Commentaria in Summam contra Gentiles, Liber II

Since it has been shown that the intellectual soul is immortal, in order to make the doctrine more complete, lest anyone think the same of the souls of brute animals, Saint Thomas shows that they are not immortal ¹. Concerning this he does two things: first he proves the proposition; second he removes certain objections ².

I. As to the first, he argues first as follows. The soul of a brute animal, separated from the body, has no operation. Therefore, when the body perishes, it perishes. — The consequence is evident, because every substance has some operation. — But the antecedent is proved thus: because in the souls of brutes there is not to be found any operation superior to the operations of the sensitive part. For it is evident that they do not understand nor reason: since all animals of the same species, moved as it were by nature and not operating by art, operate alike. But no operation of the sensitive part can be without a body. Therefore etc.

Secondly ³. The soul of a brute animal, remaining after the body is corrupted, will be a separate substance. Therefore it will be understood in act. Therefore it will be intellectual. This is impossible. Therefore, and so on. — The first consequence is proved: because every form separate from matter is understood in act. — The second is also proved: because, as is said in III de Anima, text 15, in things separate from matter, the one understanding and the thing understood are the same.

II. Concerning this argument a twofold doubt arises. First, concerning the proof of the first inference. For if every form separate from matter is understood in act, it follows that the human intellect is something understood in act: for it itself is separate from matter, as not being attached to any bodily organ. But this is false: because, as Saint Thomas says in III de Anima ⁴, expounding text 15, and in many other places, the possible intellect is pure potency in the genus of intelligibles.

Second, doubt is raised concerning the proof of the second consequence ⁵. For the assumption does not seem to be to the point, namely: In things separate from matter, the one understanding and the thing understood are the same. For Saint Thomas himself, in III De Anima, expounds this proposition not of immaterial substances and forms, but of those things which are actually understood as abstracted from material conditions. Hence in the First Part, q. 55, a. 1, ad 2, he says that it is the same to say, of things that are without matter, that "the one understanding and the thing understood are the same," as if one were to say that "intellect in act is the thing understood in act," just as sense in act is the sensible in act. He says something similar in De Spiritualibus Creaturis, a. 8, ad 14. — Likewise, he expounds it not as numerical identity according to substance and entity, for the intellect of a man is not the same entity as the stone actually understood; but through a conformity in one form, which is the likeness of the thing understood, by which the thing is actually understood and the intellect is in act, inasmuch as the species of the thing understood informs it so that it can consider actually. For through the species of the stone existing in the intellect, both the stone is actually understood and the intellect itself is actually understanding. — Now, this discourse here concerns a substantial form separated from the body, and numerical identity according to essence and nature. For it is argued that if the soul of a brute animal be actually understood, it will be the same in number, and according to substance, as understanding or intellectual. And thus that authority, according to the exposition of Saint Thomas, does not seem to be to the point.

III. For the clarification of the first doubt, two terms must be explained: namely, intellect in act; and pure potency in the order of intelligibles. As to the first, it must be considered that, since there is a twofold order and genus of things—namely, the genus of material things and the genus of intelligible things—something can be said to be understood in act in two ways: in one way, because it belongs to the genus of intelligibles, and not outside that genus as material things do; in another way, because it belongs to the genus and order of intelligibles as an act or as having act, and not as potency. In the first way, every form not dependent on matter is understood in act in some sense, that is, it belongs to the genus and order of intelligibles. But not in the second way: for a certain form can be non-dependent on matter, and thus belong to the order of intelligibles; and yet in that order it will not be as an act or existing in act, but rather as potency in some way, as will be shown immediately below, even though it is act in the genus of being. For it stands together that something be act in the genus of being, and yet potency in the genus of intelligibles: just as a diaphanous body is indeed body in act, yet colored only in potency. — Nor does it stand against this that Saint Thomas often says that each thing is intelligible insofar as it is in act ⁶. For this is not said as though everything that is in act in the genus of beings were in the genus of intelligibles as an act: but because everything of this kind is intelligible either as existing within the order of intelligibles, or as able to be raised to that order by abstraction from matter or in any other way; and everything intelligible has that it is intelligible insofar as it is in act, but not insofar as it is in potency, as is said in Prima, q. xiv, 2, ad 3⁷. Hence the Commentator, in De Sensu et Sensato⁸, says that, since the sensible thing is intelligible in act through the agent intellect, it is transferred from one order to another.

