Paul Dirac...new book

The Strangest Man: The Hidden Life of Paul Dirac, Quantum Genius

by

Graham Farmelo

ISBN-10: 0571222781
ISBN-13: 978-0571222780

"Studying the Strangest Man"

by

Lee Billings

September 15th, 2009

Seed

For more than five years, former physicist Graham Farmelo devoted himself to unlocking the secrets of one of the most important and curious figures of 20th century science, Paul Dirac. He was born in 1902 and died in 1984, and though lionized by his peers for his fundamental work in quantum mechanics (among other things, he predicted the existence of antimatter and won a Nobel Prize when he was only 31), Dirac’s legacy has fared poorly among the general public. During his research, Farmelo found that most residents of the “famous” physicist’s hometown of Bristol didn’t even know who Dirac was. Unquestionably, this is due to Dirac’s reclusive and taciturn behavior; his social quiescence was so extreme that it inspired his fellow physicists to invent an unofficial unit of measure for the minimal number of words a person could speak in polite company: a “Dirac,” roughly one utterance per hour.

But as Farmelo delved deeper into Dirac’s life for his new biography, The Strangest Man, he discovered surprising complexity and contradiction that gives new appreciation to the physicist’s character: Despite what many perceived as a lack of empathy, Dirac married, raised children, and forged several close lifelong friendships. Despite his professed distaste for unscientific reasoning, in his later life he became increasingly obsessed with philosophical, even religious, questions. And despite his love for the rarefied subject of theoretical physics, Dirac also had a passion for “lowbrow” cartoons and comic books.

Farmelo spoke with Seed’s Lee Billings about the process of researching the book and his astonishing hypothesis that could explain, once and for all, Dirac’s enigmatic behavior.

Seed: What motivated you to spend five years writing a book about Paul Dirac?

Graham Farmelo: I used to be a theoretical physicist, and I can say that everyone in that profession is interested in Dirac. He’s often said to be “the first really modern theoretician” or “the theorist’s theorist.” I remember as an undergraduate coming across my first taste of Dirac’s physics, something called Fermi-Dirac statistics, which governs the transistors and electron flow in your computer. I was blown away, a bit like a young music student listening to Beethoven’s “Moonlight Sonata.” Dirac’s first papers on quantum mechanics still look modern, more than those of any of his fellow pioneers. The mathematical imagination and beauty of those articles is amazing. I wanted to write a biography of him to try to communicate the power and scope of his work to non-specialists who are nevertheless curious about science, and to try to understand his remarkable personality.

In my time in physics, I met quite a few “Dirac fanatics,” people who are obsessive about him. I’m speaking to you from the Institute for Advanced Study in Princeton, and I’ve spent several lunchtimes recounting to the physicists here some new “Dirac stories.”

Seed: “Dirac stories?” Can you give me some examples?

GF: Certainly. At the end of a lecture, Dirac agreed to answer questions. Someone in the audience piped up: “I didn’t understand the equation on the top right of the blackboard, professor.” Dirac was silent for more than a minute. When the moderator asked him if he’d like to answer the question, Dirac shook his head and said, “That wasn’t a question. It was a comment.”

Here’s another: Over dinner one evening at Saint John’s College, Cambridge, an American visitor who was desperate to meet the formidable Dirac steeled himself to ask, “Are you going on vacation this summer, professor?” Silence. About 20 minutes later, Dirac turned to the visitor and said, “Why do you ask?”

Seed: He sounds like quite a deep, literal thinker. Did Dirac have any interests outside physics?

GF: Yes, a lot, but he just didn’t talk about them. He read widely, from Tolstoy to John le Carré. Among artists, he loved Rembrandt and Salvador Dali. Like Einstein, Dirac’s taste in music was mainly classical, but in later life he had a thing about Cher. To settle a dispute with his wife, he bought a second television so that he could watch a Cher special while she watched the Oscars.

Seed: The book includes several revelatory passages documenting Dirac’s personal life. How did you research and verify that material?

GF: I devoted a lot of time tracking down Dirac’s surviving friends, people who knew him very well. The most important one I found was his last great friend, Leopold Halpern, an expert on relativity who slept in the open air, refused to wash with soap, and liked to slice open baked potatoes with a karate chop. A few years ago, when Halpern was at death’s door with prostate cancer, he flew across the country to Florida, where Dirac spent the latter part of his life, just so he could row me up Wakulla Springs. He and Dirac used to go rowing every weekend. That was a special trip for me: Even now I’m looking at my arm and there are goose bumps. He showed me places where they talked, even where they went skinny dipping. Two and a half months later, Halpern died.

