Commentaria in Summam contra Gentiles, Liber II

After St. Thomas has determined the question of the cognition of separate substance with respect to its objects absolutely, he determines, in the final place, the simultaneity of those objects in their cognized esse.¹

First, he raises the doubt; second, he responds by determining the truth².

I. As to the first: it seems that there cannot be several intelligibles simultaneously in the intellect of a separate substance according to their species. For intellect in act is the intelligible in act. But one and the same thing cannot be many things in act at once. Therefore, etc.

II. Saint Thomas answers first, to the major: that not everything whose intelligible species is in the intellect is understood in act, as is supposed. For, since the intelligent substance is also willing, it is within its power, after it has the intelligible species, to use it by understanding in act; and if it has several, to use one of them.

Second, he responds to the minor premise: that * all things that a separate substance knows through one species, it knows in act simultaneously. And then those things are as one intelligible: just as our intellect knows many things at once as one. But things it knows through diverse species, it does not know simultaneously. And therefore, just as there is one intellect in act, so there is one thing understood in act.*

From these it follows that in the intellect of a separate substance there is a certain succession of intelligences or intellections, yet not motion, properly speaking: since act does not succeed potency, but act succeeds act. — In the divine intellect, however, which understands all things at once, because it knows all things through its essence and its action is its essence, there is no succession of intellections, but its understanding is wholly simultaneous, etc.

III. For the clarification of what is said in this place, it must be considered, according to the doctrine of Saint Thomas Verit., q. viii, a. 14, that intelligible species can exist actually in the intellect in two ways: namely, in imperfect act, when the intellect does not actually consider by means of them; and in perfect act, when it considers actually according to them. When they are in the latter imperfect act, the intellect is said to be in act imperfectly; and likewise those things of which they are the likenesses are understood in act imperfectly, or understood in habit. But when they are in the latter perfect act, then the intellect is said to be in act perfectly, and the thing understood is understood in act perfectly. Therefore, when Saint Thomas says not everything whose species is in the intellect is understood in act, this must be understood of the thing understood in act completely and perfectly. For thus it is repugnant that several things understood in act should be simultaneously in the intellect (according to the argument of Algazel³), just as it is repugnant that one body should be figured by diverse figures according to the same part: but not that several things be understood in act imperfectly, or habitually.

IV. But a doubt arises concerning what is adduced as the reason for that statement, namely that the understanding substance is also willing, and therefore it is within its power to use the species for actually understanding. For this does not seem true, for two reasons. First, because the species is a natural agent.

Second, because then a separate substance understanding by some species would previously will, at least by priority of nature, to understand by that species. But the will cannot will something unknown, according to Augustine, X Trin., chapter 1. Therefore that volition was preceded by cognition of that species; and if that cognition was preceded by another volition, that volition is preceded by another intellection; and so on to infinity.

2. To the first, one may first reply, as Capreolus replies in II Sent.⁴, that although the intelligible species is a form naturally acting, it does not proceed into act except through the will. Thus it is not removed that it lies within the power of the intelligent substance whether it understands through it or does not understand.

Second, it can be answered—and perhaps better—that the intelligible species is not a natural agent, neither as an agent that acts nor as an agent by which something acts. For it belongs to the notion of a natural agent that acts that it be determined to one effect, so that it cannot fail to act if a suitably disposed patient is brought near and impediments are removed, as is clear from Book IX of the Metaphysics.⁵ And it belongs to the notion of a natural agent by which something acts that the agent be determined to one thing and not be able through it not to act. But it is evident that neither of these belongs to the species: for it does not produce intellection as the thing that brings it about; nor does the intellect possessing the species through it necessarily understand, as we experience in ourselves. Therefore it should rather be said to be the formal principle of intellection in a free manner: not indeed having freedom formally in itself, for this is the condition belonging principally to the agent; but because the substance possessing it operates freely by means of it.

