Encyclopedia Apologia: Kalam 4

Scientific arguments for a first moment

The Universe began to exist

Scientific Arguments

The following argument is scientific data which Craig points to in order to provide inductive support for the second premise. Craig argues that the Big Bang model is most consistent with, and possibly reveals, the universe beginning to exist. My readers who deny the Big Bang are free to read this section per impossible. It’s short and should not be too great a hassle. I don’t really understand advanced science, so I tried not to say too much. If you have seen the most recent Schmid and Linford critique of WLC’s scientific arguments, then you are probably more knowledgeable on this than me. That being said, this might still be useful because it’s pretty basic.

The Big Bang

I will give a brief description of the Big Bang theory. Next, I will try to explain how people think that it supports a temporal beginning. Then, I will explain why many people deny this conclusion. After that, we can leave the Kalām and move on to the much shorter New Kalām.

According to renowned physicist ChatGPT,

The Big Bang theory is based on the observation that galaxies are moving away from each other. Scientists infer that if we rewind this cosmic expansion, everything must have been closer together in the past. Going back far enough, we reach a point of infinite density and temperature called a singularity. This singularity marks the beginning of our universe. This singularity then rapidly expanded, leading to the formation of the universe. The universe has been expanding ever since, and this expansion is still happening today.

The machine even said that the Big Bang ‘marks the beginning of our universe’. Craig (or maybe his coauthor James Sinclair, who wrote the scientific section for him) has more to say about this,

The standard Hot Big Bang model, as the Friedmann–Lemaître model came to be called, thus describes a universe which is not eternal in the past, but which came into being a finite time ago. Moreover – and this deserves underscoring – the origin it posits is an absolute origin ex nihilo. For not only all matter and energy but also space and time themselves come into being at the initial cosmological singularity.¹

Thus, the point is pretty straightforward, the standard mode in cosmology describes a universe beginning to exist. If this model is correct as stated, that is a pretty cut-and-dry defense of premise two.

Theorems with a beginning

Another thing which Craig has popularized is the Borde-Guth-Vilenkin (BGV) theorem. This, I am led to believe, shows that a constantly expanding universe must have had a beginning.² Or, more fancifully, that generally inflationary geodesics are incomplete.³ Notice how that’s not necessarily the same as saying that the universe must have had a beginning. This point was famously made by Sean Carroll in his debate with WLC. For, Borde and Guth deny that. Vilenkin, on the other hand, is a critic of all eternal past models.⁴ The main eternal model which the BGV rules out is one of ‘eternal inflation’. On an eternal inflation model, our universe is a ‘bubble’ universe or ‘pocket’ universe which forms out of a larger sludge of eternally expanding universes comprising a multiverse. According to the BGV theorem, this is impossible. There would have to be a significant amount of past time when the universe was not expanding. Vilenkin believes that every current physical model, including models which include amounts of time where the universe was not expanding or even contracting, ultimately involves more expansion than contraction, and thus fulfills the criterion for the theorem (see footnote 2).

Overshadowed by the infamous BGV theorem, the Hawking-Penrose singularity theorems have been used to attempt to prove that the universe must have started from a singularity. Some of these theorems have been falsified. For instance, one relied on the assumption that the force of anti-gravity produced by negative pressure, aka tension, cannot exceed the gravity produced by positive pressure. Apparently, however, this assumption, called the strong energy condition, is demonstrably false.⁵ Other singularity theorems have lasted longer, but they usually come with other setbacks, such as only cohering with General Relativity and not Quantum Mechanics, or requiring that space be infinite, or more sophisticated stuff which I don’t really understand.⁶

There is one other avenue which may shine a light on universal origins. This being Einstein’s Field Equations. Here is a chopped up explanation from Kenny Pearce,

