Article XI

THE last question is: Are the powers of the soul the same as the essence of the soul?

And it would seem that they are. 1 For Augustine says in IX De Trinitate [IV, 5]: "We are reminded . . . that these things (namely, mind, knowledge, and love) exist in the soul . . . substantially or essentially, not as in a subject, like color or shape in a body or like any other quantity or quality."

2 Furthermore, in the book De Spiritu et Anima [XIII, PL XL, 789] it is said that "God is all the things that He has, but the soul is some of the things that it has", namely, powers; and is not some of the things that it has, namely, virtues.

3 Futhermore, substantial differences are not derived from any accidents. But "sensible" and "rational" are substantial differences, and they are derived from sense and reason. Therefore sense and reason are not accidents, and by a parallel argument, neither are the other powers of the soul; and so they seem to belong to the essence of the soul.

But the objector said that the powers of the soul are not accidents and do not belong to the essence of the soul, but that they are natural or substantial properties; and so they are something intermediate between a subject and an accident. But on the other hand, 4 between an affirmation and a denial there is nothing intermediate. But a substance and an accident are differentiated by way of affirmation and denial: because an accident is that which is in a subject, but a substance is that which is not in a subject. Therefore between the essence of a thing and an accident there is nothing intermediate.

5 Furthermore, if the powers of the soul are called natural or essential properties, this is either because they are essential parts, or because they are caused by the principles of the essence. If in the first sense, then they pertain to the essence of the soul, because essential parts are of the essence of a thing. If in the second sense, then even accidents can be called essential, because they are caused by the principles of a subject. Therefore it must be the case that the powers of the soul either pertain to the essence of the soul, or else are accidents.

But the objector said that, although accidents are caused by the principles of a substance, yet not every thing which is caused by the principles of a substance is an accident. But on the other hand, 6 every thing that is intermediate must be distinguished from both extremes. If, then, the powers of the soul are intermediate between an essence and an accident, it must be the case that they are differentiated from an essence as well as from an accident. But nothing can be differentiated from a thing by something that is common to both. Since, then, to flow from the principles of a substance, which is the reason why the powers are said to be essential, is an attribute even of accidents, it would seem that the powers of the soul are not differentiated from accidents; and so it would seem that there is no intermediate between substance and accident.

But the objector said that they are differentiated from accidents by the fact that a soul can be conceived apart from accidents, but cannot be conceived apart from its own powers. But on the other hand, 7 each individual thing is understood through its own essence, because the proper object of the intellect is what a thing is, as is said in III De Anima [4, 429b 19]. Whatever there is, then, apart from which a thing cannot be understood, belongs to the essence of that thing.

If, then, the soul cannot be understood apart from its powers, it follows that the powers belong to the essence of the soul and that they are not something intermediate between essence and accidents.

8 Furthermore, Augustine says in X De Trinitate [XI, 18] that memory, understanding, and will are "one life, one mind, one substance." And so it would seem that the powers of the soul are its very essence.

9 Furthermore, as the whole soul is to the whole body, so a part of the soul is to a part of the body. But the whole soul is the substantial form of the body. Therefore a part of the soul, e.g., sight, is the substantial form of a part of the body, namely, of the eye. But the soul by its own essence is the substantial form of the whole body and of every one of its parts. Therefore the power of sight is identical with the essence of the soul; and for the same reason so are all the other powers.

10 Furthermore, the soul is nobler than an accidental form. But an active accidental form is its own power of action. Therefore, so much the more is the soul its own powers.

11 Furthermore, Anselm says in his Monologium [LXVII, PL CLVIII, 213] that nothing greater could be given to the soul than remembering, understanding, and willing. But among all the things that belong to the soul, the chief thing is its own essence, which has been given to it by God. Therefore the powers of the soul are identical with its essence.

12 Furthermore, if the powers of the soul are something other than its essence, it must be the case that they flow from the essence of the soul as from a principle. But this is impossible, because it would follow that a principiate would be more immaterial than its own principle: for the intellect, which is one of the powers, is not an act of any body; whereas the soul by its own essence is the act of the body. Therefore, too, the first statement is incongruous, namely, that the powers of the soul are not its essence.

