The first new work for a decade by the physicist Stephen Hawking, after “A Brief History of Time”, starts in characteristically robust style. “Philosophy is dead” he proclaims on the first page, ending the book by stating that, if M-theory is confirmed by observation, “We will have found the grand design.”. It is statements like these which made it a slow but unstoppable read.
M-theory turns out to say that we actually live in a ten-dimensional universe (plus time), but we don’t notice the extra seven dimensions of space because they are curled up into an infinitesimally small size. They precise way they are curled up defines the laws of nature, or at least the laws the govern sub-atomic particles out of which everything else is constructed. There are, it seems, 10 to the power of 500 ways that this could have happened – in other words, a nearly infinite number of possible universes with different laws of nature to ours.
There are two ways you can react to this. The common, but broadly illogical view is to declare it as open and shut evidence of God. The other is the Multiverse – the idea that in some absolute sense all these possible universes exist.
However the authors point out that the laws of nature seem to be tuned incredibly precisely to allow life to exist. Tweak them every so slightly, and there might not even be suns and planets, let alone living things. So the vast majority of those different universes would be uninhabitable.
I’ve always been interested in Quantum theory for it suggests that what we think of as reality is the result of observation. Without observation, all possibilities exist equally. By being here, by observing, we selected one of the very few universes that could have given rise to us.
I find books about cosmology and quantum theory are never easy to read, but Hawking and Leonard Mlodinow do a creditable job with this lucidly written book, nicely illustrated with some witty cartoons and sprinkled with impish humour.
The Grand Design – Stephen Hawkings and Leonard Mlodinow (Bantam Press 2010)