Commentaria in Summam contra Gentiles, Liber II

Having resolved the arguments of Averroes, which were drawn from the sayings of Aristotle, St. Thomas wishes to show that even from Aristotle's words it is necessary to hold that the intellect is united to the body as its form¹. And he argues thus.

I. The heavens, according to the opinion of Aristotle, are animated by an intellective soul. Therefore an intellectual substance is united to the celestial body as its form. Therefore it is also united to the human body, which is the noblest of all inferior bodies, and most like the heavens in the equality of its complexion, being free from all contrariety.

The antecedent is proved, as to its first part, namely that the heaven is animate: first, from Book VIII of the Physics. For there it is shown that the first mobile must move itself; then it is proved that a self-mover is necessarily divided into two parts, one of which moves and the other is moved. But everything of this sort is animate, according to Aristotle. Therefore, etc. — Second, from Book II of the De Caelo. For there it is expressly stated that the heaven is animate; and that for this reason we must posit in it differences of position, not only with respect to us, but also in itself.

As for the second part, namely that its soul is intellective, it is proved first, because in Book XI of the Metaphysics ² it is shown that the completely unmoved mover moves as something desirable to that which is moved. But not by the desire of concupiscence, which is the desire of sense, but by an intellectual desire: hence it is said there that the first unmoved mover is desirable and intelligible. And thus the heaven, which is moved by it, must be desiring and understanding, in a manner even nobler than we are. — Second, because in Book II of the De Anima it is said that intellective soul and intellect belong to certain beings, such as men, and if there is anything of this kind that is more active ³ or more honorable, namely the heaven.

If it is said that the intellect is joined to the heavenly bodies through phantasms, and not as a form giving esse, it is argued against this. For it is established, according to Aristotle, that the heaven has no sensitive soul. Then also because it would have diverse organs, which is not fitting to the simplicity of the heavens. — Then also because in Book II On the Soul, to intimate this very point, Aristotle said that those things among corruptible beings that possess intellect possess all the other powers as well, so as to give us to understand that some incorruptible things, namely the heavenly bodies, have intellect, though they do not have the other powers.

Lest anyone think that Thomas himself assertively held that the heavens are animate, as something pertaining to the faith, he added that he did not say this by way of assertion according to the doctrine of faith, because it is of no concern to the doctrine of faith whether it be said one way or the other. Hence Augustine too left this in doubt in the book Enchiridion.

2. Concerning the last consequence of the principal argument, it must be noted, from the teaching of Saint Thomas in Questions on the Soul, art. 8, ad 2, that the consequent is not inferred as though the intellectual soul were united to the human body on account of the likeness it has to the heavens, as would have to be said according to Avicenna's opinion⁴; but because it is fitting that, if it is united to the heavens, it should also be united to the human body, which is the noblest among inferior bodies, on account of the equality of complexion, so that through the senses it may acquire intelligible species. To this there follows a certain likeness to the heavens: for just as the heavens are entirely without contraries, so too a body brought to an equality of complexion is most removed from contraries.

Note, however, regarding this very inference that Saint Thomas does not posit it as absolutely necessary, but as probable according to the opinion of Aristotle. For if he held that an intellectual substance is united to a celestial body not through phantasms but according to its very substance as form, it seems it must likewise be said that to the noblest body, which is the human body, he willed the intellectual soul to be united not only through phantasms, as Averroes held, but also as its form. Nor does it repel an intellectual substance any more to be united to a body of balanced complexion than to a celestial body: since on this account it is no more posited as depending on this matter than on that.

II. Concerning the foundation of this chapter and of the argument adduced, a not inconsiderable doubt arises: for it does not seem to be Aristotle's view that the heavens are animated by way of information, as Saint Thomas attributed to him.

