Alex Vilenkin is a real physicist and he's been at the cutting edge of cosmology research so it's no surprise that he has a solid grip on the theoretical underpinnings and major issues and problems facing modern cosmology. What's unexpected is that he is such a fluid and comprehensible author. Dr. Vilenkin writes beautifully - with humor, vision, impeccable organization - and great mercy for the layman. He spares us the math, but gives us a real mental picture of the issues at play. This is a great review and explanation of the modern scientific picture of the creation of the universe.
And what a picture it is. Exotic states of vacuum engendering faster than light expansion; infinities contained in bubbles inside finite spaces; multiverses with endless variations in the laws of physics, most inhospitable to life. We see the history of the subject from Copernicus, Galileo, Kepler, and Newton up through Einstein and into the modern period. We get a great view of how Guth's expansion theory resolves a host of problems and suggests, tantalizing, the nature of the stuff that gives birth to our universe (higher energy false vacuums). Much of the resulting weirdness comes about as consequences contingent on expansion. There's a great explication of the cosmological constant and how the recent observational proof of it shatters particle physics independence from the anthropic principle (the notion that our presence here as observers is evidence that must be used to help gauge odds in a scenario of multiverses in which only some outcomes are hospitable to life such as ourselves. I find myself thrilled by these ideas and enthralled that Vilenkin gives me the impression that I'm really following along.
I'd give it an unqualified rave except that I have a major problem with his central thesis that a consequence of our island universe's infinite size is an infinity of parallel worlds and an infinity of identical earths with identical "you"s doing the same things. It's poetic, and certainly shocking and gets the point across that infinity is a really weird concept with very strange consequences. However, his assumption that the quantum fudge factor necessary to his proof of truly duplicate universes can give rise to a truly duplicate earth with duplicate people betrays an empiricist fallacy of particle physics' reductionism: the same particles will not build the same individual life forms because emergent complexity makes liberal use of chaotic recursive phenomena. It's the genotype/phenotype divergence. Even if the all the particles end up in the same places (by pure chance alone like monkeys typing Shakespeare, since there's an infinity of universes, some will bound to have all the particles in the same places) the way these particles code for complex emergent phenomena like life, brains and social structures makes use of chaos' sensitive dependence on initial conditions to yield divergence on the quantum fudge factors alone - in direct contradiction to Dr. Vilenkin's central conclusion.
So - I'm totally down with "Many Worlds in One" as the best explication I've encountered on the history and evolution of the ideas and theories of particle physics as it relates to cosmology. But I'm completely at odds with Vilenkin's central wowser that there's an infinity of each of us in a weird cosmic hall of mirrors because it's an inescapable consequence of infinity. I think that's just too simplistic and reductionist a reading of how particles combine to manifest the complex emergent phenomena all the way up from molecules to life forms and higher levels of reality. The way Vilenkin blithely ignores emergent complexity reflects physicists bias that particles are an ultimate reality completely encapsulating all higher order reality in and of themselves. It's a pretty picture; but it just isn't that easy. Maybe my insistence that the infinities involved in chaos and emergence trump the infinity of universes reflects my own cowardice and bias - but I couldn't help being disappointed that Vilenkin didn't seem to have recognized that issue with that facet of his really cool theory. Ultimately, my issue here is really just a quibble since that aspect is just one in a long series of amazing ideas that get presented here. On the whole, this book is the most stimulating thing you can expose yourself to from a philosophical, spiritual, and intellectual perspective. I might dock it a point because I don't like the pop aspect of the central thesis, but I'd highly recommend it to anyone at all for all the rest of it.
A special note on the Kindle edition: footnotes are rendered with direct links, but end notes are not (forcing you to jump locations manually - annoyingly - if you want to read the end notes). The index is totally lost because of the relative locations - there are no listed page numbers, no live links, no location numbers - nothing - on the index. So if you want to use the index - buy the printed book because the Kindle version has no functioning index. The Kindle edition also has a some spelling errors from the scan, but the pictures are OK and it all works fine otherwise.
Time to eat some crow. I had a nice long conversation about Mr. Vilenkin's theory via e-mail with Mr. Vilenkin himself and he very patiently worked the idea through with me and I am forced to admit that if there are an infinite number of O-regions, then there must be duplicate Earths. All that quantum weirdness, chaos and self organizing complexity just ups the number of possible histories each particle can take. But in a universe of finite age and finite size the number of those particle histories is certainly vast but unavoidably finite, just like Mr. Vilenkin says in the book. All the ranting I just did in my review about 'physicist's arrogance about particles constituting an ultimate reality' really was just intellectual cowardice - just like I hinted it might be.
Our conversation isn't quite finished yet. I'm still clinginging to a shred of hope - that the central mechanism that gives our island universe an infinite number of O-regions might not give us an infinite number of particles to populate those regions at any particular moment in time - but only trends towards infinity over infinite time. This particular objection has nothing in common with the failed avenue of attack I make in my original review. I'll wait to hear more about that.
The real upshot here is that this book is incredibly stimulating, mind bending, and mind expanding. If you really read this, you'll never be the same. Highly recommended.
Final update - I have nowhere to hide with Dr. Vilenkin; I lack the background to either full understand or debate his points about the equation of infinite time on an island universe viewed from the outside equating into infinite volume (and infinite matter present simultaneously). I'm going to have do a lot more studying. Meanwhile - definitely read this book. There's nothing else out there like it.