Commentaria in Summam contra Gentiles, Liber III

After St. Thomas has shown that all things are ordered to the good and to the divine likeness as to an end, he now shows how things are ordered to this end in diverse ways ¹. Concerning this, however, he does two things: first, he shows the proposition; second, he deduces a corollary in the following chapter.

I. As to the first, he posits two conclusions. The first is ²: Lower bodies, according to what they are moved by natural motions, tend toward the divine likeness as to this: that they be perfect in themselves according to their proper form and proper where, but not that they be the cause of others.

The second is ³: The end of heavenly bodies is to attain the divine likeness both as to their proper perfection and in that they are causes of others.

2. For the declaration of these conclusions, however, he premises two things. One is that things are ordered to an end in diverse ways according to the diversity of operation: because that ultimate thing through which a thing is ordered to an end is its operation. The other is that a certain operation belongs to a thing as moving, like heating. A certain operation belongs to a thing as moved by another, like being heated. A certain operation, however, is the perfection of the operator existing in act, not tending into another thing to be transmuted: by the first of these, namely in that it is the perfection of that which exists in act, it differs from passion and motion, which are indeed perfections of that which exists in potency; by the second, however, namely in that it does not tend into another thing to be transmuted, it differs from an action that transmutes exterior matter. An operation of this kind is understanding, sensing, and willing.

3. Concerning the first statement, it should be noted, as will be more fully explained below ⁴, that when an extrinsic thing is the ultimate end of something, the intrinsic ultimate end is that by which the thing is conjoined to the exterior end itself and formally attains it. This, however, is the operation of the thing, taking the name of operation as it is used in this chapter. Therefore it is well said here that the ultimate thing through which each thing is ordered to an end is its operation: namely, because through its operation each thing is conjoined to the end.

Concerning the second, it should be observed that, although operation may seem from its mode of signifying to import action, nevertheless, as to the thing signified, it does not import action alone, but is a common name for action and passion. For operation is taken here for the first act immediately corresponding to a potency, of which the potency is indeed the immediate principle by which. Potency, moreover, is divided into active and passive: of which the active is that by which the agent acts; the passive, however, is that by which the patient suffers. Therefore also operation, to which potency is spoken of, is divided into action and passion: as is clear in Qu. de Anima, a. 12. For this reason St. Thomas well says in this place that a certain operation belongs to a thing as moving another, that is, it is an action; while a certain operation belongs to a thing as moved by another, that is, it is a passion.

II. These things having been presupposed, he proves the first conclusion by this reason. Those things which are moved and operate only, without moving or making other things, tend toward the divine likeness only as to this: that they be perfect in themselves, since they have only that operation which is a passion. But lower bodies, as they are moved by natural motions, are considered as moved only, not however as moving, except per accidens. Therefore etc. It should be noted that, although the agent, while it moves something, can intend something else through such motion besides the perfection of the moved thing—just as the builder, besides the perfection of the house, intends habitation and the conservation of things—nevertheless the motion of the moved thing, as compared to the moved thing itself, tends only to acquiring the end of the motion of the moved thing: because passion and being moved, taken precisely as such, are only for this, that something come to be in the mobile thing, not however that the mobile thing cause something else. For this reason it is well assigned as the reason why lower bodies, according to what they are moved by natural motions, intend the divine likeness as to their proper perfection only, because, as such, they are considered as moved only, not however as moving: namely, because those things which are moved and do not move nor act can indeed through motion attain their proper perfection, but cannot be the cause of others. It should also be observed that St. Thomas does not say absolutely that lower bodies tend toward the divine likeness only as to the attainment of their proper perfection, not however as to causality; but he added, according to what they are moved by natural motions. For lower bodies themselves also have proper powers by which they can effect something, just as fire heats and water moistens: and according to this reason, since they move and act, they intend to be assimilated to God also in causing. But it is true that, according to what they are moved by natural motions—because they do not move by the fact that they are moved, but are moved only, unless perchance they move per accidens, as happens to a stone when in descending it strikes something in its path—therefore, as such, they do not tend toward the divine likeness in causing, but only in acquiring their proper form or their proper where, as is said here.

