Lecture 2 — Arguments for the eternity of motion

Let us take our start from what we have already laid down in our course on physics. Motion, we say, is the act of the movable insofar as it is movable. Each kind of motion, therefore, necessarily involves the presence of the things that are capable of that motion.

In fact, even apart from the definition of motion, everyone would admit that, in each kind of motion, it is that which is capable of that motion that is in motion, and thus it is that which is capable of alteration that is altered, and that which is capable of local change that is in locomotion.

And, likewise, there must be something combustible before there can be a being burned, and something combustive before there can be a burning.

Moreover, these things also must either have a beginning before which they had no being, or they must be eternal. Now, if there was a becoming of every movable thing, it follows that, before the motion in question, another change or motion must have taken place in which that which was capable of being moved or of causing motion had its becoming.

To suppose, on the other hand, that these things were in being throughout all previous time without there being any motion appears unreasonable on a moment’s thought, and still more unreasonable, we shall find, on further consideration.

For if, while there are things that are movable and things that are motive, there is a time when there is a first mover and a first moved and another time when there is no such thing, but only something that is at rest, then what is at rest must previously have been in process of change.

And there must have been some cause of its rest, rest being the privation of motion. Therefore, before this first change, there will be a previous change.

For some things cause motion singularly, while others can produce either of two contrary motions: fire causes heating but not cooling, while it would seem that knowledge may be directed to two contrary ends while remaining one and the same.

Even in the former class, however, there seems to be something similar, for a cold thing causes heating, in a sense, by turning away and retiring, just as one possessed of knowledge voluntarily makes an error when he uses his knowledge in the reverse way.

But, at any rate, all things that are capable respectively of affecting and being affected, or of causing motion and being moved, are capable of it not under all conditions, but only when they are in a particular condition and approach one another.

It is on the approach of one thing to another that the one causes motion and the other is moved, and when they are present under such conditions as rendered the one motive and the other movable.

So, if the motion was not always in process, it is clear that they must have been in a condition not such as to render them capable respectively of being moved and of causing motion, and one or other of them must have been in process of change.

For in what is relative, this is a necessary consequence. For instance, if one thing is double another when before it was not so, one or other of them (if not both) must have been in process of change. It follows, then, that there will be a process of change previous to the first.

Further, how can there be any “before” and “after” without the existence of time? Or how can there be any time without the existence of motion?

If, then, time is the number of motion or itself a kind of motion, it follows that, if there is always time, motion must also be eternal.

But, so far as time is concerned, we see that all, with one exception, are in agreement in saying that it is uncreated.

In fact, it is just this that enables Democritus to show that all things cannot have had a generation, for time, he says, is not begotten.

Plato alone generates time, saying that it had a generation together with the universe, the universe according to him having had a generation.

Now, since time cannot exist and is unthinkable apart from the moment, and the moment is a kind of middle point, uniting as it does in itself both a beginning and an end—a beginning of future time and an end of past time—it follows that there must always be time.

For the extremity of the last period of time that we take must be found in some moment, since time contains no point of contact for us except the moment.

Therefore, since the moment is both a beginning and an end, there must always be time on both sides of it. But, if this is true of time, it is evident that it must also be true of motion, time being a kind of passion of motion.

The same reasoning will also serve to show that motion is incorruptible.

Just as a becoming of motion would involve, as we saw, the existence of a process of change previous to the first, in the same way, a corruption of motion would involve the existence of a process of change subsequent to the last.

For when a thing ceases to move, it does not therefore at the same time cease to be movable.

For instance, the cessation of being burned does not involve the cessation of the capacity of being burned, since a thing may be capable of being burned without being burned.

Nor, when a thing ceases to be mover, does it therefore at the same time cease to be motive.

Again, the destructive agent will have to be destroyed after what it destroys has been destroyed, and then that which has the capacity of destroying it will have to be destroyed afterward, for being destroyed also is a kind of change.

