The Complete Aristotle (eng.)

is
present potentially is already in the physician’s power.
    The active principle then and the starting point for the process
of becoming healthy is, if it happens by art, the form in the soul,
and if spontaneously, it is that, whatever it is, which starts the
making, for the man who makes by art, as in healing the
starting-point is perhaps the production of warmth (and this the
physician produces by rubbing). Warmth in the body, then, is either
a part of health or is followed (either directly or through several
intermediate steps) by something similar which is a part of health;
and this, viz. that which produces the part of health, is the
limiting-point—and so too with a house (the stones are the
limiting-point here) and in all other cases. Therefore, as the
saying goes, it is impossible that anything should be produced if
there were nothing existing before. Obviously then some part of the
result will pre-exist of necessity; for the matter is a part; for
this is present in the process and it is this that becomes
something. But is the matter an element even in the formula? We
certainly describe in both ways what brazen circles are; we
describe both the matter by saying it is brass, and the form by
saying that it is such and such a figure; and figure is the
proximate genus in which it is placed. The brazen circle, then, has
its matter in its formula.
    As for that out of which as matter they are produced, some
things are said, when they have been produced, to be not that but
‘thaten’; e.g. the statue is not gold but golden. And a healthy man
is not said to be that from which he has come. The reason is that
though a thing comes both from its privation and from its
substratum, which we call its matter (e.g. what becomes healthy is
both a man and an invalid), it is said to come rather from its
privation (e.g. it is from an invalid rather than from a man that a
healthy subject is produced). And so the healthy subject is not
said to he an invalid, but to be a man, and the man is said to be
healthy. But as for the things whose privation is obscure and
nameless, e.g. in brass the privation of a particular shape or in
bricks and timber the privation of arrangement as a house, the
thing is thought to be produced from these materials, as in the
former case the healthy man is produced from an invalid. And so, as
there also a thing is not said to be that from which it comes, here
the statue is not said to be wood but is said by a verbal change to
be wooden, not brass but brazen, not gold but golden, and the house
is said to be not bricks but bricken (though we should not say
without qualification, if we looked at the matter carefully, even
that a statue is produced from wood or a house from bricks, because
coming to be implies change in that from which a thing comes to be,
and not permanence). It is for this reason, then, that we use this
way of speaking.
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    div id="section83" class="section" title="8">
8
    Since anything which is produced is produced by something (and
this I call the starting-point of the production), and from
something (and let this be taken to be not the privation but the
matter; for the meaning we attach to this has already been
explained), and since something is produced (and this is either a
sphere or a circle or whatever else it may chance to be), just as
we do not make the substratum (the brass), so we do not make the
sphere, except incidentally, because the brazen sphere is a sphere
and we make the forme. For to make a ‘this’ is to make a ‘this’ out
of the substratum in the full sense of the word. (I mean that to
make the brass round is not to make the round or the sphere, but
something else, i.e. to produce this form in something different
from itself. For if we make the form, we must make it out of
something else; for this was assumed. E.g. we make a brazen sphere;
and that in the sense that out of this, which is brass, we make
this other, which is a sphere.) If, then, we also make the
substratum itself, clearly we shall make it in the same way, and
the processes of making will regress to infinity. Obviously then
the form also, or whatever we ought to call the shape present in
the sensible thing, is not produced, nor is there any production of
it, nor is the essence produced; for this is that which is made to
be in something else either by art or by nature or by some faculty.
But that there is a brazen sphere, this we make. For we make it out
of brass and the sphere; we bring the form