III. He proves the second conclusion ⁵, however, through the fact that heavenly bodies move as moved. For inasmuch as they are moved, they tend toward their proper perfection, from the fact that they come to be in some where in which they previously were in potency, namely according to part; and thus they intend to attain the divine likeness as to their proper perfection, just as other bodies do through their natural motions. Inasmuch as they move by moving, however, the end of their motion is to attain the divine likeness in this, that they are causes of others. And because they are causes of others through the fact that they cause generation and corruption and other motions in these lower things, therefore their motion, inasmuch as they move, is ordered to the generation and corruption that is in these lower things.

It should be noted that, although heavenly bodies through their motions are the cause not only of generation and corruption in these lower things, but also of other motions, as is said here; nevertheless, because they principally intend the substantial esse of lower things, to the generation of which corruption is necessarily conjoined, whereas they do not intend other accidental perfections except as they contribute to the perfection of the substance: therefore, although St. Thomas said that heavenly bodies through their motions are causes also of other motions besides generation and corruption, he nevertheless concludes this alone, namely that their motions are ordered to the generation and corruption of things; namely, because generation and corruption are principally intended, not however the other motions. — Although it can also be said that under the name of generation and corruption he comprehends all motions, inasmuch as generation and corruption are conjoined in some way to every motion, at least accidentally, while the terminus a quo is lost and the terminus ad quem is acquired.

IV. But against those things that were said in this second conclusion, St. Thomas raises two doubts. The first is concerning what was said, that a heavenly body attains its perfection through motion inasmuch as it comes to be in act in some where in which it was previously in potency. For it does not seem that from the acquisition of such a where it acquires its proper perfection: because, while it acquires one where, it remains in potency to the where in which it previously was in act, and thus it seems to be made imperfect.

The second ⁶ is concerning what was said, that heavenly bodies through their motion are ordered to the generation of these lower things. For the end is nobler than those things which are for the end. Lower bodies, however, are less noble than heavenly bodies. Therefore heavenly bodies are not ordered through their motion to the generation of lower things.

V. To the first of these, St. Thomas answers that, on account of the fact that a heavenly body, while acquiring one where in act, to which it was previously in potency, remains in potency to another where, in which it was in act, it attains its perfection none the less. Because a heavenly body, which is in potency to a where as prime matter is to a form, attains its perfection through the fact that its whole potency is reduced to act successively, which could not occur all at once; just as matter also, while it receives one form, although it loses another, tends toward its perfection, because in this way its whole potency is reduced to act successively, which could not occur all at once.

2. It should be noted in this place that by successive perfections, or those which are acquired in a certain succession and cannot be acquired otherwise, a subject has to be perfected in that way in which the perfection itself is naturally apt to have esse in act: because a subject is not perfected by its perfection except according as it has esse; and therefore according as perfections are naturally apt to be in act in diverse ways, so in diverse ways does the potency have to be perfected by them. But a perfection which is naturally apt to have esse in a certain succession can never have its whole esse in act all at once, but through part after part, in such a way that, one part arriving, the other recedes: as is clear in motion and time. Therefore the subject has to be perfected by it not by receiving it all at once, but one part after another, and in the reception of a subsequent part losing the prior part: just as, while the mobile thing receives one part of motion, it loses another part. But a perfection which does not have esse in succession is naturally apt to have its whole esse all at once, like the soul. Therefore the subject is perfected according to it all at once, and not by receiving one part of it after another.

Therefore, because all the wheres taken together to which the heavenly body is in potency, and all the forms to which prime matter is in potency, compared to their subjects, have the ratio of a successive being, because they cannot be all at once in their subject; therefore the heavenly body also has to be perfected by those wheres by receiving one after another, and losing that which it had in act while it receives that to which it was in potency, nor can it be perfected and actuated by those wheres in any other way; and similarly prime matter has to be perfected by substantial forms successively, losing the prior while it receives the posterior, nor can it be perfected in any other way by a multitude of forms. For this reason St. Thomas excellently answers that the heaven attains its perfection none the less while, acquiring one where, it loses another where; and he says the same of prime matter with respect to forms: because, I say, this is the nature of such acts, that they perfect their potencies with such succession. Whence they are said to be perfected simpliciter; although secundum quid they can be said to be made imperfect, inasmuch as they cease to be actuated by the prior where and the prior form; just as every subject also, while it receives a form to which it is naturally inclined, is said to be perfected simpliciter, although it can be said to be made imperfect secundum quid, inasmuch as the preceding opposite form is cast away from it.

