Assessing the Kalam Cosmological Argument, Part II: Aristotle vs. Philoponus on Eternity

*Introductory note: This is a series exploring and assessing the Kalam Cosmological Argument. I am a theist, but am currently unsure of where I stand in relation to this particular argument, i.e. I’m not yet sure whether I think it is successful or not. This provides me the opportunity to approach the argument from a somewhat neutral and distanced perspective. I’m not committed to defending or rejecting the argument. Here, all I want to do is think about and discuss it. 

In the first post of the series, we briefly explored what the Kalam Cosmological Argument is, as well as several reasons which help explain its contemporary prominence as one of, if not the, most popular arguments for the existence of God currently in use. We concluded by examining the roots of the argument’s premises in Plato’s Timaeus.

What we today know as the “Kalam” itself was developed by early medieval Islamic thinkers, but its foundations go back further, to Christian defenders of creatio ex nihilo (creation out of nothing). The roots of the argument were originally intended not as an instance of positive natural theology in its own right, aimed at establishing the existence of God; but rather as a response to the classical understanding of the world, and specifically Aristotle’s defense thereof, in which the universe was held to be eternal.

The doctrine of creatio ex nihilo was really quite unique and unprecedented when it arose within the framework of Christian theology. At this point, we take it almost for granted that theism and creation ex nihilo are interrelated, but that has not always been the case. Indeed, for the first great proponents of classical theism — the Greek philosophers — it was accepted pretty much without question that at least the underlying matter of the universe had always existed uncreated. This was because the metaphysical principle ex nihilo nihil fit was axiomatic in their thought, and as such it was inconceivable to them that matter could have been brought into existence from nothing. God was seen not so much as a “creator” in the sense of a source/originator of all being, but rather as more of a “designer” or craftsman, an agent that orders and directs all things within the universe. We saw this in the previous post when we examined sections of the origins account in Plato’s Timaeus. Even in earlier creation mythologies, the gods were usually depicted as applying order to a pre-existing disorder or “chaos”, not as bringing it all into existence themselves. So when the early Christians developed the doctrine of creatio ex nihilo, it introduced a novel and monumental shift into the western philosophical tradition [1].

Creatio ex nihilo seems to have been partly derived from certain scriptural passages (including a few key ones from the New Testament), but partly also from a process of thought and reflection upon the central belief of the whole Faith: the resurrection [*]. From the perspective of the Greek worldview, as well as that of pagan mythologies, a physical resurrection of the body was largely perceived as ridiculous and even abhorrent. The desire of an afterlife was for escape from the body and the physical world, not return to it, to be imprisoned in it forever! This is directly related to the prevalent conception of matter itself explored above. Matter was equated with disorder, chaos, passivity, and limitation; while spirit and divinity were equated with freedom, order, life, activity, etc. From this view, the resurrection might actually appear not as a triumph but as a cruel defeat! For the Christians proclaiming the victory of Christ’s bodily resurrection, then, the underlying metaphysical framework itself of their audience needed to be addressed. The Christians thus needed to show that matter itself was inherently good, not inherently discordant or inherently evil. And they did so by arguing that even matter, along with everything else, had been completely created by God, given its very being from absolute nothing, as opposed to eternally pre-existing and merely being “ordered” or “informed” by God.

This is seen, for instance, in a typical passage from St. Augustine:

“In the beginning . . . you [God] made something and made it out of nothing. For you made heaven and earth not out of your own self, or it would be equal to your only-begotten Son and therefore to yourself. It cannot possibly be right for anything which is not of you to be equal to you. Moreover, there was nothing apart from you out of which you could make them . . . That is why you made heaven and earth out of nothing . . . since you, both omnipotent and good, make all things good” [2].

God is Goodness Itself, and all things that God creates/gives being to are good by participation in and derivation from Him. Since God created all things other than Himself, even matter, then all things are intrinsically good, including the physical body.

