Article 8 — Whether the rational soul should be united to a body such as man possesses

Eighth, it is asked whether the rational soul should be united to a body such as man possesses. (Parallel texts: ST I.76.5; SCG II.90; In II Sent., d. 1, q. 2, a. 5; On Evil, q. 5, a. 5; Commentary on Aristotle’s On the Soul, bk. 1, lect. 8; bk. 3, lect. 11–12.)

Obj. 1: It seems that it should not. For the rational soul is the subtlest of all forms united to a body. (Cf. Aquinas, Commentary on Aristotle’s On the Soul, bk. 1, lect. 6, n. 68; On Truth, q. 8, a. 12, obj. 3; Gregory the Great, Dialogues, bk. 4, ch. 27 (PL 77:357; Sources Chrétiennes [SC] 265:86).) Now earth is the lowest of all bodies. (Cf. above: q. 7, resp.; Aquinas, On Evil, q. 16, a. 1, obj. 4.) Therefore, the soul is not fittingly united to an earthly body.

Obj. 2: But in view of the fact that an earthly body is reduced to a harmonious combination of the elements, (Cf. Aquinas, On Evil, q. 5, a. 5, resp.) it might be said that such a body is similar to a heavenly body, which is without contraries altogether, and thus is ennobled in order that a rational soul may be fittingly united to it. (Avicenna, De anima, part 5, ch. 7.)

On the contrary, if the nobility of the human body consists in its likeness to a heavenly body, it follows that a heavenly body is nobler. But the rational soul is nobler than all other forms because it transcends all bodies by its intellectual capacity. Therefore, the rational soul should be united rather to a heavenly body. (Cf. Aquinas, In II Sent., d. 1, q. 2, a. 5, obj. 1.)

Obj. 3: But it was said that a heavenly body is perfected by a nobler perfection than the rational soul.

On the contrary, if the perfection of a heavenly body is nobler than that of a rational soul, it must be intelligent, because any intelligent being is nobler than any non-intelligent being whatever. (Cf. Aristotle, On the Soul 2.3, 414b18–19.) Therefore, if a heavenly body is perfected by an intellectual substance, this substance will be either the mover only of such a body or will be its form. If it is only a mover, it follows that the human body is perfected in a nobler way than a heavenly body is, for a form gives species to the thing of which it is the form, whereas a mover does not. (Cf. Aristotle, Metaphysics 10.9, 1058a36–b3; Aquinas, Commentary on Aristotle’s On the Soul, bk. 1, lect. 11.) Again, nothing prevents certain things ignoble by nature from being instruments of the noblest agent. (Cf. Aquinas, On Truth, q. 26, a. 1, ad 1, ad 9.) However, if an intellectual substance is the form of a heavenly body, such a substance has either an intellect alone, or senses and other powers together with an intellect. If it has senses and other powers, it follows that a heavenly body is an organic body, because powers of this sort must be the acts of organs, which are required for the operations of such powers. This is opposed to the simplicity, uniformity, and unity of a heavenly body. If, indeed, such a substance has an intellect alone and receives nothing from sense, then it does not need to be united to a body, because the operation of an intellect is not performed through a bodily organ. Therefore, since the body is united to the soul not for the sake of the body but for that of the soul, because any matter exists for the sake of form, and not vice versa, it follows that an intellectual substance is not united as a form to a heavenly body.

Obj. 4: Further, every created intellectual substance is capable of sinning by reason of its nature, because it can turn away from the highest good, which is God. Therefore, if intellectual substances were united as forms to heavenly bodies, it would follow that they could commit sin. But the punishment for sin is death, that is, the separation of the soul from the body, and the punishment of the sinners in hell. Consequently, it could happen that heavenly bodies would corrupt by having their souls separated from them, and that these souls would be cast into hell.

Obj. 5: Further, every intellectual substance is capable of attaining beatitude. Therefore, if heavenly bodies are animated by intellectual souls, such souls are capable of beatitude; and thus, not only angels and men but also certain intermediate natures enjoy eternal beatitude. However, when the holy doctors consider this matter, they say that the society of the blessed is composed of men and angels.

Obj. 6: Further, the body of Adam was proportioned to a rational soul. But our body is unlike his, for his body was immortal and unchangeable before he sinned. Our bodies do not have these characteristics. Therefore, bodies such as we possess are not proportioned to a rational soul.

Obj. 7: Further, the best disposed instruments, and those which cooperate in operation, belong to the noblest mover. Now the rational soul is nobler than all other inferior movers. Hence, the rational soul should have a body that cooperates with it to the fullest extent in carrying out its operations. However, a body such as ours is not of this sort, because the flesh lusts against the spirit (Gal 5:17), and the soul is drawn here and there as a result of the struggle between concupiscences. Consequently, the rational soul should not be united to a body such as we possess.

