Commentaria in Summam contra Gentiles, Liber III

After St. Thomas has shown that heavenly bodies are not directly the cause of our choices, he intends consequently to show that neither are separate substances the cause of them, but God alone ¹.

Concerning this, however, he does two things: first, he shows the proposition; second, in the following chapter, he shows that the authorities of Sacred Scripture by which it is shown that God is the cause of our choices are badly interpreted by some.

I. As to the first, this conclusion is posited: Neither the souls of the heavens, if there are any, nor other created separate intellectual substances, can directly instill into us the will, that is, the act of the will, or be the cause of our choice.

It is proved first thus ². It is the law of providence that each thing is moved immediately by the cause proximate to it. Therefore a higher created cause, having omitted such an order, can neither move nor act. Therefore an intellectual substance cannot move the will except through the medium of the understood good. Therefore it cannot act upon the will except in the manner of one who persuades ³.

The first consequence is proved. Because, since all actions of creatures are contained under the order of divine providence, they cannot act outside its laws. — But the second is proved. Because the proximate motive of the will is the understood good, which is its object, and it is moved by it just as sight is by color. — The third is also proved. Because to move the will through the medium of the understood good is to manifest to it that something is good to do. Which is to persuade.

II. But this argument seems to be ineffective. For it could be said that, since we are speaking here of the motion of the will by another in the manner of an efficient cause, that the understood good is the proximate motive of the will does not seem to be to the point: because the good does not move the will in the manner of an efficient cause, but in the manner of an end and of an object. Hence these stand together: that an intellectual substance moves the will efficiently and proximately; and that the proximate motive of the will in the manner of an object is the understood good. And thus the order of divine providence is not removed by the fact that an intellectual substance moves the will immediately: for it is denied that the known good is the proximate motive of the will efficiently.

2. For the evidence of this, it must be considered, from the teaching of St. Thomas in Qu. Verit., q. 22, a. 9, that, since the act of the will is as it were midway between the potency and the object, the changing of the will by something in the manner of an efficient cause can be considered either on the part of the will, or on the part of the object. On the part of the will, that alone has to change the will efficiently which operates within it by causing the very act of the will, namely, that which is within it and works its act. But on the part of the object, that is said to change the will efficiently which does not operate intrinsically in the will, but proposes the object to the will extrinsically. But such a thing is said to move the will indirectly: because it does this alone, that it makes something appear to be good, from which appearance the will moves itself toward that good. And if indeed it proposes such an object as is suited by nature to necessitate the will either to elicit an operation concerning it, which pertains to the exercise of the act; or, if it elicits an act, that its act be pursuit or avoidance, which is to necessitate as to the specification of the act: then such a thing is said to move the will sufficiently on the part of the object, not indeed by causing the very act of the will, but by proposing such an object, and making it appear good in such a way, that at its presence the will is necessitated to produce such an act in itself, or rather the man through the will, as was shown in the preceding sections ⁴. But if it proposes an object that is not suited by nature to necessitate the will, as are all created things: then it is said to move the will on the part of the object in the manner of one persuading only, and in some way inclining indirectly, but not in the manner of one necessitating to the act; for persuasion does not compel the unwilling, as Augustine says in the book of Eighty-Three Questions ⁵.

This argument, therefore, proceeds very well concerning the motion of the will by an intellectual substance efficiently. For because a created thing cannot change the will efficiently except by proposing the known good and making it appear good, since the known good is the object of the will and the object is the proximate motive of the potency; therefore it is concluded that an intellectual substance cannot move the will except through the medium of the understood good, and consequently not except in the manner of one persuading and indirectly inclining the will.

3. To the objection, therefore, it is said that, although we are inquiring here concerning motion in the manner of an efficient cause, and the understood good does not move the will except in the manner of an end, the efficacy of the argument is not on this account removed. Because this is universally true in the order of divine providence, that a higher creature does not move except through the medium of the proximate cause, in whatever genus of cause it acts. Therefore, since its immediate and proximate motive is the understood good, which moves in the manner of an end and a form, although not in the manner of efficiency, just as every potency has to be moved proximately by its object; it is necessary, if any intellectual substance moves the will, that it move it through the medium of the understood good; and consequently that it move it, not by operating intrinsically in the will, but only indirectly and extrinsically.

It should be noted, however, when St. Thomas says that the will is moved by the good just as sight is by color, that this is to be understood absolutely, but not as to the same manner of motion.

III. Secondly ⁶. In the divine good alone is the desire of the will quieted as in the ultimate end. Therefore God alone can move the will in the manner of an agent. — The consequence is proved. Because a thing is suited by nature to be moved and to be acted upon by that agent through whose form it can be brought into act: since every agent acts through a form. But the will is brought into act through the appetible object which quiets the motion of its desire.