If, then, the view which we are criticizing involves these impossible consequences, it is clear that motion is eternal.

971. After raising the problem of the eternity of motion, the Philosopher now intends to show that motion is eternal.

His treatment is divided into two parts:

in the first, he explains his proposition;

in the second, he solves objections contrary to his proposition, at the arguments that may be (252b7; [997]).

About the first, he does two things:

first, he presents arguments to show the eternity of motion;

second, he answers opinions to the contrary, at it is clear then that motion (252a4; [991]).

About the first, he does two things:

first, he shows that motion always has been;

second, that it always will be, at the same reasoning (251b28; [985]).

About the first, he does two things:

first, he explains his proposition with an argument from motion;

second, he uses an argument from time, at further, how can there be (251b10; [979]).

About the first, he does three things:

first, he sets down something needed for his proposition;

second, he presents a proof that manifests his proposition, at moreover, these things also (251a16; [976]);

third, he shows that his argument proceeds necessarily, at for some things cause (251a28; [977]).

972. He first says, therefore (251a8), that, in order to demonstrate the proposition, we must begin with things determined at the very beginning of the Physics and use them as principles. By this, he gives us to understand that the preceding books, in which he determined about motion in general and that, for this reason, are universally called About Natural Things, are set off from this book 8, in which he begins to apply motion to things.

He assumes, therefore, what was said in Physics 3, namely, that motion is the act of a mobile precisely as such. (Lect. 2, n. 285; lect. 5, n. 325.) From this, it appears that, in order for motion to exist, there must exist things that can be moved with some sort of motion, because an act cannot exist without the thing of which it is the act. Accordingly, from the definition of motion, it is evident that there must be a subject of motion if there is to be motion at all.

But, even without the definition of motion, that fact is per se evident from the general consent of all, for everyone admits as a necessary fact that nothing is moved except what can be moved, and this with reference to any and all motion. For example, nothing can be altered except what is alterable, or be moved with respect to place unless it be changeable with respect to place.

And, because the subject is by nature prior to what is in the subject, we can conclude that, in individual changes—both from the viewpoint of the mobile and from that of the mover—the combustible subject is prior to its being set afire, and the combustive, that is, the subject capable of setting it afire, is prior to its setting afire—prior, I say, not always in time, but in nature.

973. From this argument of Aristotle, Averroes took occasion to speak against what is held by faith about creation. For if coming to be is a kind of change and every change requires a subject, as Aristotle here proves, it is necessary that whatever comes to be does so from a subject; therefore, it is not possible for something to come to be from nothing.

He confirms this with another argument: when it is said that the black comes to be from the white, this is not to speak per se, in the sense that the white itself is converted into the black, but it is to speak per accidens, in the sense that, upon the departure of the white, the black succeeds it.

Now, whatever is per accidens is reduced to what is per se. But that from which something comes to be per se is the subject, which enters into the substance of what comes to be. Therefore, whatever is said to come to be from its opposite comes to be from it per accidens, but per se it comes to be from the subject. Accordingly, it is not possible for being to come to be from non-being absolutely.

In further support of his position, Averroes adduces the common opinion of the early philosophers that nothing comes to be from nothing.

He also gives two reasons from which he considers that the position arose that something should come to be from nothing.

The first is that ordinary people do not consider anything to exist but what is comprehensible by sight; therefore, because they see something visible come to be that previously was not visible, they think that it is possible for something to come to be from nothing.

The second reason is that, among the common people, it could be thought to be a weakening of the virtue of the agent that it should need matter in order to act. But that condition, however, does not derive from the impotency of the agent, but from the very account of motion. Therefore, because the first agent does not have a power that is in any way deficient, it follows that it should act without a subject.

974. But, if one considers rightly, he was deceived by a cause similar to the cause by which he claimed we are deceived: by considering particular things. For it is clear that a particular active power presupposes the matter that a more universal agent produces, just as an artisan uses the matter that nature makes. Therefore, from the fact that every particular agent presupposes matter that it does not produce, one should not suppose that the first universal agent—which is active with respect to all being—should presuppose something not caused by it.