13 Furthermore, it is especially proper to a substance to be something that is able to take on contraries. But the powers of the soul are able to take on contraries: thus the will, for instance, is able to take on virtue and vice, and the intellect, knowledge and error. Therefore, the powers of the soul are a substance. But they are not a different substance from the substance of the soul. Therefore they are identical with the very substance of the soul.

14 Furthermore, the soul is united to the body as its form immediately, and not through the medium of some power. Now inasmuch as it is the form of the body, it gives some act to the body. But not the act of existence, because this act is found even in things that have no soul; and again, it does not give the act of being alive, because this act is found in things wherein there is no rational soul. Therefore, the only remaining alternative is that it gives the act of understanding. But this act is given by the intellectual power. Therefore the intellectual power is identical with the essence of the soul.

15 Furthermore, the soul is nobler and more perfect than prime matter. But prime matter is identical with its own potency. For it cannot be said that the potency of matter is an accident of it, because in that case an accident would exist prior to a substantial form, since potency in one and the same thing is temporally prior to act, as is said in IX Metaphysica [8, 1049b 19]; and in the second place, neither is it the substantial form, because a form is an act, which is the opposite of a potency; and similarly neither is it a composite substance, because in that case a composite substance would precede a form, which is impossible. And thus the only remaining alternative is that the potency of matter is the very essence of matter. Much more, then, are the powers of the soul its essence.

16 Furthermore, an accident does not extend beyond its own subject. But the powers of the soul extend beyond the soul itself, because the soul not only understands and wills itself, but also other things. Therefore the powers of the soul are not its accidents. The only remaining alternative, therefore, is that they are the very essence of the soul.

17 Furthermore, every substance is intellectual by the very fact that it is free from matter, as Avicenna says [VIII Met., 6]. But immaterial actual being is proper to the soul by its own essence: therefore, intellectual actual being is also proper to it. Therefore the intellect is its own essence, and by a parallel argument so are its other powers.

18 Furthermore, "in those things which are without matter, the intellect and the thing that is understood are the same thing," according to the Philosopher [III De An., 4, 430a 2]. But the very essence of the soul is what is understood. Therefore the very essence of the soul is the understanding intellect; and by a parallel argument the soul is its other powers.

19 Furthermore, the parts of a thing belong to its substance. But the powers of the soul are said to be its parts. Therefore they pertain to the substance of the soul.

20 Furthermore, the soul is a simple substance, as was said above; but the powers of the soul are several. If, then, the powers of the soul are not its essence, but are kinds of accidents, it follows that in one simple thing there are several and different accidents, which seems incongruous. Therefore the powers of the soul are not its accidents but its very essence.

But on the other hand there is i what Dionysius says in the eleventh chapter of De Caelesti Hierarchia [§2, PG I, 283D], that the higher essences are divided into substance, power, and activity. Much more, then, in souls, their essence is one thing and the virtue or power is another.

ii Furthermore, Augustine says in XV De Trinitate [XXIII, 43] that the soul is called the image of God, as a board is, "because of the picture which is on it." But a picture is not the very essence of the board. Therefore neither are the powers of the soul, by which the image of God is stamped upon the soul, the soul's very substance.

iii Furthermore, all things that are counted like essences are not one essence. But the three things in view of which the image is considered to be in the soul are counted like essences or substances. Therefore they are not the very essence of the soul, which is one.

iv Furthermore, a power is something intermediate between a substance and an activity. But an activity differs from the substance of the soul. Therefore a power differs from both; otherwise it would not be something intermediate if it were identical with an extreme.

v Furthermore, a principal and an instrumental agent are not one thing. But a power of the soul is related to its essence as an instrumental agent is to a principal agent; for Anselm says in his book De Concordia Praescientiae et Liberi Arbitrii [XI, PL 158, 534] that the will, which is a power of the soul, is like an instrument. Therefore the soul is not its own powers.

vi Furthermore, the Philosopher says in the first chapter of De Memoria et Reminiscentia [in fin.] that memory is a passion or a habit of the sense faculty or of the imaginative faculty. Now a passion and a habit is an accident. Therefore memory is an accident; and for the same reason so are the other powers of the soul.

