The Science of Kalam: The Big Bang

The Kalam Cosmological Argument for the Existence of God has had amazing success over the past few decades. In religious apologetic books, professional debates concerning the existence of God, and even among informal arguments, you will likely hear the famous syllogism:

P1. Everything that begins to exist has a cause
P2. The universe began to exist
C. The universe had a cause

It’s not hard to see why this argument has gotten so much traction since William Lane Craig popularized it in the late 1970s. In the age of science, where skeptics demand things like physical evidence, the religious apologists’ arsenal of philosophical arguments have become unappealing to many. Kalam, on the other hand, stakes its roots in the science of cosmology. William Lane Craig, during his debate with Christopher Hitchens in 2009, drove this point home: “In one of the most startling developments of modern science, we now have pretty strong evidence that the universe is not eternal in the past but had an absolute beginning about thirteen billion years ago in a cataclysmic event known as the Big Bang. What makes the big bang so startling is that it represents the origin of the universe from literally nothing, for all matter and energy, even physical space and time themselves, came into existence at the Big Bang.”

It turns out this “absolute beginning” from “literally nothing” is very important to the Kalam argument. If according to modern cosmology the universe came from nothing physical (after all, science can only speak for physical reality), then it allows for the possibility of a non-physical cause which Craig thinks of as his God. In his Christian apologetics book Reasonable Faith, Craig puts it like this: “For as the cause of space and time, this entity must transcend space and time and therefore exist atemporally and non-spatially … This transcendent cause must therefore be changeless and immaterial … Such a cause must be beginningless and uncaused … This entity must be unimaginably powerful, since it created the universe without any material cause” (Pg. 152). And so on.

But does modern physics and cosmology really support the Kalam Cosmological Argument? In this post, I’m taking a look at Craig’s scientific justification of the second premise of the Kalam argument: “the universe began to exist.”

It’s probably a good idea to precisely define what we mean by “universe,” as this seems to often be a point of unnecessary confusion.  In his latest book, The Hidden Reality, Brian Greene writes, “There was once a time when ‘universe’ meant ‘all there is.’ Everything. The whole shebang. The notion of more than one universe, more than one everything, would seemingly be a contradiction in terms. Yet a range of theoretical developments has gradually qualified the interpretation of ‘universe.’ The word’s meaning now depends on context. Sometimes ‘universe’ still connotes absolutely everything. Sometimes it refers only to those parts of everything that someone such as you or I could, in principle, have access to. Sometimes it’s applied to separate realms, ones that are partly or fully, temporarily or permanently, inaccessible to us; in this sense, the word relegates our universe to membership in a large, perhaps infinitely large, collection.” (Pg. 4).

So, how does Craig define the word? According to his website, he defines the universe as “the whole of material reality.” And with this definition in place, we can take another look at the argument:

P1. Everything that begins to exist has a cause
P2. The whole of material reality began to exist
C. The whole of material reality had a cause

Looking at the argument this way, it doesn’t seem nearly as intuitive. After all, if it’s the Big Bang that Craig uses to scientifically justify the second premise, how does he know that what we view in the sky encompasses the whole of physical reality? In short, he doesn’t; it’s an added assumption. However, because all such proposals of universes outside our own are speculative at this point, we will bite the bullet and assume that our universe is the only one. In doing so, we can easily examine the question, does the Big Bang theory show that our universe (i.e. all of physical reality) began to exist from nothing? Well, maybe we can start with a simpler question: what is the Big Bang theory?

To understand the Big Bang theory, you must first accept two facts. #1: The universe is expanding. Like dots printed on an inflating balloon, galaxies (or rather local groups of galaxies) are all moving away from each other. #2: The universe was once much more dense and hot than it is today. Everything the universe contains was smushed together in a situation hotter than you can imagine. These two facts are known through observation – the former through galactic spectroscopy, the latter through the probing of the Cosmic Microwave Background Radiation – and, as far as I can tell, no serious cosmologist disputes them. These facts lead, of course, to the conclusion that the universe expanded from a hot dense state. Over time the universe cooled, matter coalesced, and eventually formed the universe we now observe. This is the Big Bang theory in a nutshell.

Take note that I never used the phrase, “began to exist from literally nothing.” Though my explanation was very simplified, I made no mention of an “absolute beginning” because the theory does not include any such absolute beginning. As physicist Alan Guth explains, “Despite its name, the big bang theory is not really a theory of a bang at all. It is really only a theory of the aftermath of a bang. … But the standard big bang theory says nothing about what banged, why it banged, or what happened before it banged.” (The Inflationary Universe, Pg. xiii) Physicist Brian Greene echos the same sentiment: “In the standard big bang theory, the observable universe was ever-smaller at ever-earlier times, but the stupendous quantities of matter and energy we now measure were always present; they were just squeezed into an ever smaller volume. … The big bang theory takes such raw material as an unexplained given.”  (The Hidden Reality, Pg. 275)

To anybody who is familiar with Craig’s debates, these two quotes might be a bit shocking. After all, you can often hear Craig saying the following at the end of his summary of the Big Bang theory: “Therefore, as the Cambridge astronomer Fred Hoyle points out, the Big Bang Theory requires the creation of the universe from nothing. This is because if you go back in time, you reach a point, at which, in Hoyle’s words, ‘the universe was shrunk down to nothing at all.’” But anybody who does a little digging will see that such quotes are almost always misleading. The aforementioned quote, for example, was cherry-picked from a 1975 textbook in which Fred Hoyle was simply discussing the scale of the universe when extrapolate backwards in time. The matter in the universe never “disappears” in this manner, and Hoyle never claims that it does.

To get to a universe that has an “absolute beginning” from “literally nothing,” it is necessary to appeal to something outside the standard Big Bang model. Namely, singularity theorems. Though Craig hardly makes this clear in his popular work, he certainly understands how singularity theorems are important to his argument when doing more scholarly work. So, it is these singularities which we will discuss next time.

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Tagged as: Alan Guth, Big Bang Cosmology, Brian Greene, cosmogony, Fred Hoyle, Kalam Cosmological Argument, Reasonable Faith, William Lane Craig