I spent several months consulting the Dirac archive at Florida State University in Tallahassee, which was virtually untouched. Dirac was an FSU professor for the last 14 years of his life. I found amazing things, not just letters from great physicists like Heisenberg and Schrödinger but also an amazing cache of weekly letters from Dirac’s mother, spanning almost 20 years. Many historians would’ve probably turned their noses up at these, but I found in them a dramatic story that illuminates Dirac’s home life and upbringing. I was also blessed with beginner’s luck when I happened to meet Dirac’s younger daughter at a centenary celebration of his birth. We hit it off well, and one day in her kitchen while I was visiting her, she showed me something like 120 private letters between Dirac and his first serious girlfriend, later his wife. Keep in mind, this man hardly spoke a word, and here he was opening up, writing whole pages—epics for him. I couldn’t believe my luck. Here was Dirac talking about his father with whom he didn’t get along at all, and about what it felt like to be someone conscious, that he was unlike most other people, unable to empathize with them. This is just my opinion here, but I believe he demonstrated many symptoms of what we now call autism, though that condition had not been identified at the time.

Seed: You think Dirac had undiagnosed autism?

GF: I did not go into this book project thinking Dirac was autistic in any way. When I started researching him all those years ago, I barely even knew what the term “autism” meant, and certainly didn’t apply it to Dirac. But as I researched, I encountered rumors about Dirac being autistic, about Einstein being autistic, and speculations that autism was more prevalent in scientists and mathematicians. So during one of my stays at Cambridge, I went to see Simon Baron-Cohen, who is arguably Britain’s leading expert on autism. He knew nothing about Dirac, but, to my amazement, he began describing patterns of behavior that exactly correspond to Dirac’s. Let me stress that this is just a hypothesis, and that I’m personally very skeptical of attempts to psychoanalyze people who are dead. This isn’t theoretical physics; I can’t do a slam-dunk experiment to prove it.

Seed: What were some of the behavioral indicators?

GF: There are many of them: inability to empathize, extreme taciturnity and literal-mindedness, a passion for a routine, narrow interests, a lack of physical coordination, dislike of sudden loud noises, and so on. Many of the “Dirac stories” told by physicists are, in my opinion, actually autism stories. When people are laughing at these things, they forget what they’re actually doing is mocking.

Seed: Do you think those traits might have helped him in his work or given him a unique perspective?

GF: Well, he was certainly as focused as a laser and as logical as a computer. He also had a fascinating way of looking at mathematics. He had a phrase, “My equation is smarter than I am.” He really did think that a good equation could be more intelligent than its creator. There’s a kind of mysticism in that. In the last 15 or 20 years of his life, he became obsessed with the philosophy that, for a piece of mathematics to be useful in fundamental physics, it must be beautiful. For instance, he thought the theory of photon and electron interactions—what we call quantum electrodynamics—was ugly, so he wouldn’t accept it. He had this extremely rigorous sense of beauty, and saw each successive revolution in physics progressing through increasingly beautiful mathematics.

Dirac, to his dying breath, pursued this quest for mathematical beauty. For him, everything apart from that principle was just details. The job of the fundamental theorist was to look for mathematically beautiful laws. That’s why the string theorists are on the right track, even though there aren’t experiments to bear them out at the moment.

Seed: So Dirac would be a fan of string theory, you think?

GF: Well, when people get old, they tend to basically think that everything’s gone to the dogs, and there was an element to that in Dirac, who took virtually no interest in the latest findings in his field. But if you apply his idea about sticking to mathematically beautiful generalizations of past theories and to hell with experiments in the short term, then this philosophy should embolden string theorists, yes.

"Quantum Leap"

by

Louisa Gilder

New York Times

This biography is a gift. It is both wonderfully written (certainly not a given in the category Accessible Biographies of Mathematical Physicists) and a thought-provoking meditation on human achievement, limitations and the relations between the two. Here we find a man with an almost miraculous apprehension of the structure of the physical world, coupled with gentle incomprehension of that less logical, messier world, the world of other people.

At Cambridge University in 1930, Subrahmanyan Chandrasekhar took a class in quantum mechanics from the 28-year-old Paul Dirac. Three years later, Dirac would become the youngest theoretician to receive the Nobel Prize in Physics up to that time (50 years after that, Chandrasekhar would become one of the older ones). Chandrasekhar described Dirac as a “lean, meek, shy young ‘Fellow’ ” (i.e., of the Royal Society) “who goes slyly along the streets. He walks quite close to the walls (like a thief!), and is not at all healthy.” Dirac’s class — which Chandrasekhar took in its entirety four times, even though Dirac taught it by repeating material from his recently published textbook word for word — was “just like a piece of music you want to hear over and over again.”