Obj. 8: Further, an abundance of spirits falls to the lot of a rational soul in a perfectible body. Hence, in contrast to other animals, the heart of man is the hottest so far as the power of generating spirits is concerned. (Cf. Aristotle, On Youth and Old Age, ch. 4, 469b10; Aquinas, Commentary on Aristotle’s On the Soul, bk. 2, lect. 18.) The human body’s erectness, resulting from the power of heat and spirits, is a sign of this. Therefore, it would be most fitting for the rational soul to be united entirely to a spiritual body.

Obj. 9: Further, the soul is an incorruptible substance. However, our bodies are corruptible. Consequently, rational souls are not fittingly united to bodies such as we possess.

Obj. 10: Further, the rational soul is united to the body in order to constitute the human species. Now the human species would be better preserved if the body to which the rational soul is united were incorruptible. Then it would not be necessary for the human species to be preserved by generation, for it would be preserved numerically in the same individuals. (Cf. Aristotle, On the Soul 2.4, 415b1–7.) Hence, the human soul should be united to an incorruptible body.

Obj. 11: Further, the human body, being the noblest of inferior bodies, should resemble most a heavenly body, which is the noblest of bodies. However, a heavenly body lacks contrariety altogether. Therefore, the human body ought to have the least contrariety. But our bodies do not have the least contrariety, because other bodies, such as stones and trees, are more enduring, and contrariety is the principle of disintegration. Consequently, the rational soul should not be united to bodies such as we have.

Obj. 12: Further, the soul is a simple form. Now a simple matter befits a simple form. Hence the rational soul should be united to some simple body such as fire or gold or something of this kind. (Cf. Albert the Great, Commentary on the Sentences, bk. 2, d. 17, a. 3; Aquinas, In II Sent., d. 1, q. 2, a. 5, obj. 2.)

Obj. 13: Further, the human soul seems to have something in common with principles. Hence, the ancient philosophers maintained that the soul is composed of principles, as is clear in On the Soul 1. (Aristotle, On the Soul 1.2, 403b31–405b30; cf. Aquinas, Commentary on Aristotle’s On the Soul, bk. 1, lect. 3; bk. 1. lect. 4; bk. 1, lect. 5.) Now the principles of bodies are the elements. Therefore, if the soul is not an element, nor composed of elements, it should at least be united to some elementary body such as fire (This is the position of Democritus. See Aristotle, On the Soul 1.2, 403b31.) or gold, or something of this sort.

Obj. 14: Further, bodies composed of similar parts come closer to being simple than bodies composed of dissimilar parts. Consequently, the soul should be united to a body composed of similar parts rather than to one composed of dissimilar parts because the soul is a form in its entirety. (Cf. Aquinas, In II Sent., d. 1, q. 2, a. 5, obj. 3.)

Obj. 15: Further, the soul is united both as a form and as a mover to the body. (Cf. Aquinas, Commentary on Aristotle’s On the Soul, bk. 2, lect. 2.) Therefore, the rational soul, which is the noblest of forms, should be united to a body best adapted for movement. But we see that the contrary of this is true, for the bodies of birds and those of many other animals as well are better adapted for movement than the human body is.

Obj. 16: Further, Plato says that forms are conferred by the giver of forms according to the merits of matter, which are called material dispositions. (Plato, Timaeus 50d–51a; cf. Aquinas, In II Sent., d. 27, q. 1, a. 4, obj. 5; On the Power of God, q. 3, a. 10, ad 15.) But apparently the human body does not have a disposition in keeping with the nobility of its form, for the body is coarse and corruptible. Therefore, the soul should not be united to such a body.

Obj. 17: Further, the intelligible forms existing in the human soul, in contrast to those in superior intellectual substances, are in the highest degree representative of particulars. (Cf. The Book of Causes, proposition 9 [10]; Pseudo-Dionysius, The Celestial Hierarchy, ch. 12, para. 2 (PG 3:201–4).) But such forms befit the operation of a heavenly body, which is the cause of the generation and corruption of these particulars. Consequently, the human soul should be united to a heavenly body.

Obj. 18: Further, nothing is moved naturally so long as it occupies its proper place, but only when it is outside its proper place. (Cf. Aristotle, On the Heavens 1.8, 276a21–25; 1.9, 279b1–3; 3.2, 300a28–29.) However, heaven is moved while it exists in its proper place. Therefore, it is not moved naturally. Consequently, it is moved with respect to place by a soul and thus has a soul united to it.