Nor is this in keeping with the intention of Aristotle, who, in Metaphysics 2, (Aristotle, Metaphysics α.1; cf. St. Thomas, Commentary on Metaphysics, bk. 2, lect. 2.) proves that the supremely true and the supreme being is the cause of being for all existents. Hence the being that prime matter has—namely, being in potency—is derived from the first principle of being, which is a being in a supreme way. Therefore, it is not necessary to presuppose for its action anything not produced by it.

And because every motion needs a subject (as Aristotle proves here, and as is the truth of the matter), it follows that the universal production of being by God is neither motion nor change, but a certain simple coming forth. Consequently, “to be made” and “to make” are used in an equivocal sense when applied to this universal production of being and to other productions.

Therefore, just as, if we should understand the production of things to be from God from eternity, as Aristotle and a number of the Platonists supposed, it is not necessary—indeed, it is impossible—that there have been a preexisting but unproduced subject of this universal production, so also, in accord with the tenets of our faith, if we posit that he did not produce things from eternity, but produced them after they had not existed, it is not necessary to posit a subject for this universal production.

It is evident, therefore, that what Aristotle proves here (namely, that every motion requires a mobile subject) is not against a tenet of our faith, for it has already been said that the universal production of things, whether from eternity or not, is neither a motion nor a change. For in order that there be motion or change, it is required that something be otherwise now than previously, and thus there would be something previously existing, and consequently, this would not be the universal production of things about which we are now speaking.

975. Similarly, Averroes’ statement that something is said to come to be from its opposite per accidens and from a subject per se is true in particular productions according to which this or that being comes to be (such as a man or a dog), but is not true in the universal production of being.

This is clear from what the Philosopher said in Physics 1. (Lect. 14, n. 125.) For he said there that, if this animal comes to be inasmuch as it is this animal, it ought not to come to be from “non-animal,” but from “non-this-animal”—for example, if a man comes to be from non-man or a horse from non-horse.

But, if animal is produced precisely as animal, it must come to be from non-animal. Accordingly, if some particular being comes to be, it does not come to be from absolute non-being; but if the whole being comes to be (that is, if being precisely as being comes to be), it must be made from absolute non-being—if this should still be called “being made,” for it is an equivocal way of speaking, as has been said.

What Averroes introduces about the early philosophers has no value, for they were unable to arrive at the first cause of all being, but considered the causes of particular changes.

The first of these philosophers considered the causes solely of accidental changes, and posited all “being made” to be alteration. Those who succeeded them arrived at a knowledge of substantial changes, but those who came still later, such as Plato and Aristotle, arrived at a knowledge of the principle of all existence.

Consequently, it is clear that we are not moved to assert that something comes to be from nothing because we suppose only visible things to be beings; rather, it is because we do not content ourselves with considering merely the particular productions of particular causes, but go on to consider the universal production of all being from the first principle of being.

Nor do we assert that to need matter in order to act is due to a diminished power, in the sense of such a power lacking its natural energy; rather, what we say is that this is proper to a particular power, which does not extend to all being but makes a particular being.

Hence, one can say that it is characteristic of a diminished power to make something from something in the sense that we would say that a particular power is less than the universal power.

976. Then, at moreover, these things also (251a16), assuming that a mobile and a mover are required in order that there be motion, Aristotle argues in the following manner. If motion has not always existed, it is necessary to say either that mobiles and movers were at some time made, having previously not existed, or are eternal.

If, therefore, it is held that each mobile has been made, it is necessary to say that, prior to the change that is taken as the first, there was another change and motion according to which was made the very mobile that is able to be moved and to have been moved.

