The First Split Second of the Universe

Reasonable Faith

Using a segment of a Sean Carroll interview. Dr. Craig discusses the beginning of the universe, certainty, and science.

Kevin Harris: Welcome to Reasonable Faith with Dr. William Lane Craig. I’m Kevin Harris. Just having a little fun with an interview between Robert Kuhn and Sean Carroll. Dr. Carroll does answer the question in this interview in a rather interesting way. We’ll talk about it with Dr. Craig. We appreciate Sean Carroll’s work in cosmology and astrophysics. We have several podcasts on him including the debate with Dr. Craig. So check out our archives at In the meantime, let’s go to the studio with Dr. Craig.

Dr. Craig, you’ve had an opportunity to be on the TV program Closer to Truth with Robert Kuhn. A lot of good people on that.

Dr. Craig: Yes, indeed. Very eminent cosmologists and philosophers are on that program.

Kevin Harris: He interviewed Sean Carroll as well. We wanted to interact with various portions of that. It is a long interview, but we looked at a few things of interest. Robert Kuhn really pressed Sean on “Did the universe have a beginning.” Carroll’s answer was, We don’t know.

Dr. Craig: Right. He says we don’t know if the universe had a beginning. His skepticism is based upon the fact that we don’t have a quantum theory of gravity yet to describe the earliest split second of the existence of the universe. The hope here, I think on his part, is that such a theory of gravity might enable us to save the past eternality of the universe. All the evidence that we do have points to a beginning of the universe, but the hope is that if you can find this quantum theory of gravity then that might serve to avert it.

I think that there is an epistemological issue that is in play here when he says, We don’t know. When he uses the word “know” he is using this in a very strong sense to say we are not scientifically certain. But that does nothing to negate the fact that the evidence makes it highly probable that the universe did have a beginning. You don’t need to have certainty about something in order to say where the evidence points and which conclusion is probably true. Even Lawrence Krauss, you may remember in our dialogues in Australia, said that if he had to decide he said the universe probably did begin to exist, even given quantum theories of gravity. So our uncertainty about how to describe the first split second of the origin of the universe doesn’t necessarily negate the fact that the universe is finite in the past. I think even if we don’t know that with certainty, nevertheless we have good reason to think that the universe is finite in the past even given a quantum theory of gravity.

Alex Vilenkin, who is a very prominent cosmologist at Tufts University, in 2012 gave a lecture at a conference for Stephen Hawking’s 70th birthday in Cambridge University where he surveys all of the attempts to avoid the beginning of the universe which the evidence seems to predict. What he shows is that none of these scenarios is able to actually avoid the beginning of the universe…


The First Split Second of the Universe | Reasonable Faith