Obj. 19: Further, “to proclaim” is an act of an intellectual substance. But the heavens proclaim the glory of God (Ps 19:1 [18:2]) as is said in the Psalms. Hence, the heavens are intelligent and thus possess an intellective soul.

Obj. 20: Further, the soul is the most perfect of forms. Therefore, it should be united to a most perfect body. However, the human body seems to be most imperfect, for it neither has arms to defend itself and to fight, nor covering nor anything of this sort which nature has bestowed on the bodies of other animals. (Cf. ST I.76.5, obj. 4.) Therefore, a soul of this kind should not be united to a body such as ours.

On the contrary, it is said, God created man of the earth and made him after his image (Sir 17:1–3). But the works of God are fitting works, for it is said, God saw everything that he had made, and behold, it was very good (Gen 1:31). Therefore, the rational soul, in which the image of God exists, is fittingly united to an earthly body.

I answer that, since matter exists for the sake of form and not vice versa, we must discover, on the side of the soul, the reason why the body should be united to it. (Aristotle, Physics 2.2, 194a15–b15; Averroes, Commentary on Aristotle’s Physics, bk. 2, comm. 26; Commentary on Aristotle’s On the Soul, bk. 2, comm. 36; cf. Aquinas, In IV Sent., d. 49, q. 1, a. 1, ad 6; SCG II.22, 88–89; III.75, 129; ST I.76.5, resp.; On Spiritual Creatures, a. 3, obj. 11, ad 6; On Evil, q. 5, a. 5, resp.; q. 16, a. 1, resp.; Commentary on Aristotle’s On the Soul, bk. 2, lect. 7.) Hence, it is said in On the Soul 2 that the soul is not only the form and mover of the body but also its end. (Aristotle, On the Soul 2.4, 415b10–15.) Moreover, it is evident from the preceding Disputed Questions that it is natural for the human soul to be united to the body. (Above: q. 1, resp.; q. 7, resp.; Aquinas, On Spiritual Creatures, a. 3.) For, although the soul is lowest in the order of intellectual substances, as primary matter is lowest in the order of sensible things, (Cf. Averroes, Commentary on Aristotle’s On the Soul, bk. 3, comm. 5, 17; Aquinas, On Truth, q. 10, a. 8, resp.; ST I.76.5, resp.; I.55.2; On Evil, q. 16, a. 10, ad 2; Pseudo-Dionysius, On the Divine Names, ch. 7, para. 2 (PG 3:867–70); Augustine, On the Literal Interpretation of Genesis, bk. 2, ch. 8 (CSEL 28.1:43; PL 34:269–70).) it does not have intelligible species naturally impressed on it, as superior intellectual substances have, whereby it can perform its proper operation of understanding, but is in potency to them because it is like a wax tablet on which nothing is written, as is said in On the Soul 3. (Aristotle, On the Soul 3.4, 429b32–430a1.) For this reason, it must receive its intelligible species from external things through its sensory powers, which cannot perform their proper operations without bodily organs. Consequently, it is necessary for the human soul to be united to a body.

Therefore, if the human soul is capable of being united to a body, because it needs to receive intelligible species from things through the intermediary of the senses, then the body, to which the rational soul is united, must be one which can most adequately present to the intellect those sensible species from which are derived the intelligible species existing in the intellect. Hence, the body to which the rational soul is united must be best disposed for sensory operation.

But although there are several sensory powers, still there is one which is the basis of the others, namely, touch, in which every sensible nature is principally rooted. For this reason, it is also said in On the Soul 2 that an animal derives its name from this sense. (Aristotle, On the Soul 2.2, 413b2–8.) This is the reason why, when this sense is unmoved, as occurs during sleep, all other senses are unmoved. Again, not only are all the other senses rendered inactive by an excess of their proper sensible objects—as sight, for instance, is made inoperative by very bright objects, and hearing by too intense sounds—but so also is the sense of touch rendered incapable of performing its proper operation by an excess of its sensible object, for example, excessive warmth or cold. Therefore, since the body to which the rational soul is united must be best disposed for a sensitive nature, it must have the most competent organ of touch. And so, it is said in On the Soul 2 that among all animals we have this sense to a greater degree, and also that one man is more adept than another in intellectual operations as a result of this sense. (Aristotle, On the Soul 2.9, 421a20–26; cf. Nemesius, On the Nature of Man, ch. 7.) For we see that those who have tender flesh, that is, those who are of good touch, are well-endowed mentally. (Cf. Aristotle, On the Soul 2.5, 417a6–7; 2.11, 424a7–10.)

