summa-contra-gentiles

CHAPTER LIV 127
Wherefore in things composed of matter and form,
neither matter nor form, nor even being itself, can be^
described as that which is. Yet the form can be described
as that ivhereby it is, forasmuch as it is the principle of
being: but the whole substance is what is; and being
is
that whereby the substance is called a being.
But in intellectual substances, which are not composed
of matter and form, as shown
^
above, and wherein the form
itself is a subsistent substance, the form is-whxit is, and
being is the act whereby
it is.
Consequently in them there is but one composition of
act and potentiality, a composition namely of substance and
being, which by some is said to be of what is and hevngf or
of what is and whereby
it is.
On the other hand in things composed of matter and
form there is a twofold composition of act and poten- ^
tiality : the first, of the substance itself which is composed
of matter and form ;
the second, of the already
composite substance, and being, which composition can
also be said to be of what is and being, or of what is and
whereby
it is. «^u4«sV
It is therefore evident that composition of act and potentiality
covers more ground than composition of form and
matter. Wherefore matter and form divide a natural
substance, while potentiality and act divide being in
general. For this reason whatever is
consequent upon
potentiality and act, as such, is common to created substances
whether material or immaterial ;
for instance to
receive and to be received, to perfect and to be perfected.
Whereas whatsoever things are proper to matter and form,
as such, for instance to be generated and to he corrupted
and so forth, are proper to material substances, and are
nowise applicable to created immaterial substances.
1 Chs. 1., li.