2. As to the second point, it must be known that, since in the order of intelligible things something belongs to it as an intelligible object, while something else belongs to it as intellective, namely that to which it belongs to understand, a thing can be called pure potency in the genus of intelligible things in two ways: either in the manner of an object, because it has in itself no act by which it can be understood; or in the manner of what is intellective, namely as lacking every act by which it can understand. In both ways it is true that the possible intellect is pure potency in the genus of intelligible things. In the manner indeed of what is intellective: because, since the intelligible species is the form by which the intellect understands (for the intelligible must be united to the intellect if understanding is to take place); and since the possible intellect has in itself no intelligible species connatural and inborn to it (although in itself it has the power of understanding), but at the beginning of its existence is like a blank tablet, on which nothing is written, as is said in On the Soul III⁹: it follows that, considered in itself, it lacks every act by which something is naturally apt to understand, and thus is pure potency in the genus of what is intellective (for it would have some form connatural to it, if it were in act in itself); just as prime matter is pure potency in the genus of beings, because in itself it lacks every form, which is the principle of action. — Also in the manner of an intelligible object it is, according to its own nature, pure potency in the genus of intelligible things, as is stated below in chap. XCVIII, and in the Prima, q. lxxxvii, a. 1. For something is said to be actual in the genus of intelligible things if, according to itself, with any extrinsic agent and any other object removed, it is naturally apt to actualize the intellect to the understanding of itself. But this does not belong to the human intellect, or to the conjoined intellective soul: since each thing is known insofar as it is in act; but it itself, according to itself, has no act, but is only potency in the genus of intelligible things, as having no inborn species by which it is constituted in act, but existing in potency to all intelligible things.

3. But if one presses Scotus's arguments in the First Book, distinction iii, question vii¹⁰: namely, that the intellect is in itself a certain act; and that a power for operating is not grounded upon pure potency: — it is answered that, although it is an act in the genus of beings, it is nevertheless not an act in the genus of intelligibles, but a potency. Nor is it unfitting, as we have said, that something be an act in the genus of being and yet be a potency in the genus of intelligibles.

Even if it were said that, although it is intelligible in potency with respect to itself, it is nevertheless actually intelligible with respect to the angelic intellect, whose it is to understand everything that exists in act as being — it is clear that this amounts to nothing. For that an angel understands something does not show that thing to be actually in the genus of intelligibles as it is in itself. Material things are in themselves only potentially intelligible, and yet they are understood by an angel: because in him they exist through their similitudes as actually intelligible. The same holds for the intellect. For as it is in itself, it is not actually intelligible; although, because it is an act in the genus of beings, it belongs to the genus of intelligibles, inasmuch as according to its esse it does not depend on matter.

4. And thus it is clear that the possible intellect is called pure potency in the genus of intelligibles in two ways: namely, both because it lacks, in itself, every form of the genus of intelligibles that is a principle of understanding; and because it lacks every form of the genus of intelligibles by which it could be understood.

To the doubt, therefore, the consequence is denied. For the soul joined to the body is not a form separate from matter, although it is a form not dependent upon matter. — How it stands with respect to intelligibility while it is separate will be said below, chapter XCVIII.