Now since the organ of any sense must not possess actually any of the contraries of which a sense is perceptive, but must be in potency to them in order that it may be able to receive them—because the recipient must be deprived of the thing received—the case must be otherwise for the organ of touch than it is for the organs of the other senses. For the organ of sight, that is, the pupil of the eye, is deprived completely of white and of black, and of every kind of color whatever. It is similar in the case of hearing and smell. But this cannot occur in the case of the sense of touch, for touch is capable of experiencing those qualities which the animal body must be composed of, namely, hot and cold, wet and dry. For this reason, it is impossible for the organ of touch to be deprived completely of its sensible objects; rather, it must be reduced to a mean, because in this way it is in potency to contraries. Therefore, since the body to which the rational soul is united must be best disposed for the sense of touch, (Cf. Aristotle, On the Soul 3.12, 434b23–24; 3.13, 435b4–5; 435b16.) it must be brought in the fullest measure to an intermediate state by the harmonious combination of its constituent elements and their qualities.

In this way it is evident that the total operation of an inferior nature reaches its highest peak in man as a most perfect being. For we see that the operation of nature ascends progressively from the simple elements, by blending them, until it reaches the most perfect mode of combination, which is the human body. (Cf. Aristotle, The History of Animals 8.1, 588b4–17; Aquinas, Commentary on Aristotle’s On Memory and Recollection, tract. 2, ch. 1; Commentary on Aristotle’s On the Soul, bk. 2, lect. 5.) Consequently, this disposition of the human body, to which the rational soul is united, must exist in order that the body may possess the most tempered combination. (Cf. Aquinas, In II Sent., d. 17, q. 3, a. 1, ad 1; d. 19, q. 1, a. 4, ad 1; On Truth, q. 18, a. 8, ad 6; On Evil, q. 5, a. 5, resp.)

Moreover, if anyone also wishes to examine the particular dispositions of the human body, he will find them ordered to this end, that man may have the best sense. Therefore, man, in proportion to his size, has a larger brain than any other animal, because a good disposition of the brain is necessary for the good condition of the internal sensitive powers, namely, the imagination, the memory, and the cogitative power. (Cf. Aquinas, On Truth, q. 10, a. 5, resp.; Commentary on Aristotle’s On the Soul, bk. 2, lect. 19; ST I.91.3, ad 1; Aristotle, On the Parts of Animals 2.7, 653a27–28.) And in order that his operation may be freer, he has his head placed on high. For man is the only erect animal; the others, indeed, are bent over. (Cf. Ecclesiastes 7:29; ST I.91.3, ad 3.) Furthermore, in order to have this erectness and to preserve it, there must exist in the heart an abundance of heat, by which many spirits are generated, so that the body may be maintained erect by this copious amount of heat and spirits. (Cf. Aristotle, On the Generation of Animals 1.20, 728a10; 728b28; 2.2, 736b35; Aquinas, Commentary on Aristotle’s On the Soul, bk. 2, lect. 18; bk. 1, lect. 10; In II Sent., d. 30, q. 2, a. 1, ad 5; On Evil, q. 16, a. 1, obj. 5.) The fact that a man stoops over when he is old is a sign of this, because his natural heat is diminished. (Aquinas, Commentary on Aristotle’s On the Soul, bk. 2, lect. 7.) In the light of what is stated above, the account of a disposition of the human body must be determined in relation to the particular dispositions proper to man.

However, we must take into consideration that in those things which are constituted of matter, some dispositions exist in the matter itself, and that on account of these a definite matter is chosen for a definite form. There are also some dispositions which proceed from the necessary character of matter, and not from the choice of the agent; for instance, when an artisan chooses hardness in iron to make a saw in order that it may be useful for sawing. But the fact that sharpness can be given to iron, and that it can rust, results from the necessary character of matter. For the artisan would rather choose a matter in which defects are not present, if it could be found. But because it cannot be found, the artisan does not neglect to work with the available matter of this kind simply because of the defects intrinsic to such matter. (Cf. Aristotle, Physics 2.7, 198b8; 2.9, 200a30–b8; Aquinas, On Evil, q. 5, a. 5, resp.; ST I.76.5, ad 1; I.91.3.)

This also occurs in the human body, for, likewise, whatever is combined and disposed according to parts in order that such a body may be best fitted for sensitive operations, is selected in this matter by the maker of man. But that this body is corruptible, that it may become fatigued, and have defects of this kind, follows from the necessary character of this matter. For the body, as a mixture of contraries, must be subject to such defects. Nor can any objection be raised in view of the fact that God could make it otherwise, because we do not investigate what God could make in the establishment of nature, but what the nature of things undergoes as made, as Augustine says in On the Literal Interpretation of Genesis. (Augustine, On the Literal Interpretation of Genesis, bk. 2, ch. 1 (CSEL 28.1:33; PL 34:263); cf. ST I.76.5, ad 1.)

