Multiverse Musings

I'm may be a little late to this party, but Dr Stephen Barr has an article on First Things about multiverses and the LHC. It is a sort of follow-up to an older article of his, both of which were recently linked by Michael Flynn. In the article in question, Dr Barr discusses the likelihood that we live in a multiverse, and comes down in favor pf the idea.

I found this interesting, because I was under the impression that the people who largely favor the idea of a multiverse are those who do so for the ideological grounds of getting around fine-tuning arguments for theism. As an argument for atheism (of sorts)--this is largely the context that I have encountered the multiverse in, aside from Star Trek (but I repeat myself). Oddly enough, of the four authors of the paper which Dr Barr references (and is a co-author of), two are Catholics and one is an atheist.

Another musing on the same subject: the multiverse might (or might not) serve as an argument against a theistic basis for fine-tuning. Sure, it provides a multitude of universes, perhaps even infinitely many. But infinitely many does not mean "every possible combination," and we could indeed have infinitely many universes in which everything is nearly fine-tuned for life on earth: or even infinitely many in which all of the parameters relevant to the creation/evolution of life on earth are still so-tuned.


I also agree with Ye Olde Statistician (TOF)'s remark that physicists do themselves a disservice when referring to connected localities as universes. While I understand Dr Barr's exchange with commenter Boonton about two interpretations of the multiverse and the difference between the multiverse and many worlds, the change in the word's definition without any real fanfare does lead to confusion, and not just for amateurs.  Universe, cosmos: these two things have generally been used to mean "everything there is" (or at the least, "everything there is in the natural order" in the case of the universe). Thus, saying that the multiverse consists of a multitude of universes tends to make the reader think of something akin to the mirror universe in Star Trek, even though many physicists merely mean a realm of connected space-time and matter in which the various physical constants are, well, constant. It also gets the physicists into trouble when they attempt to comment on philosophical matters (which tend to use more traditional definitions like "the universe is defined as everything which exists in the natural order").


Finally, it occurs to me that regardless of whether there are infinitely many "universes" in the multiverse, none of St Thomas Five Ways are encessarily refuted. Indeed, the Fourth and Fifth way in particular might plausibly be said to be strengthened by the exist of many universes--and that's true whether we mean universes in the sense used by Dr Barr and other "cosmologists", or in the science fiction sense of "parallel universes," or in the "many worlds" interpretation of quantum mechanics (to say nothing of philosophy).