Whether the Formless Matter of All Corporeal Things Is the Same?
Objection 1: It would seem that the formless matter of all corporeal
things is the same. For Augustine says (Confess. xii, 12): "I find
two things Thou hast made, one formed, the other formless," and he
says that the latter was the earth invisible and shapeless, whereby,
he says, the matter of all corporeal things is designated. Therefore
the matter of all corporeal things is the same.
Obj. 2: Further, the Philosopher says (Metaph. v, text. 10): "Things
that are one in genus are one in matter." But all corporeal things
are in the same genus of body. Therefore the matter of all bodies is
the same.
Obj. 3: Further, different acts befit different potentialities, and
the same act befits the same potentiality. But all bodies have the
same form, corporeity. Therefore all bodies have the same matter.
Obj. 4: Further, matter, considered in itself, is only in
potentiality. But distinction is due to form. Therefore matter
considered in itself is the same in all corporeal things.
_On the contrary,_ Things of which the matter is the same are
mutually interchangeable and mutually active or passive, as is said
(De Gener. i, text. 50). But heavenly and earthly bodies do not act
upon each other mutually. Therefore their matter is not the same.
_I answer that,_ On this question the opinions of philosophers have
differed. Plato and all who preceded Aristotle held that all bodies
are of the nature of the four elements. Hence because the four
elements have one common matter, as their mutual generation and
corruption prove, it followed that the matter of all bodies is the
same. But the fact of the incorruptibility of some bodies was ascribed
by Plato, not to the condition of matter, but to the will of the
artificer, God, Whom he represents as saying to the heavenly bodies:
"By your own nature you are subject to dissolution, but by My will you
are indissoluble, for My will is more powerful than the link that
binds you together." But this theory Aristotle (De Caelo i, text. 5)
disproves by the natural movements of bodies. For since, he says, the
heavenly bodies have a natural movement, different from that of the
elements, it follows that they have a different nature from them. For
movement in a circle, which is proper to the heavenly bodies, is not
by contraries, whereas the movements of the elements are mutually
opposite, one tending upwards, another downwards: so, therefore, the
heavenly body is without contrariety, whereas the elemental bodies
have contrariety in their nature. And as generation and corruption are
from contraries, it follows that, whereas the elements are
corruptible, the heavenly bodies are incorruptible. But in spite of
this difference of natural corruption and incorruption, Avicebron
taught unity of matter in all bodies, arguing from their unity of
form. And, indeed, if corporeity were one form in itself, on which the
other forms that distinguish bodies from each other supervene, this
argument would necessarily be true; for this form of corporeity would
inhere in matter immutably and so far all bodies would be
incorruptible. But corruption would then be merely accidental through
the disappearance of successive forms--that is to say, it would be
corruption, not pure and simple, but partial, since a being in act
would subsist under the transient form. Thus the ancient natural
philosophers taught that the substratum of bodies was some actual
being, such as air or fire. But supposing that no form exists in
corruptible bodies which remains subsisting beneath generation and
corruption, it follows necessarily that the matter of corruptible and
incorruptible bodies is not the same. For matter, as it is in itself,
is in potentiality to form.
Considered in itself, then, it is in potentiality in respect to all
those forms to which it is common, and in receiving any one form it is
in act only as regards that form. Hence it remains in potentiality to
all other forms. And this is the case even where some forms are more
perfect than others, and contain these others virtually in themselves.
For potentiality in itself is indifferent with respect to perfection
and imperfection, so that under an imperfect form it is in
potentiality to a perfect form, and _vice versa._ Matter, therefore,
whilst existing under the form of an incorruptible body, would be in
potentiality to the form of a corruptible body; and as it does not
actually possess the latter, it has both form and the privation of
form; for want of a form in that which is in potentiality thereto is
privation. But this condition implies corruptibility. It is therefore
impossible that bodies by nature corruptible, and those by nature
incorruptible, should possess the same matter.
Neither can we say, as Averroes [*De Substantia Orbis ii.] imagines,
that a heavenly body itself is the matter of the heaven--being in
potentiality with regard to place, though not to being, and that its
form is a separate substance united to it as its motive force. For it
is impossible to suppose any being in act, unless in its totality it
be act and form, or be something which has act or form. Setting aside,
then, in thought, the separate substance stated to be endowed with
motive power, if the heavenly body is not something having form--that
is, something composed of a form and the subject of that form--it
follows that in its totality it is form and act. But every such thing
is something actually understood, which the heavenly bodies are not,
being sensible. It follows, then, that the matter of the heavenly
bodies, considered in itself, is in potentiality to that form alone
which it actually possesses. Nor does it concern the point at issue to
inquire whether this is a soul or any other thing. Hence this form
perfects this matter in such a way that there remains in it no
potentiality with respect to being, but only to place, as Aristotle
[*De Coelo i, text. 20] says. So, then, the matter of the heavenly
bodies and of the elements is not the same, except by analogy, in so
far as they agree in the character of potentiality.
Reply Obj. 1: Augustine follows in this the opinion of Plato,
who does not admit a fifth essence. Or we may say that formless matter
is one with the unity of order, as all bodies are one in the order of
corporeal creatures.
Reply Obj. 2: If genus is taken in a physical sense,
corruptible and incorruptible things are not in the same genus, on
account of their different modes of potentiality, as is said in
_Metaph._ x, text. 26. Logically considered, however, there is but one
genus of all bodies, since they are all included in the one notion of
corporeity.
Reply Obj. 3: The form of corporeity is not one and the same
in all bodies, being no other than the various forms by which bodies
are distinguished, as stated above.
Reply Obj. 4: As potentiality is directed towards act,
potential beings are differentiated by their different acts, as sight
is by color, hearing by sound. Therefore for this reason the matter of
the celestial bodies is different from that of the elemental, because
the matter of the celestial is not in potentiality to an elemental
form.
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