Moreover, it must be recognized that when God remedied these defects in man at his creation, he employed the help of original justice (Cf. ST I.97.1; On Evil, q. 5, a. 1, resp.) whereby the body was made subject completely to the soul and the soul to God, so that neither death nor passion nor any defect could affect man unless the soul were first separated from God. (See above: q. 1, ad 5; Aquinas, Compendium theologiae, bk. 1, ch. 152.) But when the soul turned away from God through sin, man was deprived of this gift, and is subject to the defects which are intrinsic to the nature of matter.

Reply Obj. 1: The soul, being intellectual, is the subtlest of forms, (Cf. Gregory the Great, Dialogues, bk. 4, ch. 27 (SC 265:86; PL 77:357C–D); Aquinas, On Truth, q. 8, a. 12, obj. 3.) but it is lowest in the order of intellectual forms and must be united to a body in order to acquire intelligible species through the senses. (Cf. Aquinas, Commentary on Aristotle’s On the Soul, bk. 2, lect. 23.) This union is effected through a combination of the elements. The body, to which the soul is united, had to contain a greater quantity of the heavy elements, namely, of earth and water. (And thus, the body would then contain a lesser quantity of the light elements: fire and air; cf. Aquinas, In II Sent., d. 15, q. 2, a. 1; Aristotle, On the Soul 3.11, 423a11–17; Averroes, Commentary on Aristotle’s On the Soul, bk. 2, comm. 111.) For fire is the most active of all the elements. (See above: q. 7, resp.; Aquinas, Commentary on Aristotle’s On the Soul, bk. 2, lect. 25.) If the lower elements (Namely, earth and water.) were not present in greater quantity, the aforesaid combination could not be brought about nor above all be reduced to a mean, because fire would consume the other elements. For this reason, the Philosopher, in On Generation and Corruption 2, states that earth and water are more abundant than the other elements in mixed bodies. (Aristotle, On Generation and Corruption 2.8, 334b31–335a5; cf. On the Soul 3.13, 435a11; Averroes, Commentary on Aristotle’s On the Soul, bk. 3, comm. 66; Aquinas, Commentary on Aristotle’s On the Soul, bk. 3, lect. 12.)

Reply Obj. 2: The rational soul is united to this kind of body, not because it is like a heavenly body, but because it is composed of a harmonious combination of the elements. But it follows that it bears some likeness to a heavenly body, in this way, by being relatively independent of contraries. However, according to the opinion of Avicenna, the soul is united to such a body particularly because of its likeness to a heavenly body. (Avicenna, De anima, part 5, ch. 7; Metaphysics, bk. 9, ch. 4.) For he desired that inferior things be caused by the superior beings, in order that inferior bodies might be caused by the heavenly bodies. And he maintained that these inferior bodies possess a form similar to that of a heavenly body, which is considered to be animated, since such inferior bodies bear some likeness to heavenly bodies because of their harmonious combination.

