One of the consequences of belonging to a book club is the pressure it exerts to buy something from each monthly brochure. Paying later by credit card also seems, utterly illogically, less traumatic than forking out real money in a bookshop. So I get to read books that might otherwise pass me by, some of which I even finish reading. The book of the year (1997) for me was undoubtedly The Life of the Cosmos by Lee Smolin. Lee Smolin is a physics professor at Penn State University, and his expertise is in the rarefied field of quantum gravity, an entity that not everyone agrees exists.

At the age of 65 going on 16 the first thing that revived my anarchic tendencies was his account of how he came to be a physicist. It all started by his being refused entry to the advanced math (as they say) class at high school, because his teachers thought he wasn't good enough. So he decided to learn maths on his own. One thing led to another, and maths led to architecture, which led to geodesic domes, tensors, Einstein and then a teenage decision to devote his life to physics so that he could sort out the problems of linking quantum theory and gravity. What else was there for a `failed rock-and-roll star' to do? By this time he had been refused entry to the physics class at high school (blame possibly a mixture of rock-and-roll and politics; after all, this was California) so he taught himself enough to get into university anyway. I can understand how some students prosper in spite of their teachers, but this is the only one I have heard of who did so just to spite them.

But all this happens in the first few pages. What was really fascinating about the book - which should entrance any sixth-former - is Smolin's ideas in physics. In developing these he avoids all equations and gives us clear and well-written accounts of cosmology, the evolution of stars and the universe, string theory, relativity, quantum physics and gravity, and the `dream of unification'. His approach may be too philosophical for some (see the review by B Carr in Physics World 10 December 1997, p 39) but don't be put off by his adoration of Leibnitz compared, say, with Newton. He is strongly critical of a `mechanical' world view, and a major strand in the book is that physics may be more like biology than most of us might like to think.

Smolin's key idea is that universes are created in black holes, a basis on which he builds a cosmology in which relationships are more important than abstract concepts like space and time. When a new universe forms from a black hole the laws and constants are changed: G, e, h and the critical things like the fine-structure constant that cosmic anthropicists put forward as evidence for a purposive universe get changed. Sometimes they change a lot, sometimes in ways too small to have much effect. A kind of Darwinian survival effect takes over: successful universes are good at producing black holes and mature stars that can build up the heavy elements which allow life to develop. So our values of G, e, h etc have evolved. The more black holes they produce, the more likely it is that some of the baby universes are reasonably successful. So our universe is not unique, but just one of a set that has cosmological and physical properties that allow people like us to develop. The improbably anthropic universe we live in is as improbable as an eye or a peacock's tail. Just as Stephen Jay Gould teaches us that life as we know it is not designed but the result of more or less simple rules applied in an accidental, contingent history, so Smolin considers the universe(s). Galaxies have ecologies: `... our life is situated inside a nested hierarchy of self-organized systems that begin with our local ecologies and extend upwards at least to the galaxy.' Our universe is really very young - not much older than a typical star. The theory has testable predictions, to do with the formation of spiral arms in galaxies, supernovae and the rate of production of black holes. What is yet to be shown is exactly what happens in a black hole to make the changes in constants and laws, which is where quantum gravity comes in.

Some quotes: <BLOCKQUOTE> This distinction between an equation that one believes to be a true mirror of nature and a game whose rules capture some observed regularity is often expressed by making a distinction between a theory and a model. The notion of a theory carries with it... the mysticism of the desire to capture reality in symbolic expression. A model is just a game, meant to mimic some aspect of the world whose observed regularities can be posited in some simple rules. ... At present the great question in theoretical physics is whether the desire to invent a beautiful equation that will capture the whole world will in the end succeed. Will there be a final game, and will it be of the kind that Newton, Maxwell and Einstein played? Against this we have the possibility that many questions about the world might be answered by playing games more analogous to those played by biologists. </BLOCKQUOTE>

From black hole theory - no fields: <BLOCKQUOTE> The existence of a bound on the amount of information that can be contained in a region of space opposes directly one of the basic principles of twentieth-century physics, which is that the world is made of fields. </BLOCKQUOTE>

<BLOCKQUOTE> I must stress that I do not know why Heisenberg's Uncertainty Principle is true. Neither, as far as I have been able to tell, does anyone else. </BLOCKQUOTE>

Buy or borrow, read, enjoy. Anticipate the problem of having to divert more often than usual the attentions of your students back to the syllabus, at least until the new IoP syllabus comes along (?).

Smolin L 1997 The Life of the Cosmos (London: Weidenfeld and Nicolson) ISBN 0 297 81727 2.