The Road to Reality by Roger Penrose

When I noticed that there are roughly as many pages in the latest blockbuster from Roger Penrose as the number of words allocated for my review, I was tempted to give each page a single-word comment. There is certainly no point in trying to assess the scientific content of the book in detail here, although I do feel Lee Smolin's work on baby universes could have been handled better. What is much more interesting than the details is Penrose's take on science, and his remarkable faith in the stamina of the reading public. Bill Bryson took science back to the top of the bestseller lists partly by eschewing equations and concentrating on people and places. Penrose's epic exposition of the laws that govern the physical universe goes to the opposite extreme, replete as it is with equations and with little sense of people and places. It is, essentially, just the facts.

Penrose believes that by starting out with the simple stuff - Pythagoras and the Greek thinkers - and working slowly up to quantum gravity, he can carry the reader with him. It is in this sense that you should take the book's claim that "no particular specialist knowledge is needed". It would be just as true to say that no particular specialist knowledge is needed to complete a PhD in string theory; all you need is to start out aged five with simple arithmetic. When Penrose says he is an "incurable optimist" in matters of conveying understanding, believe him.

The journey he takes us on is a heroic one, starting with a discussion of the nature of scientific models, passing through nearly 400 pages of essentially introductory material, and then getting on to the nitty-gritty of the nature of space-time, the standard model of particle physics, quantum field theory, black holes, cosmology and the latest efforts to find a "final theory". It's just unfortunate for the innumerate that "the more deeply we probe the fundamentals of physical behaviour, the more we find that it is very precisely controlled by mathematics... of a profoundly sophisticated character, where there is subtlety and beauty of a kind that is not to be seen in the mathematics that is relevant to physics at a less fundamental level."

As Penrose says, you can skip the equations, or even large chunks of the book, and still get a lot out of it by reading the linking text. But if that is what you want, in all but one respect you would be far better off reading other books, such as The Fabric of Reality by David Deutsch (Penguin), or The Great Beyond by Paul Halpern (John Wiley).

The one thing you would miss, though, is the one thing that the publishers of The Road to Reality seem desperate to hide. The book is presented as if it offers "the" road to reality, the final "theory of everything" that has been widely hyped in recent years. But after more than a thousand pages of exposition, Penrose says that: "I do not believe that we have yet found the true 'road to reality'." Indeed, the book should have been called The Roads to Reality.

What the publishers have desperately, but misguidedly, avoided pointing out is that Penrose is something of a maverick in scientific terms, as well as in his faith in the brainpower and willingness for hard intellectual effort of the reading public. He does not agree with his peers who think that a final theory lies just around the corner, and he has interesting and provocative things to say about the flaws in current models in cosmology (the idea that the early universe went through a phase of rapid expansion called inflation) and string theory (the idea that fundamental "particles" are made of tiny extended objects called strings, wrapped around in multi-dimensional space).

The subtext is that Penrose has his own axe to grind: the Penrose vision of the universe, based on an idea known as twistor theory. But that does not detract from the significance of his sideways look at things that all too many people believe to be "proven" triumphs.

This message is particularly important, of course, for the particle theorists and cosmologists themselves. But there is no reason at all why the committed general reader should be excluded from listening in on the debate.

So The Road to Reality is good where it doesn't live up to its title and publicity, and Penrose gets (scientifically) personal. Where it does live up to the title, it is not so much that it's bad, but that it's no better than many other books. It is probably not a book that will appeal to the intended audience of interested non-scientists; but it is one that should be required reading for all research physicists - who can skip the first 400 pages.

Penrose says that the book took him eight years to complete, and it will take some readers just as long to understand him. In the saying attributed to PT Barnum: "Nobody ever went broke by underestimating the intelligence of the public." In spite of overestimating the intelligence of the public, Penrose is unlikely to go broke; but with his super-optimistic assessment of the intelligence and willingness of the public for hard intellectual work, he is unlikely ever to reap the rewards commensurate with his eight-year effort.

But then, as an academic he has already been handsomely rewarded, as he acknowledges, by the National Science Foundation, the Leverhulme Foundation, Gresham College, London, and the Center for Gravitational Physics and Geometry at Penn State University (apart from his day job at Oxford University). This was clearly money well spent, even if it does not result in an international bestseller. Science needs more people like Penrose, willing and able to point out the flaws in fashionable models from a position of authority, and to signpost alternative roads to follow.

Dr John Gribbin is a Visiting Fellow in Astronomy at the University of Sussex, and author of 'Deep Simplicity' (Allen Lane)

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