VI. But concerning this response of St. Thomas, a doubt arises. Because he himself in Qq. de Potentia Dei, q. 5, a. 5, holds that the end of the motion of heaven is not that it attain in act the where to which it is in potency, although Avicenna seems to say this ⁷. And below he says that it is not probable that the end of the motion of heaven is any perfection of it. And in the response to the seventh argument, he says that the heaven is not perfected by place, as are lower bodies, which are preserved in their proper where.

2. It is answered, and it is said first, that it can be understood in two ways that the end of the motion of heaven is that it attain in act the where to which it is in potency. In one way, so that this which I say—to attain in act the where to which it is in potency—is indistinctly and indeterminately the end of the motion of heaven. And in this way it is not true: because since the heaven, in whatever where it is placed, is in potency to another where, the heaven could never attain its end; for it always remains in potency to some where. And in this sense St. Thomas speaks in Qq. de Potentia Dei. — In another way, so that some determinate where, say east or west, is posited to be the end of some determinate part of the motion of heaven. And in this way it is not inappropriate that the secondary end, though not the principal end, is that it attain the where to which it is in potency: for the end of the motion of the sun tending from the east to the west, as such, is to attain the position of the west. In this sense he speaks in this place. Whence what is said here does not contradict what is brought in the first place from Qq. de Potentia to the contrary.

It is said secondly, that something can be called the perfection of something in two ways: in one way, because it belongs to the integrity of the thing, or is the complement of the thing, to which the thing is naturally inclined through its form; in another way, because it is an act to which the thing has a natural aptitude, although the thing does not remain incomplete and imperfect if it lacks it. In the first way, a where is not the perfection of a heavenly body: and in this way it is understood in the cited place. In the second way, it is its perfection: and in this way it is understood in this place. — This answer can be had from St. Thomas himself in the cited place ⁸; and in the Fourth Book, d. 48, q. 2, a. 2 ⁹.

VII. Responding to the second doubt ¹⁰, St. Thomas does two things: first, he satisfies the objection; second, he clarifies the understanding of the response ¹¹.

As to the first, he responds substantially that the motion of heaven is ordered to the generation of these lower things, not as to an ultimate end, since that is to be assimilated to God in this, that it exists as the cause of others ¹²: but as to a proximate end. Such an end, however, does not need to be nobler than that which is for the end, as is clear in univocal agents: but only the ultimate and principal end.

VIII. As to the second, he says two things ¹³. The first is that, since heavenly bodies are higher, and consequently participate more simply and universally in the likeness of the divine goodness than do lower bodies, in which such likeness is more particularly and dividedly; and through this, are more assimilated to the divine will, because something participates in the likeness of the divine will to the extent that it participates in the likeness of the divine goodness, which is its object: heavenly bodies are compared to lower bodies as a universal agent to a particular effect; and the intention of a heavenly body is borne to the common good of corporeal substance, just as the intention of a particular agent in these lower things is contracted to the good of this or that species.

2. From these things St. Thomas wishes to have two points. One is that, when it is said that the heaven through its motion is ordered to the generation of lower things, it must be understood that it is ordered to the generation of lower things in common, and to their common good; not however to the generation of this particular thing, or to its good inasmuch as it is of this kind (namely primarily); for this belongs to a particular agent, not however to a universal agent.

The other is that, when it is said that the heaven through its motion intends the divine likeness in causing, it must be understood that it intends the divine likeness in causing after the manner of a universal agent, not however after the manner of a particular agent.

3. It should be noted, however, lest St. Thomas seem to have assumed this proposition in vain—Every single thing, inasmuch as it participates in the likeness of the divine goodness, to that extent participates in the likeness of the divine will—that, since the divine will is that through whose intention things are produced and conserved in esse, each thing is assimilated to God in causing inasmuch as its intention in causing is assimilated to the intention of His will. Therefore that agent which has a more universal intention in causing is more assimilated to the divine will, which is most universal, than that which has a more particular intention. But that whose goodness and perfection is simpler and more universal has a more universal intention: because the primary and per se effect of any agent is proportioned to the power and perfection of the agent. Whence, since heavenly bodies have a simpler and more universal goodness, by universality of perfectional containment, than lower bodies; it follows that the intention of heavenly bodies in acting is more universal, and is borne to a more universal good, than the intention of lower agents. And this is the intention of St. Thomas.

IX. The second thing that St. Thomas says ¹⁴ is that, because the whole of generation is ordered to man as to an ultimate end in the genus of generable and mobile things, and the movement of heaven is ordered to generation, it follows that the end of the motion of heaven is ordered to man as to an ultimate end in the genus of generable and mobile things.

