The Complete Aristotle (eng.)

matter itself. But only the parts of the form are
parts of the formula, and the formula is of the universal; for
‘being a circle’ is the same as the circle, and ‘being a soul’ the
same as the soul. But when we come to the concrete thing, e.g. this
circle, i.e. one of the individual circles, whether perceptible or
intelligible (I mean by intelligible circles the mathematical, and
by perceptible circles those of bronze and of wood),-of these there
is no definition, but they are known by the aid of intuitive
thinking or of perception; and when they pass out of this complete
realization it is not clear whether they exist or not; but they are
always stated and recognized by means of the universal formula. But
matter is unknowable in itself. And some matter is perceptible and
some intelligible, perceptible matter being for instance bronze and
wood and all matter that is changeable, and intelligible matter
being that which is present in perceptible things not qua
perceptible, i.e. the objects of mathematics.
    We have stated, then, how matters stand with regard to whole and
part, and their priority and posteriority. But when any one asks
whether the right angle and the circle and the animal are prior, or
the things into which they are divided and of which they consist,
i.e. the parts, we must meet the inquiry by saying that the
question cannot be answered simply. For if even bare soul is the
animal or the living thing, or the soul of each individual is the
individual itself, and ‘being a circle’ is the circle, and ‘being a
right angle’ and the essence of the right angle is the right angle,
then the whole in one sense must be called posterior to the art in
one sense, i.e. to the parts included in the formula and to the
parts of the individual right angle (for both the material right
angle which is made of bronze, and that which is formed by
individual lines, are posterior to their parts); while the
immaterial right angle is posterior to the parts included in the
formula, but prior to those included in the particular instance,
and the question must not be answered simply. If, however, the soul
is something different and is not identical with the animal, even
so some parts must, as we have maintained, be called prior and
others must not.
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11
    Another question is naturally raised, viz. what sort of parts
belong to the form and what sort not to the form, but to the
concrete thing. Yet if this is not plain it is not possible to
define any thing; for definition is of the universal and of the
form. If then it is not evident what sort of parts are of the
nature of matter and what sort are not, neither will the formula of
the thing be evident. In the case of things which are found to
occur in specifically different materials, as a circle may exist in
bronze or stone or wood, it seems plain that these, the bronze or
the stone, are no part of the essence of the circle, since it is
found apart from them. Of things which are not seen to exist apart,
there is no reason why the same may not be true, just as if all
circles that had ever been seen were of bronze; for none the less
the bronze would be no part of the form; but it is hard to
eliminate it in thought. E.g. the form of man is always found in
flesh and bones and parts of this kind; are these then also parts
of the form and the formula? No, they are matter; but because man
is not found also in other matters we are unable to perform the
abstraction.
    Since this is thought to be possible, but it is not clear when
it is the case, some people already raise the question even in the
case of the circle and the triangle, thinking that it is not right
to define these by reference to lines and to the continuous, but
that all these are to the circle or the triangle as flesh and bones
are to man, and bronze or stone to the statue; and they reduce all
things to numbers, and they say the formula of ‘line’ is that of
‘two’. And of those who assert the Ideas some make ‘two’ the
line-itself, and others make it the Form of the line; for in some
cases they say the Form and that of which it is the Form are the
same, e.g. ‘two’ and the Form of two; but in the case of ‘line’
they say this is no longer so.
    It follows then that there is one Form for many things whose
form is evidently different (a conclusion which confronted the
Pythagoreans also); and it is possible to make one thing the
Form-itself of all, and to hold