The Complete Aristotle (eng.)

this nature, all their ignorance would
have been dispelled.
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    Others, indeed, have apprehended the nature in question, but not
adequately.
    In the first place they allow that a thing may come to be
without qualification from not being, accepting on this point the
statement of Parmenides. Secondly, they think that if the
substratum is one numerically, it must have also only a single
potentiality-which is a very different thing.
    Now we distinguish matter and privation, and hold that one of
these, namely the matter, is not-being only in virtue of an
attribute which it has, while the privation in its own nature is
not-being; and that the matter is nearly, in a sense is, substance,
while the privation in no sense is. They, on the other hand,
identify their Great and Small alike with not being, and that
whether they are taken together as one or separately. Their triad
is therefore of quite a different kind from ours. For they got so
far as to see that there must be some underlying nature, but they
make it one-for even if one philosopher makes a dyad of it, which
he calls Great and Small, the effect is the same, for he overlooked
the other nature. For the one which persists is a joint cause, with
the form, of what comes to be-a mother, as it were. But the
negative part of the contrariety may often seem, if you concentrate
your attention on it as an evil agent, not to exist at all.
    For admitting with them that there is something divine, good,
and desirable, we hold that there are two other principles, the one
contrary to it, the other such as of its own nature to desire and
yearn for it. But the consequence of their view is that the
contrary desires its wtextinction. Yet the form cannot desire
itself, for it is not defective; nor can the contrary desire it,
for contraries are mutually destructive. The truth is that what
desires the form is matter, as the female desires the male and the
ugly the beautiful-only the ugly or the female not per se but per
accidens.
    The matter comes to be and ceases to be in one sense, while in
another it does not. As that which contains the privation, it
ceases to be in its own nature, for what ceases to be-the
privation-is contained within it. But as potentiality it does not
cease to be in its own nature, but is necessarily outside the
sphere of becoming and ceasing to be. For if it came to be,
something must have existed as a primary substratum from which it
should come and which should persist in it; but this is its own
special nature, so that it will be before coming to be. (For my
definition of matter is just this-the primary substratum of each
thing, from which it comes to be without qualification, and which
persists in the result.) And if it ceases to be it will pass into
that at the last, so it will have ceased to be before ceasing to
be.
    The accurate determination of the first principle in respect of
form, whether it is one or many and what it is or what they are, is
the province of the primary type of science; so these questions may
stand over till then. But of the natural, i.e. perishable, forms we
shall speak in the expositions which follow.
    The above, then, may be taken as sufficient to establish that
there are principles and what they are and how many there are. Now
let us make a fresh start and proceed.

Physics, Book II
    Translated by R. P. Hardie and R. K. Gaye
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    Of things that exist, some exist by nature, some from other
causes.
    ‘By nature’ the animals and their parts exist, and the plants
and the simple bodies (earth, fire, air, water)-for we say that
these and the like exist ‘by nature’.
    All the things mentioned present a feature in which they differ
from things which are not constituted by nature. Each of them has
within itself a principle of motion and of stationariness (in
respect of place, or of growth and decrease, or by way of
alteration). On the other hand, a bed and a coat and anything else
of that sort, qua receiving these designations i.e. in so far as
they are products of art-have no innate impulse to change. But in
so far as they happen to be composed of stone or of earth or of a
mixture of the two, they do have such an impulse, and just to that
extent which seems to indicate that nature is a source or cause of
being moved and of being at rest in that to which it belongs
primarily, in virtue of itself and not in virtue of a concomitant
attribute.
    I say