An email written on : Monday, September 01, 2008 10:09 PM
Today, I’ve finshed reading the book called "Universe or Multiverse ?", edited by Bernard Carr. It’s a book made up of contributions mainly from a Stanford conference in 2003 as well as 2 similar ones in Cambridge, UK in 2001 and 2005. It’s not really a compilation of scientific papers as the writers have kind of tried to make the articles more accessible for more people by reducing the no. of equations in most articles. But it’s not really a coherently arranged book as there are strong overlaps in topics that the writers have discussed. Sometimes, you read the same thing over and over again though each has a slightly different spin on it. This feature per se is not really bad as you’ve got the opportunity to understand the same thing more than one time ….
The multiverse theories are probably not something that the graduate schools are teaching but the writers do include 2 Nobel Prize winners Steven Weinberg and Frank Wilczek and famous guys such as Stephen Hawking and Lee Smolin et. al. Most writers are kind of pro-multiverse one way or another (including the first three folks that I’ve mentioned).
The 1st instance of serious Multiverse came from the effort to avoid wavefunction collapse in the canonical Copenhagen interpretation of quantum mechanics (QM). But now "multiverse" seems to be used as a way of working together with Anthropic Principle (AP) in cosmology and avoiding a Creator. Multiverse seems necessary in many inflationary models and also "convenient" for the superstring/M theory as the latter may have a lanscape of ~10^100 possible vacuum states/possibilities and multiverse/AP is a cheap way to "solve" the problem.
I feel that I have learnt a lot in the > 500 pages but at the same time, I’ve kind of felt that I’ve learnt virtually zil. M. Tegmark has 4 levels of multiverse which many writers mention. His level 4 (version) of multiverse (any laws and anything can happen) to the extreme might as well be a religion as P. Davies puts it. Brandon Carter has kind of reformulated (QM) in his micro-anthropic principle stuff with all detailed equations … but at the end, it goes nowhere but just leave us with an empty framework.
Lee Smolin sounded the strongest opponent against AP but then he talks about Cosmological Natural Selection. It’s slightly different (the distribution function needs to peak at the chosen state) but it’s not that different to me. S. Hawking also claims to avoid AP but says instead that we just need to pick the one path integral that we’ve gone thru’ among all the possible paths. He tries to sound funny by saying that there is a non-zero probability that he’s a Chinese (especially there are so many Chinese than British) but he’s not interested in this possibility because he’s already a British. Kind of AP to me …
Paul Davis sounds very skeptical and against AP, too. He introduced his "3rd way" (in addition to God and AP/multiverse) which is like feedback loop to me (just like in electronics/logics) … is not really totally different from some sorts of AP.
The most likable article and also the shortest article is called "Living in a simulated universe". It’s actually quite convincing to me that all these apparent fine-tunings in our Universe and hierarchy problems (ie. scale problems) could be just that we’re just somebody else’s simulation. And those simulation creators (though smarter than us) are not God and like our own simulations, they make mistakes and there are gaps. So, they need to make corrections and make patches from time to time — just like everybody’s OS (Windows/Linux) being patched all the time. This sounds so right (for all the fine-tunings and broken laws at different scales) !!
This book’s purpose is not about God but unavoidably it appears. All authors acknowledges this possibility and all but one just avoids talking about it as they say it’s outside the boundary of science and their expertises. Of course, when something is not science, it doesn’t mean that that something is wrong but just the scientists don’t know how to do about it (in any way better than any non-scientists anyway). But one author (who is also a theist) talks about it explicity together with everything else, multiverse, AP, superstring, inflation etc. I don’t quite remember the technical stuff that he’s said except that he somehow wants to say that there is no warfare between science and Church (presumably against R. Dawkins et. al.) … If this is genuine, in this era of lack of funding, we should at least try to gain funding from the Church .. I believe, from what I’ve read, those theorists can do a lot without any conflict with the Church. God can hide easily behind the "multiverse" as multiverse doesn’t exclude God at all.
And after all, all these conferences (and most authors as well) get their fundings from John Templeton Foundation (you know this Foundation, don’t you ?) which is very compatible with the Church. I didn’t spot and was not aware of this part until I’m in the middle of the book. But to be fair to these authors, most of most of the book is nothing about God but they just try to have some solutions about the cosmological problems …
Since Standard Model (in particle physics), the reductionist’s success seems to have disappeared. Supersymmetry doesn’t reduce the no. of constants etc. (as there are so many super-partner for each existing particle) … Superstring/M theory leaves us a landscape of possibilities. Some people still hope that superstring would lead us to uniquely define all the constants … But the AP/multiverse does seem to become a bigger industry. I read this book because somebody else in "CERN Courier" recommends quite strongly about it … and this is a sign how big the industry is. At least, scientists don’t feel ashamed talking about it …….