Of course, St. Thomas Aquinas would centuries later argue that creation ex nihilo does not necessarily entail that the universe had a beginning. God could, he postulated, have been eternally creating and sustaining the universe from nothing. But the focus of the early Christians was mainly on just establishing the non self-existence of matter, i.e. in showing that matter could not have eternally existed on its own, without having been created by God. And while creation ex nihilo does not necessarily entail a temporally finite universe, it does seem to be the case that a temporally finite universe does entail creation ex nihilo, for if the entire universe came into existence, including all matter, then it could not have been eternally self-existent.

What was at stake was not just the question of whether or not the universe had a beginning, but the intrinsic nature of physical reality itself; and the early Christians took this issue very seriously.

The dominant competing models of the universe thus came to be the creatio ex nihilo model of the Christians, and the eternal world model of the pagans and Greek philosophers. Of the latter, it was Aristotle’s defense especially (although often given neoplatonist interpretations) which was heralded as the foremost, exemplar challenge to creation ex nihilo and a temporally finite universe. And so it was largely as a response to Aristotle that the foundations of the later Kalam were developed, principally by the sixth century Christian philosopher John Philoponus.

Aristotle’s belief in the eternality of the universe was the result of a thoroughly developed analysis of motion, which is the primary subject of his Physics. In this work, Aristotle spends eight books developing an argument from the reality of physical motion to the necessity of an ultimate prime mover, the first cause of all change in the world (this argument would later be used by St. Thomas Aquinas as his famous “First Way”). Based on his understanding of God (the prime mover), time, and motion, Aristotle concluded that the universe must have been eternally in motion.

He supports this conclusion with a number of different arguments throughout his works, but here we’ll examine just three, from Book VIII of the Physics.

Aristotle begins the book by asking:

“Was there ever a becoming of motion before which it had no being, and is it perishing again so as to leave nothing in motion? Or are we to say that it never had any becoming and is not perishing, but always was and always will be? Is it in fact an immortal never-failing property of things that are, a sort of life as it were to all naturally constituted things?” [3].

Notice that his question here is directed primarily to motion, and not existence per se. It seems to be taken for granted that the underlying “stuff” of the universe has always existed, but the object of inquiry is whether the universe itself, marked by its constant change, has always been in motion, or else began to be in motion.

He answers the question by considering the definition of motion he established earlier in the Physics: “Motion, we say, is the fulfillment of the movable in so far as it is movable” [4]. If something is “movable”, it has the potential for being moved in a certain way. Wood, we might say, is “burnable”, meaning that as it is it has the potential to be burned. The “motion” of the wood, then, would be the process of change from not burning to burning. During this process of change, its potential for burning is “fulfilled” or actualized. And so, says Aristotle, “Each kind of motion, therefore, necessarily involves the presence of the things that are capable of motion . . . In each kind of motion it is that which is capable of motion that is in motion . . . and so there must be something capable of being burned before there can be a process of being burned” [5]. In other words, change presupposes the existence of that which is changed. In order for wood to change from not burning to burning, the wood itself, and its potential for burning, must already exist.

From this fact, Aristotle argues, it becomes clear that the universe must always have been in motion, and hence always in existence, and could never have come into existence. Why so?

“These things [that change] 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” [6].

Take our piece of wood. The log has either always existed, or it began to exist at some point of time, before which it did not exist. If the latter case is correct, then the log must have had a “becoming”, which is a kind of change (either a change from something into something else, such as from a tree to a log; or a change of something from a state of non-existence to existence). But, as we’ve already seen, all change presupposes the existence of that which has the potential for the change.

Suppose everything in the universe could trace its origin back to some first object. That object would either have existed eternally, or else would have come into existence. But if it came into existence, there must have been a process of change, and hence something that had the potential to be changed into that object. Pure “nothingness” has no such potentials at all, so the object could not have come into existence from nothing. As such, Aristotle would say, there could not have been some first object of the universe that came into existence or “began” to exist, and hence the universe must always have existed, eternally in motion.

