Article 12 — Whether the soul is its powers

Twelfth, it is asked whether the soul is its powers. (Parallel texts: ST I.77.1; I.79.1; I.54.3; In I Sent., d. 3, q. 4, a. 2; Quodlibet VII, q. 2, a. 1; Quodlibet X, q. 3, a. 1; On Spiritual Creatures, a. 11; Compendium theologiae, bk. 1, ch. 89.)

Obj. 1: It seems that it is. For it is said in the work The Spirit and the Soul that the soul has its own natural powers, and is all of these, for its active and passive powers are the same as itself. It has accidents, and these are not its powers, nor are its virtues itself; for it is not its own prudence, temperance, justice, and fortitude. (Pseudo-Augustine (Alcher of Clairvaux), The Spirit and the Soul, ch. 13 (PL 40:788–89); cf. John of Rupella, Summa de anima, bk. 2, ch. 60 [I]; Aquinas, Quodlibet X, q. 3, a. 1, obj. 1; On Spiritual Creatures, a. 11, obj. 2.) According to this, it seems to be clearly maintained that the soul is its powers.

Obj. 2: Further, it is stated in the same work, the soul is designated by different names in accordance with the way in which it operates. For it is called soul when it vegetates, sense when it senses, spirit when it knows, mind when it understands, reason when it discerns, memory when it remembers, and will when it wills. However, these do not differ substantially but only in name, because all of these are the soul itself. (Pseudo-Augustine (Alcher of Clairvaux), The Spirit and the Soul, ch. 13 (PL 40:788–89); ch. 4 (PL 40:782); cf. John of Rupella, Summa de anima, bk. 1, ch. 26 [XXIV]; bk. 2, ch. 60 [I].) According to this, the same thing would be maintained as is stated above. (Above: obj. 1.)

Obj. 3: Further, Bernard says, I distinguish three powers in the soul: memory, understanding, and will; and these three are the soul itself. (Pseudo-Bernard of Clairvaux, Meditations, ch. 1, para. 1 (PL 184:487); Bernard of Clairvaux, Sermons on the Song of Songs, sermon 11, para. 5 (PL 183:826).) But the same thing is also true of the other powers of the soul. Hence, the soul is its powers.

Obj. 4: Further, Augustine says in On the Trinity that memory, understanding, and will, are one life, one essence. (Augustine, On the Trinity, bk. 10, ch. 11, para. 18 (CCSL 50:329–31; PL 42:983); bk. 9, ch. 4, para. 7 (CCSL 50:299; PL 42:965); cf. ST I.77.1, obj. 1; Quodlibet X, q. 3, a. 1, obj. 2; On Spiritual Creatures, a. 11, obj. 8.) Now the essence of the soul is nothing if not one. Therefore, the powers of the soul are the same as its essence.

Obj. 5: Further, no accident goes beyond its subject. Now memory, understanding, and will go beyond the soul. For the soul not only remembers itself, and understands and wills itself, but other things as well. (Cf. Augustine, On the Trinity, bk. 9, ch. 4, para. 5 (CCSL 50:298; PL 42:963).) Therefore, these three powers are not accidents of the soul. Hence, they are the same as its essence, and so also are its other powers for the same reason.

Obj. 6: Further, an image of the Trinity is found in the soul with respect to these three powers. (Cf. Augustine, On the Trinity, bk. 15, ch. 3, para. 5 (CCSL 50A:465–66; PL 42:1060).) But an image of the Trinity is present in the soul so far as the soul itself is concerned, and not merely so far as its accidents are concerned. Therefore, the aforementioned powers are not accidents of the soul and, consequently, belong to its essence.

Obj. 7: Further, an accident is something that can be present or absent without its subject being corrupted. (Peter Lombard (d. 1160 AD), Sentences, bk. 1, d. 3, ch. 2 (PL 192:529); cf. SCG I.23.) But the powers of the soul cannot be withdrawn from the soul. Therefore, they are not accidents of it. Thus, the conclusion here is the same as the foregoing.

