The Complete Aristotle (eng.)

not use the expression ‘come to be’, but ‘come to be
so-and-so’. Only substances are said to ‘come to be’ in the
unqualified sense.
    Now in all cases other than substance it is plain that there
must be some subject, namely, that which becomes. For we know that
when a thing comes to be of such a quantity or quality or in such a
relation, time, or place, a subject is always presupposed, since
substance alone is not predicated of another subject, but
everything else of substance.
    But that substances too, and anything else that can be said ‘to
be’ without qualification, come to be from some substratum, will
appear on examination. For we find in every case something that
underlies from which proceeds that which comes to be; for instance,
animals and plants from seed.
    Generally things which come to be, come to be in different ways:
(1) by change of shape, as a statue; (2) by addition, as things
which grow; (3) by taking away, as the Hermes from the stone; (4)
by putting together, as a house; (5) by alteration, as things which
‘turn’ in respect of their material substance.
    It is plain that these are all cases of coming to be from a
substratum.
    Thus, clearly, from what has been said, whatever comes to be is
always complex. There is, on the one hand, (a) something which
comes into existence, and again (b) something which becomes
that-the latter (b) in two senses, either the subject or the
opposite. By the ‘opposite’ I mean the ‘unmusical’, by the
‘subject’ ‘man’, and similarly I call the absence of shape or form
or order the ‘opposite’, and the bronze or stone or gold the
‘subject’.
    Plainly then, if there are conditions and principles which
constitute natural objects and from which they primarily are or
have come to be-have come to be, I mean, what each is said to be in
its essential nature, not what each is in respect of a concomitant
attribute-plainly, I say, everything comes to be from both subject
and form. For ‘musical man’ is composed (in a way) of ‘man’ and
‘musical’: you can analyse it into the definitions of its elements.
It is clear then that what comes to be will come to be from these
elements.
    Now the subject is one numerically, though it is two in form.
(For it is the man, the gold-the ‘matter’ generally-that is
counted, for it is more of the nature of a ‘this’, and what comes
to be does not come from it in virtue of a concomitant attribute;
the privation, on the other hand, and the contrary are incidental
in the process.) And the positive form is one-the order, the
acquired art of music, or any similar predicate.
    There is a sense, therefore, in which we must declare the
principles to be two, and a sense in which they are three; a sense
in which the contraries are the principles-say for example the
musical and the unmusical, the hot and the cold, the tuned and the
untuned-and a sense in which they are not, since it is impossible
for the contraries to be acted on by each other. But this
difficulty also is solved by the fact that the substratum is
different from the contraries, for it is itself not a contrary. The
principles therefore are, in a way, not more in number than the
contraries, but as it were two, nor yet precisely two, since there
is a difference of essential nature, but three. For ‘to be man’ is
different from ‘to be unmusical’, and ‘to be unformed’ from ‘to be
bronze’.
    We have now stated the number of the principles of natural
objects which are subject to generation, and how the number is
reached: and it is clear that there must be a substratum for the
contraries, and that the contraries must be two. (Yet in another
way of putting it this is not necessary, as one of the contraries
will serve to effect the change by its successive absence and
presence.)
    The underlying nature is an object of scientific knowledge, by
an analogy. For as the bronze is to the statue, the wood to the
bed, or the matter and the formless before receiving form to any
thing which has form, so is the underlying nature to substance,
i.e. the ‘this’ or existent.
    This then is one principle (though not one or existent in the
same sense as the ‘this’), and the definition was one as we agreed;
then further there is its contrary, the privation. In what sense
these are two, and in what sense more, has been stated above.
Briefly, we explained first that only the contraries were
principles, and later that a substratum was indispensable, and