3. To the second it is said that knowledge is twofold: one confused and indeterminate; the other distinct and determinate. Distinct and determinate knowledge must precede volition, but not every confused knowledge. And thus there is no regress to infinity. — Saint Thomas therefore intends to speak of distinct knowledge through a species, not of confused and indeterminate knowledge. For in us, from something occurring to the senses, the intellect is aroused to some confused knowledge of a thing; and from that the will is moved to desire distinct knowledge of it; and thus the will moves the intellect to that distinct knowledge of it. In separate substances, however, since there is no sense to which anything could occur unexpectedly, I think that confused and indeterminate knowledge does not come from without but from within. For since a separate substance always sees its own substance in act and all its natural perfections, it always beholds the intelligible species existing in its intellect, insofar as its natural conditions are ordered to understanding things; and from this it has confused and indeterminate knowledge of all things naturally knowable by it. Hence it lies within its power to use any of them it wills for distinct knowledge.

It may also be said that every actual cognition is preceded by volition, except the first cognition, which God causes immediately in the intellect. Yet not every volition is necessarily preceded by an actual cognition: it suffices that it be preceded by an actual or habitual cognition. And therefore, in order for someone to will to use one of the species he possesses, no actual knowledge is required; habitual knowledge through the species itself and the freedom of the knower suffice. Hence the Commentator, III de Anima ⁶, says that habit is that by which one uses something when one wills.

V. Concerning the reply to the minor ⁷, note that from that passage Saint Thomas wishes to have it that the same thing can be many in some way in act insofar as those things are one, but not insofar as they are many. And because things understood through diverse species, insofar as they are diverse, are formally many intelligibles, therefore the intellect cannot be simultaneously those many things in perfect act. But things understood through one species are not formally many intelligibles, but one. Therefore the intellect can be simultaneously those many things in perfect act. For then, just as there is one intellect in act insofar as it understands by a single species, so there is one thing understood in act, insofar as those many things are understood by a single species.

But note, as was made clear above ⁸, that not only from the unity of species are many things represented by one species said to be one intelligible, but also from a single formal ratio found in them. For it was said above, according to the mind of St. Thomas, that to one intelligible species there must correspond one formal ratio. And by this many things have it that they are formally one intelligible, and are knowable by the intellect in one act. — That this is indeed the mind of St. Thomas is evident, because here he illustrates in our intellect with respect to many things composed or related to one another, which are agreed to converge in one common ratio. And in the First Part, at the place cited ⁹, he illustrates with the parts of a continuum and of a proposition, which converge in the whole, and with things compared, which converge in one comparison.

VI. Concerning what Saint Thomas says ¹⁰, namely that all things which an intelligence knows through one species it knows simultaneously in act, a curious doubt arises. Whether, I say, it knows those things simultaneously in such a way that it necessarily knows all of them at once, and cannot consider one without considering the other? Or whether it should rather be said that it can know all those things simultaneously, yet can nevertheless consider one without the other if it wills? For example, since it knows all actually existing human individuals through the species of the quiddity of man, the doubt is whether, using the species of human quiddity, it necessarily sees and considers all men, and cannot consider one man without considering all; or whether by means of it it can consider the Emperor without considering the King of France?

For both seem to have a reason. For that God necessarily sees all things can be proved, because the intelligible species naturally and equally represents all things actually existing that are intelligible through it. Therefore, if the intellect understands by one species, it cannot fail to consider all things intelligible through it, since that species cannot fail to represent them. — It is also confirmed. Because we see that God cannot fail to have actual consideration of all intelligibles, since the divine essence naturally represents all things, at least positive ones.

That the angel does not see necessarily can be argued as follows: our intellect, understanding through the species of man, does not necessarily consider all things knowable about man through that species; for it can consider of him only that he is a substance, without considering that he is an animal or that he is rational. Therefore the angel, too, does not necessarily consider all things knowable to him through one species.

2. But although either side of this doubt can be supported with probability, the second seems to me more probable, on account of the argument adduced and on account of the words of St. Thomas. For in Qu. de Veritate, q. 8, a. 13, in reply to the second and to the last argument, by which it was proved that an angel can know the thoughts of hearts, because he sees the species and habits existing in the mind of the angel, he denies the consequence: to the second, indeed, because from one species which the intellect possesses within itself it proceeds to various thoughts, just as by the species of man we can think various things about man; but to the last, because from one habitual knowledge many actual considerations proceed. For from these words it appears to be St. Thomas's mind that an angel, using one intelligible species, does not necessarily consider all the things knowable through it, but can consider of them whatever he wills: and on this account it is not necessary that one who knows a habit or a species should know determinately what the intellect considers through that species or habit.