IV. To the second doubt¹¹ there can be a twofold reply. First, by granting that St. Thomas wishes to deduce that the soul of the brute will be intellective, it is answered that that authority of Aristotle fits the point very well. For he intends to argue: If a material thing, because it is abstracted from material conditions and is made actually understood, is one with the one understanding or with the intellect in act—as being in accord with it in one form through which both the intellect is in act and the material thing itself is actually understood—then those substances which are entirely separate from matter, since they are by their nature actually understood as belonging per se to the genus of intelligibles, must also be by their nature intellective; so that it may be universally true that in things abstracted from matter, to be something actually understood and to be intellective are one and the same. For if a thing is actually understood through the form made by the agent intellect, then through that same form the intellect is made actual. But if a thing is actually understood of itself, that is, by its own nature, then it must also be intellectual by its proper nature.

2. But someone might say that from the fact that by the same thing something is constituted in the esse of being actually understood, and the intellect is constituted in act, it does not follow that a form separated from matter, which is actually understood by its own nature, is intellective according to its own nature; but only that, just as it is itself actually understood through itself, so too it is united to the intellect that understands it through itself, not through another intermediary species, as making the intellect actual through itself. And thus what Saint Thomas seems to wish to infer does not appear to be established on this basis, namely, that every form separated from matter is intelligent, and consequently that the soul of a brute animal, separated from matter, will be intellective.

It is answered, according to the doctrine of Saint Thomas in the First Part, q. 35, a. 1, that just as matter is the principle of particularization, so intelligibility is owed to form: for form is the principle of cognition. Hence, if a form is separate from matter, it must be of an intellectual nature, according to the condition of the form itself: namely, if it is a form not subsisting in itself but the perfection of some subsistent thing, it is also intelligible as the principle by which something understands, not however as understanding by itself, just as every other non-subsisting form, ordered to operation, is a principle of operating for another, but does not itself operate; but if it is subsistent, it is intelligible in the manner of one understanding, for it belongs to a subsistent thing to operate according to the condition of its nature. Therefore Saint Thomas wishes to argue from the sign as follows. A material thing becomes one with the intellect, as existing for it the principle of intellection, by this that it is abstracted from matter and made understood in act. Therefore the sign is that intellectualitas, namely being the principle of understanding, belongs to a thing through abstraction from matter. Therefore every form separate from matter is a principle of understanding in its own way: namely, a subsisting form, as producing by itself the act of intellection and understanding by itself; but a form existing in another, as existing as the principle of understanding for another. And thus, since the soul of a brute animal, if it is posited to remain after the body, would be a subsisting form separate from matter, it follows that it is intellective.

3. Second, it can be answered that St. Thomas does not infer the inconvenient consequence that the soul of a brute will be intellective, but that it will be intellectual. Now, since a form is said to be intellectual in two ways, as is clear in the place cited above¹², namely either because it is understanding, or because it is the principle of understanding for another; from the fact that in things separate from matter to be understood and to understand are the same, and that the soul of a brute is understood in act, it follows that it is intellectual in one of those two ways, at least by way of being a principle of intellection, if it is posited as separate from matter. But since it cannot be intellectual in either of these ways—for it cannot be understanding, nor can it of itself be united to an intellect as a principle of intellection, since it is posited as a created subsisting form—it follows that it cannot remain separate from matter. And thus the argument of St. Thomas has its force.

V. Thirdly¹³ an argument is brought against the conclusion. In brutes there is no appetite for perpetual esse except according to the species: which is found also in plants and inanimate things. Therefore the soul of a brute is not capable of perpetual esse. — The consequence is proved. Because in any thing that can attain some perfection, there is found a natural appetite for that perfection. — The antecedent is also proved. Because the sensitive soul apprehends only here and now. Therefore it does not apprehend perpetual esse. Therefore the animal, insofar as it is an animal, does not by its appetite, which is the appetite consequent upon apprehension, desire perpetual esse.

Note that Saint Thomas does not commit an equivocation when he seems to pass from natural appetite to animal appetite: for natural appetite is not taken here as distinguished against appetite following upon cognition, but only as distinguished against free appetite. For in this way even animal appetite is called natural appetite. But how the sensitive soul does not apprehend perpetual esse can be established from what was said above ¹⁴, where it was shown conversely that the intellect does apprehend perpetual esse.