IV. But this argument seems not to be conclusive. First, because the consequence can be denied. In proof of which it would be said that, if the assumption is understood in this sense, that a thing is suited by nature to be moved and to be acted upon by that agent alone through whose form it can be brought into act according to its whole potentiality, it is false: for prime matter can be brought into act by some agent by which it is not brought into act as to its whole potentiality. — But if it is understood according to a part of its potentiality, thus it is false that the will is brought into act by that appetible object alone which quiets the motion of its desire: for even that appetible object which does not quiet the motion of desire brings the will to act, as is clear through experience.

Secondly, because, if the minor premise must be subsumed rightly, it must be understood that the appetible object is the form through which the agent moves the will. But this is false: because the appetible object names the terminus of the motion of the will, but not the form by which some agent operates intrinsically in the will.

Thirdly, because, if this argument concludes anything, it concludes that God alone can move the will in the manner of one quieting it, or its desire. But it would be said that, this having been admitted, it does not follow that nothing else acts on the will: because, although other things do not act on it by causing the rest of desire, they will act nonetheless by causing the love that precedes desire, and by causing the very motion of desire.

V. For the evidence of this, it must be considered first that, since something can be understood to be the cause of the human will and of our choice in the manner of an agent acting intrinsically upon the potency of the will in two ways: namely, either as a sufficient and adequate agent for the will, just as the agent intellect is a sufficient and adequate agent for the possible intellect; or as an insufficient agent, namely, one able to incline the will toward the willed object, but not able to necessitate it to elicit the act of willing that quiets the will: — through the first argument St. Thomas proved that the will can in no way be moved intrinsically by an intellectual substance, but only extrinsically; but through this argument he proves in particular that God alone can sufficiently, and as an adequate agent, move the will intrinsically in the manner of a sufficient agent; while in the third argument ⁷ he proves in particular that, even in the manner of an agent intrinsically inclining in any way whatever, God alone can move the will.

It must be considered secondly, that the good and appetible object, which is the object of the will, is the formal cause by which the will has to be brought into act, and by which its operation is specified: but that appetible object alone has sufficiently and adequately to bring the will into act, namely as an extrinsic form, which is suited by nature to quiet it so that it may not desire any further appetible object. Because, if some appetible object is not suited by nature entirely to quiet the will, it is evident that it cannot sufficiently and adequately bring the will into act: for with the volition of that object the desire of another thing will be able to remain, and thus the will will not be totally brought to act.

It must be considered thirdly that, since every agent acts through the form through which the movable object has to be brought into act, it is necessary, if the appetible object is the form by which the will is brought into act, that the appetible object be the form of the agent acting intrinsically in the will: for each thing acts formally through its own form, by which it is in act. And if something ought to act upon the will as a sufficient and adequate agent, it is necessary that its form by which it is in act, and by which it acts upon the will, be the appetible and good object that is suited by nature to quiet the will entirely, lest it desire anything else further. And because the divine good alone, which is namely the universal good and the ultimate end, can entirely quiet the will, since the will is quieted in the ultimate end alone; therefore that alone will be a sufficient and adequate and proportionate agent for the will, whose proper form is the divine good. And because this is God alone, therefore God alone is such an agent. And this is the foundation of this argument.

2. Hence the argument can be formed thus: Something is suited by nature to be moved and to be acted upon by that agent, namely sufficiently and adequately, through whose form it can be brought into act, namely entirely. But by the form of God alone can the will be brought entirely into act. Therefore by Him alone can it be efficiently, sufficiently, and adequately moved and acted upon.

The major is proved. Because every agent acts through its own form. — But the minor is proved thus. The will can be brought entirely into act by the form of that alone whose form is the appetible object that quiets the motion of the will's desire: since through this alone is the will entirely brought formally into act. But the form of God alone, namely the very divine good, is an appetible object of this kind: since the divine good itself alone is the ultimate end. Therefore etc.

It is clear, therefore, that this argument is effective, and proceeds from what is known.

3. Hence to the first objection ⁸ it is said that the assumption for the proof of the consequence is to be understood as we have said: — A thing is suited by nature to be moved and to be acted upon as by a sufficient, proportionate, and adequate agent by that agent alone through whose form it can be brought into act entirely. But it is clear that this proposition, thus understood, has no fault: for matter is brought into act sufficiently and adequately as to its whole potentiality by no particular agent.