First ⁵, because, if the heaven is held to be animated by an intellective soul alone, then that soul is united to the orb either for the sake of its intellective operation, or for the sake of motion. Not the first: since intellection is an operation in which the body does not share, the intellect does not need a body except insofar as phantasms are ministered to it through the senses; but sensitive operations do not belong to celestial bodies, in which there are not even organs of sense. — Nor the second. First, because in order to move, it is not necessary for it to be united to the orb as a form giving esse; union by contact of power suffices: as is stated in VIII Physics, text 43 ⁶. Second, because its moving is nothing other than its understanding and willing: as is stated by the Commentator, XII Metaphysics, commentary 36, where he says that celestial bodies are animated, and have of the powers of the soul only intellect and the desiderative power, which moves locally. — Therefore Aristotle did not hold the heaven to be animated by a soul giving esse formally.

Second ⁷, because then the first mover would be moved per accidens by the motion of the orb itself: for as is said in VIII Physics, text 51 ⁸, when the body is moved, what is in the body is also moved. But the first mover, which Aristotle said was a part of the self-mover, is moved neither per se nor per accidens, as is said in the same place, text 52 ⁹ Therefore the first mover is not the form of a heavenly body. Therefore, by the same reasoning, neither are the movers of the other orbs. — The final inference is evident. Because, if any of the heavenly bodies were supposed to be animated, this would be attributed especially to the first.

Third ¹⁰, because then heaven would be an organic body: since the soul is the first act of an organic body, as is said in II On the Soul ¹¹. But this is repugnant to its simplicity. Therefore, and so on.

Fourth ¹², because St. Thomas, in the First Part, question LXX, article 3, seems to hold that Aristotle wished the heaven to be animated by a moving soul only, and not by a soul that gives it being. — And on Spiritual Creatures, article 6, he says that to save the opinion of Aristotle and Plato it seems sufficient that the intellectual substance be united to the heavenly body in the manner in which a mover is united to what is moved. — And he adds, ¹³ that between those who hold the heavenly bodies to be animate and those who hold them inanimate there is found little or no difference in reality, but only in words.

Fifth ¹⁴. It would follow that the heavens, or at least the lower spheres, would have three movers, namely God, an intelligence, and a soul. But this is false: because the heavens have only two movers, as the Commentator says in XII Metaphysics, comment. 41. Therefore etc.

Sixth. It would follow that the heavens could naturally be at rest of themselves. This is against the Philosopher. — The consequence is proved: because the soul moves by appetite.

Seventh. All of Aristotle's demonstrations for proving a first mover altogether unmoved would cease. For the adversary will say that there is no need to posit a separate mover: since the heaven is animate, it moves itself, and is divided into a moving part and a moved part, just like the other animals.

Eighth ¹⁵. If the mover of a sphere were its soul, it would be moved per accidens by that motion, just as the souls of animals are moved by the motion of their bodies. But this is not the mind of the Philosopher, who proves in VIII Physics ¹⁶ that a part of the first mover must be immovable both per se and per accidens, since it causes eternal motion. This must surely hold true of the mover of any sphere, since all of them move with eternal motion. Therefore, etc.

Ninth ¹⁷. If the intelligence that moves the heavens were the soul of the heavens, it would not have a determinate position in the heavens, but would be in the whole as in an adequate subject: as is evident in the case of the intellectual soul, which has the whole body for its adequate subject. But this is against the mind of the Philosopher, who holds that the intelligence that moves the heavens is in its circumference: as is clear from VIII Physics, text 84 ¹⁸. Therefore etc.

III. To this difficulty it must be said that one thing in Aristotle's doctrine is clear, while another is doubtful. For it is clear that he did in some way hold the heavens to be animated, as is evident from what St. Thomas adduces in this chapter. This was also held by the Commentator, chapter I of On the Substance of the Orb; VIII Metaphysics, comm. 12; II On the Heavens, comm. 61; II On the Soul, comm. 15 and 32; likewise XII Metaphysics, comm. 36; and in many other places. What is doubtful, however, is how he held them to be animated: namely, whether the soul gives esse in the manner of a form, or whether the soul only moves and is united by contact of its power. For this is explained neither by Aristotle nor by the Commentator.

For this reason some hold that, according to Aristotle's mind, an intelligence is united to the heaven in the manner of a form giving esse; others, however, that it is united only in the manner of a mover. And Saint Thomas sometimes holds one position, sometimes the other.

