Whether an Angel's Act of Understanding Is His Substance?
Objection 1: It would seem that the angel's act of understanding is
his substance. For the angel is both higher and simpler than the
active intellect of a soul. But the substance of the active intellect
is its own action; as is evident from Aristotle (De Anima iii) and
from his Commentator [*Averroes, A.D. 1126-1198]. Therefore much more
is the angel's substance his action--that is, his act of
understanding.
Obj. 2: Further, the Philosopher says (Metaph. xii, text 39) that
"the action of the intellect is life." But "since in living things to
live is to be," as he says (De Anima ii, text 37), it seems that life
is essence. Therefore the action of the intellect is the essence of
an angel who understands.
Obj. 3: Further, if the extremes be one, then the middle does not
differ from them; because extreme is farther from extreme than the
middle is. But in an angel the intellect and the object understood
are the same, at least in so far as he understands his own essence.
Therefore the act of understanding, which is between the intellect
and the thing understood, is one with the substance of the angel who
understands.
_On the contrary,_ The action of anything differs more from its
substance than does its existence. But no creature's existence is its
substance, for this belongs to God only, as is evident from what was
said above (Q. 3, A. 4). Therefore neither the action of an angel,
nor of any other creature, is its substance.
_I answer that,_ It is impossible for the action of an angel, or of
any creature, to be its own substance. For an action is properly the
actuality of a power; just as existence is the actuality of a
substance or of an essence. Now it is impossible for anything which
is not a pure act, but which has some admixture of potentiality, to
be its own actuality: because actuality is opposed to potentiality.
But God alone is pure act. Hence only in God is His substance the
same as His existence and His action.
Besides, if an angel's act of understanding were his substance, it
would be necessary for it to be subsisting. Now a subsisting act of
intelligence can be but one; just as an abstract thing that subsists.
Consequently an angel's substance would neither be distinguished from
God's substance, which is His very act of understanding subsisting in
itself, nor from the substance of another angel.
Also, if the angel were his own act of understanding, there could then
be no degrees of understanding more or less perfectly; for this comes
about through the diverse participation of the act of understanding.
Reply Obj. 1: When the active intellect is said to be its own action,
such predication is not essential, but concomitant, because, since
its very nature consists in act, instantly, so far as lies in itself,
action accompanies it: which cannot be said of the passive intellect,
for this has no actions until after it has been reduced to act.
Reply Obj. 2: The relation between "life" and "to live" is not the
same as that between "essence" and "to be"; but rather as that
between "a race" and "to run," one of which signifies the act in the
abstract, and the other in the concrete. Hence it does not follow,
if "to live" is "to be," that "life" is "essence." Although life is
sometimes put for the essence, as Augustine says (De Trin. x),
"Memory and understanding and will are one essence, one life": yet it
is not taken in this sense by the Philosopher, when he says that "the
act of the intellect is life."
Reply Obj. 3: The action which is transient, passing to some
extrinsic object, is really a medium between the agent and the
subject receiving the action. The action which remains within the
agent, is not really a medium between the agent and the object, but
only according to the manner of expression; for it really follows the
union of the object with the agent. For the act of understanding is
brought about by the union of the object understood with the one who
understands it, as an effect which differs from both.
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