I am in the early sections of Theism, Atheism, and Big Bang Cosmology by William Lane Craig and Quentin Smith, but I am beginning to doubt that it will inform my views about cosmology. (These are spelled out with increasing refinement here, here, here, and here.) The book consists of alternating essays by Craig and Smith, in which Craig defends the classical argument for a creation (the Kalām cosmological argument) against Smith’s counter-arguments.
For one thing, Smith — who takes the position that the universe wasn’t created — seems to pin a lot on the belief prevalent at the time of the book’s publication (1993) that the universe was expanding but at a decreasing rate. It is now believed generally among physicists that the universe is expanding at an accelerating rate. I must therefore assess Smith’s argument in light of the current belief.
For another thing, Craig and Smith (in the early going, at least) seem to be bogged down in an arcane argument about the meaning of infinity. Craig takes the position, understandably, that an actual infinity is impossible in the physical world. Smith, of course, takes the opposite position. The problem here is that Craig and Smith argue about what is an empirical (if empirically undecidable) matter by resorting to philosophical and mathematical concepts. The observed and observable facts are on Craig’s side: Nothing is known to have happened in the material universe without an antecedent material cause. Philosophical and mathematical arguments about the nature of infinity seem beside the point.
For a third thing, Craig seems to pin a lot on the Big Bang, while Smith is at pains to deny its significance. Smith seems to claim that the Big Bang wasn’t the beginning of the universe; rather, the universe was present in the singularity from which the Big Bang arose. The singularity might therefore have existed all along.
Craig, on the other hand, sees the hand of God in the Big Bang. The presence of the singularity (the original clump of material “stuff”) had to have been created so that the Big Bang could follow. That’s all well and good, but what was God doing before the Big Bang, that is, in the infinite span of time before 15 billion years ago? (Is it presumptuous of me to ask?) And why should the Big Bang prove God’s existence any more than, say, a universe that came into being at an indeterminate time? The necessity of God (or some kind of creator) arises from the known character of the universe: material effects follow from material causes, which cannot cause themselves. In short, Craig pins too much on the Big Bang, and his argument would collapse if the Big Bang is found to be a figment of observational error.
There’s much more to come, I hope.