For where, absolutely speaking, according to his own opinion, he holds that the heavenly bodies are not animated, so as to show that the Philosopher does not expressly oppose this view, he demonstrates how, according to Aristotle's intention, it seems sufficient for the heaven to be animated by a soul that moves only, and not by a soul that gives esse. And he holds this in the First Part, and in Question On Spiritual Creatures ¹⁹.

But where he argues against the Commentator, as here, he holds the opposite position. For since the Commentator wished to argue, from a superficial reading of Aristotle's words, that the intellect is a separate substance and that the intellectual soul is not the form of man in Aristotle himself; therefore St. Thomas also, against him, wishes to show that if we were to attend only to Aristotle's words, it would rather have to be said that he posited the intellectual substance to be the form of the body than that he denied this universally; since he expressly posited that the heaven is animated, and attributed to it none other than an intellectual soul, and assigned to it the conditions of an animated thing, which are to move itself and to have differences of position according to nature; but where he said that the intellect is separate and unmixed, he was speaking not of the substance itself in which the intellect is grounded, but of the intellective power. — This also seems to be what St. Thomas attributes to Aristotle in XII Metaph., in his exposition of text 25, ²⁰; and in II Caeli ²¹.

For which reason, two things seem to me to be said concerning the mind of Saint Thomas. The first is that he himself inclines more toward this position, that the heaven is not animated, according to the mind of Aristotle, with the soul giving esse, than toward the opposite. The second is that he wished that either position could probably be maintained. — The first of these is clear from the passages cited above. The second, however, is shown in Qu. de Anima, art. 8, ad 3: where he also resolves the first argument brought forward here, by which it is proved that the heaven is not animated.

From which matter, sustaining both parts, as St. Thomas sustains in Qu. de Anima, we shall answer the arguments of each part from his doctrine.

IV. If, therefore, we wish to defend the position that, according to Aristotle's mind, the heaven is not animate by an informing soul, it must be said, on the basis of the passages adduced ²² in the First Part and On Spiritual Creatures, against the argument here assumed against Averroes, that Aristotle did not understand the heaven to be animated as though a spiritual substance were united to the heavenly body as a form giving esse, but because it is united to it as a mover to a movable thing: for thus he willed the spiritual substance to be united to the heavenly body and to be contained within it, just as Plato ²³ willed the intellective soul to be united to the human body, namely by contact of power; and to be within it as a mover in the movable thing, and in the instrument which it uses and to which it is intrinsically conjoined. — But when the opposite is proved, because he held that the heaven moves itself and has differences of position according to nature: it is said that these do not argue that it has an informing intelligence, but one united only after the manner of a mover. For thus the heaven, as said to be composed of an intelligence and an orb united by contact of power, is composed of a mover and a movable thing; and thus it is self-moving; and it has differences of position, which are taken in the heaven only in relation to local motion, as is said in Book II of On the Heaven ²⁴.

2. But against this argument an objection could be urged: because, if heaven is said to move itself on the ground that it is composed of a mover and a mobile united according to contact of power, then by the same reasoning it could be said that a cart moves itself, because oxen are united to it in the manner of a mover; and likewise that a ship moves itself, because the sailor who moves it is joined to it.

It is answered that the case of these things is not the same as that of the heavens, for two reasons. First, because according to Aristotle, the spiritual substance that moves the heaven has a power determined to the motion of such a body; and the body of the heaven itself has a natural aptitude to be moved in this way by such a spiritual substance. But this is not found in the instances adduced. — Second, because in those cases there is quantitative contact, which occurs at the extremities. Between an intelligence, however, and a celestial body there is only contact of power. Now it was shown above, in this Second Book, chapter 56, that in quantitative contact the touching thing must be extrinsic to what is touched, and cannot move through it, but is impeded by it: whereas in contact of power, which belongs to spiritual substances, since it reaches to the innermost parts, the touching substance is within what is touched, and moves through it without any impediment. — From these two considerations it follows that a greater unity results from an intelligence and a celestial body—although from them there is not made one thing simply, but only in moving—than from a sailor and a ship, or from oxen and a cart. And therefore it can more fittingly be said that the heaven moves itself than that a ship or a cart joined to oxen does. For thus the celestial body is united to its mover as intrinsic to it, and determined by natural power to its motion: which does not apply to those other cases. — It could also be granted that in the same way it may be said that a cart is moved of itself, if by the name cart we understand the aggregate of cart and oxen.

