As you read these words the world around you seems pretty solid, pretty stable: The device you’re using seems to exist on its own, with its own properties of shape and weight and color. So does the chair you’re sitting in, the table your coffee cup is resting on and the coffee cup itself.
But that solidity and independence is a kind illusion or, at least, so says the very physics that lets these words appear on the screen of your computer, smart phone or tablet.
That physics, called quantum mechanics, represents the most powerful theory human beings have ever developed. And while we scientists know how to use it to make all those digital devices, we do not know what it means. We don’t know what it’s telling us about the fundamental nature of reality. It is into that chasm that acclaimed theoretical physicist and author Carlo Rovelli leaps with his new book Helgoland. Making Sense of the Quantum Revolution.
It’s a leap you will want to take with him.
Quantum mechanics is now more than 100 years old. It was born at the turn of the 20th century as physicists probed the atomic and subatomic realms. Much to their chagrin, reality turned out to be a lot weirder at those scales than in the “classical” realm of ordinary experience. The theory they developed to control the objects of their experiments was an intellectual triumph. Almost all of the technological miracles we live with now — from CAT scans to computers — can be traced to that achievement. But quantum mechanics never really “explained” the strangeness of the microworld. It just gave us a method for making incredibly accurate predictions and building stuff.
Chief among the quantum weirdnesses (and there are many) was the fact that particles, like an electron, exist in superpositions of possibilities before they are observed. A rotating electron is neither spinning left nor spinning right until its measured. Instead, it’s spinning both ways at the same time. Similarly, that same electron will be neither over here nor over there before a measurement, but exist in both places at the same time.
For Carlo Rovelli the radical uncertainty forced on us by quantum mechanics holds an equally radical lesson about how wrong we have been about the nature of the universe. Rovelli is one of the worlds’ leading theoretical physicists. He is also a lyrical writer whose previous bestsellers have have offered beautiful meditations on the “the adventure of science.”
What Rovelli offers in this new book is an interpretation of quantum mechanics. There are many such interpretations out there and in recent years a spate of works by well-known physicists have appeared defending some of these. There’s Sean Carroll’s recent book on the many-worlds interpretation, which says there are parallel realities that explain quantum weirdness. There’s also Lee Smolin’s argument for the pilot-wave interpretation, which claims there are hidden variables that explain quantum weirdness. Rovelli has developed his own relational interpretation — and Helgoland represents a clear and yet poetic argument for its vision.
Helgoland is a barren island in the North Sea where a 23-year-old Werner Heisenberg (of the uncertainty principle) hid himself in 1925 to work out the details of the new quantum theory. Rovelli begins the book with this story to lay out the central tenet of his relational interpretation. To get a feeling for Rovelli’s perspective, imagine of a blue bowling ball that’s 10 in. across and weighs 25 lbs. We think those properties — the ball’s color, weight and size — are real in and of themselves. If the bowling ball were the only thing in the whole universe, it would still be blue, 10 in. across and weigh 25 lbs. But the lesson Rovelli wants us to learn is that nothing has any properties at all until it interacts with something else. And between those interactions there are no properties at all. What quantum mechanics is teaching us, Rovelli says, is that reality is a vast net of interactions where there are no things, only relationships. “This is the radical leap,” he writes, that “… everything exists solely in the way it affects something else.”
Helgoland offers a dizzying perspective, but because Rovelli is such a gifted writer he packages it in a slim volume that carefully deploys a minimum of scientific facts and theories in service of the greater theme. And it’s that greater theme that makes Helgoland worth reading. It’s not often that a “popular” book on quantum physics will include descriptions of arguments between Lenin and fellow Bolshevik Alexander Bogdanov or an account of the 3rd century Buddhist philosopher Nagarjuna. Rovelli takes readers through both in an effort to show how mistaken our ideas about matter and “materialism” have been.
As someone who has thought and written a lot about quantum mechanics, I found Rovelli’s perspective to be both bracing and refreshing. Without diving off the deep end into New Age fuzz or forcing a previous philosophical bias down quantum mechanics’ throat, he sees its questions as a challenge to invent and investigate radical possibilities. “Not to fear rethinking the world is the power of science,” Rovelli writes.
Helgoland is not, however, a book to learn quantum mechanics from. Rovelli’s description of superposition is sparse and gives readers only what they need to know. His descriptions of the other interpretations are also thin and sometimes misleading. But those descriptions are not the point of Helgoland. Instead Rovelli is offering a new way to understand not just the world but our place in it, too. “If the physical world is woven from the subtle interplay of images in mirrors reflected in mirrors,” he writes, then “… perhaps it becomes easier to recognize ourselves as part of that whole.”
That perspective alone makes the journey to Helgoland worthwhile.
Adam Frank is an astrophysics professor at the University of Rochester and author of Light of the Stars: Alien Worlds and the Fate of the Earth. You can find more from Adam here: @adamfrank4.