The equations that describe the bending of spacetime are called Einstein’s Field Equations... A global solution (to the equations) describes a possible shape for the totality of spacetime… If,…, we’re taking our cues from current, well-established science, we should endorse the following principle: any solution to Einstein’s Field Equations should be assumed to describe a physical possibility unless there are compelling reasons to the contrary… One class of global solutions to Einstein’s Field Equations has the universe beginning as a tiny point and expanding outward from that point, growing larger and larger forever… there are ‘static’ solutions—which Einstein himself initially favored (Singh 2004, 146–149)—on which the universe does not expand or contract at all. A static universe would not have a beginning or an end…If we are to respect the idea that all of these solutions to Einstein’s Field Equations describe physical possibilities, then we need to hold that it is physically possible for the total sequence of causes and effects either to have a beginning or not.⁷

While I do not think this tells us anything more than the Hot Bang model does, it does leave us in the situation where the Hot Bang model is a confirmed physical possibility. At least, insofar as we think our current models in physics correctly describe reality, which I have argued above in the section on time that we maybe shouldn’t. However, in case we should, then there may be the potential for a modalized Kalām. You didn’t hear it from me though.

Objections to Big Bang Beginnings

Carroll’s critiques

The first thing I want to mention is the first trillionth of a second after the Big Bang and before. We have no clue what was going on before that. I was recently at an event with Sean Carroll and Michael Strauss. Both agreed that we have no idea what happened before that moment. Strauss takes there to have been a beginning, while Carroll has a model which I do not understand but sounds like it says that time moves backwards and forwards, so (maybe) the dating system of counting down to Christ is scientifically accurate after all.⁸ Carroll’s model has the interesting implication that the past is infinite, but not actually infinite unless the Malpass-Dretske argument works. Along with the Carroll-Chen model, there is the Aguirre-Gratton model. This is another bang-crunch model where the universe increases and decreases in entropy between big bangs and big crunches in an infinite cycle. It has been argued that both of these models still have a relevant beginning point in time, due to both models including at least one thermodynamic starting point for the system which everything else, past and future for Carroll, depends on, but which itself is uncaused by anything else in the system. This first moment would be where entropy is 0.⁹

Keeping with Carroll, in the Carroll-Craig debate, Carroll states that the Schrodinger equation implies an eternal universe immediately after he disputes Craig’s reading of the BGV theorem. The idea here is that since we can know the superposition of any particle based on its previous state, then there must always be a previous state for that particle, so long as the energy in the system is non-zero. However, I don’t see why we would think that the energy at t=0 would be non-zero, so I don’t think this argument from Carroll works.

Oppy’s Critiques

Graham Oppy has argued that our science can give us no evidence one way or the other on the question of whether the universe began to exist, since we do not know what, if anything, was prior to the Big Bang.¹⁰ This, however, I find suspicious. For, it is obvious that any model which entails an infinite past provides evidence against a finite past. Any evidence against models which posit an infinite past will then be some evidence for models of a finite past. That there is a suspiciously beginning-like moment in time is evidence for finite-past models, though certainly not conclusive. More generally, the best philosophical argument in favor of an infinite past, in my opinion, is that it is a reasonable inductive inference from our experience of the past. Every past moment we know has had a prior moment, so every past moment had a prior moment. However, such an argument faces an undercutting defeater from the standard Big Bang model, since we can see a past moment and definitely cannot be sure that there was a moment before it.

However, Oppy has four more arguments to justify skepticism about an ‘absolute cosmic beginning’. The first two are that there is scientific and mathematical reason to think that the Big Bang theory will be replaced with a broader theory of quantum gravity. The latter two are the familiar point made by Grunbaum that the Big Bang is no mere event, and finally the similar point that the universe being finitely old does not entail that it had a true beginning.

More concretely, despite the BGV theorem, new inflationary counterparts to the Single Bang model have become more common among physicists. Or, at least, so pop science would have me believe.

Hawking’s Critique

A favorite of Quentin Smith, as we will see in a later post, Stephen Hawking and James Hartle offer a model which has sometimes been interpreted as meaning that the universe causes itself to exist. They proposed that there was space before time, and that the beginning of time was preceded by a wave-function. Later, I will assess this model as primarily one which concedes that the universe has a beginning, but here I will evaluate it as saying that there is no beginning to time.