Reply Obj. 3: There is a diversity of opinion, both among philosophers and among the doctors of the faith, concerning the animation of the heavenly bodies. For among the philosophers, Anaxagoras maintained that the agent intellect was altogether simple and existed apart from things, and that the heavenly bodies were inanimate. (Diogenes Laertius (3rd cent. AD), Lives of the Eminent Philosophers, bk. 2, ch. 8; though Aquinas attributes this report to Augustine: City of God, bk. 18, ch. 41 (CCSL 48:635–38; PL 41:600–602); bk. 8, ch. 2 (CCSL 47:218; PL 41:226).) Hence, it is said that he was even condemned to death because he claimed that the sun was a fiery stone, as Augustine relates in the work City of God. (Augustine, City of God, bk. 18, ch. 41 (CCSL 48:635–38; PL 41:600–602); bk. 8, ch. 2 (CCSL 47:218; PL 41:226).) Other philosophers, indeed, maintained that the heavenly bodies are animated. Some of these stated that God is the soul of the heavens, which was idolatrous inasmuch as it attributed divine worship to the heavens and the heavenly bodies. Others, indeed, such as Plato and Aristotle, although they claimed that the heavenly bodies are animated, nevertheless maintained that God is a supreme being, quite distinct from the soul of the heavens. (Plato, Timaeus 38e; 39e–40b; Aristotle, On the Heavens 2.2, 285a29–30; Physics 8.5; Metaphysics 12.7, 1072a20–b1; On the Soul 2.3, 414b17–19; cf. Aquinas, Commentary on Aristotle’s On the Heavens, bk. 2, lect. 3, n. 314; SCG II.70.) Among the doctors of the faith as well, Origen and his followers held that such bodies are inanimate, as Damascene did. (Origen, On First Principles, bk. 1, ch. 7, paras. 3–4; John Damascene, On the Orthodox Faith, bk. 2, ch. 6 [ch. 20] (PG 94:879–86).) This is also the more common position among modern theologians. (Cf. Aquinas, On the Power of God, q. 6, a. 6; Bonaventure, In II Sent., d. 14, P. 1, a. 3, q. 2.) That Augustine remained in doubt on the question is shown in On the Literal Interpretation of Genesis 2, and in the work Enchiridion on Faith, Hope, and Charity. (Augustine, On the Literal Interpretation of Genesis, bk. 2, ch. 18 (CSEL 28.1:62; PL 34:279–80); Enchiridion on Faith, Hope, and Charity, bk. 1, ch. 58, n. 15 (CCSL 46:80–81; PL 40:259–60); cf. ST I.70.3, resp.) Therefore, holding this for a fact, that the heavenly bodies are moved by an intellect which is separate, (This question regarding the animation of the heavenly bodies is an important consideration in the thought of Aquinas. See Aquinas, In II Sent., d. 14, q. 1, a. 3; On Truth, q. 5, a. 9, ad 14; SCG II.70; III.23; On the Power of God, q. 3, a. 11, ad 13; q. 6, a. 6. resp., ad 10; ST I.70.3; Compendium theologiae, bk. 1, ch. 171; Commentary on Aristotle’s On the Soul, bk. 2, lect. 3; On Spiritual Creatures, a. 6; Quodlibet XII, q. 6, a. 2; Commentary on Aristotle’s Metaphysics, bk. 12, lect. 4, n. 2476; bk. 5, lect. 21, n. 1100; Commentary on Aristotle’s On the Heavens, bk. 2, lect. 3, nn. 314–19; lect. 13, nn. 414–19; Letter to John Vercelii on the 43 Articles, aa. 1–18; Letter to Bassiano of Lodi on the 36 Articles, aa. 1–3; Commentary on the Book of Causes, propositions 5, 30.) we say—maintaining both positions on account of the arguments supporting both sides—that an intellectual substance, as a form, is the perfection of the heavenly body, and that it has an intellective power alone but no sensory power, as can be seen from the words of Aristotle in On the Soul 2 and in Metaphysics 11, even though Avicenna maintains that the soul of the heavens has an imagination in addition to its intellect. (Avicenna, Metaphysics, bk. 10, ch. 1; Aristotle, On the Soul 2.1, 413a6; 2.3, 414b17–19; 3.12, 434a27–28; 3.13, 435a11–b4; Metaphysics 11.2, 1060a10; 10.1; 12.7 1072a20–b1.) However, if it has an intellect only, it is still united as a form to the body, not for the sake of intellectual operation, but for the sake of executing its active power according to which it can attain a certain likeness to divine causality by moving the heavens. (Cf. Aquinas, On the Power of God, q. 5, a. 5, resp.; SCG IV.97; On Spiritual Creatures, a. 6; Commentary on Aristotle’s Metaphysics, bk. 12, lect. 7, n. 2519.)

Reply Obj. 4: Although all created intellectual substances by nature are capable of committing sin, still many are preserved from so doing by divine choice and predestination through the aid of grace. One can maintain that the souls of the heavenly bodies are among this number, particularly if the demons who sinned were of an inferior order, as Damascene held. (John Damascene, On the Orthodox Faith, bk. 2, ch. 4 [ch. 18] (PG 94:874–78).)

Reply Obj. 5: If the heavenly bodies are animated, their souls belong to the society of the angels. For Augustine says in Enchiridion, that I do not hold for certain that the sun and moon, and the other stars belong to the same society, namely, that of the angels, for although some are luminous bodies, still they do not appear to be sensitive or intellective. (Augustine, Enchiridion, bk. 1, ch. 58, n. 15 (CCSL 46:80–81; PL 40:259–60); cf. SCG II.70; On Spiritual Creatures, a. 6, ad 3.)

Reply Obj. 6: The body of Adam was made proportionate to a human soul, as was explained, not only with respect to what nature requires, but also with respect to what grace conferred. Now, we are deprived of this grace, but our nature remains the same.

