I will comment on the article from the ex-apologist, noting first that we must distinguish between physical explanations, i.e. according to natural science, and metaphysical explanations. The explanations that Scott referred to in his previous comments are metaphysical explanations.
With that in mind, let's quote from the article:
"Two questions that contingency arguments aim to answer are:
Contingent Particularity: Why does this particular universe exist (with its particular set of particles, history, laws of nature, etc.), and not some other?
Contingent Existence: Why does the universe exist at all, rather than just nothing?"
First of all, the metaphysical argument from contingency is all about contingent existence, not contingent particularity. So from a metaphysical viewpoint you can just ignore the article's "objection 1" and "objection 2", which deal with contingent particularity. From a physical viewpoint, it might be worth to point out that the multiverse is currently just an unfalsifiable conjecture and not a solid theory. If you care to know the views of a multiverse-skeptic (and also string theory-skeptic) atheist scientist, have a look at this blog.
Turning now to the objection that deals with contingent existence, his argument is:
"For we have good scientific theories that entail that the universe could've had different laws and/or constants, whereas we have no comparable evidence-sensitive theory to support our modal intuitions about the possible non-existence of all matter-energy. At best, our modal intuitions about the possible non-existence of all matter-energy are on a par with our modal intuitions about the possible non-existence of God."
He wholly misses the point. There's no need for any "evidence-sensitive theory to support our modal intuitions about the possible non-existence of all matter-energy", i.e. of the universe. Moreover, it is quite clear that there cannot possibly be any such "evidence-sensitive theory"! The whole point is that the universe, and even a hypothetical multiverse, is contingent. Therefore, with "universe" in a broad sense, i.e. including a hypothetical multiverse, we have the following possible cases, listed along with their facticity regarding physical evidence and their rational explainability:
a. Universe, God: possibly factual, rationally explainable.
b. Universe, no God: possibly factual, not rationally explainable.
c. No universe, God: not factual, rationally explainable (only by God, since only He exists in this case).
d. No universe, no God: not factual, rationally explainable (actually by nobody, since nothing exists in this case).
Last edited by Johannes (8/08/2015 2:30 pm)