Carlo Rovelli, the Italian theoretical physicist, is one of the great scientific explicators of our time. Your wafer-thin essay collection, Seven short physics lessons, It sold more than 1 million copies in English translation in 2015 and remains the best-selling science book in the world. In The order of time Y Reality is not what it seems, Rovelli illuminated the disturbing uncertainties of Einstein’s relativity, gravitational waves, and other physical attempts. No one said post-Newtonian physics was easy, but Rovelli’s gift is taking difficult ideas one notch. His books continue a tradition of jargon-free popular scientific writing from Galileo to Darwin that disappeared in the academic specializations of the last century. It is only in recent years that science has become, in editorial terms, popular and attractive again.
Rovelli’s new book, Helgoland, tries to explain the desperately difficult theory of quantum mechanics. The theory was first developed in 1925 by the young German physicist Werner Heisenberg during a summer vacation on the arid island of Heligoland in the North Sea. It was there that the 23-year-old, affected by hay fever, conceived the “strangely beautiful interior” of the mathematical structure of an atom and, at a stroke, overturned the certainties of classical physics. Gone is the old idea that atoms consisted of tiny electrons that moved mechanically around heavier protons, while planets orbit the sun. Heisenberg’s intuition was that electrons moved in diffuse waves, like clouds.
Excited, he devised mathematical tables (“matrices”) to predict the wave mechanics of electrons. His work was soon refined by other progressive physicists such as Erwin Schrödinger and Paul Dirac. Quantum theory originated from Heisenberg’s observations and Einstein’s earlier theory of relativity. Until Einstein, scientists believed in a predictable deterministic universe, driven by a clockwork mechanism. Newton’s idea of an absolute “true time” relentlessly marking the entire universe was countered by Einstein’s theory that there is not just one “now”, but a multitude of “now.” Heisenberg and his followers, even more radical than Einstein, argued that we cannot know the current state of the world in detail, but only through models of uncertainty and probability. The enigma of quantum theory may ultimately be beyond our tentative understanding and limited to Earth, says Rovelli; but Newtonian mechanics, although far from being obsolete, can no longer account for all aspects of the world in which we live.
Our world is understood to be non-deterministic and essentially unpredictable; moreover, it works in ways that often seem unintuitive to us. Quantum theory invites us to see the world as the cradle of relationships of a giant cat, where objects exist only in terms of their interaction with each other. Ultimately, says Rovelli, Heisenberg’s is a theory of how things “influence” one another. It forms the basis of all modern technologies, from computers to nuclear power, lasers, transistors and MRI scanners.
Fortified with reflections on Vedanta Hinduism (the author has a hippy past), Buddhism, Dante, Empedocles, and Democritus, Rovelli applies quantum theory to various philosophies. Human beings exist by virtue of their continuous interactions with each other; so do atoms and electrons. As a happy integration of science, literature and philosophy, Helgoland owes something to the Italian chemist and writer Primo Levi, whose scientific-literary memoirs, The periodic table, it reached the UK bestseller list in 1985 alongside Dick Francis. Rovelli’s book displays a much like Levi’s enthusiasm for abstruse facts of all kinds. (We know that German director FW Murnau had filmed parts of Nosferatu in Helgoland in 1922, a couple of years before Heisenberg’s arrival).
Without a doubt, the book is difficult at times. (“I hope I haven’t lost my reader,” Rovelli says at one point). The American physicist Richard Feynman presumably meant it when he said that “nobody understands quantum mechanics.” In his trademark lucid prose, Rovelli goes out of his way to explain why this could be so. Known for his work on loop quantum gravity theory and for the pre-Socratic Greek philosopher Anaximander, Rovelli is a spirit of restless inquiry and deep thinking who sees no incompatibility between physics and philosophy, only mutual attraction.
Science, in Rovelli’s view, is not about certainty; he is informed by a radical mistrust of certainty. That is real? That exists? Helgoland, Beautifully translated by Erica Segre and Simon Carnell, it is the beginning of wisdom in these things.
• Helgoland by Carlo Rovelli, translated by Erica Segre and Simon Carnell, is published by Allen Lane (£ 20). To order a copy, go to guardianbookshop.com. Shipping charges may apply
George is Digismak’s reported cum editor with 13 years of experience in Journalism