Aristotle’s second argument for the eternality of the universe is based on the nature of time. For Aristotle, time and motion are inextricably connected; they cannot exist apart from each other. If there is time, there must be motion; and if there is motion, there must be time: “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” [7]. If motion takes place, there must be time, because motion is a process extended through a duration of moments. And if time is passing, there must be motion, because there must be something changing from past, to present, to future.

So if time is eternal, motion is eternal. And Aristotle argues that time must be eternal. Why so? Because time consists of “moments”, and moments are points passing from past to future: “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” [8]. As such, “since the moment is both a beginning and an end, there must always be time on both sides of it” [9]. In other words, you could never have just one moment on its own, in isolation from past and future. Earlier in the Physics, Aristotle remarks that a moment without a “before” and “after” is just not a moment in time at all [10]. The present is the point of transition from past to future. Because of this fact, that “there must always be time on both sides of” a moment, it is impossible that there could be some first moment. A first moment, qua moment, would have to have a previous moment, in which case it could not actually be a first moment at all. So time could not have ever begun, and hence must be eternal; and motion as a result must also be eternal.

The third and final argument appeals to the nature of God. Aristotle has concluded that the reality of motion in the universe requires the existence of an ultimate, first mover, that is itself unmoved but causes all other motion. But if the first mover is unmoving, it must be eternal, since beginning to exist would be to undergo change. And if the first mover is eternal, so must be the motion that it causes:

“If there is always something of this nature, a movent that is itself unmoved and eternal, then that which is first moved by it must be eternal. Indeed this is clear from the consideration that there would otherwise be no becoming and perishing and no change of any kind in other things, which require something that is in motion to move them: for the motion imparted by the unmoved will always be imparted in the same way and be one and the same, since the unmoved does not itself change in relation to that which is moved by it” [11].

In other words, God, in order to be the cause of all change, must Himself be eternal and unchanging. But to “begin” to cause anything would be to undergo change, since it would be to go from a state of not causing to a state of causing. As such, whatever is caused by God must always have been being caused by God. The motion in the universe is caused by God, and so God must always have been eternally causing the motion in the universe.

And so, says Aristotle:

“Let this conclude what we have to say in support of our contention that there never was a time when there was not motion, and never will be a time when there will not be motion” [12].

Quite obviously, these arguments (and others throughout Aristotle’s works), and the model of the world they upheld, were significant challenges to the Christian doctrines of creatio ex nihilo and the temporal finitude of the universe (i.e. that the universe had a beginning). As a result, intellectually serious Christians attempting to engage the classical philosophical worldview needed to offer a response to the Aristotelian arguments. This is precisely what the sixth century Christian philosopher John Philoponus set out to do, whose refutation of the Aristotelian doctrine of the eternity of the world would become the foundation of the Kalam in later centuries.

We’ll explore Philoponus’s response to the first two of the above Aristotelian arguments briefly here.

Remember that Aristotle had defined motion as “the fulfillment [or actualization] of the movable in so far as it is movable”. Since the potential for change must exist prior to the change itself, Aristotle argued that the universe could not have come into existence, and must have been eternally in motion. But Philoponus uses Aristotle’s own definition to turn the argument around on him:

“The definition of motion applies equally to beginningless motion — if there is such a thing — and to <motion> which possesses a beginning. Then, if it follows from the definition that in the case of non-etemal <motion> the moved object must pre exist the motion in time, the same will follow in the case of eternal <motion> too” [13].

On Aristotle’s definition, he contends, for any motion, there must be a movable object that exists prior in time to that motion. E.g., if a log changes from not burning to burning, the log itself must preexist the change. But if the universe is eternally in motion, then there must be some time prior to the eternal motion of the universe, in which the universe existed not actually in motion, but only potentially in motion. In other words, if the universe is in motion, then at some point before that motion the potential for motion must have existed unfulfilled. But it is absurd that a time could exist before something eternal.