That the whole of generation is ordered to man, however, he declares from two things. First, from the fact that, since the intention of whatever exists in potency, namely that which is moved, is that through motion it tend into act, the more posterior and more perfect any act is, the more principally is the appetite of matter, by which it appetizes form, borne toward it; and it is borne toward the further and most perfect act that it can attain as toward the ultimate end of generation. It is clear, however, from the order of the forms themselves and from the order of generation, that the human soul is the ultimate among all forms and the most perfect. Therefore matter tends into this through generation as into the ultimate end of generation. And thus man is the end of generation.

Second, he declares the same from the fact that man uses all kinds of things for his usefulness: some, I say, for food, some for clothing, some for transport, but all sensible things for the perfection of intellectual cognition. Which is signified in the Psalm, where it is said, You have subjected all things under his feet; and Aristotle shows this in Politics I, saying that man has natural dominion over all animals.

Since therefore things are conserved in esse according to the order recounted in the text regarding generation, it follows manifestly that man is the end of the whole of generation.

2. From these things St. Thomas wishes to have it that, when it was said that generation is the proximate end of the motion of heaven, but assimilation to God in causing is the ultimate end, it is not to be understood as if the motion of heaven had no other ultimate end than assimilation to God in causing: but because that is the ultimate end simpliciter. Besides this, however, it has another ultimate end, not indeed simpliciter, but in the genus of generable and mobile things, namely man.

Note, when it is said, in recounting the order of forms, that the sensitive soul is in potency to the intellective, and the vegetative to the sensitive, that it is not to be understood as if the preceding sensitive soul were receptive of the intellective, or the same could become intellective: but because matter existing under the sensitive is in potency to the intellective, as is clear in the process of the generation of man. And similarly must it be said of the vegetative with respect to the sensitive.

X. For the declaration of the principal response to the doubt ¹⁵, where it is said that heavenly bodies intend as an ultimate end the divine likeness in that they exist as causes of others, it should be noted first, from the teaching of St. Thomas in II Sent., d. 1, q. 2, a. 2, that an end proportioned to the thing which is for the end differs from an end disproportionately exceeding it, because a proportioned end is acquired according to itself by that which is moved to the end as a perfection received in it, as health is acquired by that which is moved to health through medicine; but a disproportionate end is not acquired as an inherent perfection in that which is moved toward it, but some likeness of it is acquired. Since therefore the divine goodness is an end disproportionately exceeding every created thing, it cannot be acquired by the heaven through its motion so as to be its form, but some likeness of it is acquired. Therefore, when it is said that the divine likeness in causing is the ultimate end of the motion of heavenly bodies, it is not excluded by this that the divine goodness is its ultimate end. Rather, it is made more manifest that it is the ultimate end, which cannot be possessed by a heavenly body except through a certain likeness.

2. It should be noted secondly that, when it is said that the divine likeness in causing is the ultimate end of this motion, it can be understood in two ways. In one way, that the causing itself, in which a certain divine likeness is preserved, is its end. And it is not understood in this way here: since the operation itself, or the causing itself, as such, tends into another, namely into the effect. — In another way, that the ultimate end is assimilation to God, while causing is that according to which the heaven intends and attains this likeness. And this sense is intended here. For the likeness to God according to itself is the intended end: causing, however, is that according to which the heaven attains such a likeness, and God Himself through a certain participation in likeness. — This sense is had from St. Thomas, I Sent., d. 37, q. 4, a. 1, ad 2.

3. But a doubt arises concerning this. For St. Thomas, in the question cited above ¹⁶ On the Power of God, attacks this opinion which he follows here—namely, the one stating that the end of the motion of the heaven is to be assimilated to God in causing. And he posits that the end of this motion is a determined multitude of souls, such that the motion of the heaven exists for the purpose of fulfilling the number of the elect.

He answers that St. Thomas rejects there the opinion posited here (which is that of the philosophers) not as false, since he says that it can be reasonably maintained, but because the other opinion, which is that of the theologians, seems more probable to him. Hence, since both opinions are probable in his judgment, there he follows the opinion of the theologians, but here he follows the opinion of the philosophers. Moreover, he does this because, since he wrote this book against the Gentiles, he takes as true those things which can be maintained with probability and are conceded by them, so that he may have an easier way against them: and not those things which they would in no way admit.