Chapter 13

No ens moves itself, that is, makes transient acts solely by itself;
it needs the concourse of something different from itself.

1229. We move now to another difficulty presented by the concept of transient act.
Transient acts cannot be other than acts coming from immanent acts. That which is, is immanent. As we saw, an ens without duration is absurd. An instant is the limit of duration, and thus supposes duration; it does not stand by itself. It is like a mathematical point which is the limit of a line and does not stand on its own. Now, an immanent act which produces a transient act either produces it with an eternal act, which is also immanent, or produces a transient act of which it is the subject. In the first case, the immanent act is not the subject of the transient act which it produces.

This, as we saw, happens only in creation. In the second case, the immanent act produces a transient act of which it is the subject. For example, the act with which the sentient principle acquires a new sensation, or the act with which the rational principle elicits some thought. These are transient acts whose subject is the sentient principle or the rational principle. These transient acts modify the subject which carries them out; they produce something new in the subject and, as we saw, their explanation presents difficulties, one of which can be expressed in the following way.

If an ens, an immanent act, becomes the subject of transient acts, that is, modifies itself, there has to be a sufficient reason, a cause of this modification, according to the principle of cause.
The ens, that is, the immanent act itself, does not contain this sufficient reason or full cause of the new happening. If it did, the act produced would be immanent, not transient; in other words, it would always have been in the immanent act. Granted the full cause, the effect exists. But the immanent act existed before the transient act appeared. The immanent act, therefore, is not the full cause of the transient acts which, as its accidents, are manifested in it. This is a new proof that the immanent act, as the subject of a transient act, cannot be the full cause of the transient act. This proof must be added to that which we have already given.

1230. Consequently, no ens is truly and rigorously self-moving. Some foreign agent must concur in its movement, that is, in its change.

1231. This consequence appeared to pose difficulties to many ancient philosophers who, to avoid it, posited the essence of the soul in movement [App., no. 11]. Movement, however, is not substance. It needs a substance as its subject, and it also needs a cause. Moreover, such movement would always have to be equal. If it varied, recourse would be necessary to the intervention of yet another cause to explain the variation. Aristotle concludes, therefore, that rest, rather than motion, is proper to the soul.(123)

1232. Aristotle observes that these philosophers came to their conclusion because of their inability to conceive how a mover can itself not be in motion.(124) He arrives at a contrary conclusion after proving that the soul does not move of itself:(125) non necesse est id quod movet, ipsum quoque moveri.(126)

This opinion raises many difficulties, however. Either the word 'movement' is understood in its proper sense of local movement of bodies, or in a wider meaning. In the former case, it is easy to prove that the soul, as simple and spiritual, is immune from movement; it can move bodies without moving itself. The soul is principle and bodies, where space, place and motion have their seat, are its term. In the second case, movement is a transient act of change, an act in which something new occurs. This is the meaning often given to movement by Aristotle. Unable to deny that the potencies of the soul break forth into transient acts, and noting that Democrites spoke of the soul as moving, he confuses the soul's potency, to which motion belongs, with the soul,(127) to which it does not belong.

If however potencies are only activities of the soul, residing in its essence, we have to say that the soul itself is modified by the acts of its potencies not only when they are in act, but afterwards. Habit remains in the soul as a kind of residue of the act. Although the soul possesses the nature of principle, this principle receives or loses some of its activity. Consequently, change arises in it. Some motion is present metaphorically in it, therefore, in the sense that the soul is the subject of all the acts of the potencies, and the subject is modified through its transient acts.

Aristotle does indeed say that the soul is act (the act of the living body), but he cannot deny that this first act is in potency to other transient acts. As such, the soul is not pure, immutable act, but passes from potency to act.(128)

1233. If, therefore, the word 'movement' is taken for every passage from potency to act (the nature of the transient act lies precisely here), we have to say that the true opinion lies between that of those philosophers who posited the essence of the soul in motion, and the opinion of Aristotle, who denied all motion to the soul. In other words, 'the soul, like every ens other than the first, is an immanent act and the subject of transient acts, but not their complete cause.'(129) If it were the full cause, the acts, which could never cease as long as the cause endures, would be immanent. This is the case with God's creative act which, as eternal, neither has nor posits in God change or passage of any sort. Otherwise, the soul would be a self-mover - a contradictory concept, as we have seen.

1234. If it is impossible for any ens to be a true self-mover, that is, a full cause of its own transient acts, we have to investigate how these acts rise. In other words, what is their complete cause?

To do this, we have to recall what has already been said. The soul is by nature a principle, and the concept of principle involves that of act. But no principle exists without its term, from which it receives its actuality and activity.
The sensitive soul has space and body as its term.
The rational soul has an ens as its term.

