This, however, does not happen in
our intellect, which discourses from one thing to another, forasmuch
as the intelligible species represents one thing in such a way as not
to represent another. Hence when we understand what man is, we do not
forthwith understand other things which belong to him, but we
understand them one by one, according to a certain succession. On this
account the things we understand as separated, we must reduce to one
by way of composition or division, by forming an enunciation. Now the
species of the divine intellect, which is God's essence, suffices to
represent all things. Hence by understanding His essence, God knows
the essences of all things, and also whatever can be accidental to
them.

Reply Obj. 1: This objection would avail if God knew enunciable
things after the manner of enunciable things.

Reply Obj. 2: Enunciatory composition signifies some existence of a
thing; and thus God by His existence, which is His essence, is the
similitude of all those things which are signified by enunciation.
_______________________

FIFTEENTH ARTICLE [I, Q. 14, Art. 15]

Whether the Knowledge of God Is Variable?

Objection 1: It seems that the knowledge of God is variable. For
knowledge is related to what is knowable. But whatever imports
relation to the creature is applied to God from time, and varies
according to the variation of creatures. Therefore the knowledge of
God is variable according to the variation of creatures.

Obj. 2: Further, whatever God can make, He can know. But God can
make more than He does. Therefore He can know more than He knows.
Thus His knowledge can vary according to increase and diminution.

Obj. 3: Further, God knew that Christ would be born. But He does
not know now that Christ will be born; because Christ is not to be
born in the future. Therefore God does not know everything He once
knew; and thus the knowledge of God is variable.

_On the contrary,_ It is said, that in God "there is no change nor
shadow of alteration" (James 1:17).

_I answer that,_ Since the knowledge of God is His substance, as is
clear from the foregoing (A. 4), just as His substance is altogether
immutable, as shown above (Q. 9, A. 1), so His knowledge likewise
must be altogether invariable.

Reply Obj. 1: "Lord", "Creator" and the like, import relations to
creatures in so far as they are in themselves. But the knowledge of
God imports relation to creatures in so far as they are in God;