Reply Obj. 3: The word "wholly" denotes a mode of the object; not that the whole object does not come under knowledge, but that the mode of the object is not the mode of the one who knows. Therefore he who sees God's essence, sees in Him that He exists infinitely, and is infinitely knowable; nevertheless, this infinite mode does not extend to enable the knower to know infinitely; thus, for instance, a person can have a probable opinion that a proposition is demonstrable, although he himself does not know it as demonstrated. _______________________
EIGHTH ARTICLE [I, Q. 12, Art. 8]
Whether Those Who See the Essence of God See All in God?
Objection 1: It seems that those who see the essence of God see all things in God. For Gregory says (Dialog. iv): "What do they not see, who see Him Who sees all things?" But God sees all things. Therefore those who see God see all things.
Obj. 2: Further, whoever sees a mirror, sees what is reflected in the mirror. But all actual or possible things shine forth in God as in a mirror; for He knows all things in Himself. Therefore whoever sees God, sees all actual things in Him, and also all possible things.
Obj. 3: Further, whoever understands the greater, can understand the least, as is said in De Anima iii. But all that God does, or can do, are less than His essence. Therefore whoever understands God, can understand all that God does, or can do.
Obj. 4: Further, the rational creature naturally desires to know all things. Therefore if in seeing God it does not know all things, its natural desire will not rest satisfied; thus, in seeing God it will not be fully happy; which is incongruous. Therefore he who sees God knows all things.
On the contrary, The angels see the essence of God; and yet do not know all things. For as Dionysius says (Coel. Hier. vii), "the inferior angels are cleansed from ignorance by the superior angels." Also they are ignorant of future contingent things, and of secret thoughts; for this knowledge belongs to God alone. Therefore whosoever sees the essence of God, does not know all things.
I answer that, The created intellect, in seeing the divine essence, does not see in it all that God does or can do. For it is manifest that things are seen in God as they are in Him. But all other things are in God as effects are in the power of their cause. Therefore all things are seen in God as an effect is seen in its cause. Now it is clear that the more perfectly a cause is seen, the more of its effects can be seen in it. For whoever has a lofty understanding, as soon as one demonstrative principle is put before him can gather the knowledge of many conclusions; but this is beyond one of a weaker intellect, for he needs things to be explained to him separately. And so an intellect can know all the effects of a cause and the reasons for those effects in the cause itself, if it comprehends the cause wholly. Now no created intellect can comprehend God wholly, as shown above (A. 7). Therefore no created intellect in seeing God can know all that God does or can do, for this would be to comprehend His power; but of what God does or can do any intellect can know the more, the more perfectly it sees God.
Reply Obj. 1: Gregory speaks as regards the object being sufficient, namely, God, who in Himself sufficiently contains and shows forth all things; but it does not follow that whoever sees God knows all things, for he does not perfectly comprehend Him.