In his opening remarks that I discussed yesterday, William Lane Craig made the standard opening move within the college debate framework for those speaking first and arguing the affirmative by framing the question in the most minimal way, thus making it harder to counter. He said that all he was seeking to show was that modern cosmology provided “significant evidence in support of premises in philosophical arguments for conclusions having theological significance”.

In his opening, Sean Carroll made a non-standard move for a respondent by ignoring Craig’s framing and reframing the debate as to whether naturalism or theism is the better way of understanding the universe. In a college debate contest, this would have been a dicey move with judges looking askance. But here Carroll did not have to worry about being judged by a panel using a debate-scoring rubric. Here he was trying to persuade a general audience and for them these debates, however they are worded or framed, are always about naturalism versus theism, so Carroll only risked annoying Craig with this gambit.

So Carroll began by saying that he was going to show that naturalism is superior to theism in understanding the universe. He pointed out that at cosmology conferences no one takes god seriously as a proposition to be included in understanding the universe. He said that naturalism is preferable to theism because:

1. Naturalism works
2. The evidence is against theism
3. Theism is not well-defined

He immediately challenged the first Kalam premise (that if the universe began to exist, then there is a transcendent cause which brought the universe into existence) that Craig said was so obvious as to not need any argument in support. Carroll invoked Wolfgang Pauli’s famous dismissal of a paper by saying “It is not even wrong”. He said the first Kalam premise is worse than false because it is not even the kind of question that should be asked or the vocabulary that should be used, and that the kind of causal reasoning it invokes is dependent on a two-thousand year old form of metaphysical thinking that is no longer valid.

What modern science deals with are not transcendent causes but differential equations that reflect patterns, models, unbreakable rules, and laws of nature that connect events at one time to events at another. There is no need for any transcendent causes. The real question is what is the best model (i.e., formal mathematical system) of the universe that most closely matches what we observe.

He said that there are many models in which you can have universes that have a beginning but did not have a cause and this has been known for over 30 years. We also have many models of the universe that are ‘past eternal’, i.e., did not have a beginning.

Carroll pointed out that ‘theorems’ in science (like the BGV theorem repeatedly used by Craig) are not ironclad brute facts of nature but are conclusions that depend upon the assumptions that go into them. All that the BGV theorem states is that classical space-time breaks down at some time in the past. But this does not mean that the universe had a beginning because it may mean that it is eternal and that quantum mechanics becomes important.

Also when cosmological models speak of a finite lifetime of the universe, what they mean is that the models they use point towards a moment when t=0 in their equations. But while cosmologists do use locutions like “the universe began to exist” or “popped into existence”, they do not necessarily imply what Craig thinks they do, that there necessarily existed some pre-existing period before t=0 and that the universe came into being at that time.

Carroll granted that the teleological argument is the best argument that religious people have because it plays by the rules and compares two models that can be compared with the data, the theistic one and the naturalistic one. As for the argument about fine-tuning, the real question is why the universe ‘began’ (i.e., at t=0) in a low entropy state. In this way of looking at things, the thermodynamic ‘beginning’ suggested by the Second Law is not a beginning in time but the time at which the entropy of the universe was at a minimum. While we don’t know yet why this is so, we have various possible explanations.

He said that the theistic model fails for five reasons.

1. It is not clear that there is a fine-tuning problem at all because we don’t know a priori what conditions are life-permitting. There may be many values of the fundamental constants that are life-supporting.
2. God does not need to fine-tune anything because he can do anything what he wants. Fine-tuning may be apparent rather than real and the common arguments given by theists that the expansion rate of the universe must be tuned to one part in 10⁶⁰ is simply wrong and the correct derivation shows that the probability is 1. i.e., all the early universe models have the right expansion rate for the universe to exist.
3. The cosmological multiverse is not a theory but a prediction of a concise self-contained theory and allows for many universes being created continuously of which ours is just one. It allows for comparing with data
4. There are plenty of viable models of the universe in which random fluctuations produce ordinary observers and not Boltzmann brains. Different multiverse models make different predictions for the ratio of ordinary observers to random observers. There are plenty of viable multiverse models in which Boltzmann brains or random fluctuations do not dominate. Furthermore a better understanding of quantum fluctuations suggest that Boltzmann brains and random fluctuations occur much less frequently than previously thought.
5. Theism is a terrible theory of the universe. If it is done properly, then theists should be able to say what kind of universe they expect to see under theism and compare with the data. The universe we see has the kind of randomness and messiness that one would expect from naturalism than from any kind of purposeful design. Furthermore, theism would predict that life should be important in the universe while naturalism predicts it should be insignificant, that the presence of god should be obvious while naturalism predicts that god hides, that religious beliefs should be universal while naturalism says that it would reflect local conditions, that religious doctrines should be eternal and unchanging while naturalism says that it should reflect social progress, that moral teachings should be transcendent and progressive (i.e., sexism and slavery should have been always wrong) instead of inconsistent and tribal, that sacred texts should give us useful and interesting information which they do not, that biological forms should be designed rather than the end product of twists and turns of evolutionary history, that minds should be independent of bodies instead of changing with our bodies, should explain the problem of evil and not have random suffering, that the universe should be perfect instead of a mess, and so on. While theists can give explanations for all this, this is because theism is not well defined and so can come up with all manner of ex post facto explanations for what we see.

In reframing the debate in terms of the relative merits of naturalism versus theism in understanding the universe, Carroll wrong-footed Craig because the debate shifted to the merits of cosmological models and Carroll knows far more about this stuff first-hand than Craig, who has to depend on quote-mining of the scientific literature. Furthermore, Carroll is honest and does not make claims that are without merit just to score debating points. So when Carroll says that Craig has misunderstood what various cosmological models say and is wrong, it carries far more weight than Craig’s assertions to the contrary.