2. Fourth. The whole operation of brute animals tends toward the conservation of the being of the body as its end. Therefore there is no esse in them apart from the body. — The consequence is evident. — But the antecedent is proved thus: because the operation of any thing is ordered to that end in which its delight is fixed, since delights perfect operations, from Book I of the Ethics ¹⁵. But all the delights of brutes are referred to the preservation ¹⁶ of the body.

It must be noted that Saint Thomas does not say that every thing is ordered to its own delight as to an end; rather, that is the end of each thing in which all its delight is fixed. For in Saint Thomas, delight is not the end, but accompanies the end intrinsically. For the end is that which is most desired. Such a thing, when possessed, causes delight. And thus delight is joined to the attainment of the end, which is the intrinsic end, or the end by which.

The conclusion is confirmed by the authority of Genesis 9, where it is said: "The soul of that man is in his blood." — In the book On Ecclesiastical Dogmas it is said: "We say that man alone, etc." — Likewise in Book II On the Soul, text 21, it is said that "the intellective part is separated from the others as the perpetual from the corruptible."

This conclusion also refutes Plato's error, in the Phaedo, where he holds that the souls of brute animals are also immortal.

VI. As to the second point ¹⁷, certain objections are raised against the said conclusion and are answered. For it is argued as follows. The soul of a brute animal is not corruptible: neither per se, because it has no contrary nor is it composed of contraries; nor even per accidens, because it is self-subsistent, since it has an operation of its own in which the body does not share, namely, to move ¹⁸; for the body is moved, and only the soul moves. Therefore, etc.

But Saint Thomas says this argument comes to the same thing as Plato's argument, by which he proved that every soul is immortal. For Plato posited, first, that the soul is a self-mover ¹⁹. From this it follows that every soul is immortal. For whatever moves itself is immortal: for the body does not die except by the departure of that by which it was moved; but a thing cannot depart from itself.

He further posited that nothing moves unless moved ²⁰. From this it followed that what is self-moving is by itself a source of motion, and thus has some operation of itself.

He held, third, that the sensitive soul has its own proper operation not only in moving, but also in sensing ²¹: since he held that to sense is a certain motion of the sensing soul; and that the soul, thus moved, moves the body to sense.

From all of which it followed that the sensitive soul is subsistent in itself, as was argued: and consequently, immortal.

VII. In answering these, Saint Thomas first destroys Plato's foundations; second, he infers the solution to the principal argument, which seems to derive its force from those foundations ²².

First, then, he destroys this foundation, that to sense, which he calls motion, belongs to the soul alone without a bodily instrument ²³. And he supposes that it cannot be called motion in the manner of an action, as if, namely, sensing were to move; but rather in the manner of a passion, so that it is like being moved and undergoing, since the animal is made actually sentient through sensible things, by which the sense is altered.

With this supposition, it is argued first ²⁴ as follows. If sensing is posited to be an operation of the soul without a bodily organ, this seems to be posited for the reason that, just as the intellect is acted upon by the intelligible, so too is the sense by the sensible; and therefore, since understanding is without a corporeal organ, so also is sensing. But this does not follow: because the intellect is acted upon by the intelligible in one way, and the sense by the sensible in another. For the sense is acted upon by things insofar as they are in matter; but the intellect not so, rather insofar as they are abstracted, since it apprehends things in abstraction from matter and material conditions. Hence the passion of the intellect is without corporeal matter: but not the passion of the sense.

2. Note that a receptive power is said to be acted upon by its object in two ways: namely, formally and effectively. It is said to be acted upon formally, insofar as the object is united to it through its species as a form; effectively, however, insofar as it causes its species in the power in the manner of an agent: just as the colored thing is the form of the visual power by reason of the visible species received in it, and acts upon it, causing in it the visible species of itself. Therefore, when it is said that sense is acted upon by things according as they are in matter, but intellect is acted upon by things according as they are abstracted, this can be understood either of formal or of effective being acted upon. If it is understood of formal being acted upon, then the meaning is that the form received in sense is a form having esse in matter, whereas the form of intellect is a form abstracted from matter. But if it is understood of effective being acted upon, then the meaning is that the thing which acts, namely immediately, upon sense, altering it, is a thing having esse in matter; whereas the thing which acts upon the intellect is a thing abstracted from matter, namely the phantasm.

