This is the weekly Q & A blog post by our Research Professor in Philosophy, Dr. William Lane Craig.
Hello Dr. Craig. I'm an agnostic atheist, and currently studying as an undergraduate in CS, so I do deal with logic quite a lot. I find your debates interesting, because you almost always have your opponents on the edge, such as in the Hitchens debate, apart from the few occasions; such as the debate with Sean Carroll. Sean did a great job in that debate.
Well my first question is, are you still going to use the BGV theorem for evidence of the beginning of the universe? Because Carroll seemed to completely debunk the claim this proves a beginning. As he stated: The BGV theorem proves our current physics breaks down at a certain point, not that the universe began. Sure, some past eternal models have problems, but not all. Even if all of them failed, that is only evidence our models are not good enough, not that there was a beginning. Even if a beginning was proven, it's probably not a type of beginning you would need in order to show god would be needed to create the universe. While I agree, something cannot come from nothing, that is quite absurd, if you have laws of physics that exist before (before is probably the wrong word) the universe, its not surprising to get a universe since because of the laws of gravity and quantum physics, a vacuum is generated due to quantum laws, and thus eventually a universe.
Even Hawking isn't claiming the universe came from nothing with M-theory, because he still thinks there was laws which were in place prior to the universe in a sort of platonic state. Aren't numbers considered spaceless, timeless, and immaterial? So even if we followed your logic, the conclusion could still be there are physical laws which are spaceless, timeless and immaterial which tell us there needs to be a universe, and these laws are necessary, like 2 + 2 = 4. So it seems to me, a beginning of the universe isn't threatening to atheism at all, and neither is the kalam argument. Well, it wouldn't be the mathematics 'causing' the universe to come into being, but these physical laws 'allow' a universe to come into being.
You say that something cannot come into existence uncaused, well, this just seems to be a metaphysical assumption, which you probably have a good defense for. Sure, things don't pop into existence without a cause within our experience, but we're talking about a macro level. On a micro level, our common intuitions seem to be false. I don't want to open that quantum can of worms, but anyway... So why think macro level causation is appropriate language to use in an extremely small state of the universe, where our intuitions are likely to be false? Just as our intuitions about time are false on the very large scale (relativity). You say: "Well, if things can come into existence uncaused, why doesn't anything and everything come into existence uncaused out of nothing?", you often call out Krauss on false equivocating nothing with the vacuum, but here you false equivocate nothing with the vacuum. Regardless, it seems appropriate to point out our universe follows 'laws of physics', such as the conservation of energy. So within our universe, entire objects can't come into being uncaused. So it seems to me saying something can come into being without a cause only violates the laws we know within the universe.
Dr. William Lane Craig’s Response
Thanks so much for your question, Matt! I never tire of talking about the origin of the universe! I agree with you that Sean Carroll did an excellent job and therefore think that our debate was one of the best I’ve had, right up there with the Doug Jesseph and Austin Dacey debates. In fact, to really absorb it, you have to study the transcript, not just watch the debate.
When you do, I think you’ll find that many of your questions have already been addressed. For example, you’ll find that my opening argument was formulated precisely in such a way as to be immune to Carroll’s anticipated criticism that the Borde-Guth-Vilenkin theorem concerns classical spacetime and so does not take quantum physics into account. Here is the outline of my case:
1.0 Evidence from Expansion of the Universe
1.1 Classical spacetime began to exist
1.11 Borde Guth Vilenkin theorem
1.12 Carroll’s model ruled out on other grounds
1.2 Quantum Gravity era began to exist
1.21 If such a state did not begin to exist, it would produce our classical spacetime either from eternity or not at all. So if such an era exists, it is the beginning of the universe.
2.0 Evidence from Thermodynamics
2.1 Universe began to exist in a low entropy condition
2.11 Carroll’s Model
2.111 Carroll’s model violates unitarity of quantum physics
2.112 Carroll’s model doesn’t solve Boltzmann Brain problem
2.2 Quantum Gravity era began to exist
2.21 Wall theorem holds for Quantum Gravity era and requires a beginning. One can avoid it only by having a reversal of time’s arrow, which implies a thermodynamic beginning of time and the universe.
As you can see, in both cases I argued first for the beginning of classical spacetime and then for a beginning of any hypothetical quantum gravity era. Thus, my use of the BGV theorem was impeccable. That theorem proves that any classical spacetime which has, on average, been expanding over the course of its history cannot be past-eternal but must terminate in a spacetime boundary. That boundary need not be singular; hence, it’s just mistaken to say that the theorem predicts a breakdown of physics’ laws. In the Hartle-Hawking model which you mention, for example, there is no breakdown of the laws nor a singular beginning, but there is a beginning nonetheless, and the universe is finite to the past. It thus is in line with the theorem.
So the controversial steps in the argument are not, or ought not to be, (1.1) or (2.1), but rather (1.2) and (2.2). Carroll had little to say on those matters and later admitted that he hadn’t even heard of Aron Wall’s theorem.