Therefore it seems probable to me that it is within the angel's freedom to use a single intellectual species according to its own good pleasure. For the angel can know all things at once and distinctly, if it wills, which can be known through one species, namely by eliciting an act adequate to that species. And it can use that same species to understand only one or several of those things, but not all, by eliciting an act inadequate to that species and deficient.

3. To the argument on the opposite side, however, the reply is that, although the intelligible species naturally and equally represents in a habitual and imperfect manner all the things that are intelligible through it, it does not do so actually and perfectly: but just as from the intention of its will it comes about that it uses this species, and consequently that it is actually present in the intellect in perfect act, so too from its intention it comes about that it is applied to the consideration of this or that thing knowable through it.

In confirmation it is said that the case is not the same with God as with an angel. For the divine essence, in an actual and perfect manner, by its own nature represents to God all things intelligible by Him (I speak of positive things), and its actual representation does not depend on His will. But the species of the angelic intellect does not of itself represent actually and perfectly the intelligible thing through itself, but only habitually and imperfectly; and that it represent it actually depends on the will.

VII. Concerning that proposition, "In the intellect of a separate substance there is a certain succession of intelligences, yet not motion, properly speaking, since act does not succeed potency, but act succeeds act" ¹¹, it must be noted that this can be understood in two ways, according to the twofold manner in which we previously explained ¹² how understanding is a motion of one existing in act, but not of one existing in potency. For if we refer the operation of understanding to the understander as to its receptive subject, then we said, following the mind of the Commentator, that it is an act of one existing in act, insofar as it is the ultimate completion and does not leave its receptive subject in potency to a further act through itself, so as to be acquired, as properly so-called motion does. According to this sense, in the succession of intellections act does not succeed potency, just as in motion the terminus succeeds the motion constituting the subject in potential act tending toward a further act, as potency tends toward act and the perfectible toward perfection; or even as one part of a motion succeeds another, as act succeeds potency and the more perfect the less perfect: rather, a completed act succeeds another completed act. For two acts of understanding of a separate substance are not parts of one imperfect act; nor is one a potency tending successively toward the other; but each is a complete act, constituting the intellect in perfect and ultimate act with respect to one intelligible.

But if we refer the intellection to the intelligent being as to its productive principle in this way, then, while one operation succeeds another, it is not an act of a potency that succeeds, but act succeeding to act: because each of these acts is attributed to one existing in act through a species. For thus the intelligent being first produces one act through one species, by which it is in act; and afterward, through another species, by which it is in act, it produces another act of understanding. And then an act, or a being existing in act, succeeds a being existing in act: but a being existing in act does not succeed a being existing in potency.

Yet in some way, in the intellections of a separate substance, it can be said that act succeeds potency, insofar as it previously did not have that act of understanding and afterwards has it. But Saint Thomas is not speaking of that succession by which one who previously understood afterwards understands in act; rather, of the succession of diverse acts of understanding.

VIII. Concerning what is said here, that the intellect does not simultaneously understand the things it understands through diverse species ¹³, certain difficulties arise.

First. A separate substance sees God through God's essence; itself through its own essence; but certain other things through other species. Therefore it can understand several things at once through several species.

Second. The substances that move the spheres always understand motion itself and the movable thing, as Saint Thomas said above, chapter xcvii ¹⁴. And it is likely that they also understand something else. But they understand these things through superadded species of the same kind. Therefore, and so on.

Third. The damned always know the punishments by which they are afflicted, and also certain other things. But they know these through species. Therefore, and so on.

Fourth. The angel, as is said in Prima, q. 58, a. 4, ad 1, by understanding the quiddity of a thing understands whatever can be attributed to the thing or removed from it. But from any one quiddity all the others can be removed and denied. Therefore, by understanding one quiddity it understands all quiddities. But it understands them through innate species. Therefore etc.

IX. To the first, the answer was given above, in Book One, where God's knowledge was under discussion ¹⁵.

2. To the second, the answer is given from the teaching of Saint Thomas, Book II, d. XI, q. II, a. 3, ad 4: and it is said first that a separate substance is for itself the principle of knowing all things that pertain to it. And therefore, since the motion of a heavenly body is among the things pertaining to the substance that moves it, inasmuch as that motion has been assigned to it by its creation; it is necessary to say that the substance moving the heaven knows not through innate species, but through its own essence both the motion and the heaven insofar as it is its own movable thing, though not distinctly and quidditatively.