The options, then, are either that Aristotle’s definition of motion does not necessarily apply to all motion, since it obviously cannot apply to eternal motion; or that eternal motion is not actually eternal, because there is a time prior to the motion, in which case “the argument has turned the tables on itself” [14]; or that Aristotle’s definition does not actually require there to be a pre-existing movable object (or potential) prior in time to motion, in which case his argument for the eternality of motion doesn’t work in the first place. Philoponus himself thinks the third option is correct.

To see what he’s getting at, think back to our “first object” illustration above. Aristotle’s argument is that there could not be such a first object of the universe that comes into existence, because that would be a change, and so there must have been something pre-existing with the potential for that change. Philoponus counters that a potential does not have to pre-exist a change, but rather can exist simultaneously with the change. For example, think of fire. Fire, by its very nature, has the potential to give off smoke. Before a fire exists, nothing exists with the potential to give off smoke (since it is the fire itself that has that potential, and it is not yet in existence). But as soon as you light a fire, it will give off smoke instantaneously. Smoke has come into existence, but it does so simultaneously with that which has the potential for it. The fire with its potential to give off smoke does not temporally precede the smoke, but only causally. And so, Philoponus insists, it is possible that the motion of the universe could have begun simultaneously with the potential for that motion; and hence the motion of the universe is not necessarily eternal [15].

Aristotle’s second argument was that time cannot exist without motion; time consists of moments; moments necessarily have a “before” and “after” and so there could not be a first moment; and therefore time must be eternal, and with it motion. In response, Philoponus actually accuses Aristotle of begging the question in his definition of “moment”. For if you define “moment” as the midpoint between the before and after, then of course wherever you have a moment, you will necessarily have a before. He writes:

“Someone who wants to show that time is eternal and then assumes as an axiom and premise that time exists on either <side> of the ‘now’, has assumed the question itself, <i.e.> that time is without a beginning and without an end” [16].

Indeed, Philoponus suggests that in order to demonstrate that the present moment is always a mean between the past and future, you would first have to demonstrate that time is eternal and hence that there is always a past and a future. Since Aristotle, he maintains, has failed in his other arguments to demonstrate that time is eternal, he cannot demonstrate that a moment necessarily exists between a before and after [17].

Based on statements Philoponus makes elsewhere, we can draw out his responding argument a bit further: time is dependent upon the motion of bodies; the motion of bodies, and indeed the existence of the bodies themselves, had a beginning; therefore time had a beginning, and there can be at least one moment without a “before”, because there was one moment before which there was no motion. Of course, so far Philoponus has not established that motion had a beginning. The arguments he has given here have just been aimed at showing that Aristotle has not proved his own position. It is only after he has responded to Aristotle that Philoponus then turns and offers positive arguments for the temporal finitude of the universe. In particular, Philoponus will go on to argue from the nature of infinity that the past must be finite; which has been, as many readers are likely aware, the principal metaphysical defense of the Kalam even up until today.

In the next post, then, we will examine Philoponus’s argument from infinities, as well as how it and other arguments were adopted and expanded by early medieval Islamic thinkers in their formulation of the Kalam as an actual argument for the existence of God.



Much general background/historical knowledge comes from: Craig, William Lane. The Kalam Cosmological Argument. Eugene: Wipf and Stock Publishers, 1979. ebook version accessed via Google Books. Pages 3-9.

[1]. For more on the history and background of these various philosophical world views, as well as a metaphysical defense of creatio ex nihilo, see  here.

[*]. This argumen: Hubler, James Noel. “Creatio ex Nihilo: Matter, Creation, and the Body in Classical and Christian Philosophy Through Aquinas.” 1995. Publicly Accessible Penn Dissertations,  

[2]. Augustine. Confessions. Translated by Henry Chadwick. New York: Oxford University Press, 1991. 249.

[3]. McKeon, Richard, editor. The Basic Works of Aristotle. New York: Random House, Inc, 1941. Physics 8.1, 250b11-14.

[4]. Ibid. 251a9-10.

[5]. Ibid. 251a10-17.

[6]. Ibid. 251a17-19.

[7]. Ibid. 251b11-13.

