We have now
stated the truth; nevertheless let us recapitulate and state it more
clearly. All constituents which are parts of the formula, and into
which the formula can be divided, are prior to their
wholesâ€”either all or some of them. But the formula of the
right angle is not divisible into the formula of an acute angle, but
vice versa; since in defining the acute angle we use the right angle,
because "the acute angle is less than a right angle."It is the same with the
circle and the semicircle; for the semicircle is defined by means of
the circle. And the finger is defined by means of the whole body; for
a finger is a particular kind of part of a man. Thus such parts as are
material, and into which the whole is resolved as into matter, are
posterior to the whole; but such as are parts in the sense of parts of
the formula and of the essence as expressed in the formula, are prior;
either all or some of them.And since the soul of animals (which is the
substance of the living creature) is their substance in accordance
with the formula, and the form and essence of that particular kind of
body (at least each part, if it is to be properly defined, will not be
defined apart from its function; and this will not belong to it apart
from perception^{1}); therefore the parts of the soul are prior, either
all or some of them, to the concrete animal; and similarly in other
individual cases.
[20]
But the body and its parts
are posterior to this substance, and it is not the substance, but the
concrete whole, which is resolved into these parts as into matter.
Therefore in one sense these parts are prior to the concrete whole,
and in another not; for they cannot exist in separation. A finger
cannot in every state be a part of a living animal; for the dead
finger has only the name in common with the living one.Some parts are contemporary
with the whole: such as are indispensable and in which the formula and
the essence are primarily present; e.g. the heart or perhaps the
brain,^{2} for it does not matter
which of them is of this nature. But "man" and "horse" and terms which
are applied in this way to individuals, but universally, are not
substance, but a kind of concrete whole composed of **this**
particular formula and **this** particular matter regarded as
universal. But individually
Socrates is already composed of ultimate matter; and
similarly in all other cases.

A part, then, may be part of the form (by form I mean essence), or of the concrete whole composed of form and matter, or of the matter itself. But only the parts of the form are parts of the formula, and the formula refers to the universal;