Chapter IV -- 15
However, it is manifest that the sensitive appetite changes the man to some disposition according to the passion. Whence, inasmuch as a man is in a certain passion, something appears to him appropriate that does not appear thus to him when he is outside the passion: just as something appears good to the angry man that does not appear good to the man who is calm. And in this way the sensitive appetite moves the will—from the point of view of its object.
What St Thomas is saying is that the passions move the will only in the sense that they modify the man’s apprehension of the good, goal or end. We will see that this applies to the case where the passion has not completely overwhelmed the man and incapacitated his reason.
The researcher into artificial intelligence might find this difficult to implement in a robot, since what is involved is the relation of the robot’s ‘emotions’ to its goals. However, it would be the starting-point for the introduction of affective coloration into the behaviour of the robot. Difficult. However, we propose the following: Let the designer design a desire subsystem and a temper subsystem. Let these two subsystems be dependent on the vegetative and perceptual subsystems of the robot, which subsystems would of course be based on St Thomas’ analyses of the vegetative soul and of perception, including the four internal senses. Let the desire subsystem respond with hunger, say, to a low-battery condition, and with joy, sadness, Eros (amor), hatred and such-like to those things which the robot perceived. Let the desire subsystem transmit messages on its state to the intellect subsystem so that the intellect subsystem evaluates ends in various ways according to the state of the desire subsystem. Since the robot must necessarily monitor (‘perceive’) the progress of its accomplishment of means in relation to its ends, let the temper subsystem respond to perceived impediments to the accomplishment of the robot’s actions with bravery, fear, hope and such-like: St Thomas later says that the temper responds to the difficulty of attaining the desirable or of avoiding the undesirable. Let the temper subsystem send messages on its state to the intellect and will subsystems: for example, if the temper should become incensed, then it might send a message to fortify the will to persist and another message to alter the intellect subsystem’s criteria for the evaluation of ends. Of course the temper subsystem would also have to respond to perceived threats to the robot—or perhaps even to the robot’s master!—and send the appropriate messages, whether of fear or of anger, to the intellect and will subsystems.
St Thomas establishes that the will can move itself. It is in our power, he says, to will or not to will, something that would be impossible if the will could not move itself. He writes this:
[Contrary Assertion:] But it is the contrary, since the will is master of its act (actus), and in the will itself is ‘to will’ or ‘not to will’, which would not be the case if it did not have it in its power to move itself to willing. Therefore it itself moves itself.
[Body of Article:] As has been said above, it pertains to the will to move the other powers [of the soul] on account of the end, which is the object of the will. But as has been said, the end has the same role in appetites that the [first] principle has in things that are understood. It is manifest, however, that the intellect, in that it knows the [first] principle, leads itself from potency (potentia) to act (actus), insofar as it pertains to the understanding of conclusions, and in this way moves itself. And similarly the will, in that it wills an end, moves itself to willing those things which are towards the end.
It might be thought that here St Thomas has replied to our difficulties with the freedom of the person to which we referred above. For here he argues in the contrary assertion that the will can move itself to will. However, in the body of the article he states that the will moves itself to will the means to the end that it has adopted, thus restricting the nature of the self-movement of the will, as he himself later clarifies.
This article is otherwise important for an understanding of how ends and means are tied together in the will: when I will an end, my will moves itself to will the means too. However, St Thomas later clarifies that an act of the intellect caused by the will interposes itself: having adopted the end, the will moves the intellect to deliberate over possible means to the end, and after that deliberation adopts the means to the end. We will encounter deliberation just below.
In artificial intelligence, once the will subsystem has received its goal from the intellect subsystem, then the will subsystem must put itself into operation to adopt the means to the end. Having accepted the end, it must send a message to the intellect subsystem to search for and evaluate possible means to accomplish the end, that is, to perform an act of deliberation over the possible means to the end.
St Thomas establishes that the will can be moved to the exercise of its act by an external object. He says this:
Inasmuch as the will is moved by its object, it is manifest that it can be moved by something external. But in regard to its being moved to the exercise of its act, it is necessary to posit that the will is moved by some external principle. For every thing which is an agent sometimes in act and sometimes in potency needs to be moved by some mover. However, it is manifest that the will begins to will something when it has not previously willed it. Therefore it is necessary that it be moved to willing by something.
As we have already seen, as regards the actual content of the act of willing, the will is moved or determined by something external to it, its object. But, St Thomas wants to say, this also is true in the case where the will is moved in the sense of being put into action at all: since the will up to a certain time was not willing its goal and then came to be willing that goal, something external put it into operation. Here we see the freedom of the human person running up against the metaphysical necessity, in St Thomas’ Aristotelian system, of the movement of the will’s being caused by something. St Thomas then turns to examine just what external causes can move our will.
St Thomas denies that the will is moved in a direct way by the celestial bodies. That is, he denies the necessity of astrological influences on human action.
