Paul Davies (1) (1946–)

I found this short book a delightful read. Davies gives us a brief overview of how current physics theory, in particular relativity and quantum mechanics, can allow the possibility for time travel, both to the future and, more surprisingly, to the past. He also briefly describes the kinds of paradoxes that can result from time travel to the past and how these paradoxes might be resolved. This brief introduction motivates me to seek more detailed treatments in the popularized science genre and the more technical physics research literature.… (more)

This a top-class survey of the subject—including some of its profounder aspects because this isn’t just a scientific problem, it’s a philosophical and even religious one too.
    Scientifically, it hinges on the role which chance may, or may not, have played. Is life an inevitable expression of the various laws of nature: “run” the universe a thousand times over and would you always get life (and perhaps mind)? Or is it a flukey outcome of those laws, a falling of the cosmic dice so improbable it would likely never be repeated? The first possibility not only sounds like foresight, a Plan, but since the laws of nature work the same way everywhere then life will prove to be common throughout the universe. The second, by contrast, leaves us alone and, perhaps, meaningless as well.
    To explore such ideas, though, you need the relevant background information, and Davies guides us through it in exceptionally plain language. For a start, there’s the whole business of what “life” actually is, and what it is not. Creationists, for instance, often argue that its mere existence contradicts the laws of physics—entropy and all that, the thermodynamic running down of the universe—and Chapter 2 includes a wonderfully clear explanation of how that is a misunderstanding both of living things and the universe itself. Then there’s DNA and the mind-numbing complexity of cell and genetic code alike. And there’s the whole subject of where life may have begun (if indeed it ever did): on the Earth’s surface, or perhaps miles beneath it inside rocks then spreading up to the surface? This latter, the world of subterranean “extremophile” microbes, is a fascinating and relatively new subject which questions the assumption “…that surface life is ‘normal’, and subterranean life is an off-beat adaptation… Could it be that the reasoning is literally upside down, and that the truth is just the opposite?” Then again though, did life begin on Earth at all, or did it arrive here from elsewhere (from Mars for instance, which early in its own history was very Earthlike)? Or did life never have a beginning and has always existed? This last one is just part of the whole question of whether the universe itself had a beginning or not, or is infinitely old.
    There’s a lot more here besides and, although it was last updated in 2003, this book is still not only a clear-headed guide through its subject, but an unusually deep one too. Absolutely excellent.… (more)