To the second it is said that the minor proposition is very well subsumed: as was clear in the final formation of the argument ⁹. For although the appetible object names the terminus of the appetite's motion, it is nevertheless the formal cause of the motion of the will. And therefore, if something ought to operate efficiently in the will intrinsically by bringing it to the act of volition, it must act through the appetible object itself as through its own form, so that the appetible object is thus the principle and the terminus of the motion of the will. For the will also does not move itself to those things that are for the end, unless actuated in some way by the end: insofar, namely, as from the fact that it has in act the volition of the end, it causes in itself the volition of those things that are for the end. And man does not cause in himself the volition of the end through the will, unless he is actuated by the end itself on the part of the intellect: for unless he has knowledge of the end, he cannot will the end. Just as a natural agent also cannot introduce a form into matter unless it has it in itself, either formally or virtually, so that the form is thus the principle and terminus of the action.

To the third, it is conceded that this argument only concludes that God alone can move the will in the manner of one quieting it, and as an adequate agent. Indeed rather, from the fact that He alone can quiet the will by His form, it is concluded that He alone is the one who can sufficiently and adequately move it.

VI. Thirdly ¹⁰. To give natural inclinations belongs only to him who instituted nature. Therefore to incline the will to something also belongs only to him who is the cause of intellectual nature. But this belongs to God alone. Therefore etc. — The first consequence is proved. Because as the natural inclination, which is called natural appetite, is related to its proper end in an inanimate thing, so in an intellectual substance is the will related, which is called intellectual appetite.

2. For the evidence of this argument, it must be considered that, since appetite is nothing other than a certain inclination following upon a form, the will, which names the appetite of an intellectual nature insofar as it is intellectual, names the inclination of the intellectual nature toward something: although these inclinations are of different genera and of different modes. But just as in an intellectual nature there is to be considered both the power, by which it can actually understand, and the act of understanding and the understood form, according to which it is said to be actually understanding: so on the part of the intellectual inclination two things are to be considered, namely the power, by which the intellectual nature can be actually inclined toward something; and the operation of such a power, according to which the intellectual nature is said to be actually willing. The first is the virtual or habitual inclination, upon which the name of the will is imposed: and this corresponds proportionally to the intellectual nature able actually to understand. But the second is the actual inclination, proportionally corresponding to the operation of the intellectual nature. Hence, just as in inanimate things appetite is the inclination of nature toward something, and is called natural appetite; so in an intellectual nature appetite is the inclination of the intellectual nature insofar as it is intellective. On this account every act of the will is an actual inclination of the intellectual nature itself: and to give an actual inclination to such a nature, and to incline the will, are taken for the same thing. But it is manifest that the inclination of a nature toward something does not arise except from the nature itself and from the giver of the nature, namely as from that which causes the inclination itself (for the argument proceeds concerning such motion): just as the downward motion of a heavy body is only from the form of the heavy body, and from the generator giving such a form. Therefore it clearly remains that the act of the will is caused by God alone, who alone, according to faith, causes intellectual nature; and by the willing intellectual nature itself.

VII. Fourthly ¹¹. If the will is moved by some exterior principle, namely in the manner of an agent, not in the manner of an end, the motion will be violent. But the violent is repugnant to the voluntary. Therefore the motion of the will cannot arise from an extrinsic agent, but from an interior one. Therefore it can be caused by God alone. — The assumption is proved by the definition of the violent in Ethics III. — But the last consequence is proved. Because no created substance is conjoined to the intellectual soul as to its interior parts, but God alone, who alone is the cause of it, and sustains it in being.

Note that an agent can be intrinsic to something that moves and operates in two ways. In one way, virtually only: namely because the form by which the operator operates is caused by it, although it does not conserve it in being, and consequently the power of the agent remains in it; just as the generator of heavy bodies is said to be virtually contained in the heavy body by reason of the heaviness given to it by the generator itself. In another way, not only virtually, but also according to its proper essence: just as an immaterial substance that has not only given to the operator the form by which it operates, but also conserves that form in being by its action; in which way it was said above ¹² that God is in all things by essence, insofar as He gives being to all things and conserves all things in being. For this, therefore, that the operation of something caused by some moving cause not be violent, it is required that the agent and moving cause itself toward such an operation be intrinsic to the operator either according to essence and power together, or according to the power of the form by which the operator operates: for if the moving cause is intrinsic in neither of those ways, the operation will be violent, as arising entirely from the outside. But a created substance is intrinsic to an intellectual nature in neither of these ways. Which St. Thomas gave to be understood when he said that God alone causes it, by which it is excluded that a created substance is not intrinsic to it virtually, by reason of the form by which it operates; and that He sustains it in being, by which it is excluded that a created substance is not intrinsic to it by essence. Therefore it very well follows, if it is posited that it moves the will directly by causing the act of the will, that such motion will be violent.