As universal mover, God moves the will of man to the universal object of the will, which is the good, and without this universal motion, man is not able to will anything. However, by reason man determines himself to willing this or that which is truly good or the apparent good. But sometimes, however, God in a special way moves certain persons to willing something determinate which is good, as in those whom he moves by grace, as is said below.
It seems to us that while St Thomas has found the solution to his problem of the metaphysical origin of the movement of the will to act or not to act in the fact that God moves the will to the good as universal mover, he has not answered our objection concerning the freedom of the person. For, first of all, we see that only sometimes does God by a special grace move someone to will a determinate, good end. Moreover, St Thomas emphasizes that ‘by reason man determines himself to willing this or that which is truly good or the apparent good.’ But St Thomas has not yet explained how things ‘start off’: why the intellect came to begin its act of reasoning that led to its presenting the will with the real or apparent good. St Thomas elsewhere posits that the reason commands the will, an act of the will being presupposed in the act of the reason—and, similarly, that the will puts the reason into operation, an act of the reason being presupposed in the act of the will—but we do not see how he escapes an endless chain of causal relations among the powers of the soul. When I woke up this morning, what was it that made me get out of bed? Was it an act of my will? Or an act of my intellect that presented my will with its object? If it was an act of my will, why did my will come to act, since it had need of an external cause to bring it from potentiality to act? If it was an act of my intellect, why did my intellect come to pass from potentiality to act? For I was asleep. An appeal to habit merely evades the issue. The problem is in the attempt of St Thomas to give an Aristotelian causal analysis of the freedom of the human person.
St Thomas establishes that the will naturally tends towards certain things. For, he says, the intellect naturally comprehends certain things, and since the will follows the intellect, it too naturally tends towards a certain thing. That certain thing is ‘good in general’, towards which the will naturally tends, as each power of the soul tends towards its object. The final end, beatitude, the Beatific Vision, plays the role for the will—that of final end to which the will naturally tends—that the first principles of reason play for the intellect. But just as the intellect can occupy itself with contingent propositions, thus the will can tend to ends other than the Beatific Vision. Moreover, the will naturally can tend to the ends of all the other powers of the soul, since it is by use of his will that a man puts all the other powers of the soul into operation.
This is a very important and central doctrine of St Thomas’ theory of action and of his psychology in general. The human will naturally tends towards the Beatific Vision just as the intellect naturally occupies itself with the first principles. However, before death, it is possible for the will naturally to tend to ends other than the Beatific Vision, just as the intellect naturally can occupy itself with contingent propositions. The will is a hunger, a desire. In the first place it is a hunger after the Beatific Vision. In the second place, in this life it can hunger after secondary goals. We have already seen, however, that these secondary goals have, in St Thomas’ doctrine, an intrinsic metaphysical relation of goodness to the final end of the Beatific Vision. Moreover, in St Thomas’ doctrine the intellect by an act of reasoning presents to the will the secondary goal.
In artificial intelligence, we admit to finding it difficult to cull a lesson from this very important doctrine, possibly because robots are machines. It seems that the import of this doctrine for the will subsystem is that it must be designed always to aim for the ‘good’. But it is the intellect subsystem that must provide the will subsystem with its goal.
St Thomas establishes that the will is not necessarily moved towards its object. The will is moved in two manners: in the first place, in regard to the exercise of its act of actually willing; in the second place, in regard to the determination of the content of that act, which depends on the object willed. In the first case, the will is not moved necessarily by any object, since it is within our power not to think of a thing and therefore not to will it. In the second case, certain objects or ends necessarily move the will as to its determination, while other objects or ends do not necessarily move the will as to its determination. Therefore, if one presents to the will an object or end which is good universally and according to every consideration (i.e. the Beatific Vision), then the will, if it wills anything, will tend towards that object or end, because it would not be able to will anything opposed to it. (Recall that the will is a hunger after the perfect good, the Beatific Vision.) If, however, the intellect were to present the will with an object or end which under some aspect were not good, then the will would not necessarily tend towards that object or end. St Thomas states:
And since the deprivation of some good has the nature (rationem) of the ‘not good’, only the good which is perfect and in which nothing is lacking, that is to say beatitude [i.e. the Beatific Vision], is that which the will cannot prevent itself from willing. However, in the case of particular goods of any sort, as much as they are deficient in some good, they can be perceived as ‘not good’, and according to this consideration they can be repudiated or approved by the will, which can be moved in the same matter by different considerations.
We see here the central role of St Thomas’ definition of the will as a hunger or thirst for the good: when the will is presented with the perfect good, beatitude, it cannot prevent itself from willing it. St Thomas goes on to say that except for the Beatific Vision, every good has from some point of view or other something ‘not good’ in it and that such a secondary good can therefore be accepted or rejected by the will—note that it is the will that accepts or rejects the end, even though the end is presented to it by the intellect—according to how that end is viewed.
