- Helgoland, by Carlo Rovelli. Allen Lane, $39.99.
As a teenager, my heroes were not footballers or pop singers but physicists. In time, I was persuaded away from these superstars, so I welcomed the opportunity to update fusty knowledge with a modern book on quantum theory. Unfortunately, Helgoland is not it.
The book takes its title from a small treeless island in the North Sea where in 1924, Heisenberg went to escape his chronic allergies. While there, still aged only 23, he proposed the uncertainty principle that bears his name. Returning to Germany, he developed the theory with the help of his professor Max Born. In its simplest form it says that the more we know about the position of a particle, the less we know about its momentum and vice versa. Heisenberg and Born were the pioneers of quantum mechanics.
The story then moves to the Austrian Erwin Schrodinger. He took a different view of the uncertainty principle and proposed his famous thought experiment about a cat which could be alive and dead at the same time. With that, physics was thrown on its head: probability replaced certainty, multiplying 3 by 4 no longer gave the same answer as multiplying 4 by 3: "The conceptual clarity of classical physics has been swept away by quanta. Reality is decidedly not how it is described by classical physics."
That noise you might have heard was Newton grumbling furiously; he had enough trouble with the Christian Trinity, now this! Inevitably, Einstein joined the conversation, bringing God with him even though he was an atheist. Superposition and indeterminacy and entanglement were the new buzzwords.
This book offers a number of possible solutions to the problems raised by the quantum model of reality: the "Many Worlds" interpretation, the "Hidden Variables" theory and one called QBism. He examines each of these briefly and discards them in favour of a theory which he calls Relations; the remaining two-thirds of the book examines this, his favoured explanation of the quantum world.
Where previously, there were a few diagrams and equations to explain what he was saying, from now on, it is just words. "The well-defined and solid picture of the world given by the old physics is an illusion," he writes, as he makes his points in chapters like "What Does 'Meaning' Mean?". One imagines that these are the kinds of issues that excite philosophers and if you count yourself among that mumbling elite, you may delight in this.
The great American scientist Richard Feynman once wrote, "Anyone who claims to understand quantum theory is either lying or crazy". In fairness, Carlo Revelli does not claim to understand it, but neither does he make it any clearer.