3. But if it be asked: Why, then, did St. Thomas against Averroes in this place construct an argument which he himself saw to be solvable? — the answer is given, as has already been said ²⁵, that he does not do this as though he judged that argument simply insoluble, but because he thought it effective against Averroes, who from Aristotle's words, as was shown in the preceding chapter, wished to argue that a substance intellectual cannot be united to a body as its form. For if we were willing to look only superficially at the words, and not at their meaning, it is shown more clearly from his words and arguments, in which he plainly wishes heaven to be animated, that a substance intellectual can be united to a body as its form, than from his other words does it appear that it cannot be so united: for we are accustomed to call "animated" those things whose form giving esse is the soul.

That this was the mind of St. Thomas is evident from the beginning of this chapter, where he says: And because Averroes relies chiefly on the words and demonstration of Aristotle to confirm his opinion, it remains to be shown that it is necessary to hold, according to the opinion of Aristotle (supply: insofar as his words sound when understood superficially), that the intellect in its substance is united to some body as its form. For from these things it appears that St. Thomas, confronted with the words and demonstration of Aristotle as adduced by the Commentator, intended to oppose to them other words of Aristotle that are more manifest, and other demonstrations of his.

Therefore, following the reasoning here adduced by St. Thomas, while holding that heaven, according to the mind of Aristotle, is not properly animated, in accordance with his doctrine handed down elsewhere, we must respond.

V. But if we wish to maintain the opposite position, as St. Thomas maintains in the Quaestio de Anima, cited above ²⁶, holding that, according to Aristotle's mind, an intellectual substance gives formal esse to a heavenly body: it is answered to the first argument brought against this position ²⁷, according to the doctrine of St. Thomas in II De Caelo, lecture 3, and in the place immediately cited, that an intelligence is united to a heavenly body as form on account of motion and action—not simply, for even without such a union it could act and move things, as was argued—but on account of the nobility of its action. For a spiritual substance that is assigned to the motion of the heavens, which it moves without labor, operates and acts more nobly through the motion of the heavens if it is united to them according to esse than if it were separate from them: for more perfect is the action one performs by means of an instrument conjoined to oneself than that which one performs by means of a separate instrument.

To the first proof, it is evident from what has been said.

To the second, it is said first that the moving of an intellectual substance by way of command is only willing and understanding; but not moving by way of execution. Indeed, the very motion caused in the heavens by the intelligence, through which it causes these lower things, insofar as it is from the will of the angel, is execution. — It is said second that, however "moving" be taken, namely either by way of command or by way of execution, no motive or active power distinct from intellect and will is posited in the intelligence itself. And therefore the saying of the Commentator is most true. — It is said third that, although the moving of the intelligence by way of execution comes from the will and the intellect; and although the intelligence has no motive power really distinct from intellect and will, but only by reason: nevertheless the intelligence is united to the heavenly body as form for the sake of the execution of its active power, namely so that the execution may be more perfect. Hence the consequence of that argument does not hold, namely: The moving of the intelligence, namely by way of commanding motion, is its understanding and willing; therefore it is not united to a body on account of motion. For although understanding and willing, which are immanent actions, as such do not require a body to which the intelligence be united as form; nevertheless the transient operation itself, or the execution of active power, which proceeds from the will, requires for its perfection that the intelligence be the form of a body.

VI. To the second ²⁸ it is said first that, since Aristotle posits some substance that moves the heavenly body and is itself moved neither per se nor per accidens, he understands this of a substance moving in the manner of an end: as is clear from his argument in Metaphysics XII, where, in positing a multitude of separate substances, he posits a multitude of those which are ends, as is expressly stated in text 48 ²⁹. This is clearly the mind of St. Thomas, ibidem, and De Spiritualibus, art. 5.

