LECTURE 12 (258 b 10-259 a 21)

THE FIRST MOVER IS IMMOBILE AND ONE

1069. The Philosopher has shown that there is no infinite series of things which are moved by another, but that there is some first thing which is either immobile or a self-mover. And he has shown further that one part of a self-mover is an immobile mover. Hence in either case the first mover is immobile. Since in the self-movers among us, that is, in corruptible animals, the moving part of the self-mover, that is, the soul, is corruptible and is moved per accidens, he wishes to show here that the first mover is incorruptible, and that it is not moved per se or per accidens.

             Concerning this he makes two points. First he states his position. Secondly, where he says, 'Let us suppose . . .' (258 b 17), he proves his position.

             Concerning the first part he makes three points. First he summarizes what was proven above. Secondly, where he says, 'Now the question . . .' (258 b 12), he omits something which might seem to pertain to his position. Thirdly, where he says, '. . . but the following . . .' (258 b 14), he explains his position.

             He says, therefore, first that it has been proven above that motion is eternal and never ceases; and since every motion is from some mover, and since movers do not proceed to infinity, there must be a first mover. But since it has not yet been proven that the first mover is one, there still remains the question of whether it is one or many. And it has been shown further that the first mover is immobile, either by ascending from things moved to movers immediately to a first immobile mover or else by ascending to a first self-mover, one part of which is an immobile mover.

             1070. However, some have held that all moving principles in things which move themselves are eternal. For Plato held that all animal souls are eternal. And if this opinion were true, Aristotle would have already established the proposition that the first mover is eternal. But Aristotle's opinion is that only the intellective part of the soul is incorruptible, even though other parts of the soul are movers.

             Consequently, he omits this where he says, 'Now the question . . .' (258 b 12). He says that it is irrelevant to the argument at hand whether all principles which move and are immobile are eternal, although some have held this, saying that all souls are incorruptible. He says that this is not pertinent to the present argument, because he will prove his position without this assumption.

             1071. Next where he says, '. . . but the following . . .' (258 b 14), he explains what he intends to prove.

             He says that from a consideration of what follows it can be made clear that even if not every immobile mover is eternal, nevertheless there must be some immobile being which is in no way moved by anything extrinsic, either simply or per accidens, and yet is that which moves another.

             However when he says, '. . . exempt from all change . . .' (258 b 15), he does not intend to exclude that motion or operation which is in that which acts insofar as understanding is called a motion and insofar as the appetite is moved by that which is desirable. For such motion is not excluded from the first mover which he intends.

             1072. Next where he says, 'Let us suppose . . .' (258 b 17), he proves his assertion that there is a first mover which is eternal and absolutely immobile.

             He proves this first by means of self-movers which sometimes are and sometimes are not. Secondly, where he says, '. . . but also by considering . . .' (259 a 22), he proves the same thing by means of moving principles which sometimes move and sometimes do not.

             Concerning the first part he makes three points. First he shows that there must be an eternal first mover. Secondly, where he says, 'We ought, however . . .' (259 a 8), he shows that such a mover ought to be one rather than many. Thirdly, where he says, 'The following argument . . .' (259 a 14), he proves both points, namely, the first mover is both one and eternal.

             Concerning the first part he makes two points. First he rejects a certain argument which someone might use to prove the proposition. Secondly, where he says, '. . . since there must clearly . . .' (258 b 23), he proves the proposition.

             1073. Someone might argue as follows. Anything which cannot at one time exist and at another not exist is eternal. But since the first mover is immobile, as was shown, it cannot at one time exist and at another not exist. For that which sometimes exists and sometimes does not exist is generated and corrupted. And that which is generated and corrupted is moved. Therefore, the first mover is eternal.

             Aristotle is not impressed with this argument. For someone might say, if he wishes, that certain things sometimes exist and sometimes do not, and yet are not generated and corrupted per se. Consequently, they are not moved per se. For if a thing which has no parts, that is, a thing which is not a composite of matter and form, sometimes is and sometimes is not, it is necessary that this occur without any mutation in it, as can be said of a point and whiteness and any such thing. For it was proven in Book VI that whatever is moved is divisible, and in Metaphysics, VII, it is proven that whatever is generated is composed of matter and form. Therefore, such indivisible things are not generated or changed per se, but per accidens, when other things were generated or changed.

