In 1979, when Freeman Dyson published Disturbing the Universe, his candid book of memoiristic essays, I was an itinerant postdoc doing research in theoretical particle physics, saddled with the young physicist’s dream of discovering something wonder-full about the laws of the universe. Some of my friends were “freebies,” dream-prolonging postdocs who arranged to do theoretical research at top-notch physics departments in exchange for a desk and no pay. All I knew then about Dyson was that he had once done something wonderful: proving a very important result in the theory of quantum electrodynamics when he was in his early twenties, but I had never read his original papers whose results were now incorporated almost namelessly into advanced courses.
In 1979 Dyson wasn’t a suitable subject for a popular biography. He was known to physicists for his famous proof and to government for his consulting work on science and defense. Though Phillip Schewe has a PhD in physics, his book „Maverick Genius: The Pioneering Odyssey of Freeman Dyson“ (Thomas Dunne Books, 2013) is more an account of Dyson’s varied lives, the multiple paths through space and time he traversed, rather than the details of his work, though it covers his work too.
Interested in the non-scientific side of reality
Initially respected for his powers of abstraction, Dyson was also an aficionado of the concrete, of engineering and technology, of emigration to distant stars, of the possibilities in genetic engineering, of literature and music, of human progress of all kinds. He could have been a poster child for C. P. Snow’s two cultures. In the 1950s he devoted several years to the commercial construction of an inherently safe nuclear reactor. Thereafter he worked for several years on Project Orion, a scheme, quite serious, to send nuclear-powered spaceships to the planets and stars. (Conventional rockets spend most of their energy lifting chemical fuels into space. You will understand much about Dyson’s mix of naivete, practicality and sophistication when you learn that Project Orion planned on dropping nuclear bombs one at a time out of the rear of the spacecraft, exploding them, and then surfing on their shock waves. )
In recent years he’s become notorious for his non-scepticism about ESP and his reasoned scepticism about global warming. He likes to point out that much of what humans have done to the earth is precisely to have created environmental change: England’s supposedly natural green and pleasant land is not “natural” but a result of centuries of cultivation. Dyson won the 2000 Templeton Prize (awarded annually “for outstanding originality in advancing the world’s understanding of God or spirituality”) for an interest in the non-scientific side of reality that doesn’t endear him to believers of pure reason. His elegant essays in the New York Review of Books about the intersection of the personal and the scientific are a pleasure worth anticipating. All this and much much more, as well as his sometimes unconventional personal life, is admiringly described by Schewe. Dyson is a polymath, a fantastically skilled mathematical professional who also, as Jeremy Bernstein once said, “knows more about everything than I know about anything.”
A totally new and astonishingly imaginative method
Let me explain the source of Dyson’s authority. Right after World War II, wartime physicists returned to investigating fundamentals. The most fundamental theory at that time was quantum electrodynamics (QED), whose equations, known since the late 1920s, successfully described the interaction of electrons with light, and are the basis of all we understand about everyday physics and chemistry. Calculations via QED agreed perfectly with everything one could measure. Then, in the late 1940s, experimental physicists at Columbia University discovered tiny but very precise discrepancies between experiment and theory in the radiation emitted from a hydrogen atom. A careful examination of the puzzling intrinsically quantum nature of electrons and light showed that subtle “higher-order” quantum corrections were implied by the 1920s theory and that they could in principle explain the small discrepancies. However, when theorists set about calculating their size, they ran into two brick walls. First, the higher-order calculations in QED required elaborate mathematical skill and exhaustive care and patience. Second, and even worse, these ostensibly “small” effects, when calculated, turned out to be infinitely large in a mathematical sense. Something was badly wrong, but a lot was right too.
Three people found the solution. Schwinger in the USA and Tomonaga in Japan solved it by successfully calculating the size of the subtle corrections with more formidable mathematical techniques than anyone had succeeded in doing before. Feynman, also in the USA, calculated the corrections by a totally new and astonishingly imaginative method that he invented from scratch; it involved drawing intuitive diagrams of the electron interacting with light, and yielded the same accurate answers with much simpler mathematics. He could, in his own way, calculate in half an hour what took others months.
Many could, with enough effort, understand the Schwinger-Tomonaga method but few had the skill to carry it out. No one could understand the validity of Feynman method’s but, if they were willing to accept it, everyone could use it with ease. Dyson, without a PhD (he never subsequently obtained one) and visiting the USA from Britain, was the sole person to immerse himself in both approaches, and, one day, after an epiphany on a Greyhound bus, showed how Feynman’s easy picturesque methods followed rigorously from Schwinger’s traditional approach. Ever since, all physicists use Feynman diagrams. Life without them is inconceivable. Feynman, Schwinger and Tomonaga received the 1965 Nobel Prize for physics; many believe Dyson should have been included, though Dyson gracefully says he was the intermediating technician rather than the originator of the successful theories.
When I read Disturbing the Universe, I was fascinated by Dyson’s perceptive, respectful and tender account of his relationship with Feynman at the time of their great discoveries thirty years earlier. But the rest of the book, though immensely interesting, puzzled me. At that time I believed that a physicist should dedicate himself to investigating the fundamental. Yet many of the remaining chapters described Dyson’s work on engineering problems that, it seemed to me then, were unworthy of someone who had made and could perhaps still have made more such great contributions to fundamental physics.
Bird or frog
Yet, reading Schewe’s biography and rereading Disturbing the Universe, one comes away with a sense of Dyson’s unregretful authenticity. In a recent foreword to Mathematics as Metaphor, a book of essays by the Russian mathematician Yuri Manin, Dyson wrote:
Some mathematicians are birds, others are frogs. Birds fly high in the air and survey broad vistas of mathematics out to the far horizon. They delight in concepts that unify our thinking … Frogs live in the mud below and see only the flowers that grow nearby. They delight in the details of particular objects, and they solve problems one at a time. I happen to be a frog, but many of my best friends are birds.
Touted in his twenties as “perhaps the best mathematician in England,” he made a great discovery in physics, but then remained an amateur in the best sense of the word.
“Do I dare/ Disturb the universe?” asks the protagonist in T. S. Eliot’s The Love Song of J. Alfred Prufrock. “I have heard the mermaids singing, each to each.” Dyson seems to have done both. 1979 is long gone. Now much older, I appreciate that Dyson, in the words of a Lou Reed song, was always “doing the things that he wants to.” Everyone should be so lucky.