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1070b]
[1]
What then can their common constituent
be? For there is nothing common to and yet distinct from substance and
the other predicable categories, yet the element is prior to that of
which it is an element. Moreover substance is not an element of
relations, nor is any of the latter an element of substance. Further,
how can all the categories have the same elements?For no element can be the same as that
which is composed of elements; e.g., neither B nor A can be the same
as BA (nor indeed can any of the "intelligibles,"
1 e.g.
Unity or Being, be an element; for these apply in every case, even to
composite things); hence no element can be either substance or
relation. But it must be one or the other. Therefore the categories
have not all the same elements.
The truth is
that, as we say, in one sense all things have the same elements and in
another they have not. E.g., the elements of sensible bodies are, let
us say, (1) as form, the hot, and in another sense the cold, which is
the corresponding privation; as matter, that which directly and of its
own nature is potentially hot or cold. And not only these are
substances, but so are (2) the compounds
2 of which
they are principles, and (3) any unity which is generated from hot and
cold, e.g. flesh or bone; for the product of hot and cold must be
distinct from them.These
things, then, have the same elements and principles, although
specifically different things have specifically different elements; we
cannot, however, say that all things have the same elements in this
sense, but only by analogy: i.e., one might say that there are three
principles, form, privation and matter.But each of these is different in respect of
each class of things,
[20]
e.g.,
in the case of color they are white, black, surface; or again there is
light, darkness and air, of which day and night are composed. And
since not only things which are inherent in an object are its causes,
but also certain external things, e.g. the moving cause, clearly
"principle" and "element" are not the same; but both are causes.
Principles are divided into these two kinds, and that which moves a
thing or brings it to rest is a kind of principle and
substance.Thus
analogically there are three elements and four causes or principles;
but they are different in different cases, and the proximate moving
cause is different in different cases. Health, disease, body; and the
moving cause is the art of medicine. Form, a particular kind of
disorder, bricks; and the moving cause is the art of
building.And since
in the sphere of natural objects the moving cause of man is man, while
in the sphere of objects of thought the moving cause is the form or
its contrary, in one sense there are three causes and in another four.
For in a sense the art of medicine is health, and the art of building
is the form of a house, and man begets man; but besides these there is
that which as first of all things moves all things.
3 Now
since some things can exist in separation and others cannot, it is the
former that are substances.