to court and make friends
of the art of medicine?

Yes.

Then that which is neither good nor evil becomes the friend of good, by
reason of the presence of evil?

So we may infer.

And clearly this must have happened before that which was neither good
nor evil had become altogether corrupted with the element of evil--if
itself had become evil it would not still desire and love the good; for,
as we were saying, the evil cannot be the friend of the good.

Impossible.

Further, I must observe that some substances are assimilated when others
are present with them; and there are some which are not assimilated:
take, for example, the case of an ointment or colour which is put on
another substance.

Very good.

In such a case, is the substance which is anointed the same as the
colour or ointment?

What do you mean? he said.

This is what I mean: Suppose that I were to cover your auburn locks with
white lead, would they be really white, or would they only appear to be
white?

They would only appear to be white, he replied.

And yet whiteness would be present in them?

True.

But that would not make them at all the more white, notwithstanding the
presence of white in them--they would not be white any more than black?

No.

But when old age infuses whiteness into them, then they become
assimilated, and are white by the presence of white.

Certainly.

Now I want to know whether in all cases a substance is assimilated
by the presence of another substance; or must the presence be after a
peculiar sort