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there are four. For the medical art is in some sense health, and the
building art is the form of the house, and man begets man; further,
besides these there is that which as first of all things moves all
things.
5
Some things can exist apart and some cannot, and it is the
former that are substances. And therefore all things have the same
causes, because, without substances, modifications and movements do
not exist. Further, these causes will probably be soul and body, or
reason and desire and body.
And in yet another way, analogically identical things are
principles, i.e. actuality and potency; but these also are not only
different for different things but also apply in different ways to
them. For in some cases the same thing exists at one time actually and
at another potentially, e.g. wine or flesh or man does so. (And
these too fall under the above-named causes. For the form exists
actually, if it can exist apart, and so does the complex of form and
matter, and the privation, e.g. darkness or disease; but the matter
exists potentially; for this is that which can become qualified either
by the form or by the privation.) But the distinction of actuality and
potentiality applies in another way to cases where the matter of cause
and of effect is not the same, in some of which cases the form is
not the same but different; e.g. the cause of man is (1) the
elements in man (viz. fire and earth as matter, and the peculiar
form), and further (2) something else outside, i.e. the father, and
(3) besides these the sun and its oblique course, which are neither
matter nor form nor privation of man nor of the same species with him,
but moving causes.
Further, one must observe that some causes can be expressed in
universal terms, and some cannot. The proximate principles of all
things are the 'this' which is proximate in actuality, and another
which is proximate in potentiality. The universal causes, then, of
which we spoke do not exist. For it is the individual that is the
originative principle of the individuals. For while man is the
originative principle of man universally, there is no universal man,
but Peleus is the originative principle of Achilles, and your father
of you, and this particular b of this particular ba, though b in
general is the originative principle of ba taken without
qualification.
Further, if the causes of substances are the causes of all things,
yet different things have different causes and elements, as was
said; the causes of things that are not in the same class, e.g. of
colours and sounds, of substances and quantities, are different except
in an analogical sense; and those of things in the same species are
different, not in species, but in the sense that the causes of
different individuals are different, your matter and form and moving
cause being different from mine, while in their universal definition
they are the same. And if we inquire what are the principles or
elements of substances and relations and qualities-whether they are
the same or different-clearly when the names of the causes are used in
several senses the causes of each are the same, but when the senses
are distinguished the causes are not the same but different, except
that in the following senses the causes of all are the same. They
are (1) the same or analogous in this sense, that matter, form,
privation, and the moving cause are common to all things; and (2)
the causes of substances may be treated as causes of all things in
this sense, that when substances are removed all things are removed;
further, (3) that which is first in respect of complete reality is the
cause of all things. But in another sense there are different first
causes, viz. all the contraries which are neither generic nor
ambiguous terms; and, further, the matters of different things are
different. We have stated, then, what are the principles of sensible
things and how many they are, and in what sense they are the same
and in what sense different.
6
Since there were three kinds of substance, two of them physical
and one unmovable, regarding the latter we must assert that it is
necessary that there should be an eternal unmovable substance. For
substances are the first of existing things, and if they are all
destructible, all things are destructible. But it is impossible that
movement should either have come into being or cease to be (for it
must always have existed), or that time should. For there could not be
a before and an after if time did not exist. Movement also is
continuous, then, in the sense in which time is; for time is either
the same thing as movement or an attribute of movement. And there is
no continuous movement except movement in place, and of this only that
which is circular is continuous.
But if there is something which is capable of moving things or
acting on them, but is not actually doing so, there will not
necessarily be movement; for that which has a potency need not
exercise it. Nothing, then, is gained even if we suppose eternal
substances, as the believers in the Forms do, unless there is to be in
them some principle which can cause change; nay, even this is not
enough, nor is another substance besides the Forms enough; for if it
is not to act, there will be no movement. Further even if it acts,
this will not be enough, if its essence is potency; for there will not
be eternal movement, since that which is potentially may possibly
not be. There must, then, be such a principle, whose very essence is
actuality. Further, then, these substances must be without matter; for
they must be eternal, if anything is eternal. Therefore they must be
actuality.
Yet there is a difficulty; for it is thought that everything
that acts is able to act, but that not everything that is able to [ Pobierz całość w formacie PDF ]