er Than Himself?

Objection 1: It seems that God does not know things besides Himself.
For all other things but God are outside of God. But Augustine says
(Octog. Tri. Quaest. qu. xlvi) that "God does not behold anything out
of Himself." Therefore He does not know things other than Himself.

Obj. 2: Further, the object understood is the perfection of the one
who understands. If therefore God understands other things besides
Himself, something else will be the perfection of God, and will be
nobler than He; which is impossible.

Obj. 3: Further, the act of understanding is specified by the
intelligible object, as is every other act from its own object. Hence
the intellectual act is so much the nobler, the nobler the object
understood. But God is His own intellectual act. If therefore God
understands anything other than Himself, then God Himself is specified
by something else than Himself; which cannot be. Therefore He does not
understand things other than Himself.

_On the contrary,_ It is written: "All things are naked and open to His
eyes" (Heb. 4:13).

_I answer that,_ God necessarily knows things other than Himself. For
it is manifest that He perfectly understands Himself; otherwise His
existence would not be perfect, since His existence is His act of
understanding. Now if anything is perfectly known, it follows of
necessity that its power is perfectly known. But the power of
anything can be perfectly known only by knowing to what its power
extends. Since therefore the divine power extends to other things by
the very fact that it is the first effective cause of all things, as
is clear from the aforesaid (Q. 2, A. 3), God must necessarily know
things other than Himself. And this appears still more plainly if we
add that the very existence of the first effective cause--viz.
God--is His own act of understanding. Hence whatever effects
pre-exist in God, as in the first cause, must be in His act of
understanding, and all things must be in Him according to an
intelligible mode: for everything which is in another, is in it
according to the mode of that in which it is.

Now in order to know how God knows things other than Himself, we must
consider that a thing is known in two ways: in itself, and in another.
A thing is known in itself when it is known by the proper species
adequate to the knowable object; as when the eye sees a man through
the image of a man. A thing is seen in another through the image of
that which