Under the Hawking-Hartle model, the universe is finite if we use imaginary values for our times. If we use real times, then it is infinite. However, one might reasonably suspect that imaginary values don’t belong in our metaphysics. That’s a bit uncharitable, but, roughly, what imaginary values mean is that the Hawking-Hartle model applies a non-relativistic understanding of time to a relativistic model. To many people, this will sound strange. I induce that from how strange it seems to me. Yet, most people who look into this model seem okay with calling it a beginning, so it does not provide a clear alternative to a finite past.

Linford’s critiques

Aside from all that cool science stuff, Dan Linford has appeared in recent months as a leading skeptic of the jump from ‘the universe has a finite past’ to ‘the universe began to exist’.

Linford recently finished his dissertation on the question of whether there was a beginning to the universe, and his conclusions were overwhelmingly negative. He defends the thesis of Cosmic Skepticism, that we cannot know whether or not the universe began to exist through this central argument:

1. We know the Cosmos began to exist only if we know the Cosmos satisfies the three conditions introduced in part II, i.e., the Modal Condition, the Direction Condition, and the Boundary Condition.

2. We do not know whether the Cosmos satisfies the three conditions.

3. Therefore, we do not know whether the Cosmos began to exist.¹¹

The Modal Condition: The modal condition asks if the universe could begin to exist only when nothing, not even time, existed before it. In more precise terms, the universe has a beginning only if there are no antecedent conditions that could necessitate its existence without time.

The Direction Condition: As far as our own experience goes, time moves like an arrow—always in one direction, from past to future. The direction condition asks if everything in the universe agrees on which way the arrow of time is pointing. If not, then there is no beginning (See Carroll’s Critique above for discussion on this point).

The Boundary Condition: The boundary condition requires that there is a past temporal boundary—essentially, a demarcation that signifies the start of the universe's existence. This boundary could be a closed past boundary or a finite initial segment, meaning the universe has a definite point beyond which there is no prior physical existence.

Let’s move on to the details of Linford’s most innovative arguments. The most unique aspect of Linford’s case is his emphasis on timeless and something-like-timeless models which satisfy a finite past, but do not satisfy the above three conditions. In his odd debate with Andrew Loke, Linford made the following claim-

Even if we knew that the past is not infinite, we still would not be able to conclude that physical reality began to exist. I know that sounds odd. Surely, you might think, if the past is not infinite, then the past is infinite. And if the past is infinite, then physical reality must have a beginning, right?

Well, no. In order to understand why, we need to understand the distinction between metric and non metric time. We are familiar with metric time from our everyday lives: we measure metric time on our clocks. To grasp the distinction between non-metric and metric time, consider an analogy with the real line, envisioning its points as analogous to instants in time. Picture the real line as a sequence of labeled points, each marked by a number. Calculating the distance between two points on this line involves subtracting their labels – for instance, the distance between 5 and 2 is 3. Now, liken non-metric time to a set of points without labels. Without these labels, determining the distance between any two points becomes impossible. While in our daily lives, we employ clocks to measure the duration between two instants, certain situations may present non-metric time. In these circumstances, the absence of labeled points means we cannot construct clocks, as there is no inherent information about the duration between two instants in time.¹²

Linford’s main thesis which he seeks to defend in this passage is that it is simultaneously possible that the universe have a finite past, but also have no beginning. Prima facie, a transition from non-metric time to metric time is not a temporal beginning. Such non-metric times have been defended by the Oxford school of philosophers, including Richard Swinburne and Ryan Mullins.