Obj. 8: Further, no accident is a principle of substantial difference, because a difference completes a thing’s definition, (Cf. Aristotle, Metaphysics 5.30, 1025a30–32; 10.9, 1058b1–5.) which definition signifies what a thing is. (Cf. Aristotle, Posterior Analytics 2.3, 90b30; Aquinas, Commentary on Aristotle’s Posterior Analytics, bk. 2, lect. 2.) Now powers of a soul are principles of substantial differences, for a thing is said to be sensible in virtue of sense, and to be rational in virtue of reason. (Cf. Aquinas, On Spiritual Creatures, a. 11, obj. 3; ST I.77.1, obj. 7.) Therefore, the powers of the soul are not accidents of it, but are the soul itself, which is the form of the body, for the form is the principle of substantial difference.

Obj. 9: Further, a substantial form is more efficacious than an accidental one. (Cf. Aquinas, On Spiritual Creatures, a. 11, obj. 10; ST I.77.1, obj. 3.) But an accidental form acts by itself and not by some intermediary power. Therefore, so also does a substantial form. Consequently, since the soul is a substantial form, its powers, whereby it operates, do not differ from itself.

Obj. 10: Further, the principle which gives a thing its act of existing and that responsible for its operations are one and the same. (Cf. Bonaventure, In I Sent., d. 3, P. 2, a. 1, q. 3, obj. 3; Aristotle, Physics 2.1, 192b14–15; 192b20–22; 193a29–30.) Now the soul in itself is the principle that gives a living thing its act of existing, because it is a form according to its very essence. Therefore, its essence is a principle of operation. But a power is nothing more than a principle of operation. Consequently, the essence of the soul is identical with its powers.

Obj. 11: Further, the substance of the soul, inasmuch as it is in potency to intelligibles, is the potential intellect. (Cf. Aristotle, On the Soul 3.5, 430a13–14.) However, inasmuch as the soul is in act with respect to intelligibles, its substance is the agent intellect. But to be in act and to be in potency refer only to the thing itself which is in potency and in act. Therefore, the soul is the agent intellect and the potential intellect, and is its other powers for the same reason.

Obj. 12: Further, just as prime matter is in potency to sensible forms, so also is the intellective soul in potency to intelligible forms. But prime matter is its own potency. (Cf. Aristotle, Metaphysics 7.3, 1029a20–26; 8.1, 1042a26–28; 12.5, 1071a10; On the Soul 2.1, 412a9; Averroes, Commentary on Aristotle’s On the Soul, bk. 2, comm. 20.) Therefore, the intellective soul is its own powers. (Cf. Aquinas, On Spiritual Creatures, a. 11, obj. 15; ST I.54.3, obj. 3.)

Obj. 13: Further, the Philosopher says in the book Ethics that man is an intellect. (Aristotle, Nicomachean Ethics 9.4, 1166a16–17; 1166a22–23; 9.8, 1168b28–35; 10.7, 1178a2.) But he is an intellect only by reason of his rational soul. Therefore, the soul is the intellect, and for the same reason, it is also its other powers.

Obj. 14: Further, the Philosopher says in On the Soul 2 that the soul is a first act, just as any science is. (Aristotle, On the Soul 2.1, 412a20–23; cf. ST I.77.1, obj. 4.) Now a science is the immediate principle of that second act which is cogitation itself. Therefore, the soul is the immediate principle of its own operations. But the immediate principle of an operation is called a power. Consequently, the soul is its powers.

Obj. 15: Further, all parts of a whole are consubstantial with the whole because a whole is composed of its parts. Now the powers of the soul are its parts, as is shown in On the Soul 2. (Aristotle, On the Soul 2.1, 413a3; 413b13–29.) Therefore, they are substantial parts of the soul and not accidents of it.

Obj. 16: Further, whatever is a form alone cannot be a subject. (Cf. Boethius, On the Trinity, ch. 2 (PL 64:1250); ST I.54.3, obj. 2; I.77.1, obj. 6.) But the soul is a form alone, as we have shown above. (Above: q. 6.) Therefore, it cannot be a subject of accidents. Consequently, the powers which are present in the soul are not accidents of it.

Obj. 17: Further, if the powers are accidents of the soul, they must flow from its essence, (Cf. ST I.77.6, resp.) for proper accidents are caused by the principles of a subject. But the essence of the soul, so far as it reveals itself in its powers, cannot be the cause of so great a diversity of accidents, because it is simple. Therefore, the powers of the soul are not its accidents. Consequently, it is to be concluded that the soul is its powers. (Cf. Aquinas, On Spiritual Creatures, a. 11, obj. 20.)