Both senses possess truth. For the sensible form has esse not only in the sensitive power, but also in the bodily and material organ: its proper recipient is indeed the composite of the power and the organ. But the intelligible form is not received in any material organ, but only in the intellect. — Likewise, the form that acts upon a sense is a form having esse outside the soul in matter: as color acting upon sight is color having esse in the colored body, which is its proper matter. But the form that acts upon the intellect, namely the phantasm, although it has esse in matter insofar as it is the form of the imaginative power, nevertheless insofar as it is that of which it is the phantasm, it is not in matter, because it does not have the matter that is the proper matter of that of which it is the phantasm: for the phantasm of Socrates does not have the matter that is Socrates' proper matter, but is abstracted from it.

In what sense, however, St. Thomas is speaking principally, it is difficult to see: for either sense can be adapted to his purpose. It seems to me nevertheless that it must be understood of formal passion, and thus I argue. The intellect apprehends, that is, knows things in abstraction from matter and material conditions, but sense does not: since the intellect is cognizant of universals, while sense is cognizant of particulars. Therefore the senses are acted upon by things as they exist in matter, that is, they receive forms having a material esse in some way; but the intellect is acted upon by those same things as they are abstracted. Therefore the passion of the intellect is without corporeal matter, but not the passion of the senses. — The first consequence is evident. For the intellect would not apprehend the universal without matter and the material conditions that individuate, unless the form and species by which it understands were immaterial: for if the species had material conditions, it would represent the thing with its material conditions and not in abstraction. Conversely, sense would not apprehend the thing with its material conditions unless the sensible species itself had material conditions and existed in matter, representing the thing with such conditions. — The second consequence is also manifest. For if the received species is immaterial, it is altogether certain that it is received without corporeal matter, that is, it is not received in a bodily organ: and thus the recipient is acted upon without corporeal matter. But if it is material, it must be received in matter: and thus the receiving power is acted upon with matter and a bodily organ.

3. Second. If the reception of sense were without a bodily organ, then one and the same power would be receptive of all sensibles: because an immaterial power, insofar as it is of itself, is related equally to all such qualities, as is evident in the case of intellect. But we see this to be false. Therefore, and so on.

But someone might deny the consequence, and say that the diversity of organs contributes nothing to the fact that diverse powers are receptive of diverse sensibles; rather, this is brought about by the diverse ratio and diverse nature of the powers. And therefore, even if they were posited as immaterial, it would not follow that one power should be receptive of all, but rather that diverse powers would be receptive of diverse things.

For the evidence of this, it must be known that, since power and object must be proportioned to one another, the condition of the object must correspond to the condition of the power. Now an immaterial power is not of itself determined to any sensible and material nature: it is not of the nature of fire or air or any other sensible and material nature, but is elevated above all material things. Therefore its formal object must likewise not be some determinate sensible nature, but something elevated above every sensible nature, as it were the container of all sensible natures. Hence we see, to use the example of Saint Thomas, that because the intellect is an immaterial power, its formal object is being, under which all sensible things are comprehended. Similarly the will, because it is an immaterial power, has as its object the good universally, and not this or that good. And the agent intellect can act upon all sensible things by abstracting species; and upon all beings, insofar as they can in some way be known through the species of sensible things. Therefore a sensitive power, if it is posited as immaterial (which must be posited, if it receives immaterially), cannot be determined by its own proper reason and nature alone to one genus of sensible things. But because it is a power ordered to the perception of a determinate sensible thing, nature has joined to it an organ in which it is received, proportioned to that genus of sensible things, so that, according to the diversity of organs, the powers themselves are directed to diverse objects. — It is therefore evident from these considerations that the consequence in question is most sound; and that the given response does not remove it.