ANSWER. It must be said that some have asserted that the powers of the soul are nothing else than its very essence: in such a way that one and the same essence of the soul, according as it is the principle of sense activity, is called the sense; but according as it is the principle of the intellectual activity, it is called intellect; and so of the other faculties. And they seem to have been especially moved toward this position, as Avicenna says [De An., V, 7], because of the simplicity of the soul, as though this simplicity would not permit such great diversity as is apparent in the powers of the soul. But this position is utterly impossible.

First of all, because it is impossible in the case of any created substance that its own essence should be its own active power. For it is obvious that different acts belong to different things; for an act is always proportioned to the thing whereof it is an act. Now just as actual being itself is a kind of actuality of an essence, so acting is an actuality of an active power or virtue. For on this basis both of these are in act: the essence in regard to actual being, and the power in regard to acting. And hence, since in no creature is its own activity its own actual being, but this is proper to God alone, it follows that the active power of no creature is its essence; but to God alone is it proper that His essence is His power.

Secondly, this appears impossible for a special reason in the case of the soul, on three counts. First of all, because an essence is one; whereas in regard to powers we must assert manyness because of the diversity of acts and objects. For powers must be diversified on the basis of their acts, since a potency is so called in relation to an act. Secondly, the same thing is apparent as a result of the diversity of powers, whereof certain ones are acts of certain parts of the body, as are all powers of the sensitive and the nutritive part; but certain powers are not acts of any part of the body, as, for instance, the intellect and the will. This could not be the case if the powers of the soul were nothing less than its essence; for it cannot be said that one and the same thing may be an act of the body and yet something separate, except in different respects.

Thirdly, the same is apparent as a result of the order of the powers of the soul and their relation to one another. For it is found that one power moves another: thus, for instance, reason moves the irascible and the concupiscible power, and the intellect moves the will; and this could not be the case if all the powers were the very essence of the soul, because the same thing does not move itself in the same respect, as the Philosopher proves [VIII Phys., 5]. Therefore the only remaining alternative is that the powers of the soul are not its very essence.

Some, granting this, say that they are not an accident of the soul either, but are its essential or natural properties. This opinion, in fact, if understood in one sense, can be maintained, but in another sense it is impossible. As evidence of this we must bear in mind that "accident" is taken in two senses by philosophers. In one sense, as that which is the opposite of "substance" and includes under itself nine categories of things. Now taking "accident" in this sense the position is impossible. For between a substance and an accident there cannot be anything intermediate, since substance and accident are divisions of being by way of affirmation and denial: since it is proper to a substance not to be in a subject, but to an accident to be in a subject. And hence, if the powers of the soul are not the very essence of the soul (and it is obvious that they are not other substances), it follows that they are accidents included under one of the nine categories. For they are in the second species of quality, which is called natural power or natural impotence. "Accident" is taken in another sense as being one of the four predicates put down by Aristotle in I Topica [4, 101b 17], and as being one of the five universals put down by Porphyry [Isagoge, IV]. For in this sense an accident does not signify that which is common to the nine categories, but the accidental relationship of a predicate to a subject, or the relationship of a universal to those things which are included under the universal. For if this meaning of accident were the same as the first, since accident in this sense is opposed to genus and species, it would follow that nothing which is in the nine categories could be called either a genus or a species; and it is clear that this is false, since color is the genus of whiteness, and number the genus of "couple". Taking accident in this sense, then, there is something intermediate between substance and accident, that is, between a substantial predicate and an accidental predicate; and this is a property. A property is like a substantial predicate, inasmuch as it is caused by the essential principles of a species; and consequently a property is demonstrated as belonging to a subject through a definition that signifies the essence. But it is like an accidental predicate in this sense, that it is neither the essence of a thing, nor a part of the essence, but something outside of the essence itself. Whereas it differs from an accidental predicate, because an accidental predicate is not caused by the essential principles of a species, but it accrues to an individual thing as a property accrues to a species, yet sometimes separably, and sometimes inseparably. So, then, the powers of the soul are intermediate between the essence of the soul and an accident, as natural or essential properties, that is, as properties that are a natural consequence of the essence of the soul.