On the contrary (1), essence is related to the act of existing as power is to action. Therefore, just as to be and to act are proportionally related to each other, so also are power and essence. Now to exist and to act are one and the same in God alone. Therefore, power and essence are one and the same in God alone. Consequently, the soul is not its powers. (Cf. Aquinas, In I Sent., d. 3, q. 4, a. 2, s.c. 1; ST I.54.3, resp.; I.79.1, resp.; On Spiritual Creatures, a. 11, resp.)

Furthermore (2), no quality is a substance. (Cf. Aristotle, Metaphysics 7.4, 1030a24–26.) But a natural power is a particular species of quality, as is revealed in Categories. (Aristotle, Categories 8, 9a13–28.) Consequently, the natural powers of the soul are not the essence itself of the soul.

I answer that there are different opinions about this question. For some say that the soul is its powers, and others deny this, holding that the powers of the soul are certain properties of it. (Cf. ST I.77.1, resp.; On Spiritual Creatures, a. 11, resp.; Quodlibet X, q. 3, a. 1.) In order to see wherein these opinions differ, we must understand that a power is nothing but a thing’s principle of operation, whether it be an action or a passion. (Cf. Aquinas, In I Sent., d. 42, q. 1, a. 1, ad 1; On the Power of God, q. 1, a. 1, resp.) Indeed, a principle is not the subject acting or undergoing an action, but that by which an agent acts or a patient undergoes an action; just as the art of building is a power in the builder who builds by means of that power; and as heat is a power of fire, which heats by means of its heat; and as dryness is a power in pieces of wood, because they are combustible in virtue of this dryness. Consequently, those who maintain that the soul is its powers think that the essence itself of the soul is the immediate principle of all its operations. They say that a man understands, senses, and acts, and other things of this sort, by the essence of the soul, and that the soul is referred to by different names inasmuch as its operations differ. It is called sense inasmuch as it is the principle of sensation, intellect inasmuch as it is the principle of understanding, and so on for the other powers. This is just as if, for example, we were to call the heat of fire its liquifying power, its heating power, and its drying power, because it does all of these.

Now this opinion cannot be maintained. First, indeed, because anything whatever that acts, acts according as it is in act. (Cf. Aquinas, Commentary on Aristotle’s On Sense and What Is Sensed, tract. 1, ch. 9; Commentary on Aristotle’s On the Soul, bk. 3, lect. 1; SCG II.6; ST I.25.3, resp.) For fire heats not inasmuch as it is actually bright, but inasmuch as it is actually hot. It is for this reason that every agent produces an effect similar to itself. (Cf. Aristotle, On Generation and Corruption 1.7, 324a10–11.) Wherefore, the principle by which an agent acts must be known from its effects, for both must conform. Hence, it is said in Physics 2 that the form and the thing generating are the same in species. (Aristotle, Physics 2.7, 198a24–27.) Therefore, when an effect does not result from the substantial mode of existing of the one acting, it is impossible that the principle by which such an effect is brought about belongs in any way to the essence itself of the thing acting. This is quite evident in natural agents. For since a natural agent in generating acts by changing matter with respect to some form—which change occurs inasmuch as matter is first disposed to receive the form, and then acquires it according as generation is the terminus of alteration (Cf. Aristotle, Physics 6.6, 237b9–13; On Generation and Corruption 1.2, 317a23–27; 2.4–5, 331a7–332a2; Aquinas, Commentary on Aristotle’s Physics, bk. 6, lect. 8, n. 839; Commentary on Aristotle’s On the Soul, bk. 2, lect. 23; Averroes, Commentary on Aristotle’s Physics, bk. 6, comm. 59.)—the principle which acts immediately on the side of the agent must be an accidental form corresponding to the disposition of the matter. Now an accidental form must act in virtue of a substantial form, and as an instrument of the latter, otherwise it would not induce a substantial form by its activity. For this reason, no principles of action appear in the elements except their active and passive qualities, which still act in virtue of their substantial forms, and on account of this their action is terminated not only in accidental dispositions, but in substantial forms as well. (Cf. Aristotle, On Generation and Corruption 2.6, 333b12–15; 2.9, 336a1–3; Aquinas, Commentary on Aristotle’s On the Soul, bk. 2, lect. 23.) For in things made by art, the action of an instrument is terminated in the form intended by the artisan. Indeed, if there is an agent that produces a substance directly and immediately by its action—just as we speak of God who produces the substances of things by creating them, and as Avicenna speaks of the agent intellect, which, by virtue of its own power, infuses substantial forms into these inferior things—then an agent of this sort acts through its own essence, and thus its active power will not differ from its own essence. (Avicenna, Metaphysics, bk. 1, ch. 5; bk. 8, ch. 7; bk. 9, ch. 5; cf. SCG II.9–10.)