             From this it is clear that if a thing is not moved either per se or per accidens, it is eternal. And if it is eternal, it is not moved per se or per accidens, because it is eternal. If we admit the possibility that a thing may sometimes be and sometimes not be without being generated or corrupted, we must also admit the possibility that certain immobile moving principles can be moved per accidens, since at one time they are and at another they are not. But it is in no way possible that all immobile moving principles be such that sometimes they are and sometimes they are not.

             1074. Next where he says, '. . . since there must clearly . . .' (258 b 23), he proves his position.

             He says that if certain self-movers at one time are and at another are not, there must be some cause of their generation and corruption, by which at one time they are and at another are not. For whatever is moved has a cause of its motion. Moreover, if that which at one time is and at another is not is a composite, it is generated and corrupted. Furthermore, a self-mover must have magnitude. For it is moved, and it was shown in Book VI that nothing indivisible is moved.

             But from what has been said, it cannot be concluded that a mover must have magnitude. Hence it is not moved per se, if at one time it is, and at another it is not. If, however, there is a cause of the generation and corruption of self-movers, it must be the cause of their generation and corruption being continued eternally.

             But it cannot be said that the cause of this continuation is one of those immobile things which are not eternal. Nor can it be said that the causes of the eternal generation and corruption of some self-movers are certain immobile movers which are not eternal, and that there are other causes of the others. He explains this by adding that the cause of this continuous and eternal generation cannot be one of them nor all of them.

             He shows that one of them cannot be the cause. For that which is not eternal cannot be the cause of that which is necessarily eternal.

             He shows that all of them cannot be the cause. For if generation is eternal, all such corruptible principles are infinite and do not exist together. It is impossible, however, for one effect to depend on infinite causes.

             Moreover things which do not exist together cannot be the cause of something. However, it is possible that of those things which do not exist together, certain ones dispose, and others cause, as is clear in the case of successively falling drops which erode a stone. But if many things are the direct cause of something, they must exist together.

             Therefore, it is clear that if there are a thousand thousand immobile moving principles, and if there are also many self-movers of which some are generated and some corrupted, and if among these latter some are mobile objects and others are movers, there still must be something over all of these which contains in its power everything which is generated and corrupted in the above way. This is the cause of their continuous mutation, as a result of which at one time they are and at another are not; and as a result of which some are the cause of the generation and motion of certain ones, and others are the cause of generation and motion of others. For every generator is the cause of generation in that which is generated. But corruptible generators receive their power of generation from some first incorruptible being. Therefore, if the motion as a result of which certain things at one time are and at another are not is eternal, as was shown above, and if an effect is eternal only if the cause is eternal, then the first mover must be eternal, if it is one. And if there are many first movers, they also are eternal.

             1075. Next where he says, 'We ought, however, . . .' (259 a 8), he shows that one ought to posit one eternal principle rather than many.

             He says that just as one must hold that principles are finite rather than infinite, so one must hold that the first principle is one rather than many. For if the same things happen or result from the assumption of finite principles as from the assumption of infinite principles, it is better to hold that the principles are finite rather than infinite. For in things which exist according to nature, one should always take that which is better, if it is possible. For things which exist according to nature are ordered in the best way. But finite principles are better than infinite, and one is better than many. One first immobile principle is a sufficient cause of the eternity of motion, if it is eternal. It is not necessary, therefore, to posit many first principles.

             1076. Next where he says, 'The following argument . . .' (259 a 14), he concludes from the foregoing that there must be a first mover which is one and eternal.

             Although it seems that this has been sufficiently proven by the above arguments, someone might maliciously say that the cause of this continual generation is a first eternal self-mover whose mover is not eternal and one. Rather its mover is moved by diverse movers, some of which are corrupted and some generated.

             But he intends to reject this. For if motion is eternal, as he has proven above, the motion of the first self-mover which is given as the cause of the whole eternity of motion must be eternal and continuous. For if it were not continuous, it would not be eternal. And that which is consecutive is not continuous. In order for motion to be continuous it must be one, and in order for it to be one it must be the motion of one mobile object and must be from one mover. If, then, there are different movers, the whole motion will not be continuous, but consecutive.

             It is absolutely necessary, therefore, that the first mover is one and eternal. But an immobile mover which is moved per accidens is not eternal, as was explained above. Hence it follows that the first mover is absolutely immobile, both per se and per accidens.