Linford’s argument bears structural similarity to one made by J.H. Sobel, who posited

…‘the universe began to exist’ in a sense, nothing happened when it did, nothing came into existence then, and in particular The Universe did not come into existence then. In this story it was only later that things came into existence, and they all had causes in the universe of sensible things that themselves came into existence at earlier times, but of course at times subsequent to the ‘beginning of history’¹³

Linford believes that a transition from non-metric time to metric time is analogous to Craig’s belief that God transitions from being timeless to temporal with the creation of the universe. However, it is somewhat implausible that the two cases are analogous. Furthermore, there are many apparent problems with non-metric time, such as it being really weird, not following common-sense principles of experience like the arrow of time, and generally not having great empirical support (a rather unfortunate side effect of being before the Big Bang). A timeless state and a non-metric temporal state are different, but a timeless state is not very different from a timeless state (woah), so perhaps we should compare timeless to timeless and avoid proliferating confusing concepts any further?

To this challenge, Linford is well-prepared. Linford has analyzed a large number of models of spacetime which are reducible to more fundamental realities. Here’s a list of potential alternative fundamental realities: gravitational fields, the Hawking-Hartle wave-function (remember this guy?), something like quantum gravity (whatever that is), Loop Quantum Gravity (which might actually still be fundamentally spacetime, but just fundamentally spinny spacetime. Or it’s timeless), quantum interpretations like universal (atemporal) wave-function monism (it’s back).¹⁴

Some of these theories of fundamental reality have timeless aspects, including many views which deny that the universe is ever anything but timeless, namely quantum gravity. Unless there is a good reason to prefer the Single Bang model (and there probably is), then the scientific evidence is inconclusive about the origin of the universe. Thus, a beginning remains consistent with current physics, but it is less clear that a beginningless past is inconsistent.

That’s all I know about this stuff. On to the New Kalām!

1. W. L. Craig and J. P. Moreland (eds.), Blackwell Companion to Natural Theology, Oxford: Blackwell, 2009, pg. 131

2. To have a specific picture in mind, suppose there is an observer in every galaxy of our local region. Since the universe is expanding, each of these observers will see the others moving away. Galaxies may not exist in some regions of space and time, but we can still imagine the entire universe “sprinkled” with observers in such a way that all of them are moving away from one another.bj To give these observers some name, we shall call them “spectators.”

Let us now introduce another observer who is moving relative to the spectators. We shall call him the space traveler. He is moving by inertia, with the engines of his spaceship turned off, and has been doing so for all eternity. As he passes the spectators, they register his velocity.

Since the spectators are flying apart, the space traveler’s velocity relative to each successive spectator will be smaller than his velocity relative to the preceding one. Suppose, for example, the space traveler has just zoomed by the Earth at the speed of 100,000 kilometers per second and is now headed toward a distant galaxy, about a billion light-years away. That galaxy is moving away from us at 20,000 kilometers per second, so when the space traveler catches up with it, the observers there will see him moving at 80,000 kilometers per second.

If the velocity of the space traveler relative to the spectators gets smaller and smaller into the future, it follows that his velocity should get larger and larger as we follow his history into the past. In the limit, his velocity should get arbitrarily close to the speed of light.

The key insight of my paper with Borde and Guth is that as we go into the past and approach past infinity by the clocks of the spectators, the time elapsed by the clock of the space traveler is still finite. The reason is that according to Einstein’s theory of relativity, a moving clock ticks slower, and the closer you get to the speed of light, the more slowly it ticks. As we go backward in time, the speed of the space traveler approaches the speed of light and his clock essentially comes to a halt. This is from the spectator’s point of view. But the space traveler himself does not notice anything unusual. For him, what spectators perceive as a frozen moment, stretched into eternity, is a moment like any other, which has to be preceded by earlier moments. Like the histories of the spectators, the space traveler’s history should extend into the infinite past.

The fact that the time elapsed by the space traveler’s clock is finite indicates that we do not have his full history. This means that some part of the past history of the universe is missing; it is not included in the model. Thus, the assumption that the entire spacetime can be covered by an expanding “dust” of observers has led to a contradiction, and therefore it cannot be true.

A remarkable thing about this theorem is its sweeping generality. We made no assumptions about the material content of the universe. We did not even assume that gravity is described by Einstein’s equations. So, if Einstein’s gravity requires some modification, our conclusion will still hold. The only assumption that we made was that the expansion rate of the universe never gets below some nonzero value, no matter how small. This assumption should certainly be satisfied in the inflating false vacuum. The conclusion is that past-eternal inflation without a beginning is impossible.