This inference, indeed, depends on the preceding. For if it is granted that motion has not always been, but that there is some first change before which there was none, it will follow that that first change involved a mobile and that that mobile was made, for previously, it did not exist—since it is being supposed that all mobiles have been made.

Now, whatever comes to be after having previously not existed comes to be through a motion or a change. But the motion or change through which a mobile comes to be is prior to the change by which the mobile is moved. Therefore, prior to the change that was presumed to be first, there is another change, and so on to infinity.

But, if it is held that things that are mobile always preexisted, even when no motion existed, this seems to be unreasonable and a sign of ignorance. For it immediately appears that, if mobiles exist, motion ought to exist, for natural mobiles are at once also movers, as is clear from book 3. (Lect. 2, n. 288.) But, if natural mobiles and movers are existing, there must be motion.

But, to enter more deeply into our search for the truth, it is necessary that this same thing happen—if mobiles and movers are assumed to be eternally existing prior to motion—that followed from the assumption that they were made: prior to the change supposed to be the first, there is another change, and so on to infinity.

This is evident in the following way. If it be supposed that certain mobiles and certain movers exist, and yet the first mover begins at some time or other to cause motion and something is moved by it, and before this nothing is being moved, but is at rest, it will be necessary to say that there was another change in the mover or mobile made prior to that which was assumed to be the first one produced by the mover beginning to cause motion.

The truth of this is clear from the following. Rest is the privation of motion. Privation, however, is not present in a thing capable of habit and form except on account of some cause. Therefore, there was a cause—either on the part of the mover or on the part of the mobile—of why there was rest.

Hence, as long as that cause prevailed, there was always rest. If, then, a mover begins at some time to cause motion, the cause of rest must be removed. But it cannot be removed except by a motion or change. Therefore, it follows that, before that change that was said to be first, there is a prior change by which the cause of rest is removed.

977. Then, at for some things cause motion (251a28), he proves the necessity of the foregoing argument. For someone could say that it happens that things are at rest at some time and in motion at some time without any preexisting cause of rest to be removed. Hence, he wishes to refute this.

And about this, he does two things:

first, he sets down something needed for his proof;

second, he presents the proposed proof, at but, at any rate (251b1; [978]).

He says first that, among movers, some move singularly, in just one way, while others move with respect to motions that are contrary. Things that cause motion in just one way are natural things, as fire always heats and never cools. But beings that act through intellect are causes of motions that are contrary, for one and the same knowledge seems to deal with things and their contraries, as medicine is the science of health and of sickness. Hence, one sees that a doctor, by means of his science, can cause motions that are mutually contrary.

Now, Aristotle mentioned this distinction among movers because, in things that act through intellect, it does not appear that what he had said is true—that, if something is moved when previously it had been at rest, the cause of the rest ought first be removed. For things that act according to intellect seem to be ready to move to opposites without any change of themselves being involved; hence it seems that, without any change, they can cause motion and not cause it.

Therefore, lest his argument be forestalled by this objection, he adds that his reason holds both for things that act according to intellect and for those that act by nature. For things that act by nature do always per se move to one, but per accidens they sometimes move to the contrary, and in order that such an accident occur, some change is necessary; thus, cold always per se causes coldness, but per accidens it produces warmth.

But that cold should per accidens cause warmth is due to some change affecting the cold object, either inasmuch as it is moved to another location (so that it now relates in a different way to the thing that now is heated by it than it related while chilling it), or inasmuch as it completely departs.

For we say that cold is the cause of warmth by departing in the way that a captain is, by his absence, the cause of the sinking of a ship. Again, cold becomes per accidens the cause of warmth either by moving farther away or by approaching closer, as in the winter, the interior of animals is warmer, because their heat retreats inward on account of the surrounding cold.

The same applies to things that act by intellect. For although knowledge is one thing dealing with contraries, it does not deal equally with them both, but with one principally, as medicine is per se ordained to causing health. Therefore, if it happens that a doctor uses his knowledge for the contrary purpose of causing sickness, this will not be per se from this science, but per accidens, on account of something else. And, in order that something else occur when previously it did not exist, some change is required.