4. Third. The sense is corrupted by the excellence of its objects, but not the intellect. Therefore the passion of the sense from the sensible is of a different kind from that of the intellect from the intelligible: one, namely, without a bodily organ; the other, however, with an organ, whose harmony is dissolved by the excellence of the sensibles.

VIII. According to Plato's foundation, it was that the soul moves itself ²⁵. The reason for this was: — Everything that moves is moved, as is evident in bodies. But one does not proceed to infinity such that each thing is moved by another. Therefore the first mover in each order must move itself. Now the soul is the first mover in the movements of animals. Therefore, and so on.

Against this there are two arguments. First. Everything that moves itself per se is a body. Therefore the soul is not moved, unless it be moved per accidens.

Second. The same thing cannot be in act and in potency according to the same respect. Therefore the same thing cannot move itself, unless one part is the mover and another part is moved, as in the motion of animals. — The consequence is evident. For the mover, insofar as it is such, is in act; but what is moved is in potency.

2. To this argument the reply is given according to Plato's mind: and it is said first, that he took motion not as it belongs to bodies, but for any operation whatsoever; as the Philosopher also takes it in III De Anima, text 28, when he says that to sense and to understand are certain motions. — It is said second, that motion so taken is not the act of a being in potency, but of one perfect. — It is said third, that he intended the soul to move itself, that is, to operate without the aid of the body: which does not befit other forms. From this, however, he concluded every soul to be immortal: because what operates through itself can also exist through itself.

But against this view it is argued: because neither can sensing, as has been shown, exist without a body; nor can appetition either, since it is manifestly evident that all things pertaining to sensitive appetite come about together with a bodily transmutation.

3. Concerning that proposition, Operation is a motion which is not the act of something existing in potency, but of something perfect in act, it must be noted that it can have two senses. As to the first, one should observe that when we say the agent is moved, and a body is moved, just as "motion" is taken equivocally in them, so too is being moved: for a body's being moved is its very being the subject of motion; but the being moved of an agent as such is not its being the subject of operation, but its producing operation. The first sense, then, is that motion properly so called belongs to the mobile not as subject, as such, insofar as it has form and perfection, but insofar as it is in potency to some form which it does not have and toward which it tends through motion; whereas operation belongs to the agent not insofar as it lacks a form and is in potency to it, but insofar as it is perfect in act through its form; for each thing operates insofar as it is in act through its form, and not insofar as it lacks a form.

The second sense can be that motion, properly speaking, is an imperfect act, and it leaves the mobile thing in potency to a further act; hence such an act is not the complement of the mobile thing, but is a way toward its complement. Operation, however, is a perfect act and the complement of the agent; nor does it leave the agent, as such, in potency to a further act; nor is it a way toward something else that would be the complement of the agent. And this sense the Commentator seems to hold, III de Anima, comment. 28. Saint Thomas also seems to hold it at Prima, q. XVIII, a. 3, ad 1; and IV Sent. d. XVII, q. 1, a. 5, quª. 3 ²⁶, where he says that motion that is the act of something imperfect and existing in potency always awaits something future for the perfection of its species: but motion that is the act of something perfect awaits nothing future for the complement of its species.

Both senses can possess truth. Nevertheless, the second seems to me more philosophical, and more in keeping with the mind of St. Thomas and Aristotle.

4. Note, however, that St. Thomas does not answer individually the argument of Plato brought forward to prove this foundation ²⁷, because from his first argument against that very foundation its solution appears. For since motion properly so called belongs per se to body alone, it is sufficiently clear that this proposition is false, Every mover is moved per se, when we speak of motion taken properly.

IX. Finally, to the principal argument ²⁸ Saint Thomas responds from what has been said, denying that to move is an operation of the sensitive soul without an organ. He shows its falsity, because the soul of a brute animal does not move except through sense and appetite. But it has been shown that neither sensing nor appetiting occurs without a bodily organ.