Reply Obj. 7: The struggle which occurs in man as a result of contrary concupiscences also results from the necessary character of matter. For, given the fact that man has sense, it is necessary that he sense delectable objects, and that he pursue his concupiscence for such objects, which is generally opposed to reason. (Cf. ST I.82.5, s.c.) But in the state of innocence, man was also given a remedy against this through grace, so that the inferior powers were not moved in any way contrary to reason. However, man lost this through sin. (Cf. ST I.95.1, resp.)

Reply Obj. 8: Although spirits are the vehicles of powers, they still cannot be organs of the senses. Therefore, the human body could not be composed of spirits alone.

Reply Obj. 9: Corruptibility is a result of the defects which belong intrinsically to the human body from the necessary character of matter. (Cf. Aquinas, Compendium theologiae, bk. 1, ch. 152.) This is particularly true after man sinned because sin removes the assistance of grace.

Reply Obj. 10: Whatever is better must necessarily exist in those things which exist for an end, but not in those things which are a result of the necessary character of matter. (Cf. ST I.91.3, resp.; On Evil, q. 5, a. 5, resp.) For it would be better if an animal body were incorruptible; and if this were permitted by nature, an animal form would require such a matter.

Reply Obj. 11: Those things which are most akin in nature to the elements and possess greater contrariety, such as stones and metals, are more enduring, because in them the elements are less subtly proportioned, and thus they are not easily disintegrated. For the blending of the elements in those things which are subtly proportioned is easily destroyed. Notwithstanding, the cause of longevity in animals is attributed to the fact that the moisture which they contain is not easily dried up or made inactive, nor is their heat easily extinguished, because heat and moisture are indispensable for life. Moreover, this is found in man to the extent that it is necessary for a combination of the elements reduced to a mean. Hence, in men some combinations are more enduring, others less so, and as a result of this some men live longer than others.

Reply Obj. 12: The human body could not be a simple body, (Cf. Aristotle, On the Soul 3.12, 434b8–11; Themistius (4th cent. AD), Commentary on the De anima, bk. 7, cc. 12–13; Averroes, Commentary on Aristotle’s On the Soul, bk. 3, comm. 62; Aquinas, Commentary on Aristotle’s On the Soul, bk. 2, lect. 3; bk. 3, lect. 11.) nor could it be a heavenly body, because of the determinable character of a sense organ, particularly that of touch. (Cf. SCG II.70; ST I.66.2, resp.; I.70.1, ad 1; I.91.1, ad 2; Aquinas, Commentary on Aristotle’s On the Soul, bk. 3, lect. 11; Commentary on Aristotle’s On the Heavens, bk. 2, lect. 13, n. 415.) Nor could it be a simple elementary body, because actual contraries exist in an element, whereas the human body must be reduced to a mean. (Cf. SCG II.90; Aquinas, Commentary on Aristotle’s On the Soul, bk. 3, lect. 12.)

Reply Obj. 13: The natural philosophers of antiquity thought that the soul, which knows all things, must actually be like all things. And, therefore, they maintained that the soul possessed the nature of an element, which they held was the principle from which all things are said to be constituted, so that in this way the soul knew all things inasmuch as it was like all things. However, Aristotle later showed that the soul knows all things inasmuch as it is like all things potentially, not actually. (Aristotle, On the Soul 3.4, 429a18–24; 429b29–430a2; cf. Aquinas, Commentary on Aristotle’s On the Soul, bk. 3, lect. 1.) Consequently, the body to which it is united must be composed not of extremes but of a mean, so that it may thus be in potency to contraries.

Reply Obj. 14: Although a soul is simple in essence, yet it has many powers. And the more numerous its powers, the more perfect will it be. For this reason, it requires an organic body constituted of dissimilar parts. (Cf. SCG II.86.)

Reply Obj. 15: The soul is not united to the body for the sake of local motion; rather the local motion of man, (Cf. Aristotle, On the Soul 2.3, 414b17.) like that of other animals, is directed to conserving the body which is united to the soul. But the soul is united to the body for the sake of understanding, which is its proper and principal operation. For this reason, the body, being united to the rational soul, must be best disposed to serve the soul with respect to the things necessary for understanding. It is also necessary that the body possess agility and other things of this kind, so far as such a disposition permits this.