As to the first argument, therefore, it must be said that no matter what be said of the powers of the soul, still no one ever thinks (unless he is crazy) that a habit and an act of the soul are its very essence. Now it is obvious that the knowledge and love of which Augustine speaks in that passage do not designate powers, but acts or habits. And hence Augustine does not mean to say that knowledge and love are the very essence of the soul, but that they are in it, and substantially or essentially. To understand this, we must notice that Augustine in that passage is speaking of the mind according as it knows and loves itself. From this viewpoint, then, knowledge and love can be related to the mind, either as to the mind that loves and knows, or as to the mind that is loved and known. And Augustine is speaking here in this second sense; for the reason why he says that knowledge and love exist substantially or essentially in the mind or in the soul is that the mind loves its essence, or knows its substance. And hence he later adds [De Trin. IX, 4, 7]: "How those three things are not of the same essence I do not see, since the mind loves itself, and itself knows itself."

As to the second, it must be said that the book De Spiritu et Anima is apocryphal, since its author is unknown; and there are in it many things falsely or inaccurately stated, because he who wrote the book did not understand the sayings of the saints from whom he tried to quote. Yet if the objection has to be met, we must note that there are three kinds of wholes. One is a universal whole, which is present to every part in its whole essence and power; hence it is properly predicated of its parts, as when one says: Man is an animal. But another whole is an integral whole, which is not present to any part of itself, either in its whole essence or its whole power; and consequently there is no way in which it is predicated of a part, as if one were to say: A wall is a house. The third whole is a potential whole, which is intermediate between these two: for it is present to a part of itself in its whole essence, but not in its whole power. And hence it stands in an intermediate position as a predicate: for it is sometimes predicated of its parts, but not properly, and in this sense it is sometimes said that the soul is its own powers, or vice versa.

As to the third, it must be said that because substantial forms in themselves are unknown but become known to us by their proper accidents, substantial differences are frequently taken from accidents instead of from the substantial forms which become known through such accidents; as, for example, "biped" and "able to walk" and the like; and so also "sensible" and "rational" are put down as substantial differences. Or it may be said that "sensible" and "rational", insofar as they are differences, are not derived from reason and sense according as these are names of powers, but from the rational soul and from the sentient soul.

As to the fourth, it must be said that that argument is based on "accident" in the sense of what is common to the nine categories; and in this sense there is nothing intermediate between substance and accident; but in another sense, as has been said, there is.

As to the fifth, it must be said that the powers of the soul can be called essential properties, not because they are essential parts, but because they are caused by the essence; and in this respect they are not differentiated from "accident" that is common to the nine categories; but they are differentiated from "accident" that is an accidental predicate which is not caused by the specific nature.

And hence the solution to the sixth is clear.

As to the seventh, it must be said that there are two activities of the intellect, as is said in III De Anima [6, 430a 26]. One whereby it understands what a thing is: and by this sort of activity of the intellect the essence of a thing can be known, both apart from a property and apart from an accident, since neither of these enters into the essence of a thing; and this is the sense on which the argument is based. The other is an activity of the intellect that combines and separates; and in this way a substance can be understood apart from an accidental predicate, even if it is really inseparable: thus, "a crow is white" is intelligible; for there is no repugnance of concepts there, since the opposite of the predicate does not depend on the principles of the species which is designated by the word put down as the subject. But by this activity of the intellect a substance cannot be understood without its property; for it cannot be understood that "man has not the power of laughing", or that "a triangle does not have three angles equal to two right angles"; for here there is repugnance of concepts, because the opposite of the predicate depends upon the nature of the subject. So, then, by the first sort of activity of the intellect the essence of the soul can be understood, in such a way, that is, that its essence is understood apart from its powers; but not by the second kind of activity, i.e., so that it is understood not to have powers.

