The big bang has been the standard cosmology for a half-century. The model posits that the universe suddenly appeared 13.8 billion years ago in a very dense, hot state that expanded and cooled into the universe we see today. This concept stands in stark contrast to the thinking that had dominated Western thought for more than two millennia. From the time of the ancient Greeks, most scientists thought the universe was eternal. If the universe had no beginning, the tricky question of the universe’s origin is entirely avoided. However, this contradicts the clear teaching of Scripture, for Genesis begins with “In the beginning . . . ” indicating that the universe truly had a beginning in the finite past. It’s interesting that great men of science who were influenced by biblical principles, such as Sir Isaac Newton, failed to correct this idea. Compounding this problem, the eternality of the universe prompted Newton to conclude that the universe was infinite in size as well. The eternality of the universe was so deeply engrained that the big bang model encountered much resistance after its proposal in the early and mid-20th century. However, most opposition evaporated soon after the discovery of the cosmic microwave background (CMB) in 1965.
In the aftermath of the discovery of the CMB, scientists began to grapple with possible theistic implications of the big bang model. Notable were the conclusions of the astronomer Robert Jastrow, who wrote most extensively about his thoughts on the topic in his 1978 book God and the Astronomers. Jastrow fully accepted the big bang as the proper understanding of the history of the universe. But he also reasoned that while science could explain the development of the universe since the big bang, it could not explain the big bang itself. That is, if there were no natural forces that could create the universe, then there must have been what most people would call supernatural forces at work. While Jastrow was an agnostic, he found it fascinating that modern science had begrudgingly come into agreement with the Bible that the universe had a beginning. Many contemporary Christian apologists go beyond Jastrow and argue that the big bang model is in agreement with the Biblical account of creation, and furthermore that the big bang shows that God must exist. But can one use the big bang to prove God’s existence?
One of the major proponents of using the big bang to prove God’s existence is the Christian philosopher William Lane Craig. Craig uses his updating of the kalām cosmological argument from medieval Islamic philosophy, which in turn was a variation of Aristotle’s argument for a prime mover. I will simplify the argument here. Let A be an agent that directly results in some event B. Then logically one can say that A causes B. We generally call A the cause, and we call B its effect. All effects in turn become causes of new effects, and those effects in turn become causes of even more effects, and so forth. At any time, there are countless chains of cause and effect that are parallel and intertwined with one another. This is working forward in time. However, we can work backward in time too. An effect has a preceding cause. And each cause in turn is the effect of yet an earlier cause. However, if the universe had a beginning, then there must have been an original cause that was not the effect of some earlier cause. Logicians and philosophers have called this the “uncaused cause” from which all other chains of cause and effect descended. Aristotle called this uncaused cause the prime mover. Medieval philosophers generally identified this uncaused cause as God, something that Craig attempts to replicate, but in a more sophisticated and modern manner by using the big bang.
Because of the persistent belief in an eternal universe in the West, this sort of argument for God’s existence fell out of use since the Middle Ages. In an eternal universe, there would be no need of an uncaused cause, because cause and effect would have been operating over all time. This avoidance of an uncaused cause may have been the appeal that the eternal universe had in Western thought. However, once the big bang model became widely accepted in the second half of the 20th century, it removed this objection to theism, thus preparing the way for a return to the causality argument for God’s existence.
The big bang is a poor choice for the name of the standard cosmology, for it suggests to most people that the universe began in an explosion. When properly understood, the big bang model is not an explosion of matter and energy into space and time. Rather, the big bang was the sudden appearance of matter and energy, but also of space and time. That is, space and time came into existence along with matter and energy in the big bang, so space and time did not exist prior to the big bang. Since according to the big bang model, time began with the big bang, then the big bang was the first event in time. Therefore, the big bang had no antecedent.
If A causes B, then B cannot occur before A, for no effect can precede its cause in time. It is also doubtful that an effect and its cause can occur simultaneously—to my knowledge, no one has ever provided an example of a simultaneous cause and effect. This fact is so important to what follows that it bears repeating: a cause must precede its effect in time. Craig’s approach is to argue that if B is the big bang, then the only cause, A, available is God, because nothing physical can precede the big bang. But this reveals a fundamental lack of understanding Craig has of the big bang model or causality or both. Since there was no time prior to the big bang, there was no preceding time for a cause to operate. Therefore, the big bang, as it is formulated today, amounts to an uncaused cause. Craig must have time prior to the big bang to make his causality argument work, so after he supposedly uses science to show the universe began with the big bang, he then cleverly abandons that model and substitutes the common misconception of the big bang model. If one properly states and uses the big bang model, one cannot logically argue from causality that God must have created the big bang. The causality argument is restricted to use within time, and it is an unwarranted extrapolation to apply causality across the barrier of time.
Because this flaw in Craig’s reasoning is so obvious, I once raised this issue during the Q&A after a presentation he gave. I asked Craig if he could give an example of a cause that did not precede its effect in time. Craig made an analogy to a soft cushion lying under a heavy weight, such as a bowling ball. Craig asked whether one could say the weight caused the depression or the weight and the depression occur simultaneously. I answered that physics clearly tells us that indeed the weight caused the depression in the pillow. Craig agreed that is true in a finite situation, but he asked if it would be warranted in a situation where the weight and pillow were eternally existent. The irony of his analogy appeared to escape Craig. He had just spent an hour arguing that the big bang proved the universe had a beginning and hence was not eternal, yet when I pointed out the flaw of his argument, Craig appealed to an eternal situation, a situation that is irrelevant in a universe that has a finite age.
Some Christians, wishing to salvage a causality argument for God’s existence vis-à-vis the big bang, sometimes respond that God is transcendent of time, and thus operates outside of time. Therefore, they conclude, God still was the causative agent of the big bang. It’s true that God transcends time. It also is true, from a biblical viewpoint, that God created, and hence caused, the universe. However, as it is usually pursued, the causality argument for God’s existence is made apart from Scripture. The same criticism applies here—you cannot apply the causality argument across the barrier of time.
The use of the big bang to prove God’s existence requires the use of the causality principle. However, a cause must precede its effect. If the universe, via a big bang, is the effect, then its cause, God, must precede the big bang in time. The correct view of the big bang model is one in which time began with the big bang. The big bang had no antecedent. Therefore, the use of the causality argument across the boundary of time at the beginning of the universe is an unwarranted extrapolation. This does not argue against God’s existence—it merely means that we can conclude nothing about his existence with this kind of argument. Furthermore, the atheist or agnostic could just as well conclude that the big bang is the uncaused cause. This conclusion is more economic in that the theist using the big bang apologetically must invoke two uncaused causes, the big bang and a Deity.