Now, if the term is changed, the actuality and activity of the principle is also changed. Our investigation, therefore, concerns the cause of transient acts which take place in the soul as its terms change, as we said. Thus our principle is essentially act and indifferent to its terms, nor does its activity cease, whatever term it is given. Rather, it is activated in various degrees according to the term.

1235. This teaching, which is provided by internal observation, explains the apparent contradiction of the presence in the soul of some possible potency, although the soul as principle is essentially act. Granted that this act receives varying degrees of entity according to the nature of the terms which are given it, we realise on the one hand that it always remains pure act, although in varying degree, nor properly speaking does it ever have united to itself any potency as part of its essence. On the other hand, because it is capable of increase and decrease, we say that it is in potency to this increase or decrease.

1236. Thus we have explained the true concept of potency as a negation of act, not as something positive constituting a substantial part of the principle-ens.

1237. It is true that there is a middle state between giving and totally denying a term to a principle. This state consists in the term's being given imperfectly so that the principle cannot be fully actuated. In such a case, the deficient state of the principle itself is revealed as well as the struggle between it and its term. I shall speak of this elsewhere.

1238. We can now conclude that the explanation of transient acts must never be sought in principle-entia but in term-entia. We have to examine carefully the forces or powers or causes that change the term-entia to see how such forces operate. Only then shall we have explained the possibility of transient acts because we shall have shown how they are formed. However, because their formation is different in different entia, we must consider the individual kinds of entia and their transient acts. We shall do this in the following chapter.

Notes

(123) The arguments used by Aristotle to show that the soul does not move of its nature are reduced more or less to the following:1.If the soul moved of its nature, it would have to make use of some force, in other words, it would have to do violence to itself. The same would be true if it wished to pass from motion to rest. In the nature of the soul, however, we find spontaneous, not violent motion (bk. 1, Sum . III, c. 1). - This would be contrary to the well-being of the soul; the soul would be unhappy by nature because violence is contrary to happiness.2.If the soul is in motion because the body moves, the motion of the soul ought to be like that of the body. It should be a kind of passage. In this case, the soul should be able to leave the body and then re-enter it.3.If the soul moves itself, it is mover and moved at one and the same time. Now, if what is moved goes a certain distance, the soul in so far as it is moved could go some distance from itself, from its own substance, as mover.4. If the essence of the soul consisted in motion, its rest could not be explained. Now, it is certain that the intellect, when it has intuited principles, comes to rest in them. When it has come to the conclusion of a syllogism, it rests there.5. Finally, the nature of the intellect is unalterable and hence immobile. It does not suffer corruption when the body corrupts.

(124) De An ., bk. 1.

(125) Nevertheless, he attributes movement to the soul per accidens , like people on board a ship who do not move of their own accord, but move because the boat moves. Thus the soul, although immovable in the body, moves when the body moves. This way of conceiving movement in the soul shows, however, that even Aristotle did not attain a pure, distinct concept of spirit. His defect lay in not distinguishing with sufficient care and constancy the principle from the term of the human individual. If he had seen or sensed the supreme importance of this distinction, he would have realised two things: 1. the soul is principle and, although essentially connected with its term, is not its term, but something distinct from and even opposite to the term according to substance; 2. every movement arises in the term , not in the principle. Consequently, the soul is immune from all local movement both per se and per accidens. If it were to move like the voyager in the boat, it would have local movement, and there would be no contradiction in the possibility of self-movement.

(126) Ibid . - Aristotle said that the soul moves without being itself in motion. Aureolus and others then commented that the argument about the existence of God, which proves the necessity of something immovable to move what is movable, does not strictly lead to God, but only to a world-soul. But, as Cardinal Gerdil says: 'The first ways (of proving the existence of God) from motion are sufficient for their purpose. Their conclusion, 'Therefore a first unmovable mover exists', does not ask whether this is the soul of the heavens or of the earth. We have to go to the following question for that.' This is what St. Thomas intended when he explained the demonstration of the existence of God from motion (In S.T. , I, q. 2, art. 3).

(127) De An ., 1.

(128) St. Thomas agrees that true self-movers are impossible. His principle is: 'All that moves is moved by something ELSE' (S.T. , I, q. 2, art. 3). But the soul is moved , that is, it passes to transient acts . Hence the demonstration of the existence of God from motion does not conclude only in demonstrating the soul of the world , as Cajetan grants to Averroes and Aureolus when he takes as true Aristotle's opinion that the soul does not move or suffer change from transient acts. The soul does not in fact move itself locally, but from potency to act, which is sufficient for us to appeal to some mover without transient acts, some mover who does not move from potency to act.

(129) Cajetan writes very subtly: 'Efficacy belongs to the explanation of cause. Unless cause brings something about, it cannot be called cause in act. The explanation of cause has to be preserved if its causality is to be complete' (In S.T. , I , q. 2, art. 3).