978. Then, at but, at any rate (251b1), he sets forth the proof that manifests his proposition. Therefore, he says that, from the fact that things are such—that is, that a similar situation prevails with respect to things that act by nature and things that act by intellect—then, speaking universally of all, we can say that whatever things are possible to make, or to be acted upon, or to cause motion, or to be moved, are capable of it not under all conditions; that is, they cannot cause motion or be moved in just any disposition in which they find themselves, but according as they are in some definite state and nearness with respect to each other.

And this he concludes from the premises, because it has already been said that, both in things that act according to nature and in things that act according to will, nothing is the cause of diverse things except as it is a different state.

Accordingly, it is necessary that, when the mover and the moved approach one another according to a suitable distance and, likewise, when they are in whatever disposition is required for one to cause motion and for the other to be moved, then the one must be moved and the other must cause motion.

If, therefore, there was not always motion, it is clear that existing things were not in that state that allowed for one to cause motion and another to be moved; rather, they were in the state of not being able to cause motion and of being moved at that time. But they later reached that state in which one moves and the other is moved. Therefore, one or the other of them changed.

For we see that, in all things that are said to be relative, it does not happen that a new relation arises except through a change affecting one or the other or both—as, for example, if something that previously was not double has now become double, even though not both of the extremes were changed, yet at least one of them was. Accordingly, if there newly arises a relationship by which something causes motion and something is moved, then one or the other or both had to be previously moved. Hence, it follows that there is a change prior to the one assumed to be the first.

979. Then, at further, how can there be (251b10), he explains his proposition with an argument from time.

First, he sets down two things necessary for his proposition.

The first of these is that prior and subsequent cannot occur unless there is time, since time is nothing else than prior and subsequent precisely as numbered.

The second is that, time cannot exist unless there is motion. This too is clear from the definition given in book 4, (Lect. 17, n. 580.) describing time as the number of motion with respect to prior and subsequent.

980. Second, at if, then, time (251b12), he argues for a conditional proposition from statements made in book 4. (Lect. 17, n. 580.) For there, according to his doctrine, he stated time to be the number of motion; according to the doctrine of the other philosophers, time is a motion, as he there stated. (Bk. 4, lect. 16, nn. 568–69.) But, whichever of these is true, it follows that this conditional is true: if time always exists, it is necessary that motion be perpetual.

981. Third, at but, so far as time (251b13), he proves in two ways the antecedent of this conditional.

He proves it first from the opinions of others. And he says that all the philosophers but one, Plato, seem to be in accord with regard to the opinion that time is not begotten, that is, that it did not begin to exist after previously not existing. From this, Democritus also proved that it is impossible that all things should have been made in the sense of newly beginning to be, because it is impossible that time have been so made that it begin newly to be.

Only Plato generates time, that is, says that time was newly made. For he says that time was made at the same time as the heavens, and he supposed that the heavens had a generation, that is, that they have a beginning of their duration, as Aristotle here claims, and as Plato’s words seem at first glance to indicate—although Platonists say that Plato asserted that the heavens were made in the sense that they have an active principle of their existence but not as having a principle of their duration.

Thus, therefore, does Plato alone seem to have conceived that time cannot be without motion, for he did not suppose that time existed before the motion of the heavens.

982. Second, at now, since time (251b17), he proves the same point by an argument from the fact that it is impossible to say or to understand that time exists without the now, just as it is impossible that there be a line without a point. The now, however, is something intermediate, having as part of its account that it be at once a beginning and an end—that is, the beginning of a future time but the end of a past. From this, it appears necessary for time always to be. For whatever time is taken, its boundary is a now in both senses. And this is clear from the fact that nothing is actual in time but the now, because what is past has gone by and what is future does not yet exist. But the now that is taken as the boundary of time is both a beginning and an end, as has been said. Therefore, it is necessary that, from both aspects of whatever time is taken, time always be; otherwise, the first now would not be an end and the last not a beginning.

