he knows their right form.

Most true.

And may we not say the same of all things?

What?

That there are three arts which are concerned with all things: one which uses, another which makes, a third which imitates them?

Yes.

And the excellence or beauty or truth of every structure, animate or inanimate, and of every action of man, is relative to the use for which nature or the artist has intended them.

True.

Then the user of them must have the greatest experience of them, and he must indicate to the maker the good or bad qualities which develop themselves in use; for example, the