New Scientist has a column by Amanda Gefter on the hypothesis that the fine tuning that we find in the universe is either the result of a designer or a multiverse, called Why it is not as simple as God vs the multiverse. The article notes:
"Short of invoking a benevolent creator, many physicists see only one possible explanation," writes journalist Tim Folger. "Our universe may be but one of perhaps infinitely many universes in an inconceivably vast multiverse." Folger quotes cosmologist Bernard Carr: "If you don't want God, you'd better have a multiverse."
There are plenty of reasons to take the multiverse seriously. Three key theories - quantum mechanics, cosmic inflation and string theory - all converge on the idea. But the reason physicists talk about the multiverse as an alternative to God is because it helps explain why the universe is so bio-friendly. From the strength of gravity to the mass of a proton, it's as if the universe were designed just for us. If, however, there are an infinite number of universes - with physical constants that vary from one to the next - our cosy neighbourhood isn't only possible, it's inevitable.
But to suggest that if this theory doesn't pan out our only other option is a supernatural one is to abandon science itself. Not only is it an unfounded leap of logic, it suggests intelligent design offers as valid an explanation as a cosmological theory does, and lends credence to creationists' mistaken claim that the multiverse was invented to serve as science's get-out-of-God-free card. Indeed, Folger's article was immediately referenced on creationist websites, including the Access Research Network, an intelligent-design hub, and Uncommon Descent, the blog of the Seattle-based Discovery Institute's William Dembski.
There is an elephant in the room that she is trying very hard not to see. Multiverse hypotheses are untestable—just like Intelligent Design. This is in a true sense, a Mexican Stand-off. Both sides recognize fine tuning and both sides have untestable hypotheses to explain it. Gefter continues by arguing that it is not an "either-or" problem but that there may be other explanations to the problem. She suggests a third hypothesis—that we create the universe we see. This is a hypothesis that Stephen Hawking has warmed to. He has called this "top-down" cosmology. Same problem. There is simply no way to test this. If we hypothesize that we are influencing what we see, then the very observations are being influenced by our test, whatever that would be. A gentleman by the name of Steven Pederson wrote a masters thesis on this topic called Flawed Nature Cosmology. It is long but it is here. Gefter finishes, remarking about Hawking's ideas:
That's speculative, but at least it's science.
Uh, no its not. Its speculation, based on no evidence whatsoever. Is this where modern astrophysics is going? I hope not, or else they are going to find themselves in creationist territory pretty soon.