But, from the fact that time is eternal, he concludes that motion too must be eternal; the reason for this conclusion being that time is a property of motion, for it is its number, as was said.

983. But the argument of Aristotle does not appear efficacious. For the now is to time as the point is to the line, as was explained in book 6. (Cf. lect. 5.) But it is not necessary that a point be an intermediate, for some points are merely the beginnings of lines and others the ends, although every point would be both a beginning and an end if the line were infinite. One could not, therefore, prove that a line is infinite from the fact that every point is a beginning and an end.

Rather, it is the other way around: from the fact of a line’s being infinite, one would go on to prove that every point would be both a beginning and an end.

Accordingly, it also appears that the claim that every now is a beginning and an end is not true unless time is assumed to be eternal. Therefore, in assuming this as a middle term (namely, that every now is a beginning and an end), Aristotle seems to suppose the eternity of time—the very thing he ought to prove.

Now, Averroes, in trying to save Aristotle’s argument, says that the attribute of always being both a beginning and an end belongs to the now inasmuch as time is not stationary like a line, but flowing. But this does not pertain to the proposition. For from the fact that time is flowing and not stationary, it follows that one now cannot be taken twice in the way that one point is taken twice, but the flow of time has nothing to do with the now being at once a beginning and an end. For the account of beginning and end is the same in all continua, whether they be permanent or flowing, as is clear from book 6. (Cf. lect. 4.)

984. And, therefore, another explanation must be furnished in accord with the intention of Aristotle, which is that he wishes to derive the fact that every now is a beginning and an end from what he had first supposed, namely, that prior and subsequent would not exist if time did not exist. For he uses this principle, which he supposes for no other purpose, but deduces from it that every now is a beginning and an end.

For let us suppose that some now is the beginning of a time; but it is clear from the definition of a beginning that the beginning of a time is that before which nothing of the time existed. Therefore, there must be taken something before or prior to the now that is assumed as the beginning of the time. Prior, however, does not exist without time. Therefore, the now that is taken as the beginning of a time is also the end of a time. In the same way, if the now is given as the end of a time, it follows that it will also be a beginning, because an end is by definition that after which nothing of a thing exists; but after cannot be without time. Therefore, it follows that the now that is the end of a time is also a beginning.

985. Then, at the same reasoning (251b28), he shows that motion will always be. And he shows this on the part of motion, because the argument from motion given above concluded only that motion never began, whereas the argument from time concluded both that it never began and that it never ceases. He says, therefore, that the very argument by which it was proved that motion never began can prove that motion is incorruptible, that is, that it will never end. For just as it followed from the assumption that motion began that there was a change prior to the change assumed to be first, so too, if it be supposed that motion at some time ceases, it follows that a change will occur after the one assumed to be the last.

How this follows he explains by abbreviating the more diffuse explanation he gave with regard to the beginning of motion. For he had supposed that, if motion began, the mobiles and movers either began or always were. The same alternatives can be taken here: if motion should cease, the mobiles and movers will remain or they will not. But, because he had previously shown that the same conclusion follows from either alternative, therefore he uses only the one alternative here, namely, the supposition that motion ceases in such a way that the mobiles and movers also pass away.

Therefore, beginning with the assumption mentioned, he says that both the actual motion and the mobile do not cease to move—that is, pass away—simultaneously; but, just as the generation of a mobile is prior to its motion, so the ceasing to be of a mobile is subsequent to the passing away of its motion. This is so because something combustible can remain after combustion ceases.

And what was said of the mobile must also be said of the mover, because a mover in act does not, in ceasing to be, cease at the same time to be a mover in potency. Accordingly, it is evident that, if even the mobile ceases to be after the destruction of its motion, then there has to be a process by which the mobile passes out of existence.