It is said second that, because in Physics VIII he had not yet investigated the intellectual substance that is wholly separate, moving in the manner of an end and of the desirable—for this was to be investigated in Metaphysics XII—therefore he speaks of that substance which is a part of the self-mover as if it were the first substance simply and wholly abstract, and attributes to it the conditions of first substance, as was said in Book I ³⁰. And because the first mover, and every other substance moving the heavens in the manner of an end, is immobile both per se and per accidens, he attributes to that substance which is a part of the self-mover the property of being moved neither per se nor per accidens: although in truth this does not belong to it. For since it is the form of a body, and its esse and that of the celestial body are one, it must be moved per accidens by the motion of the body. — Hence, to the argument, the consequence is denied concerning him who is truly the first mover, namely the one moving in the manner of the desirable first thing: although it is true of what is there taken as the first mover.

But when it is proved because it is said there in Book VIII of the Physics ³¹, that the first mover is not moved either per se or per accidens: it is said that this is understood of that which is truly the first mover, namely that which is entirely separate from matter; but not of the part of the self-mover, which is not truly the first mover, although that title is attributed to it suppositively and permissively, insofar as it is there admitted as the first mover simply speaking.

Therefore, since it is absolutely impossible for a part of a self-mover to be the first mover, unmoved of itself and per accidens, in Metaphysics XII the first mover is investigated as wholly separate from body, to whom the conditions of the first mover are truly attributed—conditions which, by supposition and concession, had been attributed to the mover of the first mobile, united to it in the manner of a form.

VII. To the third ³² it must be said that the organic body can be taken in two ways. In one way, as a body having diverse organs, distinct in composition, position, and figure. In another way, as a body disposed to the soul and to the operations of the soul: so that an organic body is nothing other than a body having life in potency, as the Philosopher seems to explain in Book II of the De Anima ³³, whether it has diverse organs and official members or does not have them.

If in the first way we wish to take "organic body" in the definition of the soul, as nearly all expositors take it, because they hold that the heavens are not ensouled: in this way, the consequence is denied. And in proof of this it is said that either that definition of soul belongs only to the souls of corruptible things, and that Aristotle assigned the common definition to these alone, in II De Anima. — Or that it belongs to every soul, not indeed univocally, but analogically. And thus the heaven need not be an organic body in the manner of lower bodies, but proportionately in its own way: for it is organic in the second mode.

But if "organic" is taken in the second way in the definition of the soul, then it is granted that a heavenly body is organic. Nor does this conflict with its uniformity and simplicity.

2. It could also be said that the heavens have a diversity of organs: not indeed distinct according to a variety of complexions, as happens in animals, but according to rarity and density, in the way that rarity and density are found in the heavens, namely according to a greater or lesser congregation of parts, but not according to a difference of contrariety, as is said by St. Thomas in II De Caelo, lecture 10, at the end. And according to this diversity there are in the heavens diverse powers with respect to these lower things, insofar as through those parts the soul of the heavens acts variously upon these lower things.

But do not impose on me that in the soul of the heavens I should posit other powers besides intellect and will, attached to the diverse parts of the heavens, as the souls of animals have. For this second reply does not aim at that, but at this: that the soul, moving the heavens through intellect and will, and thereby moving these lower things through that motion, acts diversely upon lower things through the diverse parts of the heavens; so that thus the diverse powers of those parts are the diverse influxes of the soul of the heavens, according to which it operates diversely upon these lower things.

VIII. To the fourth ³⁴ it is said that, since Aristotle's opinion in this matter is uncertain, and different things can be taken from his various statements, therefore Saint Thomas there interprets his words according to his own purpose. When, then, he says that Aristotle did not hold that the heaven is animated by an anima giving esse but only by an anima moving it, he does not say this as though the opposite could not be held; but because he holds that Aristotle's words can be expounded in this sense, since for saving Aristotle's opinion it seems sufficient that the heaven be animated by a merely moving anima. Hence he speaks with hesitation in Qu. de Spiritualibus Creaturis, saying that if one considers the matter closely, one will perhaps find either no or but slight discordance between these opinions. And further on in the same place he says that it seems sufficient for saving the intention of Plato and of Aristotle that a spiritual substance be united to the heavenly body as its mover. For the words perhaps and it seems are those of one not asserting, but speaking tentatively and probabilistically.

