Commentaria in Summam contra Gentiles, Liber III

Having shown that the divine essence is the intelligible form of the intellect seeing God, St. Thomas shows what disposition is required for receiving this form and for having this vision¹. In regard to this he does two things: first, he shows that the intellect cannot by its own power arrive at the vision of the divine essence; second, that for this it needs some influence of divine light, in the following chapter.

I. As to the first, this conclusion is set down: It is not possible that any created substance can attain by its own power to the vision of God through the divine essence itself: namely, sufficiently.

It is proved first. To see God through the divine essence itself is proper to the divine nature: because to operate according to one's own form is proper to every agent. Therefore an intellectual creature cannot attain to that mode of divine vision except by God doing this. — The consequence is proved. Because what is proper to a higher nature, a lower nature cannot attain except through the action of the higher nature to which it is proper: just as water cannot be hot except through the action of fire.

It should be noted that here proper is not taken as excluding everything foreign to the subject, namely for that which belongs to one alone, and to nothing foreign to it, just as risibility is proper to man: because in that way the argument would assume what it ought to prove; for it must be proved that seeing God in that way belongs to no one other than God. But proper is taken for that which is natural to someone according to that by which he differs from others: for this is the foundation and reason that something belongs to one alone; just as risibility therefore belongs to man alone, because it follows from rationality, by which man is distinguished from all others. The sense, therefore, of the argument is that, since seeing God through the divine essence itself is natural to God as to that by which He is distinguished from others, just as it is natural to every agent to operate through its own form; and what is thus natural to a higher nature cannot naturally belong to a lower nature, but, if it belongs to it, this is through the action of the higher nature, just as being hot, which is natural to fire, does not belong to water except through the action of fire: therefore seeing God in that way cannot naturally belong to any rational creature.

II. Second. The proper form of something does not become another's except by that thing acting: for an agent makes something like itself insofar as it communicates its form. Therefore, if the divine essence is the form of the intellect, which is required in the divine vision, this cannot be except through its own action. Therefore, etc.

Note, concerning the proof of the antecedent, that St. Thomas wishes to argue from the conversion of propositions, thus. An agent makes something like itself by communicating its form, and in no other way does it make something like itself. Therefore, conversely, if something is made like someone according to his proper form, it receives such a form from him whose proper form that is.

It should also be noted that this argument differs from the preceding one: because that one proceeds from the fact that the vision of God through the essence is proper to the higher nature; this one, however, proceeds from the fact that the divine essence is the proper form of God.

III. Third. For the intellect to see the divine essence, it is necessary that the divine essence itself be united to the intellect as an intelligible form. Therefore, etc. — The consequence is proved. Because if two things must be united to each other, one of which is formal and the other material, it is necessary that their union be brought about by an action that is on the part of that which is formal, not however by the action of that which is material: since it belongs to form to act, but to matter to be acted upon.

Concerning the proof of the consequence, it should be noted that St. Thomas supposes as manifest that the union of the formal and the material does not come about except through some action: for a form is not united to matter except through the action of something.

He also supposes that by the action of nothing other than the divine essence or the intellect itself can the divine essence be united to the created intellect. Because the divine essence, since it is not material, cannot be united to the possible intellect through abstraction from matter, by the action of the agent intellect; nor even through the action of some other higher agent, since the divine essence is the nature of the supreme agent. Therefore it remains that this is done either through the action of the intellect, whose act is to understand, or through the action of God, who is understood.

These things being supposed, the argument proceeds very well. For the action through which the union of these two is made holds more on the part of the divine essence than on the part of the intellect: since the intellect is compared to it as matter to form. Therefore it is not by the intellect's own power that it is united to the divine essence. And consequently it does not see it by its own power, but by the power of God having the divine nature, such union and such vision are brought about.

IV. Fourth. The created intellect sees the divine substance through the essence of God as through something other than itself. Therefore, etc. — The consequence is proved. Because the divine intellect sees the divine essence through itself: since it is the divine essence itself, as was shown in the First Book. And what is through itself is the cause of what is through another.

Fifth. To see the substance of God transcends the limits of every created nature. Therefore, etc. — The consequence is clear. Because whatever exceeds the limits of some nature cannot belong to it except through the action of another: as is clear concerning upward motion in water. — The antecedent, however, is proved. Because it is proper to every created intellectual nature to understand according to the mode of its substance. The divine substance, however, cannot be understood in that way, as was shown above.

It should be noted that the proper mode of understanding of human nature is to know from sensible things. The proper mode of a separated substance, however, is to understand, not by receiving from sensible things, but through the separated substances themselves, and through species received from the divine light. Above, however, it was shown that the divine substance cannot be understood in any of those modes. Therefore St. Thomas says that it has been shown that the divine substance cannot be understood according to the proper mode of an intellectual substance.

