Big Bang Cosmology and Atheism

Why the Big Bang is No Help to Theists

Quentin Smith

Published on February 13, 2007 

Since the mid-1960s, scientifically informed theists have been ecstatic because of Big Bang cosmology. Theists believe that the best scientific evidence that God exists is the evidence that the universe began to exist in an explosion about 15 billion years ago, an explosion called the Big Bang. Theists think it obvious that the universe could not have begun to exist uncaused. They argue that the most reasonable hypothesis is that the cause of the universe is God. This theory hinges on the assumption that it is obviously true that whatever begins to exist has a cause.

The most recent statement of this theist theory is in William Lane Craig's 1994 book Reasonable Faith.[1] In it Craig states his argument like this:

  1. Whatever begins to exist has a cause.

  2. The universe began to exist.

  3. Therefore, the universe has a cause.[2]

In a very interesting quote from this book he discusses the first premise and mentions me as one of the perverse atheists who deny the obviousness of this assumption:

The first step is so intuitively obvious that I think scarcely anyone could sincerely believe it to be false. I therefore think it somewhat unwise to argue in favor of it, for any proof of the principle is likely to be less obvious than the principle itself. And as Aristotle remarked, one ought not to try to prove the obvious via the less obvious. The old axiom that "out of nothing, nothing comes" remains as obvious today as ever. When I first wrote The Kalam Cosmological Argument, I remarked that I found it an attractive feature of this argument that it allows the atheist a way of escape: he can always deny the first premise and assert the universe sprang into existence uncaused out of nothing. I figured that few would take this option, since I believed they would thereby expose themselves as persons interested only in academic refutation of the argument and not in really discovering the truth about the universe. To my surprise, however, atheists seem to be increasingly taking this route. For example, Quentin Smith, commenting that philosophers are too often adversely affected by Heidegger's dread of "the nothing," concludes that "the most reasonable belief is that we came from nothing, by nothing, and for nothing" - a nice ending to a sort of Gettysburg address of atheism, perhaps.[3]

A Baseless Assumption

I'm going to criticize this argument from scientific cosmology, which is the most popular argument that scientifically informed theists and philosophers are now using to argue that God exists.

Let's consider the first premise of the argument, that whatever has a beginning to its existence must have a cause. What reason is there to believe this causal principle is true? It's not self-evident; something is self-evident if and only if everyone who understands it automatically believes it. But many people, including leading theists such as Richard Swinburne, understand this principle very well but think it is false. Many philosophers, scientists, and indeed the majority of graduate and undergraduate students I've had in my classes think this principle is false. This principle is not self-evident, nor can this principle be deduced from any self-evident proposition. Therefore, there's no reason to think it's true. It is either false or it has the status of a statement that we do not know is true or false. At the very least, it is clear that we do not know that it is true.

Now suppose the theist retreats to a weaker version of this principle and says, "Whatever has a beginning to its existence has a cause." Now, this does not say that whatever has a beginning to its existence must have a cause; it allows that it is possible that some things begin to exist without a cause. So we don't need to consider it as a self-evident, necessary truth. Rather, according to the theists, we can consider it to be an empirical generalization based on observation.

But there is a decisive problem with this line of thinking. There is absolutely no evidence that it is true. All of the observations we have are of changes in things - of something changing from one state to another. Things move, come to a rest, get larger, get smaller, combine with other things, divide in half, and so on. But we have no observation of things coming into existence. For example, we have no observations of people coming into existence. Here again, you merely have a change of things. An egg cell and a sperm cell change their state by combining. The combination divides, enlarges, and eventually evolves into an adult human being. Therefore, I conclude that we have no evidence at all that the empirical version of Craig's statement, "Whatever begins to exist has a `cause'," is true. All of the causes we are aware of are changes in pre-existing materials. In Craig's and other theists' causal principle, "cause" means something entirely different: it means creating material from nothingness. It is pure speculation that such a strange sort of causation is even possible, let alone even supported in our observations in our daily lives.

An Uncaused Universe

But the more important point is this: not only is there no evidence for the theist's causal assumption, there's evidence against it. The claim that the beginning of our universe has a cause conflicts with current scientific theory. The scientific theory is called the Wave Function of the Universe. It has been developed in the past 15 years or so by Stephen Hawking, Alex Vilenkin, Andre Linde, and many others. Their theory is that there is a scientific law of nature called the Wave Function of the Universe that implies that it is highly probable that a universe with our characteristics will come into existence without a cause. Hawking's theory is based on assigning numbers to all possible universes. All of the numbers cancel out except for a universe with features that our universe possesses, such as containing intelligent organisms. This remaining universe has a very high probability - near 100% - of coming into existence uncaused.

Hawking's theory is confirmed by observational evidence. The theory predicts that our universe has evenly distributed matter on a large scale - that is, on the level of super-clusters of galaxies. It predicts that the expansion rate of our universe - our universe has been expanding ever since the Big Bang - would be almost exactly between the rate of the universe expanding forever and the rate where it expands and then collapses. It also predicts the very early area of rapid expansion near the beginning of the universe called "inflation." Hawking's theory exactly predicted what the COBE satellite discovered about the irregularities of the background radiation in the universe.[4]

So scientific theory that is confirmed by observational evidence tells us that the universe began without being caused. If you want to be a rational person and accept the results of rational inquiry into nature, then you must accept the fact that God did not cause the universe to exist. The universe exists uncaused, in accordance with the Wave Function law.

Now Stephen Hawking's theory dissolves any worries about how the universe could begin to exist uncaused. He supposes that there is a timeless space, a four-dimensional hypersphere, near the beginning of the universe. It is smaller than the nucleus of an atom. It is smaller than 10 centimeters in radius. Since it was timeless, it no more needs a cause than the timeless god of theism. This timeless hypersphere is connected to our expanding universe. Our universe begins smaller than an atom and explodes in a Big Bang, and here we are today in a universe that is still expanding.

Is it nonetheless possible that God could have caused this universe? No. For the Wave Function of the Universe implies that there is a 95% probability that the universe came into existence uncaused. If God created the universe, he would contradict this scientific law in two ways. First, the scientific law says that the universe would come into existence because of its natural, mathematical properties, not because of any supernatural forces. Second, the scientific law says that the probability is only 95% that the universe would come into existence. But if God created the universe, the probability would be 100% that it would come into existence because God is allpowerful. If God wills the universe to come into existence, his will is guaranteed to be 100% effective.

So contemporary scientific cosmology is not only not supported by any theistic theory, it is actually logically inconsistent with theism.


  1. William Lane Craig, Reasonable Faith (Wheaton, Ill.: Crossway, 1994)
  2. Ibid., p. 92
  3. Ibid.
  4. Confirmation of Hawking's theory is consistent with this theory being a reasonable proposal for the form that an (as yet) undeveloped theory of quantum gravity will take, as Hawking himself emphasizes. See Chapter 12, William Lane Craig and Quentin Smith, Theism, Atheism, and Big Bang Cosmology (Oxford: Clarendon Press, 1993).

Quentin Smith is Professor of Philosophy at Western Michigan University.  The above article is from Free Inquiry magazine, Volume 18, Number 2.