[8]. Ibid. 251b20-22.

[9]. Ibid. 251b25-26.

[10]. See Ibid. 4.11.

[11]. Ibid. 8.6, 259b32-260a5.

[12]. Ibid. 8.1, 252b4-7.

[13]. Philoponus. Philoponus: Against Aristotle on the Eternity of the World. Translated by Christian Wildberg. New York: Bloomsbury Academic, 1987. ebook. Book VI, 1130, 17-20.

[14]. Ibid. VI, 1130, 26-27.

[15]. Ibid. VI, 1131, 1 – 1134,4 (see specifically his distinction between “motion” and “generation”).

[16]. Ibid. VI, 1167, 13-16.

[17]. Ibid. VI, 1168, 37-39.

Awareness of Aristotle’s three arguments comes from Bernard Boedder, S.J. Natural Theology. Second edition. Longmans, Green, and Co. 39 Paternoster Row, London, New York and Bombay, 1902.

Header image: By NASA/ESA [Public domain], via Wikimedia Commons.


Assessing the Kalam Cosmological Argument, Part I

*Introductory note: This is a new series exploring and assessing the Kalam Cosmological Argument. I am a theist, but am currently unsure of where I stand in relation to this particular argument, i.e. I’m not yet sure whether I think it is successful or not. This provides me the opportunity to approach the argument from a somewhat neutral and distanced perspective. I’m not committed to defending or rejecting the argument. Here, all I want to do is think about and discuss it. 

For the most part, the Kalam Cosmological Argument currently reigns as the most popularly defended and discussed argument for the existence of God. Mainstream apologetics circles are especially obsessed with it, but quite a decent amount of attention has been given to it within the realm of academic philosophy of religion as well. Historically, however, this has not always been the case; and indeed for many centuries the Kalam was perhaps seen as the “odd man out” when it came to cosmological arguments generally. As philosopher Edward Feser notes, “Most versions of the cosmological argument . . . are not concerned with trying to show that the universe had a beginning” [1]. For the Kalam, on the other hand, showing the universe to have had a beginning is precisely what it is concerned with. The Kalam thus occupies a unique position in all natural theology. Continue reading

Beginning Metaphysics IV: Essentialism

Central to Aquinas’s whole metaphysical system, and even central to his whole project of metaphysics, is the belief that essences are real. This is known as essentialism. Modern science and philosophy, however, have come so far from the common sense position that things have essences that to even ask the question is seen as a waste of time. This post is meant as a brief introductory look at an overview of arguments that could be presented in favor of an essentialist position.

By far the greatest reason to affirm essentialism is that it is just our starting point for understanding, describing, and interacting with reality. Whether we realize it our not, we are all at least implicit essentialists: we all look at and talk about reality as if there really are things with intrinsic unity which are distinct from other things and other kinds of things. Continue reading

Further Thoughts on Abortion Arguments

A few weeks ago, I posted some thoughts on a few arguments in favor of abortion which I considered to be less than successful. My post was directed specifically to an article by a Mr. Babinski. Babinski kindly responded to my post and then sent me a lengthy counter. That counter will be posted in full throughout the present article. I will divide it into short sections and respond to each in turn. As a preemptive note, Mr. Babinski references several times (when he uses numbers) one of my comments on the previous post. To get a full sense of our discussion, see those comments.

Before I begin, I must reiterate what I explicitly stated in my first post: I was not in that post, nor am I in this post, arguing that abortion is wrong. I certainly believe that, but I’m not arguing specifically for it here. Nor am I making a positive pro-life case. The intention of my previous post was merely to argue that certain types of arguments, which I examined in that post, are either poor or irrelevant in relation to a pro-abortion case, because they simply confuse, mistake, or ignore what is the central and fundamental issue in the abortion debate. Continue reading

Aquinas’s Argument from Design for the Existence of God: Introduction

At long last, we begin the first post on the fifth and final of Aquinas’s Five Ways, or arguments for the existence of God. Outlines of the previous four Ways can be found here, here, here, and here, respectively. The first three, as I’ve explained multiple times previously, are considered Thomistic cosmological arguments. The Fourth Way is really a unique type of argument in its own right, although it certainly has precedent in earlier arguments, including one from Augustine. It also has certain features in common with axiological (moral) arguments, although contains very important differences.

