The secret of the universe.

 A few years ago, in Berne, I visited the apartment where Einstein wrote his theory of special relativity, which changed our understanding of the world forever. It’s a small apartment, plain and nondescript. The best thing about it is the view. From the window you can see Berne’s huge medieval clock, the Zytglogge. It was this clock which inspired Einstein’s great breakthrough. At the end of every humdrum day, in his dead- end job at Berne’s patent office, he took the tram home, past the Zytglogge, back to this apartment. As he gazed at that clock through the tram window, he wondered: what if his tram could travel at the speed of light? Logically, the light from the Zytglogge should never overtake him. Relatively speaking, it should remain static, just as two trams travelling side by side at the same speed in the same direction remain static in relation to each other. But that wouldn’t work, because the speed of light never alters. Therefore time would have to change.

Carlo Rovelli doesn’t tell this story in Reality is Not What it Seems, but he tells lots of stories like it, and the result is a book that brings physics alive. If you’ve read his previous book, Seven Brief Lessons on Physics, you’ll know what to expect. If you haven’t, you’re in for a treat. Rovelli is the director of the quantum gravity research group at the Centre de Physique Théorique in Marseilles (no, I’d never heard of it either, but I imagine you must have to be pretty brainy to get a job there). Consequently, you might expect this book to be completely impenetrable. You couldn’t be more wrong. Complexity is the hallmark of second-rate minds. Like all great thinkers, Rovelli has a talent for simplicity. His prose is lucid and poetic. I scoured this book for quotable phrases, and ended up copying out entire paragraphs. It’s not a scientific treatise. It’s a paean to the wonder of the natural world.

Reality is Not What it Seems is a sort of prequel to Seven Brief Lessons in Physics. Rovelli wrote this book first, and then wrote seven shorter articles based upon it. Those articles were published as Seven Brief Lessons, and the huge success of that slim tome (translated into 31 languages) prompted this new translation of his first book. Being unable to read it in the original Italian, I can’t assess the merits of Simon Carnell and Erica Segre’s translation, save to say that their joint effort reads far better than most books by native English speakers.

So what’s this book about? Well, in the course of just 255 pages, Rovelli charts our understanding of the universe, from the astronomers of the ancient world to today’s boffins — and all the key points in between. He explains how Newton built on Galileo, how Faraday and Maxwell built on Newton, and how Einstein transformed their theorems, by uniting space and time. I scraped a C in my Physics O-level and haven’t been near a physics textbook since. If I can understand— and even enjoy — Rovelli’s book, then anyone can. What thrilled me most of all was his revelation that physics and
philosophy are actually twin disciplines — two sides of the same equation, if you like. Mind you, the ancients knew that too. Had you realised that it was Aristotle who coined the term Physics, in his book of the same name? I hadn’t until I read Rovelli. Reality is Not What it Seems is full of fascinating nuggets like these.

Rovelli concludes with some mind-boggling stuff about quantum physics. This was the only part where I got brain ache, but it seems I’m in good company. Apparently, even Einstein couldn’t quite get his head around it. Indeed, the best thing about this beautiful, compact book is its celebration of uncertainty. As Rovelli demonstrates, confusion is the creative impetus that drives us on to fresh discoveries. Certainty is the enemy of science.

He begins with a tale from Plato’s Republic, which would work just as well as an epilogue. It’s about some men imprisoned in a dark cave, whose only source of light is a hidden fire which casts strange shadows on the wall. One of the prisoners escapes, and ventures outside. For the first time he sees the sun, and all the splendours that surround us. He returns to the cave and tries, and fails, to describe the amazing things he’s seen. Like Plato’s prisoner, Rovelli has seen the splendours beyond the dark cave of our imaginations. Unlike Plato’s prisoner, he can tell us what he’s seen.