Some cosmologists consider our presence in the universe a central clue to its inner workings. Others strongly disagree.
Davies (Physics/Arizona State; How to Build a Time Machine, 2002, etc.) is one of those who embrace the so-called anthropic principle (a name many of its advocates now wish they could change): the idea that our universe’s suitability for intelligent life is not an accident but a logical development. He spends the first half of his book outlining the current state of our knowledge of the universe, from relativity and quantum theory to dark energy and M-theory. With this foundation laid, he raises a key question. Many of the fundamental properties of matter and of the forces that act upon it appear to be fine-tuned to permit the existence of living beings. Even minute changes in certain physical values would alter the universe so radically that not only life, but matter itself, could never have come into existence. The excess of matter over antimatter created in the Big Bang allowed our universe to form. A change in the strength of gravity might have prevented the formation of stars and planets. Why are these values what they are and not some other, equally plausible numbers? While many physicists are likely to shrug and say, “The universe doesn’t have to make sense,” Davies and his anthropic comrades counter with the idea that the universe we know is one of many, each slightly different, making up a multiverse; life simply arose in the area most suited to it. Davies admits that many of his colleagues detest the multiverse concept and the anthropic principle, but he clearly and comprehensively lays out their primary features and the fascinating questions they raise, without dodging the controversy they have stimulated.
A lively exposition of cutting-edge science.