Reply Obj. 16: Plato maintained that the form of things subsisted of themselves, and that the participation of forms by material things is for the sake of material things inasmuch as they are thereby perfected, and not for the sake of the forms themselves, which subsist of themselves. From this it follows that forms are given to material things so far as they merit them. (Plato, Timaeus 50b–51c; Aristotle, Metaphysics 1.6, 987b1–14.) Now, according to the view of Aristotle, natural forms do not subsist of themselves. (Aristotle, Metaphysics 1.9, 990b1–991a8; 3.2, 997b5–12.) Hence, a form is united to matter not for the sake of matter, but for the sake of form. Therefore, a certain form is given to matter not because matter is so disposed, but because a certain form requires matter to be so disposed. For this reason, it was said above that the human body is disposed in a manner befitting such a form as the human soul.

Reply Obj. 17: Although a heavenly body is the cause of the particular things which are generated and corrupted, nevertheless it causes them as a common agent. (Cf. SCG III.69; On Evil, q. 5, a. 5, ad 6; Commentary on Job, ch. 38; ST I.115.3, ad 2.) For this reason, determinate agents of a particular species are required beneath it. Hence, it is not necessary for the mover of a heavenly body, whether it be a soul or a separate mover, to have particular forms, but only universal ones. Now Avicenna maintained that the soul of a heavenly body had to have an imagination through which it could apprehend particulars. (Avicenna, Metaphysics, bk. 10, ch. 1.) For the soul of heaven, being the cause of its motion, must know the here and the now, and, therefore, must have some sensory power, because it is the cause of the heavenly motion whereby heaven revolves in this or that particular place. (Cf. Aristotle, Metaphysics 8.3, 1042b3–8; 12.2, 1069b24–26; Aquinas, In II Sent., d. 14, q. 1, a. 3, resp.; Commentary on Aristotle’s On the Heavens, bk. 2, lect. 13, n. 418; On Evil, q. 16, a. 2, ad 6; Commentary on Aristotle’s On the Soul, bk. 1, lect. 7; Commentary on Aristotle’s Physics, bk. 8, lect. 23, n. 1168.) But this is not necessary. First, indeed, because heavenly motion is always uniform and is not hindered, (Cf. Aristotle, On the Heavens 2.6, 288a13–b7.) and, therefore, a universal conception is sufficient to cause such movement. For a knowledge of the particular is required in the case of animal movements on account of the irregularity of such movement, and because obstacles can hinder such movement. Second, because superior intellectual substances can apprehend particulars without a sensory power, as was shown elsewhere. (Cf. Aquinas, In II Sent., d. 3, q. 3, a. 3; On Truth, q. 8, a. 11; SCG II.96; ST I.57.2.)

Reply Obj. 18: The movement of heaven is natural (Cf. Aristotle, On the Heavens 1.2, 269a32; Averroes, Commentary on Aristotle’s On the Heavens, bk. 1, comm. 12–14; Aquinas, In II Sent., d. 14, q. 1, a. 3, ad 1; ST I.70.3, obj. 4.) on account of a passive principle or of movement received, because such movement belongs naturally to such a body. (Cf. ST I.70.3, ad 4; Commentary on Aristotle’s On the Heavens, bk. 2, lect. 3, n. 314; On Spiritual Creatures, a. 6, ad 7.) But the active principle of this movement is a certain intellectual substance. Now the statement that no body is moved naturally when it is in its proper place is understood of a body moved by rectilinear movement, and this body changes place with respect to the whole of itself, not only from the point of view of reason, but also from that of the subject itself. But a body which is moved circularly does not change place with respect to the whole of itself from the point of view of the subject, but only from that of reason. Hence, it never is outside its proper place.

Reply Obj. 19: This argument is foolish despite the fact that Rabbi Moses proposes it. (Moses Maimonides, Guide for the Perplexed, bk. 2, ch. 6; cf. Aquinas, On Spiritual Creatures, a. 6, ad 14; John Damascene, On the Orthodox Faith, bk. 2, ch. 6 [ch. 20] (PG 94:874–78).) For if “to proclaim” is taken in its proper sense, when it is said that the heavens proclaim the glory of God, the heavens would require not only an intellect but also a tongue. Therefore, the heavens are said to proclaim the glory of God, if taken in a literal sense, inasmuch as through them the glory of God is made manifest to men. In this way, also, insensible creatures are said to praise God.

Reply Obj. 20: Other animals have a natural estimative power directed to definite activities, and, therefore, nature could provide them sufficiently with certain definite aids. But this is not so in the case of man who is capable of an unlimited number of conceptions because of his reason. Therefore, in place of all the aids which other animals possess by nature, man has an intellect, which is a mirror of all forms, and hands, which are the organs of organs, whereby he can provide for himself whatever he requires. (Cf. Aristotle, On the Soul 3.8, 432a1–2; Aquinas, Commentary on Aristotle’s On the Soul, bk. 3, lect. 7; ST I.76.5, ad 4.)