Seven Brief Lessons on Physics

by Carlo Rovelli

‘There are absolute masterpieces which move us imtensely: Mozart’s Requiem; Homer’s Odyssey; tha Sistine Chapel; King Lear…. Einstein’s jewel, the general theory of relativity, is a masterpiece of this order.’

Published around the same time as his book Reality is not what it seems, Seven Brief Lessons is a much simpler work by far. Intended for the non-scientist, it serves as a background for anyone who might want to learn a little about the key discoveries of the last hundred years. However, this book is clearly not just for the novice. The author delves deeply here into the nature of science, and the nature of humanity. Its fascination, I think, lies not so much in the science – which is minimal – as in what it says about us, the observers.

As I have discovered from his other books, Carlo Rovelli is something of a philosopher and likes to weave his philosophy continuously with his physics. But, though implied frequently throughout, we have to wait for the final chapter for his explicit reveal of our role in the universe.

‘What is quantum theory, a century after its birth? A blunder that works by chance? Or a clue to something profound …. which we have not properly digested?’

The first ‘lesson’ here deals with general relativity, in which we learn not only that space and the gravitational field are one and the same, but that Einstein in his youth spent a year loafing aimlessly. The second talks about the achievements of Plank, Bohr and Heisenberg in the field of quantum mechanics, covered more fully in Helgoland, published in translation only a year ago.

‘It is hardly surprising that there are more things in heaven and earth, dear reader, than have been dreamt of in our philosophy – or in our physics.’

The third chapter of the book deals with the size and nature of the cosmos, the fourth with particles and the so-called Standard Model. The fifth lesson is more speculative in that it discusses in outline the concepts of loops and granular space, which are developed in detail in Reality is not what it seems.

‘At first glance, the idea that our ignorance implies something about the behaviour of the world seems irrational: the cold teaspoon heats up in hot tea and the balloon flies about when it is released regardless of what I know or don’t know.’

Chapter Six has the intriguing title – Probability, Time and the Heat of Black Holes. More philosophy here! We know that heat goes from hot objects to cold, and that time flows from ‘past’ to ‘future’. But why? And what do the terms ‘past’ and ‘future’ even mean?

To gain maximum benefit from this book, it is best to read it twice; at fewer than a hundred pages, it doesn’t take long. But I think the final chapter, Ourselves, needs to be read one extra time. It contains much food for thought.

‘I believe that our species will not last long. It does not seem to be made of the stuff that has allowed the turtle, for example, to continue to exist for hundreds of millions of years…. All our cousins are already extinct. What’s more, we do damage. The brutal climate and environmental changes which we have triggered are unlikely to spare us.’

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