V. Concerning this proposition, It is proper to every created intellectual nature to understand according to the mode of its substance, it must be considered, from the teaching of St. Thomas, Prima, q. XII, a. 4; and q. LXXXIX, a. 2, that since intellection takes place through the intellect being actualized by some intelligible form; and the operation is proportioned to its formal principle, so that the more noble principle has a more noble proper operation, and the more perfect a more perfect one, and so that it cannot extend beyond the condition of that principle itself: therefore it is necessary that the mode of intellection be taken from the condition of the intelligible species by which the intellect understands. The condition of the intelligible species, however, is proportioned to the nature of the one understanding: because, namely, insofar as the species is of the thing understood, it receives determination and limitation, according to its perfection, from the condition of the nature of the one understanding. For if the nature understanding some thing is of the same mode of being as the thing understood, the intelligible species by which it naturally understands that thing will be the perfect form of the thing understood, because of the adequation of the one understanding to the thing understood in the mode of being. If, however, the nature understanding is of a lower mode of being than the thing understood, the intelligible form itself will be an imperfect intelligible form of the thing understood, representing it not quidditatively, but imperfectly: and thus it is in such a one understanding in a more imperfect way than it is in itself. It follows, therefore, that the cognition of some thing understood is also proportioned to the mode of the nature of the one knowing: because, namely, if the knowing nature adequates the thing known as to the mode of being, the natural cognition of the one understanding concerning such a thing will be its perfect cognition; if, however, the knowing nature is of a lower order and mode of being than the thing understood, the cognition that it naturally has of such a thing will not be a perfect and quidditative cognition of it, but will be inferior to that perfect cognition; and consequently the perfect cognition of such a thing will be above the natural cognition of such a knowing nature. For this reason St. Thomas rightly infers, Prima, q. XII, a. 4, that, because the cognition of every knower is according to the mode of the knowing nature, if the mode of being of some thing known exceeds the mode of the knowing nature, it is necessary that the cognition of that thing be above the nature of that knower.

Since, therefore, every created intellectual nature is of a limited and finite nature, falling short of the divine nature, all the intelligible species of a created intellectual nature, by which it naturally understands, agree in this: that they are limited and finite forms, representing limited and finite natures, and falling far short of the divine nature and quiddity according to their ratio and representation. And therefore through species of this kind the divine essence cannot be known quidditatively: but every such cognition falls short of its perfect cognition.

VI. From these things it is clear that the instances of Scotus, I Sent., d. III, q. III; Quolib., q. XIV, a. 2; and IV Sent., d. XLIX, q. XI, against St. Thomas, are of no moment. For St. Thomas does not intend, as that one thinks, that there must be an absolute equality between the nature of the one understanding and the object naturally and quidditatively known, or an excess of the nature of the one understanding: but he understands that there must be between the object and the nature of the one knowing such a proportion that that object is apt to be known through intelligible species suitable and connatural to such a nature. And because the species connatural to it are those that are likenesses of things of the same order as itself, or of a lower order; things of the same order, in this connection, are called those to which the same general mode of being is due: therefore between the knower and the known there must be a conformity in the same mode of being, or an excess of the knower over the known.

2. Nor does what he brings forward in opposition ² about the eye seeing heaven and earth, which, however, according to him, do not agree in the same mode of being, since the eye is corruptible and they are incorruptible; and about the intelligible species, which does not have the same mode of being as the object, since that one has accidental being, but the object has substantial being — this does not prevail.

For it is said first, that the eye and heaven and earth agree in this general mode of being, because they are natures having being in individual matter: although, under this genus, the eye has corruptible being, while they have incorruptible being.

It is said second, that the intelligible species of a material thing agrees in the mode of being with the material thing, not indeed as to the particular mode of being which it has insofar as it informs the intellect, but as to that which is naturally due to it insofar as it is such a nature and such a quiddity: for it was said above³ that the form that is in the intellect is of the same species as the thing understood, indeed, it is the species of the thing understood. Therefore, just as such a mode of being, namely having substantial being in matter, belongs to the thing understood, so such being is naturally due to its intelligible species, insofar as it is the species or nature of the thing understood; although, beyond its nature, from the action of the agent intellect and the condition of the possible intellect, it has another mode of being in the subject in which it is. Hence they are of the same mode of being naturally due to them, although they are not of the same mode of being as to the being which they actually have.

3. Nor does it follow that a lower angel would never know a higher one⁴. — For we say that all angels agree in the same general mode of being. For there are three genera of being, according to which the three orders of things are taken, as St. Thomas lays down, Prima, q. xii, a. 4: namely, being in this individual matter, in which all material sensible things agree; being separated from matter, yet distinct from the essence of which it is, in which all angels agree, although in that genus they have degrees; and being altogether separated from matter, which is not distinguished from the essence, which mode of being belongs to God alone.

4. What he moreover infers⁵, that then the intellect, even with the light of glory, will not be able to see God, because God exceeds the intellect even illumined with the light of glory: this, however, is false: — this does not compel. For first it can be answered, as others answer⁶, that this is not against the mind of St. Thomas. Because he does not say that a nature of a lower mode of being can in no way know a nature of a higher mode of being: but that it cannot know it by its own powers, or by its own power, as to quidditative cognition. Hence, if the consequent is understood absolutely, the consequence is denied. If, however, it is understood of the natural cognition which is from the power of one's own nature, and of quidditative cognition, the falsity of the consequent is denied.

But because someone could say that, although the intellect by itself cannot naturally see the divine essence, this vision is nevertheless natural to it as it stands under the light of glory: just as, although it is not natural for water to heat if taken by itself, and however hot it may be, this never belongs to it naturally insofar as it is water; yet water insofar as it is hot naturally heats, because that action naturally follows from heat: — therefore, second, it can be answered by absolutely denying the consequence. And to the proof, it is denied that God exceeds the intellect, as illumined with the light of glory, with that excess which impedes the vision of Him. Rather, the intellect thus illumined is of the same order with God: as will be declared in the following chapter.

VII. The conclusion is confirmed first by the authority of the Apostle, Rom. vi, saying: The grace of God is eternal life. This is said because to the vision itself of God, in which beatitude consists, which is called eternal life, man cannot arrive except by a divine gift, since it exceeds the capacity of a creature: for things that come to a creature in this way are attributed to divine grace.

It is confirmed second by Ioan. xiv, when it is said: I will manifest myself to him.