IX. To the fifth ³⁵ it is said that it is not unfitting, according to Aristotle, for the lower spheres to have three movers: namely, one common, which is the first mover simply speaking; and two appropriated ones, of which one moves as a soul, while the other moves as the proper end.

To the sixth ³⁶ it is said first that we can speak of the motion of the heavens in two ways, as is clear from Saint Thomas below, book III, chapter XXIII: namely, either on the part of the mover, or on the part of the substance of the heavens. In the first way, the motion of the heavens is voluntary; in the second way, it is natural. And therefore, on the part of the mover, speaking absolutely, the heavens could be at rest; but not on the part of the substance of the heavens itself. And this is what the Philosopher understood.

It is said secondly, as is had from the Philosopher in book XII Metaph., text. 38, and from St. Thomas there, ³⁷ that, although the necessity of the motion of the heavens is not an absolute necessity, since the heavens move themselves, and everything of this sort has in itself being moved and not being moved; it is nevertheless a necessity ex suppositione, which is a necessity of the end, insofar as without the perpetuity of such motion there would not be a fitting order to the end, according as assimilation to God is intended through motion. And therefore it is not unfitting to say that, according to Aristotle's mind, the heavens, insofar as they are animate, can of themselves rest absolutely, although by supposition and on account of the end they are necessarily moved.

To the seventh ³⁸, the inference is denied. For although the heaven may be posited as divided into a moving part and a moved part, nevertheless, besides the mover that is the part moving itself, it is necessary to posit another mover entirely separate, which moves by way of the appetible, as Aristotle argues in book XII of the Metaphysics ³⁹.

X. To the eighth ⁴⁰ it is said that we can understand a mover of some body to be moved per accidens in two ways. In one way, that it be moved simply by that local motion by which it moves the body, yet without any variation taking place in it in relation to the body, but rather always holding itself in the same way toward it, with the same disposition remaining between them. In another way, that it be moved per accidens by the motion of the body moved by itself in such a way that its disposition toward the body is also varied, so that it holds itself now one way and now another toward the body, as happens in animals: for from the motion of the body the soul holds itself now one way and now another toward the body, because the body is somehow altered by local motion. The Philosopher therefore intends that the mover which causes perpetual motion is not moved per accidens in the second way. But that it be moved per accidens in the first way does not conflict with his intention: although he does hold of the first mover simply that it is in no way moved.

This is clear first from St. Thomas. For, assigning the difference between the movers of the orbs and the soul, in VIII Phys., expounding text 52, ⁴¹, he says that the reason why the movers of the orbs are not moved per accidens by reason of themselves with respect to the motion of the orbs, while the souls of animals are moved per accidens, is because the movers of the orbs are not constituted in their esse by their union with bodies, and their attachment is invariable; but the souls that move animals are constituted in their esse according to their union with bodies (understand, except the intellective soul), and are connected to them variably. For from this St. Thomas gives us to understand that the movers of the orbs are not moved per accidens in such a way that their esse and their disposition to the orbs are altered by such a motion, as the disposition of the souls to the motion of animals is altered. With this, however, it stands that they are moved per accidens in some way, because their esse and that of the orbs is one: although from their union with the orbs they are not constituted in their esse, that is, their esse does not depend on body and matter; just as neither does the esse of the intellective soul depend on the body.

This is clear from the second argument, because the Commentator, in VIII Physics, commentary 83, says that inequality does not occur in motion except because a certain mode of transmutation befalls the mover, whereby it is sometimes strengthened and sometimes weakened. From these words he gives us to understand that only that motion which is per accidens is repugnant to a mover moving with perpetual and unvarying motion, from which the power of the mover is varied, and consequently its relation to the thing moved.

2. To the ninth ⁴² it is said that certainly the intelligence which is the soul of the heavens does not have a determinate position in the heavens according to the determination of its substance to one part of the heavens. But what Aristotle says, that it is in the circumference, is understood, as St. Thomas explains there ⁴³, through the influence of motion, and not through the determination of its substance. And this is understood of the first mover, but not of the others.