The Fifth Way is commonly categorized as a “Teleological Argument”, or an Argument from Design. Design Arguments have quite a long and impressive history going all the way back to Ancient Greece, to Socrates and perhaps even earlier. The general concept received treatment, at least implicitly, from Plato, Aristotle, some Stoics, and medieval Islamic, Jewish, and Christian philosophers. Modern philosophers such as Newton and Leibniz likewise proposed design arguments. But modern forms of the argument, while perhaps maintaining the same spirit as the classical and medieval versions, underwent somewhat drastic development, particularly in relation to the natural sciences. In fact, contemporary incarnations of the argument are, for the most part, almost entirely dependent upon, and hence most susceptible of criticism by way of, certain interpretations of findings from biology or cosmology. Unfortunately, many who are only familiar with these contemporary design arguments unjustifiably assume that all design arguments are essentially the same and hence guilty of the same or at least similar faults. In this post we will give a brief overview of some different design arguments before introducing Aquinas’s version, which, I think, is not only significantly unique, but also the best of all design arguments, precisely because, in its uniqueness, it does not commit some of the same mistakes as others. Continue reading

Thoughts on Abortion Arguments

Right now, we exist in an extremely politically divided and tension filled time; and I certainly do not in any way wish to add to this. As such, I am very much hesitant about posting on this or related topics. But since several questions were brought to me personally, I thought it might be appropriate to respond. Before I do so, however, I need to make fully clear my intentions in this post:

  1. In this post, I am not attempting to mount a positive argument in support of any sort of pro-life or anti-abortion ethical/political stance. I am both of those things, but I am not arguing positively for them here. Since I have not yet written much at all about ethics, I do not yet have a sufficient foundation for doing so
  2. In this post, I am also not arguing against any general pro-choice or pro-abortion stance. I will be arguing against some specific pro-choice arguments, as will be qualified below, but am not universally asserting opposition to all pro-choice and pro-abortion stances as such (again, I am opposed to these things, but am not here trying to argue against them generally).
  3. In this post, I am responding to several anti pro-life arguments and arguments in favor for choice/abortion. I am responding to these specific arguments here because they were presented to me personally, and because I happen to think they are very poor arguments that entirely miss the point of the debate. There may be serious arguments in favor of a pro-choice stance, but, I contend, the arguments I’m considering here very much are not. So if you personally do not think abortion is morally wrong or are in favor of a pro-choice stance, please do not consider this post a general opposition to your views. I respect your position and would gladly hold a more extended conversation about such.
  4. I am not assuming here the truth of or commitment to any religious traditions or associated beliefs. In other words, I will not be arguing on the basis of any religious beliefs. I will be arguing entirely on the basis of my own purely philosophical commitments.

So, with these preliminary notes having been established, we can begin. Continue reading

Beginning Metaphysics: First Philosophy as ‘Lord of the Sciences’


“The least initial deviation from the truth is multiplied later a thousandfold” [1] wrote Aristotle in his De Caelo. It is to this that St. Thomas refers when he begins his own brilliant metaphysical treatise, De Ente et Essentia, by stating: “A small mistake in the beginning is a big one in the end” [2]. His point is that we must start our metaphysical inquiry from the right place (which for him means noting the distinction between essence and existence) or else we will go awfully awry by the time we reach the end. But on an even broader level, we might say that we must begin all rational inquiry with a solid metaphysical foundation, or else our entire understanding of reality will be, ultimately, completely skewed and fundamentally flawed. So despite the fact that the word “meta-physics” literally means after physics, Aristotle was right all along when he originally named it “first philosophy”, to which physics is “second”, with all other sciences proceeding therefrom. Continue reading