Carroll rather surprised me by insisting that we ought to base our conclusions, not on theorems, but on models. For if we do that, then the case for the universe’s beginning becomes almost overwhelming. After surveying the field of models, including Carroll’s own model, Vilenkin says, “For all we know, there are no models at this time that provide a satisfactory model for a universe without a beginning.” Models with a beginning fit the evidence; models without a beginning do not.
Matt, please look honestly at how closed-minded you are about following the evidence where it points. With respect to past-eternal models, you say, “Even if all of them failed, that is only evidence our models are not good enough, not that there was a beginning.” Really? Why not? You say the models are not good enough. Not good enough for what? Not good enough to explain the evidence for a beginning! Recall Sean Carroll’s words,
science judges the merits of competing models in terms of their simplicity, clarity, comprehensiveness, and fit to the data. Unsuccessful theories are never disproven, as we can always concoct elaborate schemes to save the phenomena; they just fade away as better theories gain acceptance.
This paragraph needs be thoroughly absorbed. Sure, Matt, proponents of an eternal universe can keep concocting elaborate schemes to try to avoid the evidence of a beginning; but given the presence of better theories, i.e., successful models of the universe with a beginning, their hopes are fading.
Your lack of open-mindedness is further on display when you then say, “Even if a beginning was proven, it's probably not a type of beginning you would need in order to show god would be needed to create the universe.” Never mind that the argument doesn’t conclude to God but to a transcendent cause. The beginning of spacetime and its contents most certainly is the sort of beginning that carries huge metaphysical implications, as I have argued, since it is an absolute, and not merely a relative, beginning.
Your appeal to the laws of nature to explain the beginning of the spacetime universe is misconceived, for the laws of physics (as opposed to the physical states they describe) are just mathematical equations or propositions, which are abstract entities which do not stand in causal relations. (Indeed, this is one of my three arguments for the personhood of the transcendent cause reached in the argument’s conclusion.) Contrary to your claim, the laws of physics do not generate or cause anything.
You seem at the end to realize your misstep, for you add, “Well, it wouldn't be the mathematics 'causing' the universe to come into being, but these physical laws 'allow' a universe to come into being.” Ah, “allowing” is far too weak a relation to explain why the universe began to exist! Lots of things are nomologically possible (allowed by the laws of nature) but not actual. To explain why some state of affairs is actual, you have to do a lot more than show that it’s possible.
(A side note: look how willing you, as a supposed agnostic, are to embrace the reality of spaceless, timeless, immaterial, causally irrelevant, abstract objects like numbers and laws, for which I’d say we have no good evidence at all, but how unwilling you are to countenance God the Creator. Doesn’t that give you pause?)
As for the causal principle, yes, I think I have good reasons for thinking it more likely true than false. I’m baffled by the claim that causality holds on the macro-level but not on the micro-level. So things can pop into being from nothing just so long as they’re little, teeny-weeny things and not big things? Really? Does size (which is relative, after all) really have anything to do with the metaphysical possibility of being arising spontaneously from non-being? Don’t open the quantum can of worms because we’re not talking here about physical states like the vacuum, but about being coming from non-being.
This relates to my point that if anything can come into being from nothing, then anything and everything can come into being from nothing, since there are no constraints on such becoming—it’s uncaused, after all! There’s no equivocation here, Matt (see QoW #368 on A. N. Prior’s argument). I’m talking about something’s arising spontaneously from non-being.
Your final comments on the laws of conservation and energy are confusing. You seem to think that these laws somehow prevent big objects, as opposed to little objects, from popping into being without a cause; and yet you seem to think that those laws are not necessary but happen to apply to our universe. Now if big things were to pop into being without causes, then the conservation laws would be violated. So why aren’t they being violated all the time, if it is metaphysically possible for things to come into being without a cause? Remember the laws are causally impotent; they can’t constrain anything. They just describe (or fail to describe) the way physical reality is. You seem to admit that fact in saying that they hold contingently in our universe. But why, then, do they hold if it is metaphysically possible for things to arise spontaneously from nothing?
Anyway, I’ve appreciated the stimulus of interacting with your questions and wish you the best for your further studies.
This post and other resources are available on Dr. William Lane Craig's website: www.reasonablefaith.org
 As noted in (1.12) models like Carroll’s which do not meet that one condition are ruled out on other grounds.
 Alexander Vilenkin, “Did the Universe Have a Beginning?” http://www.youtube.com/watch?v=NXCQelhKJ7A. For a nice survey, see James Sinclair’s contribution to “The Kalam Cosmological Argument” in The Blackwell Companion to Natural Theology, ed. Wm. L. Craig and J. P. Moreland (Oxford: Wiley-Blackwell, 2009), pp. 101-201.
 Sean Carroll, “Does the Universe Need God?” in The Blackwell Companion to Science and Christianity, ed. J. B. Stump and Alan G. Padgett (Oxford: Wiley-Blackwell, 2012), p. 196.
 See Reasonable Faith, 3rd ed. (Wheaton, Ill.: Crossway Books, 2008), p. 153.