And again, because we are supposing that all mobiles and motions are ceasing to be, it will be necessary later that even the cause of their ceasing to be ceases to be. But because ceasing to be is a type of motion, it will follow that, after the final change, other changes occur. But, since this is impossible, it follows that motion endures forever.

986. These, therefore, are the arguments by which Aristotle intends to prove that motion always has been and will never cease. The first part of this—namely, that motion always existed—conflicts with our faith. For our faith admits nothing as eternally existing but God alone, who is utterly immobile—unless, of course, you wish to refer to the act of the divine intellect as a motion. But that would be an equivocal sense, and Aristotle is not here speaking of motion in that sense, but of motion properly so called.

The other part of the conclusion is not entirely contrary to the faith, because, as was said above, (Lect. 1, n. 966.) Aristotle is not treating of the motion of the heavens in particular but of motion universally. Now, we believe according to our faith that the substance of the world indeed began, yet so as never to cease. For we posit that some motions will always exist, especially in men, who will always remain living an unceasing life either of happiness or misery.

But some, vainly trying to show that Aristotle concluded nothing contrary to the faith, have said that Aristotle does not intend here to prove as a truth that motion is eternal, but to allege reason for both sides of a question that is doubtful. But this is a foolish statement to anyone who investigates Aristotle’s procedure here. Moreover, he uses the eternity of time and of motion as a principle to prove the existence of a first principle both here in Physics 8 (Lect. 12ff.) and in Metaphysics 12. (Aristotle, Metaphysics Λ.6; cf. St. Thomas, Commentary on Metaphysics, bk. 12, lect. 5.) This shows that he considered it proved.

987. But, if one rightly considers the arguments here given, the truth of the faith is not assailed by them. For they prove that motion did not begin through the way of nature, as some taught it did; but it cannot be proved by these arguments that it did not begin by things being created by a first principle of things, as our faith holds. And that will be evident to anyone who considers each of the inferences here drawn by Aristotle.

For when he asks whether or not the movers and mobiles always existed if motion did not always exist, the reply must be that the first mover always existed; other things—movers or mobiles—did not always exist, but began to exist from the universal cause of all existence. But it has been pointed out above that the production of all being by the first cause of being is not a motion, whether this coming forth be taken to be from eternity or not. Accordingly, it does not follow that, before the first change, there was a previous change. But this would follow if the movers and mobiles were newly brought into existence by some particular agent acting upon some presupposed subject that would be changed from non-being to being, or from privation to form—and Aristotle’s argument concerns this way of coming into existence.

988. But, because we posit that at least a first mover always existed, we need to give an answer to his subsequent deduction that, if movers and mobiles preexist and motion begins newly to be in them, then the movers or mobiles could not previously have been in that disposition in which they are while there is motion; therefore, some change must have preceded the first change.

Now, if we are speaking of the motion itself, the answer is easy. The mobiles were not previously in that disposition in which they now are, because previously they did not exist; hence, they could not be moved. But, as it has been said, they received their existence not through a change or motion, but through coming forth from the first principle of things; accordingly, it does not follow that, before the first change, there was a change. But there still remains the question about the first production of things. For if the first principle, which is God, is no different now than before, then neither does he produce things now any more than before; but if he is different, at least the change affecting him will be prior to the change that is supposed to be the first.

And indeed, if he were a cause that acts only through nature and not through intellect and will, this reason would conclude necessarily. But, because he acts through will, he can produce an effect that is non-eternal through an eternal will, just as, by his eternal intellect, he can understand a thing that is non-eternal—the thing understood being in a certain way the principle of action in causes that act by intellect, as a natural form is in causes that act by nature.

989. But a further point must be pursued. For we do not say that a will postpones doing what it wants unless something is expected in the future that does not yet exist in the present, as, for example, when I will to make a fire later rather than now because it is expected to be cold in the future (or at least this is expected at the present time), on account of which I make the fire. But that time succeeds time does not occur without motion. Therefore, it cannot be that a will, even if it be immutable, postpones doing what it wills without some motion being involved. Accordingly, the new production of things cannot come forth from the eternal will except by means of motions succeeding one another to infinity.

