Conjuring the Universe - Peter Atkins *****

It's rare that I'd use the term 'tour de force' when describing a popular science book, but it sprang to mind when I read Conjuring the Universe. It's not that the book's without flaws, but it does something truly original in a delightful way. What's more, the very British Peter Atkins hasn't fallen into the trap that particularly seems to influence US scientists when writing science books for the public of assuming that more is better. Instead of being an unwieldy brick of a book, this is a compact 168 pages that delivers splendidly on the question of where the natural laws came from.

The most obvious comparison is Richard Feynman's (equally compact) The Character of Physical Law - but despite being a great fan of Feynman's, this is the better book. Atkins begins by envisaging a universe emerging from absolutely nothing. While admitting he can't explain how that happened, his newly created universe still bears many resemblances to  nothing at all - it's empty as yet. And from that, he conjures up conservation laws using Noether's theorem, then goes on to show how other laws emerge from indolence - more technically the principles of least time and least action - and anarchy. As a final gesture, Atkins throws in the insights that even some of the constants of nature, such as the speed of light and Planck's constant don't really exist, being artefacts of the units we choose to use.

Underlying all this is mathematics, which Atkins tucks away into his notes, so that the main text puts the message across with hardly an equation in sight. What we get the strong feeling for is that it really doesn't take much for the physical laws we observe to become necessary. They aren't something complex that is imposed on us, but rather the inevitable consequence of very few simple starting points.

I mentioned there are flaws. The history of science is sometimes a little weak. We're told Aristotle should have noticed that arrows would fly better in a vacuum - he did, prefiguring Newton's first law, effectively using it as an argument as to why he thought nature abhors a vacuum. Similarly we are told that Daniel Fahrenheit 'puzzlingly' took 96 as body temperature, not 100. But we know why - it was to make it easy to draw a scale between 32 and 96, as the difference of 64 can easily be constructed by repeatedly halving the distance between the two points. (Not a great reason, admittedly, unless you're manufacturing thermometers.) The book is certainly not all bad in this respect, though - we get more about Boltzmann and his work than most popular science titles provide.

The 'conjuring' metaphor also seemed particularly apt as I found Atkins' slick, mellifluous tone reminiscent of a stage magician's patter. It may leave the reader wondering what Atkins was keeping up his sleeve. There were a couple of examples where sleight of hand appeared to happen. The emergence of some of the natural laws still requires Noether's theorem and the principle of least action/time to hold... and where did they come from in a true state of nothing whatsoever? Also, the example using Noether's theorem takes us from nothing (where symmetry is inevitable) to empty space, where that symmetry remains - which then implies various conservation laws. But we got no feel for what happens when stuff begins to emerge. As the first particles come into being, why doesn't symmetry (and the conservation laws with it) go out of the window? Atkins' magical mystery tour makes it easy to miss the questions left unanswered.

A few diagrams would have helped too - there are none at all. For example, at one point Atkins is talking about gauge invariance, and says 'Now think of shifting the whole wave along a bit, so that its peaks and troughs are moved a little. Nothing observable has changed, in the sense that if you were to evaluate the probability of finding the particle at any point, then you would find the same result.' Without a diagram, there are two problems. Firstly, how is the wave shifted? Moved in which direction with respect to the direction of travel? Secondly the wave in question is the square of the plot of Schrödinger's equation - it shows the probability of finding a quantum particle in a location. So how is it possible to move the wave - so the probabilities are higher in different locations from before the move - yet nothing has changed? An illustration might have clarified things.

Inevitably a degree of magic work was necessary, though, to achieve so much without deploying the mathematics that underlies what we were being told. And in this book, Atkins proves himself a master magician.

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Review by Brian Clegg