But if it is pressed that the soul moves also by the motive power, which is said to execute motion, and not only by sense and appetite: — it is answered that such a power makes the members obedient to the command of the appetite; whence these are rather powers perfecting the body so as to be moved than powers that move; namely, those very powers which exist in the various members of the body.

X. Concerning this response, when it is said that only sense and appetite move the animal, and that the power executing the movement is not moving, but disposes the body to be moved, a doubt arises. For to move is an action passing into the thing moved; but to sense and to desire are immanent actions. Therefore to sense and to desire are not to move. But sense and appetite have no operation besides sensing and desiring. Therefore moving does not belong to them.

Second, because Aristotle, in Book II of the Soul ²⁹, posits the motive power with respect to place as a genus of the soul's powers distinct from the sensitive and the appetitive.

XI. To make the difficulty evident, it must be considered that in the doctrine of Saint Thomas, among those who understand him rightly, there is no doubt that the motive power, in the manner of an agent moved, is not something distinct from sense and appetite in animals—taking "sense" to mean the cognitive power absolutely; and that the motive power executing motion, which is in the limbs, is not an active power moving, but a passive power by which the body is disposed to be moved. For this is expressly stated both here and in the First Part, q. 75, a. 3, ad 3. — But it is doubtful how appetite moves: namely, whether by the act alone which is to desire and command the motion, or by some other elicitive act of motion.

2. For some are pleased to hold that appetite has a twofold act: one immanent, which is to desire; the other transient, which is to move; and that the first act is the reason of the second.

They prove this, first, because if local motion were commanded only by appetite, there would be no need for such careful inquiry into appetite as the motive principle of the animal, since not only motion, but also the operations of sense and intellect are commanded by appetite.

Second, because imperated acts come only from appetite, and sometimes precede appetite; but local motion does not precede appetite.

Third, because nature always brings about the better among things possible. Now local motion befits an animal better if it belongs to it animaliter than if it belongs to it only vitaliter. But it cannot belong to it animaliter unless, as such, it proceeds from the appetite of the animal, since motion of this kind, as such, is for the sake of an end; and appetite is a tending toward an end. Therefore such a motion is necessarily elicited from appetite.

Fourth, because this is the express opinion of Aristotle, in book III of De Anima ³⁰, and in the book On the Movement of Animals, where he holds that the motive power of the animal, to which it belongs to move, is appetite.

3. Others, however, wish the appetite to be moved by no act other than that very act which is to appetize and to command the motion; and yet they hold that one need not posit a motive power distinct from the elicitive of motion. Hence this opinion agrees with the preceding one in this, that there is no power eliciting motion other than the appetite: but it differs from it insofar as this opinion holds that the moving of the appetite is nothing else in reality than the very appetizing and commanding of the motion, taking command in a broad sense, according also to what befits brute animals; whereas the other holds that moving is another act of the appetite, distinct from the command and from the act of appetizing.

XII. Although either opinion can be sustained, the second nevertheless seems to me to accord with the mind of St. Thomas. For, when he divides the motive power into appetite and sense on the one hand, and the executing power on the other, he assigns to appetite and sense, insofar as they are a motive power, only that operation which is to command movement; but to the executing power he attributes the doing, by way of a passive power, of the members obedient to the command of the appetite; as is clear both in this chapter and in the First Part, q. 75, a. 3, ad 3; and q. 78, a. 1, ad 4. — Capreolus also holds this opinion, according to the mind of St. Thomas, in the Second Book, d. 1, q. 2, against the arguments of Aureol against the first conclusion, in his response to 1, ad 12, and ad 15 ³¹.