Concerning passive power, it is clear that a passive power which is ordered to a substantial act belongs to the genus of substance, whereas one that is ordered to an accidental act belongs to the genus of accident by reduction as a principle and not as a complete species, because every genus is divided by potency and act. Accordingly, a potential man belongs to the genus of substance, and potentially white belongs to the genus of quality.

Now it is evident that the powers of the soul, whether active or passive, are not spoken of directly with respect to something substantial, but with respect to something accidental. Similarly, to be understanding or sensing actually is not a substantial mode of existing, but an accidental one to which the intellect and sense are directed. It is similar with respect to being large or small, to which the augmentative power is ordered. Indeed, the generative and nutritive powers are directed to the production or conservation of a substance, but by changing matter. (Cf. Aristotle, On the Soul 2.4, 415a22–b28; 416a16–18; 2.2, 413a30–31; Aquinas, In II Sent., d. 18, q. 2, a. 3; ST I.78.2; Commentary on Aristotle’s On the Soul, bk. 2, lect. 9.) Wherefore, an action of this kind, like that of other natural agents, is performed by a substance through the medium of an accidental principle. Hence, it is evident that the essence of the soul is not the immediate principle of its operations, but that it operates through accidental principles. Consequently, the powers of the soul are not the essence itself of the soul but are properties of it.

This is also evident from the very diversity of the soul’s actions, which differ in genus and cannot be attributed to one immediate principle, because some are actions and some are passions, and are distinguished by other differences of this sort which must be attributed to different principles. Consequently, since the essence of the soul is one principle, it cannot be the immediate principle of all its actions, but must have many different powers corresponding to its different actions, for a power is said to be reciprocally related to its act. (Cf. Aristotle, On the Soul 2.4, 415a18–20; Aquinas, Commentary on Aristotle’s On the Soul, bk. 1, lect. 8; bk. 2, lect. 6.) Hence, there must be a diversity of powers in accordance with the diversity of operations. For this reason, the Philosopher says in Ethics 6 that the scientific power of the soul, which is concerned with necessary things, and the ratiocinative power, which is concerned with contingent things, are different powers because the necessary and the contingent differ in genus. (Aristotle, Nicomachean Ethics 6.1, 1139a5–15.)

Reply Obj. 1: This book The Spirit and the Soul was not written by Augustine but is said to have been written by a certain Cistercian monk. Nor is there much to be said for the things which are set forth therein. If it is taken in an orthodox manner, however, it can be said that the soul is its powers or faculties because they are its natural properties. Wherefore, it is said in the same book that all powers are one soul, differing in property it is true, but one power. (Pseudo-Augustine (Alcher of Clairvaux), The Spirit and the Soul, ch. 13 (PL 40:788–89).) It would be a similar way of speaking if we were to say that heat, clarity, and brightness are one with fire.

Reply Obj. 2–4: The second, third, and fourth arguments are to be answered in the same way.

Reply Obj. 5: So far as its act of existing is concerned, an accident does not go beyond its subject, but insofar as its operation is concerned, it does, for the heat of fire heats something external to fire. It is in this way that the powers of the soul go beyond the soul itself, inasmuch as the soul understands and seeks not only itself but other things as well. Moreover, Augustine introduces this account when he relates knowledge and love to the mind, not as the thing knowing and loving, but as that known and loved. (Augustine, On the Trinity, bk. 9, ch. 4, para. 5 (CCSL 50:298; PL 42:963); ch. 5, para. 8 (CCSL 50:300; PL 42:965).) For if he were to relate them to the soul itself in this way, as an accident to a subject, it would follow that the soul would know and love only itself. Perhaps it is in accordance with this meaning that he said they are one life, one essence, because actual knowledge is the thing known in a certain respect, and actual love, the thing loved.

