Reality Is Not What It Seems: The Journey to Quantum Gravity

"The best book I've read in the last year."

"I know what you mean. I’ve read a number popular science books about physics over the years and acquired an elementary grasp of physics but I struggle with some of the maths. At one point, after reading Max Born’s book, I thought I had just about understood the theory of relativity, and I think I could get it again, but then I would probably forget it again. But I do think we’re all perfectly capable of understanding the essential concepts. Carlo Rovelli is one of the latest of among many to write about fundamental physics. He had quite a success with a book called Seven Brief Lessons in Physics , and this is basically the longer version of the same book. I think it’s actually a better book in some ways. He did. It goes right to the edge of his field—quantum loop gravity—but I found it a really enjoyable read for a number of reasons. For one thing he’s got a good, simple style, and he has a great capability to explain, as people know if they’ve read Seven Brief Lessons in Physics. He’s also informed by a strong literary and artistic imagination and appreciation of, for example, the mediaeval mind. There’s lovely stuff on Dante and one of the chapels in Florence, and how they inform our ways of perceiving the shape of the universe. He’s also great on Democritus. There are some simple pleasures in the book like there’s a list I’d never seen before. Democritus’s thought only survives in reported fragments from other people. All of his work has disappeared. And he wrote—it depends what you mean by a book: a book back then was different from what we think of today—something like 60 or 70 books, with these wonderful titles. Rovelli just lists them. Each one of them is like, ‘God if we could read that book, it would be just so fascinating!’ So there’s a kind of playful element to it. It’s like a serious brother to Italo Calvino’s marvellous Cosmicomics : these very funny stories, partly about cosmology but also about all kinds of other things. It has a great warmth to it. In fact, I owe the epigraph at the front of The New Map of Wonders to Rovelli, quoting Democritus:‘To a wise man, the whole earth is open because the true country of the soul is the entire universe.’ It’s about living with your fear, moving forward in spite of it, and being open to everything. Yes, he says, “The Italian policeman asked me politely if I was crazy to drive at that speed. I explained that I had found the idea I’d been seeking for so long. The policeman let me go without a ticket and wished me good luck with my book.” There’s a great generosity and humour in this, among other things. It’s delightful Quantum loop gravity. Please forgive my over-simplification and distortion but one of the great challenges, according to many people in this field, is the unification of quantum theory and general relativity. Rovelli’s thing, which is one among several contested theories, is quantum loop gravity, and the book explains what that could be. And does it in a way that’s actually quite easy to follow. That’s what he argues. He goes from pretty much the beginning of physics as we typically frame it with the Greeks. One of the things that’s quite unusual about the book is that, to my knowledge, there are few if any other popular treatments of quantum loop gravity, which is pretty much the very edge of our knowledge now. And he tries to make that clear. What he’s saying is that it’s all about relations. He finishes by saying the world should not be understood as an amorphous ensemble of atoms, but rather as a game of mirrors founded on the correlations between structures formed by the combinations of these atoms. I think even if you don’t get to the end of the book, there’s a lot in it that’s readily understood and enlightening. You will find that actually some of this stuff is really not that hard to understand, at least in general terms, and very enjoyable to read about. He stresses that quantum loop gravity itself is just just a hypothesis. It may present a way forward, he believes it does. I mean I’ve only read this one and the Seven Brief Lessons . They are refreshing and engaging treatments of a quite difficult topic. I enjoy reading about many areas of science and arguably one of the obvious choices for a discussion of science and wonder would be Oliver Sacks, writing about medicine and brain pathology and other topics related to that. So I don’t know if Rovelli is my favourite but this is a really good book. Towards the very end of the book he goes back to Democritus and he says that Democritus gave a strange definition of man, “Man is what we all know. At first sight this seems rather silly and empty but it is not so.” He cites a major scholar of Democritus who argues that it is not a banality that Democritus gave us: “The nature of man is not his internal structure, but the network of personal, familial, and social interactions within which he exists. It is these which make us, these which guard us. As humans, we are that which others know of us, that which we know of ourselves and that which others know about our knowledge. We are complex nodes in a rich web of reciprocal information.” We’re embedded. That’s what he’s saying. That’s also what he’s trying to explain in the physics. He thinks quantum loop gravity will integrate these two apparently inconsistent theories, relate them to each other and we can then, in a sense, find our place within the whole as emergent, complex phenomena—something that, wonderfully, come out of the world rather than (or as well as) being thrown into it. We are a bunch of atoms, but that’s not all we are. Reality is those atoms, but it’s many other things, including information and relationship."