Thomas Aquinas - Summa Theologica, Part I (Prima Pars)

Reply Obj. 1: So to know a thing as it is in the knower, may be understood in two ways. In one way this adverb "so" imports the mode of knowledge on the part of the thing known; and in that sense it is false. For the knower does not always know the object known according to the existence it has in the knower; since the eye does not know a stone according to the existence it has in the eye; but by the image of the stone which is in the eye, the eye knows the stone according to its existence outside the eye. And if any knower has a knowledge of the object known according to the (mode of) existence it has in the knower, the knower nevertheless knows it according to its (mode of) existence outside the knower; thus the intellect knows a stone according to the intelligible existence it has in the intellect, inasmuch as it knows that it understands; while nevertheless it knows what a stone is in its own nature. If however the adverb 'so' be understood to import the mode (of knowledge) on the part of the knower, in that sense it is true that only the knower has knowledge of the object known as it is in the knower; for the more perfectly the thing known is in the knower, the more perfect is the mode of knowledge.

We must say therefore that God not only knows that all things are in Himself; but by the fact that they are in Him, He knows them in their own nature and all the more perfectly, the more perfectly each one is in Him.

Reply Obj. 2: The created essence is compared to the essence of God as the imperfect to the perfect act. Therefore the created essence cannot sufficiently lead us to the knowledge of the divine essence, but rather the converse.

Reply Obj. 3: The same thing cannot be taken in an equal manner as the ratio of different things. But the divine essence excels all creatures. Hence it can be taken as the proper ratio of each thing according to the diverse ways in which diverse creatures participate in, and imitate it. _______________________

SEVENTH ARTICLE [I, Q. 14, Art. 7]

Whether the Knowledge of God Is Discursive?

Objection 1: It seems that the knowledge of God is discursive. For the knowledge of God is not habitual knowledge, but actual knowledge. Now the Philosopher says (Topic. ii): "The habit of knowledge may regard many things at once; but actual understanding regards only one thing at a time." Therefore as God knows many things, Himself and others, as shown above (AA. 2, 5), it seems that He does not understand all at once, but discourses from one to another.

Obj. 2: Further, discursive knowledge is to know the effect through its cause. But God knows things through Himself; as an effect (is known) through its cause. Therefore His knowledge is discursive.

Obj. 3: Further, God knows each creature more perfectly than we know it. But we know the effects in their created causes; and thus we go discursively from causes to things caused. Therefore it seems that the same applies to God.

On the contrary, Augustine says (De Trin. xv), "God does not see all things in their particularity or separately, as if He saw alternately here and there; but He sees all things together at once."

I answer that, In the divine knowledge there is no discursion; the proof of which is as follows. In our knowledge there is a twofold discursion: one is according to succession only, as when we have actually understood anything, we turn ourselves to understand something else; while the other mode of discursion is according to causality, as when through principles we arrive at the knowledge of conclusions. The first kind of discursion cannot belong to God. For many things, which we understand in succession if each is considered in itself, we understand simultaneously if we see them in some one thing; if, for instance, we understand the parts in the whole, or see different things in a mirror. Now God sees all things in one (thing), which is Himself. Therefore God sees all things together, and not successively. Likewise the second mode of discursion cannot be applied to God. First, because this second mode of discursion presupposes the first mode; for whosoever proceeds from principles to conclusions does not consider both at once; secondly, because to discourse thus is to proceed from the known to the unknown. Hence it is manifest that when the first is known, the second is still unknown; and thus the second is known not in the first, but from the first. Now the term of discursive reasoning is attained when the second is seen in the first, by resolving the effects into their causes; and then the discursion ceases. Hence as God sees His effects in Himself as their cause, His knowledge is not discursive.

Reply Obj. 1: Although there is only one act of understanding in itself, nevertheless many things may be understood in one (medium), as shown above.

Reply Obj. 2: God does not know by their cause, known, as it were previously, effects unknown; but He knows the effects in the cause; and hence His knowledge is not discursive, as was shown above.

Reply Obj. 3: God sees the effects of created causes in the causes themselves, much better than we can; but still not in such a manner that the knowledge of the effects is caused in Him by the knowledge of the created causes, as is the case with us; and hence His knowledge is not discursive. _______________________

EIGHTH ARTICLE [I, Q. 14, Art. 8]

Whether the Knowledge of God Is the Cause of Things?

Objection 1: It seems that the knowledge of God is not the cause of things. For Origen says, on Rom. 8:30, "Whom He called, them He also justified," etc.: "A thing will happen not because God knows it as future; but because it is future, it is on that account known by God, before it exists."

Obj. 2: Further, given the cause, the effect follows. But the knowledge of God is eternal. Therefore if the knowledge of God is the cause of things created, it seems that creatures are eternal.

Obj. 3: Further, "The thing known is prior to knowledge, and is its measure," as the Philosopher says (Metaph. x). But what is posterior and measured cannot be a cause. Therefore the knowledge of God is not the cause of things.

On the contrary, Augustine says (De Trin. xv), "Not because they are, does God know all creatures spiritual and temporal, but because He knows them, therefore they are."

I answer that, The knowledge of God is the cause of things. For the knowledge of God is to all creatures what the knowledge of the artificer is to things made by his art. Now the knowledge of the artificer is the cause of the things made by his art from the fact that the artificer works by his intellect. Hence the form of the intellect must be the principle of action; as heat is the principle of heating. Nevertheless, we must observe that a natural form, being a form that remains in that to which it gives existence, denotes a principle of action according only as it has an inclination to an effect; and likewise, the intelligible form does not denote a principle of action in so far as it resides in the one who understands unless there is added to it the inclination to an effect, which inclination is through the will. For since the intelligible form has a relation to opposite things (inasmuch as the same knowledge relates to opposites), it would not produce a determinate effect unless it were determined to one thing by the appetite, as the Philosopher says (Metaph. ix). Now it is manifest that God causes things by His intellect, since His being is His act of understanding; and hence His knowledge must be the cause of things, in so far as His will is joined to it. Hence the knowledge of God as the cause of things is usually called the "knowledge of approbation."

Reply Obj. 1: Origen spoke in reference to that aspect of knowledge to which the idea of causality does not belong unless the will is joined to it, as is said above.