Now, those who raise this objection fail to see that it assumes a thing acting in time, namely, something that acts on the assumption that time exists. For in this kind of action that occurs in time, one must consider some determinate relationship to this time or to things that exist in this time to explain why it be performed in this time rather than in some other time. But this reasoning has no place in the universal agent, which produces time itself at the same time that it produces other things.

For when we say that things have not always been produced by God, we do not understand that an infinite time preceded in which God refrained from acting, and that later, at a definite time, he began to act; rather, we understand that God produced at once both time and things after they did not exist. Accordingly, we must not consider in the divine will that it willed to make things not then but later, as though time were already existing; rather, we must solely consider the fact that he willed that things and the time of their duration should begin to be after they had not existed at all.

If it be asked why he willed this, it must be said without a doubt that it was for his own sake. For just as he made things because of himself, in order that, in them, the likeness of his goodness be manifested, so he willed that they not always be, in order to show his self-sufficiency through that, even though nothing else existed, he in himself had all sufficiency of happiness and of power to produce things.

And this can indeed be said as far as human reason can grasp divine things, saving, of course, the secret of divine wisdom, which cannot be comprehended by us.

990. Because the solution of this argument proceeded on the supposition that time did not always exist, there remains the problem of solving the argument that seems to prove that time always existed. And perhaps Aristotle, after the argument from motion, gave one from time, because he thought that the one from motion would be inefficacious unless time was assumed to be eternal. Thus, his statement that, whenever there is time, there must be a now existing, must be granted without demur. But the statement that every now is both a beginning and an end should not be conceded unless it be also granted that motion always existed, such that every indivisible of motion (which is called a “moment”) should be both a beginning and an end of motion, for the now is to the moment as time is to motion. If, therefore, we suppose that motion has not always existed, but that we can take some first indivisible in motion before which nothing of motion existed, we can also take some now in time before which there was no time.

Now, we have already shown, in explaining the text, that what Averroes says to bolster this argument is inefficacious. But neither is there any efficacy in what Aristotle cites to bolster his own position, namely, that before and after do not exist without time.

For when we say that a time’s beginning is that before which nothing of the time existed, we are not thereby compelled to say that the now that is the beginning of the time is preceded by a time signified by the word “before,” any more than, in magnitudes, if I say that the beginning of a magnitude is that beyond which nothing exists of that magnitude, it is necessary to say that the phrase “beyond which beginning” signifies some real place existing in nature, for it signifies an imaginary one only.

Otherwise, it would be necessary to posit a place beyond the universe, whose magnitude is finite and has a beginning and an end.

Similarly, the first now that is the beginning of time is not preceded by a time existing in reality, but only in our imagination. And this is the time that is described when one says that the first now is the beginning of time, before which nothing of time exists.

Or it may be said that, in the expression “the beginning of time is that before which nothing of time exists,” the word “before” is not affirmed, but denied—and so it is not necessary to posit a time before the beginning of time. For in things that exist in time, it happens that some certain time precedes their beginning, as, when it is said that the beginning of youth is that before which there was nothing of youth, the word “before” can be taken in an affirmative sense, because youth is measured by time. But time is not measured by time, and thus no time preceded its beginning; hence the word “before” in the definition of time is not taken affirmatively but negatively.

But, before time, there does exist a duration, namely, the eternity of God. But this eternity has no extension or any before or after as time does; rather, it is all at once and is not of the same account as time any more than the divine magnitude is of the same account as a bodily magnitude.

Therefore, just as we are not positing some dimension outside the world when we say that, outside the universe, there is nothing but God, so too, when we say that, before the universe, nothing existed, we are not positing any sort of successive duration before the universe.