VIII. But a doubt occurs. For just as St. Thomas says in Physics II ¹³ that the celestial motion is natural not by reason of form, but by reason of matter, insofar as the heaven has a natural aptitude for being moved; so in the proposed case it will be able to be said that, although the motion of the will is from an extrinsic created intellectual substance, it does not follow that it is violent, because the will has a natural aptitude for being moved by such a substance.

It is answered that one must speak in one way of the motion by which some passive subject has only to be moved: and in another way of the motion that is the operation of that which is said to be moved. Because, since motion is the act of that which exists in potency ¹⁴, the naturalness of motion can be considered not only by reason of form, but also by reason of matter, from which a thing has it that it is in potency. And on this account the motion of the heaven is called natural: because it has a natural potency for being moved by such a motion. But operation is the act of that which exists in act through a form. Therefore, in order that an operation be natural, as natural is distinguished against violent, it is required that the active principle of such an operation be intrinsic, either according to its essence, or according to the power of the form by which the operator operates. On this account, if the will is moved to its operation in no way from something intrinsic, but only by an extrinsic agent, its operation will be violent.

2. If it is said that in such motion its operation will be from within and from without, insofar as it will be from the power of the will itself and from the intellectual substance, and thus will not be entirely from without: — this is of no avail. Because, as was clear from the preceding argument ¹⁵, an operation that belongs to a thing in the manner of a certain inclination, of which kind is the operation of the will, cannot arise from a created intellectual substance through the medium of some interior principle: since it is not the cause of that interior principle. Therefore, if a created intellectual substance were to move the will efficiently to an act, that motion would be entirely from without, and not through the medium of the will as through an intrinsic principle inclining to the act: just as, if a heavy body were moved by something that did not cause the nature of the heavy body, that motion would not be the natural motion of the heavy body, as is said in Ia IIae, q. 9, a. 6, but would be another, violent motion, such as motion upward. For that which is not in some way the cause of the nature cannot cause natural motion on the part of the form. Hence he who throws a stone downward does not move the stone downward by causing the motion itself, but by applying heaviness to his work: but the generator, which gave it heaviness, is called the moving cause.

3. Concerning that clarification, Now I say to be moved from without what moves in the manner of an agent, and not in the manner of an end, note that from this the definition of the violent is clarified, by which it is said that the violent is that whose principle is outside. For it is understood of the active principle, not of the final principle. Because although the end by which someone is moved is extrinsic to that which is moved, such motion is nevertheless not called violent. Indeed it is natural motion, if it is motion arising from the ultimate end.

IX. Fifthly. That agent alone can cause the motion of the will without violence which causes the intrinsic principle of this motion, which is the will. But this is God alone, who alone creates the soul. Therefore God alone can move the will in the manner of an agent without violence.

The assumption is proved. Because the violent is opposed to natural and voluntary motion, from the fact that each of them must be from an intrinsic principle. But an external agent only moves naturally insofar as it causes in the mobile subject an intrinsic principle of motion; and nothing else extrinsic can move a natural body without violence, unless perhaps per accidens, as that which removes an obstacle, which uses the motion or action rather than causes it.

Concerning this last statement, note, from the teaching of St. Thomas in Ia-IIae, q. 16, a. 1, that the use of a thing implies its application to some operation. Therefore, because that which removes an impediment that was preventing the motion of a natural body in a certain way applies the nature of that body to its own motion, which is, as it were, its operation, toward which it is naturally inclined, and toward which it tends of itself unless it is impeded; and consequently applies it to reaching its natural and proper place; but does not give motion to that body by causing it by the power of its own nature: therefore it was most suitably said that that which removes an obstacle uses the motion or action rather than causes it.

2. Note that this argument differs from the preceding one. Because the preceding one proceeded from the fact that the principle of voluntary motion must be intrinsic, whereas a created substance is not intrinsic to the intellective soul. But this argument proceeds from the comparison of the voluntary to the natural: which, just as they are opposed to the violent by a common reason, so they agree in this, that just as an extrinsic agent does not move naturally and without violence unless it causes in the mobile subject the intrinsic principle of motion, so also it must happen in that which moves to a voluntary act. Since a created substance is not the cause of the will, which is the intrinsic principle of the voluntary act, but God alone is, it follows that it cannot move the will to a voluntary act. — Yet this argument is a kind of confirmation of the preceding one.

The conclusion is confirmed by the authority of Prov. 21 and Philipp. 2.