There is some ambiguity in this. A good other than the Beatific Vision has some deprivation or other of the good, which deprivation or lack of the good is construed to be the ‘not good’. Hence, St Thomas says, the will can repudiate or approve such a secondary good depending on different considerations. But surely in his doctrine, it is the intellect that evaluates the end, not the will. Hence, it must be the intellect, not the will, which deliberates over the end, whether to pursue it or not, just as St Thomas implies elsewhere. And does not the intellect present to the will its end, as St Thomas says? Surely St Thomas does not want to assert that the will has a judgement of the goodness of a proposed end, and that according to various considerations: surely that is the work of the intellect.
The problem here is this: St Thomas wishes to preserve both the superiority of the intellect over the will and the freedom of the man to decide. The superiority of the intellect over the will, which we see in St Thomas’ doctrine that the reason presents to the will its end, implies that the intellect determines the will; St Thomas later speaks of the command that the intellect issues to the will, what to will; this doctrine accords with the notion that the will is a hunger: the intellect directs the hunger in one direction or another, and that that is what it means to will something. However such a doctrine does not preserve the freedom of man to decide. For by implication the choice is always the product of syllogistic reasoning. Here, however, in order to preserve the freedom of the man to decide, St Thomas asserts that the will actually can choose or not choose one particular good over another based on different considerations. But his doctrine of the relation of the intellect to the will, which puts all the weight on the intellect, does not leave him with any room in the will for the will to exercise discretion: he has defined it as a hunger to which the intellect presents the goal, what to hunger after.
The matter is complicated. For in a certain place, St Thomas, evidently following a passage of St John of Damascus that we will quote later, mentions both deliberation over the end, whether the end is worth pursuing, and deliberation over the means to the end. However, in his treatment of deliberation as a separate stage of human action, he limits deliberation to a search for and evaluation of the means to the end.
How does St Thomas Aquinas understand the freedom of man? For his apparatus of the causal interactions of the will and the intellect seems to remove the freedom of decision of man. The intellect presents the object or good to the will. Can the will refuse to accept it? Why would it do so? The will and the intellect are powers of the soul; when we speak of powers of the soul and the causal relations among them, where is the person? When the intellect presents the object or the good to the will, which is a hunger after the good, where is the person who chooses? Is he in his will? In his intellect? In both? St Thomas says that the man is the composite of soul and body. How does he understand, then, the relation between the person and the powers of the soul? For I am a conscious agent and I deliberate over the end and the means to the end, and I am the conscious agent who assents to the end. What is the connection between this I who deliberates and this I who assents to the end? Moreover, since by St Thomas’ own admission, I have free decision, and that, he says, is precisely the will, how is it that my will—or I acting in my will—can decide? Do I freely accept to do a thing or not? What does it mean for the intellect to present the object to the will? To what extent can the will deliberate whether to do a thing or not? Can it merely accept or reject the result of the deliberation of the intellect, whether over the end or over the means to the end? Can the will apply criteria that have not been applied by the intellect? That seems absurd.
In artificial intelligence, the implications of this article of the Summa are two. First, the designer of the robot could program the robot to respond to him, or to the ‘master’ to whom he gave the robot, in a special, unrestricted way. Second, we here see the central role of the intellect subsystem in the evaluation, from various points of view and according to different criteria, whether the will subsystem should accept or reject a possible end. However, it is the will subsystem that adopts the end or not, evidently on the basis of the command or instruction of the intellect subsystem: we do not think that St Thomas’ model allows for evaluation of the goal from within the will subsystem. The same end might or might not be evaluated positively by the intellect subsystem depending on the circumstances in which the robot found itself, its perceived context. The significance of this should become clear if the researcher reflects that he can design the robot to have a fixed number of ends, each of which is programmed into the robot as a possible end, and a fixed repertoire of means, each of which the robot can execute—although there would be a programmed flexibility in the relationship of means to ends.
 ST Ia IIae, 9, 2.
 See ST Ia IIae, 10, 3.
 ST Ia IIae, 9.
 ST Ia IIae, 9, 1.
 ST Ia IIae, 9, 2.
 See our discussion above of ST Ia IIae, 9, 1.
 In ST Ia IIae, 9, 4.
 ST Ia IIae, 9, 4.
 ST Ia IIae, 9, 5.
 ST Ia IIae, 9, 6.
 ST Ia IIae, 9, 6, ad 3.
 In ST Ia IIae, 109 and 112.
 In ST Ia IIae, 17, 1, quoted below.
 ST Ia IIae, 10, 1.
 ST Ia IIae, 10, 2.
 ST Ia IIae, 6, 2.
 ST Ia IIae, 9, 1.
 ST Ia IIae, 6, 2.
 In discussing ST Ia IIae, 15, 1.
 In ST Ia IIae, 14.