SUMMA THEOLOGICA. Thomas Aquinas
I may by any means comprehend [Douay: 'apprehend']." But the Apostle did not follow in vain; for he said (1 Cor. 9:26): "I . . . so run, not as at an uncertainty." Therefore he comprehended; and in the same way, others also, whom he invites to do the same, saying: "So run that you may comprehend."
Objection 2: Further, Augustine says (De Vid. Deum, Ep. cxlvii): "That is comprehended which is so seen as a whole, that nothing of it is hidden from the seer." But if God is seen in His essence, He is seen whole, and nothing of Him is hidden from the seer, since God is simple. Therefore whoever sees His essence, comprehends Him.
Objection 3: Further, if we say that He is seen as a "whole," but not "wholly," it may be contrarily urged that "wholly" refers either to the mode of the seer, or to the mode of the thing seen. But he who sees the essence of God, sees Him wholly, if the mode of the thing seen is considered; forasmuch as he sees Him as He is; also, likewise, he sees Him wholly if the mode of the seer is meant, forasmuch as the intellect will with its full power see the Divine essence. Therefore all who see the essence of God see Him wholly; therefore they comprehend Him.
On the contrary, It is written: "O most mighty, great, and powerful, the Lord of hosts is Thy Name. Great in counsel, and incomprehensible in thought" (Jer. 32:18,19). Therefore He cannot be comprehended.
I answer that, It is impossible for any created intellect to comprehend God; yet "for the mind to attain to God in some degree is great beatitude," as Augustine says (De Verb. Dim., Serm. xxxvii).
In proof of this we must consider that what is comprehended is perfectly known; and that is perfectly known which is known so far as it can be known. Thus, if anything which is capable of scientific demonstration is held only by an opinion resting on a probably proof, it is not comprehended; as, for instance, if anyone knows by scientific demonstration that a triangle has three angles equal to two right angles, he comprehends that truth; whereas if anyone accepts it as a probable opinion because wise men or most men teach it, he cannot be said to comprehend the thing itself, because he does not attain to that perfect mode of knowledge of which it is intrinsically capable. But no created intellect can attain to that perfect mode of the knowledge of the Divine intellect whereof it is intrinsically capable. Which thus appears---Everything is knowable according to its actuality. But God, whose being is infinite, as was shown above ( Question [7]) is infinitely knowable. Now no created intellect can know God infinitely. For the created intellect knows the Divine essence more or less perfectly in proportion as it receives a greater or lesser light of glory. Since therefore the created light of glory received into any created intellect cannot be infinite, it is clearly impossible for any created intellect to know God in an infinite degree. Hence it is impossible that it should comprehend God.
Reply to Objection 1: "Comprehension" is twofold: in one sense it is taken strictly and properly, according as something is included in the one comprehending; and thus in no way is God comprehended either by intellect, or in any other way; forasmuch as He is infinite and cannot be included in any finite being; so that no finite being can contain Him infinitely, in the degree of His own infinity. In this sense we now take comprehension. But in another sense "comprehension" is taken more largely as opposed to "non-attainment"; for he who attains to anyone is said to comprehend him when he attains to him. And in this sense God is comprehended by the blessed, according to the words, "I held him, and I will not let him go" (Cant 3:4); in this sense also are to be understood the words quoted from the Apostle concerning comprehension. And in this way "comprehension" is one of the three prerogatives of the soul, responding to hope, as vision responds to faith, and fruition responds to charity. For even among ourselves not everything seen is held or possessed, forasmuch as things either appear sometimes afar off, or they are not in our power of attainment. Neither, again, do we always enjoy what we possess; either because we find no pleasure in them, or because such things are not the ultimate end of our desire, so as to satisfy and quell it. But the blessed possess these three things in God; because they see Him, and in seeing Him, possess Him as present, having the power to see Him always; and possessing Him, they enjoy Him as the ultimate fulfilment of desire.
Reply to Objection 2: God is called incomprehensible not because anything of Him is not seen; but because He is not seen as perfectly as He is capable of being seen; thus when any demonstrable proposition is known by probable reason only, it does not follow that any part of it is unknown, either the subject, or the predicate, or the composition; but that it is not as perfectly known as it is capable of being known. Hence Augustine, in his definition of comprehension, says the whole is comprehended when it is seen in such a way that nothing of it is hidden from the seer, or when its boundaries can be completely viewed or traced; for the boundaries of a thing are said to be completely surveyed when the end of the knowledge of it is attained.
Reply to Objection 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.
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.
Objection 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.
Objection 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.
Objection 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 ( Article [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 to Objection 1: Gregory speaks as regards the object being sufficient, namely, God, who in Himself sufficiently