What about a cyclic universe? It has alternating periods of expansion and contraction. Can this help the universe to escape from the clutches of the theorem? The answer turns out to be no. An essential feature of the cyclic scenario, which allows it to avoid the heat-death problem, is that the volume of the universe increases in every cycle, so on average the universe is expanding. In my paper with Borde and Guth, we show that as a result of this expansion, the space traveler’s velocity increases on average as we go back in time and still approaches the speed of light in the limit. Hence, the same conclusions apply.

It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man. With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape: they have to face the problem of a cosmic beginning.
Vilenkin, Alexander, Many Worlds in One: The Search for Other Universes, New York City: Hill and Wang, 2007, pg. 17

Craig loves that last paragraph.

3. In the context of general relativity, geodesics are the paths that objects follow through spacetime in the absence of any external forces except gravity. Famously, Einstein showed that the gravity of massive objects causes these geodesics to be curved. A geodesic is incomplete if it is finite.

4. Audrey Mithani and Alexander Vilenkin, “Did the universe have a beginning?” arXiv:1204.4658v1 [hep-th] 20 Apr 2012, p. 1

5. Visser, Matt; Barceló, Carlos (2000). "Energy Conditions and Their Cosmological Implications". Cosmo-99. pp. 98–112.

6. J. M. M. Senovilla, “A critical appraisal of the singularity theorems,” Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol. 380, no. 2222, May 2022. section 4

7. Oppy, Graham; Pearce, Kenneth L. Is There a God? A Debate, New York, Routledge, 2022 pg. 62-63

We must not let this appeal to Einstein’s field equations dissuade us from Oppy’s Maxim: Denying that Einstein’s Field Equations describe metaphysical possibilities is based. Humorously, and somewhat uncharitably derived from pg. 222-223

8. Carroll, S. and Jennifer Chen. “Spontaneous inflation and the origin of the arrow of time.” arXiv: High Energy Physics - Theory (2004)

and I think it’s also defended in this book which Carroll has endorsed

Barbour, Julian. The Janus Point: A New Theory of Time. Basic Books, 2020.

Underrated philosopher Christopher Weaver has a response, but I don’t know if it’s good since I haven’t bothered to read it since I don’t understand the Carroll-Chen model well enough in the first place to know if it’s a good paper or not.

Weaver, Christopher Gregory (2017). On the Carroll–Chen Model. Journal for General Philosophy of Science / Zeitschrift für Allgemeine Wissenschaftstheorie 48 (1):97-124.

9. Wall, Aron C.. “Corrigendum: The generalized second law implies a quantum singularity theorem.” Classical and Quantum Gravity 30 (2010): 199501.

10. Oppy, Graham Robert (2006). Arguing About Gods. New York: Cambridge University Press. pg. 137-155

11. Cosmic Skepticism and the Beginning of Physical Reality. Purdue University Graduate School. Thesis. pg. 161-162

12. https://www.academia.edu/110766164/Opening_Statements_and_Questions_Linford_v_Loke_Debate_

The debate is kinda hard to follow. As far as I can tell, Loke wasn’t that interested in challenging Linford’s thesis that science is inconclusive since his Modus Tollens argument would necessitate a first cause either way. So, I don’t know why it was marketed as a debate on the science. Loke interpreted the science in terms of his a priori arguments, so it seems to me that the scientific argument is not independent of the a priori arguments.

13. Sobel, Jordan Howard (2003). Logic and Theism: Arguments for and Against Beliefs in God. New York: Cambridge University Press. Edited by Jordan Howard Sobel. 198

14. For an overview, see Linford, Daniel J (2022). Cosmic Skepticism and the Beginning of Physical Reality. Purdue University Graduate School. Thesis. Section 5.3 https://doi.org/10.25394/PGS.20081270.v1