2. But for the explanation of this, it must be considered that the motion of an animal is related to appetite in one way, and the motion of some body to an extrinsic corporeal mover in another. For motion is related to an extrinsic corporeal mover not only as an effect, but also as the action by which the mover is formally said to move: for the action of the mover is the very motion together with the relation of the agent as that from which it is ³²; just as fire is formally denominated heating, by way of action, from the motion of heating with such a relation; hence to heat is nothing other than that motion with that relation. — But the motion of an animal is related to appetite not as an action formally denominating the mover itself, but only as the effect of the action by which the mover is formally said to move. For when we say that appetite moves the animal, the moving of the appetite is not the very motion with the relation of the appetite as that from which it is; rather it is the immanent act itself which is appetition and the commanding of the motion, of which the motion itself is the effect. Yet it is true that commanding does not have the character of moving unless there is joined a respect toward the animal's motion as toward an effect in act. We do not say, therefore, that one act of appetite is the commanding of the motion and another the eliciting of it; but that the same act in reality is both the commanding of the motion and the eliciting of the motion; they are distinguished, however, in reason, because eliciting the motion adds over and above commanding a relation to the motion in act as to its effect. Hence to say that appetite moves the animal is nothing other than to say that appetite commands the animal's motion, actually causing it by its command.

3. But if it be objected that immanent action leaves behind no effect other than the action itself, the answer is that indeed immanent action, insofar as it is immanent in the agent, posits no effect outside the agent which would be identical with the action itself, for this involves a contradiction; for if it posited an effect with which it were materially identical in something extrinsic to the agent, then it would already be transient and not immanent in the agent. Yet nevertheless immanent action can posit some effect really distinct from itself in something extrinsic that is acted upon: so as to be called transient into another extrinsic thing, not formally, as though received in it, but productively, because, I say, it produces an effect in another; just as by the divine understanding and willing some effect is produced in a creature. Hence this moving of the appetite is not an action of the predicament of action, which Aristotle says, III Physics ³³, is materially identical with motion and with the terminus of motion: but it is of the genus of quality, remaining indeed in the agent in itself, yet positing an effect in another.

4. To the arguments against the opposite opinion ³⁴ it is answered as follows. To the first, namely that we do not say that motion is from appetite only imperatively, as though one would have to posit another motive power that elicits the motion: rather, because it is not necessary to posit in appetite another act distinct from the command, which would be the execution of the motion, but the very command itself is the execution, with the addition of a respect toward the effect in act. The operations of sense and intellect, however, are from appetite only imperatively, not executively. Therefore it was necessary to make an inquiry into appetite itself insofar as it has the character of a motive power.

To the second it is said similarly that motion is not only commanded by appetite but also elicited by it, though not by any other act than the command, of which it is the effect.

To the third it is said that, according to the mode assigned in which appetite moves the body, the animal is moved animaliter, and not merely vitaliter.

To the fourth, it is said that from Aristotle nothing else is had than that appetite and reason, or sense (for by this the Philosopher understands the cognitive power), are the principles moving the animal's members even in their execution by the mode of an agent moving. But it is not held that to move is another act really distinct from command.

XIII. To the arguments of the principal doubt, however, ³⁵ a reply is given. To the first it is said that to move the appetite is not an action passing formally, but immanent; yet it is transitive productively, namely insofar as it produces motion in the body of the animal.

To the second, one can reply in two ways. First, that by "motive according to place," distinguished against appetite, Aristotle intends the executing motive power, which is a passive power existing in the bodily members. And this reply seems to be the mind of St. Thomas, Prima, q. 78, a. 1, ad 4.

Second, that the motive power according to place posits a power distinct from appetite, not indeed really, but formally only, on account of the diversity of acts fitting to appetite insofar as it is appetite, and fitting to it as it is the principle of motion of the animal. Which acts are indeed separated in different animals. For in some animals appetite is found with respect to the act of appetite insofar as it is appetite, in which it is not found with respect to the act which is causing motion by its command, and consequently appetite is not in them as having the character of a motive power: as is clear in animals which are not moved by progressive motion. This response the Commentator seems to touch upon, II de Anima, comment. 27, where he says that Aristotle by "desire" intends appetite for food, and therefore separated it from the mover in place, and posited it as a genus per se: since this power is found in animals which do not move.