It is said secondly that it is not unfitting for a separate substance to understand some things simultaneously through its essence, and something else through a species, since the essence and the intelligible species are the grounds of understanding different things, and one is the ground of the other, as was shown in Book I ¹⁶. Therefore it is not unfitting for a separate substance to understand simultaneously both what pertains to itself and something else.

On the contrary, the foundation of this reply seems to be the words of St. Thomas in De Veritate, q. 9, a. 4, ad 11. For he says there that one angel sees the thought of another angel speaking to him through the species by which he knows that angel. But such a thought concerns matters pertaining to the listening angel, as St. Thomas says in II Sent., at the place cited. Therefore it is false that an angel knows all things pertaining to himself through his essence.

It can be answered that by "innate species" Saint Thomas does not intend, in that passage, an intelligible species distinct from the essence of the one understanding: but absolutely the formal principle of cognition, whatever that may be. For he wishes there to reply that the thought of the speaking angel is not known by the angel to whom he speaks through some particular species of thought, but through that very principle by which the essence itself of the speaker is known.

Nevertheless, for the clarification of the above reply, when it is said that the essence of a separate substance is the reason for understanding all things that pertain to it, we must note that this can be interpreted in two ways. In one way, that the essence itself alone, with no other species concurring, is the formal principle of the understanding of those things. In another way, that both the essence and their intelligible species concur to the knowledge of those things as one total principle of understanding them, yet in such a way that the essence itself is the reason why the intellect is turned toward the use of such species, inasmuch as perfect knowledge of the essence requires that all things pertaining to it be known. — Although either sense can probably be sustained, the first seems more to accord with the intention of St. Thomas. For if a separate substance were said to be able to understand at once many things pertaining to it because its essence is the reason for knowing them through proper species, then it could understand at once all things naturally knowable by it: for, as is said in Verit., q. VIII, a. 14, ad 6 ¹⁷, the essence of an angel is for him the reason for knowing all things that he knows, according to this second sense.

3. To the third, the same foundation supplies the answer: since the separated soul knows itself through its essence, as is said in Prima, q. 89, a. 2, just as other separated substances, in knowing their own essence, know through it all things that pertain to them, so too must it be said of the separated soul. And thus, since the torments of souls concern things pertaining to them, it would be said that they know these not through species, but through their own essence. And thus they are not prevented from understanding something else at the same time along with them.

But if one presses the objection concerning the souls of the damned after the resurrection, namely that they will then not understand themselves through their essence, just as they do not now while united to bodies, and thus the same difficulty remains as before — it can be answered that the soul even after the resurrection, upon reassuming its body, will know itself through its essence. For, as is said in Book IV, d. 50, q. 2, a. 2, q.ᵃ 1, ad 2, after the resurrection, on account of the incorruptibility of the body, the soul will not be drawn down by the body in the way it is drawn down now.

4. To the fourth it is said first, in accordance with what is said in Prima, q. 85, a. 4; and Verit., q. 8, a. 14, ad 2 ¹⁸; and Quodlibet VII, a. 2 ¹⁹, that certainly an angel, by knowing the quiddity of something, knows all the things from which that thing differs, insofar as they agree in one notion of difference.

It is said second, that it sees all other quiddities, not by intuiting each one distinctly and quidditatively, but by seeing the reason in which they agree, whereby they are distinguished from the quiddity first seen. For example, because man is first distinguished from all irrational animals by the rational, therefore the angel, in intuiting man, also intuits irrationality, in which all brute animals agree and from which man is distinguished by rationality. And thus it knows all brute animals by a certain confused cognition: namely, insofar as they agree in irrationality, and are contained under one reason of negation and difference.

It is said third, that by this cognition the angel understands all things of this kind through the species of the quiddity from which they are known to be removed. And since it is not unfitting that things which are known by one species be understood together, therefore there is nothing unfitting in all quiddities being understood together in this way.

The remaining matters pertaining to this subject, see Capreolus, II Sent., d. III, q. II.

And let these remarks suffice for the explanation of the second book, to the honor of almighty God and in praise of blessed Thomas.