Reply Obj. 6: An image of the Trinity is found in the soul not only with respect to the soul’s powers, but also with respect to its essence, (John of Rupella, Summa de anima, bk. 1, ch. 28 [XXV].) for the one essence of the three persons is represented in the soul, although in a very imperfect way. Moreover, if the soul were its powers, its powers would differ from each other in name only. Consequently, the distinction between the persons which is found in God is not adequately represented in the soul.

Reply Obj. 7: There are three genera of accidents: (Cf. Aristotle, Posterior Analytics 1.6, 75a18–37; Aquinas, Commentary on Aristotle’s Posterior Analytics, bk. 1, lect. 14.) some are caused by the principles of the species, and are called proper accidents, for example, risibility in man; others are caused by the principles of the individual, and this class is spoken of in two ways: first, those that have a permanent cause in their subject, for example, masculine and feminine, and other things of this kind, and these are called inseparable accidents; (Cf. Aquinas, On Being and Essence, ch. 6.) second, those that do not have a permanent cause in their subject, such as to sit and to walk, and these are called separable accidents.

Now no accident of any kind ever constitutes part of the essence of a thing, and thus an accident is never found in a thing’s definition. Hence, we understand the essence of a thing without thinking of any of its accidents. However, the species cannot be understood without the accidents which result from the principles of the species, (That is, the proper accidents.) although the species can be understood without the accidents of the individual, even the inseparable accidents. Indeed, there can be not only a species but also an individual without the separable accidents. Now the powers of the soul are accidents in the sense of properties. Therefore, although the essence of the soul is understood without them, still the existence of the soul is neither possible nor intelligible without them.

Reply Obj. 8: Inasmuch as sensible and rational are essential differences, they are not derived from sense and intellect, but from the sensitive and intellective soul.

Reply Obj. 9: For this reason, the substantial form is not the immediate principle of action in inferior agents, as we have shown. (Above, in the response of this question.)

Reply Obj. 10: The soul is the principle of operation; however, it is the first principle, not a proximate one, for powers operate by virtue of the soul itself, just as the qualities of the elements operate by virtue of their substantial forms.

Reply Obj. 11: The soul itself is in potency to the intelligible forms themselves, but this potency is not the essence of the soul, just as the potency to be a statue, which is in the copper, is not the essence of copper. For actual and potential existence do not belong to the essence of a thing, because act is not of the essence.

Reply Obj. 12: Prime matter is in potency to substantial act which is form, and, therefore, potency is the very essence of prime matter.

Reply Obj. 13: Man is said to be an intellect because the intellect is said to be the highest thing in man, just as the state is said to be the governor of the state. However, this does not mean that the essence of the soul is the intellective power itself.

Reply Obj. 14: The soul is seen to be similar to a science inasmuch as each is a first act, but such similarity does not exist in every respect. Consequently, the soul is not necessarily the immediate principle of its operations, just as a science is.

Reply Obj. 15: The powers of the soul are not essential parts of it as though constituting its essence, but are potential parts, because a virtue of the soul is distinguished by powers of this kind.

Reply Obj. 16: Whatever is a form in its entirety and is not a subsisting thing, or if it is a subsisting thing that is pure act, cannot be the subject of an accident. (See above: q. 6, ad 1.) Now the soul is a subsisting form and is not pure act, that is, if we speak of the human soul. Therefore, it can be the subject of certain powers, such as the intellect and the will. Moreover, the powers of the sensitive and nutritive parts are in the composite as a subject, because whatever has an act, has a power, as is shown by the Philosopher in the work On Sleep and Sleeplessness. (Aristotle, On Sleep and Sleeplessness, ch. 1, 454a8; On Dreams, ch. 1, 458b34.)

Reply Obj. 17: Although the soul is one in essence, yet it contains potency and act and is diversely related to things. It is also related in a different way to the body, and for this reason different powers can proceed from one and the same essence of the soul.