As to the eighth, it must be said that those three things are said to be one life, one essence, either on the ground that they are related to the essence as to an object, or in the way in which a potential whole is predicated of its parts.

As to the ninth, it must be said that the whole soul is the substantial form of the whole body, not by reason of the totality of its powers, but by the very essence of the soul, as was said above [Art. IV]. And hence it does not follow that the power of sight itself is the substantial form of the eye, but that the very essence of the soul is, according as it is the subject or principle of this power.

As to the tenth, it must be said that an accidental form, which is a principle of action, is itself a power or a virtue of an active substance; but there is no going on to infinity, as though for every virtue there were another virtue.

As to the eleventh, it must be said that an essence is in a sense a greater gift than a power, just as a cause is more important than an effect. But powers are more important, in a sense, inasmuch as they are nearer to the acts whereby the soul holds fast to its end.

As to the twelfth, it must be said that the reason why it happens that a power which is not an act of the body flows from the essence of the soul is that the essence of the soul transcends the limitations of the body, as was said above [Art. II; Art. IX, ad 15]. And hence it does not follow that a power is more immaterial than the essence; but from the immaterial nature of the essence there follows the immaterial nature of the power.

As to the thirteenth, it must be said that among accidents one is nearer than another to a subject; thus quantity is nearer to a substance than quality; and so a substance receives one accident by means of another; thus, for instance, it receives color by means of a surface, and knowledge by means of the intellectual power. In this way, then, a power of the soul is able to take on contraries, as a surface is able to take on white and black, inasmuch, namely, as the substance receives contraries in the way spoken of above.

As to the fourteenth, it must be said that the soul, insofar as it is the form of the body by its own essence, gives actual being to the body, inasmuch as it is a substantial form; and it gives to it being of a certain sort, i.e., life, inasmuch as it is this kind of form, namely, a soul; and it gives it life of a certain sort, namely, in an intellectual nature, inasmuch as it is this kind of a soul, namely, intellectual. Now "understanding" sometimes means an activity, and in this sense its principle is a power or a habit; but sometimes it means precisely the actual being of an intellectual nature, and in this case the principle of understanding is the very essence of the intellectual soul.

As to the fifteenth, it must be said that the potency of matter is not a potency for acting, but for substantial being. And consequently the potency of matter can be in the genus "substance", but not the potency of the soul, which is a potency for acting.

As to the sixteenth, it must be said that, as was said above [ad 1], Augustine relates knowledge and love to the mind inasmuch as the mind is known and is loved; and if, because of this relationship, knowledge and love were in the mind or in the soul as in a subject, it would follow that by a parallel argument they would be in all things that are known and loved as in a subject: and in that case an accident would transcend its own subject, which is impossible. Otherwise, if Augustine were intending to prove that these were the very essence of the soul, his would be no proof. For it is no less true of the essence of a thing that it does not exist outside the thing than it is true of an accident that it does not exist outside its subject.

As to the seventeenth, it must be said that from the very fact that the soul is free from matter by its own substance, it follows that it has an intellectual power, but not in such a way that its power is its own substance.

As to the eighteenth, it must be said that the intellect is not only an intellectual power, but much rather a substance because of its power; hence it is understood not only as a power but also as a substance.

As to the nineteenth, it must be said that the powers of the soul are called parts, not of the essence of the soul, but of its total power; just as if one were to say that the power of a bailiff is a part of the royal power as a whole.

As to the twentieth, it must be said that many of the powers of the soul are not in the soul as in a subject, but in the composite; and the multiformity of the parts of the body fits in with this multiplicity of powers. But the powers, which are in the substance of the soul alone as in a subject, are the agent intellect and the possible intellect, and the will. And for this multiplicity of powers it is sufficient that in the substance of the soul there is some composition of act and of potency, as was said above [Art. I].