Dirac is the main character of a thousand humorous tales told among physicists for his monosyllabic approach to conversation and his innocent, relentless application of logic to everything. Listening to a Dirac story is like slipping into an alternate universe: Dirac reads “Crime and Punishment” and reports it “nice” but notes that in one place the sun rises two times in a day; Dirac eats his dinner in silence until his companion asks, “Have you been to the theater or cinema this week?” and Dirac replies, “Why do you wish to know?”

His work was as sui generis as his social skills. “The great papers of the other quantum pioneers were more ragged, less perfectly formed than Dirac’s,” explained Freeman Dyson, who took Dirac’s course as a precocious 19-year-old. Dirac’s discoveries “were like exquisitely carved marble statues falling out of the sky, one after another. He seemed to be able to conjure laws of nature from pure thought.” (Most notably, Dirac predicted the existence of antimatter in 1928 because his just discovered relativistic electron equation required it.) “It was this purity that made him unique.”

In 1990, Helge Kragh wrote “Dirac: A Scientific Biography,” a useful resource comprising physics, a little history and a dessert of Dirac stories in a chapter entitled “The Purest Soul.” And indeed, what else besides quantum mechanics and amusing anecdotes did this great and single-minded physicist’s life hold?

“The purest soul” is a quotation about Dirac from Niels Bohr, as is Graham Farmelo’s title. (“Dirac is the strangest man,” Bohr said, “who ever visited my institute.”) But purity and strangeness were not the whole story. Kragh’s book offers a collage of a brilliant and peculiar man seen from the outside; Farmelo’s is a tapestry, and he provides glimpses of the inside.

A senior research fellow at the Science Museum in London, Farmelo gives us the texture of Dirac’s life, much of it spent outdoors — from long Sunday walks as a young man, looking like “the bridegroom in an Italian wedding photograph,” “dressed in the suit he wore all week, his hands joined behind his back, both feet pointing outwards as he made his way around the countryside in his metronomic stride”; to late-life canoeing trips with Leopold Halpern, a physicist even stranger than he, “through forests of sassafras and American beech trees, draped with Spanish moss. The alligators made scarcely a sound: the silence was broken only by the rhythmic sloshing of the paddles, the cry of a circling osprey, the occasional shuffling of wind passing through shoreline gaps in the forest.” (After lunch, they swam and paddled back, “scarcely exchanging a word.”)

We follow Dirac from his pinched and chilly childhood in Bristol (a few blocks away from the two-years-younger Archie Leach, a k a Cary Grant); through his discovery, visiting the Bohrs in Copenhagen, of what a happy family was like; his fiercely loyal friendship with Werner Heisenberg; his joyful beach honeymoon, still in a three-piece suit; his careful fatherhood (constructing for his daughters’ cat a door wider than its whiskers); to his death in Florida — “a place where recreational walkers are regarded as perverse” — in 1984.

The science writing in “The Strangest Man” isn’t glib, but neither does it require problem-solving on the part of the reader. In most cases, Farmelo presents the technical matter clearly and efficiently, and in all cases — one of the great joys of the book — Dirac’s scientific insights are placed within the circumstances in which they were born: e.g., the “sweltering July” of 1926 when Dirac, sitting at his college desk, produced his paper on what became Fermi-Dirac statistics.

In a prologue, Farmelo describes a visit to the elderly Dirac paid by his biologist colleague Kurt Hofer. Through the eyes of Hofer, we see Dirac suddenly break out of monosyllables to talk for two hours with increasing vehemence about his monstrous father. This represents the author’s careful decision to keep the tale Dirac told about his childhood separate from — even as it overshadows — the rest of the book, and it ends with Hofer’s thoughts, not Dirac’s: “ ‘I simply could not conceive of any childhood as dreadful as Dirac’s.’ . . . Could it be that Dirac — usually as literal-minded as a computer — was exaggerating? Hofer could not help asking himself, over and again: ‘Why was Paul so bitter, so obsessed with his father?’ ”

The conflict between this prologue (which gives ample reason for Dirac to be bitter about his father) and the seemingly warm family life that emerges in the first chapter casts a tension over the rest of the book very similar to that felt when reading a mystery. And as in a mystery, the penultimate chapter sheds new light. There Farmelo delves into a sensitive exploration of the possibility that Dirac was autistic, and of the ways in which his lack of facility in reading the emotions of others affected their perceptions of him and his perceptions of them. The emphasis on Dirac’s childhood as a story — one Farmelo (along with me) believes to be true — usefully reinforces the importance of point of view.

In a memorable episode, Dirac and his wife visit their closest friends, Peter and Anna Kapitza, in Russia. In 1934, the long arm of the Soviet state had wrenched Kapitza, despite his devoted long-distance fellow-traveling, away from his lab at Cambridge under Ernest Rutherford and back into the Soviet Union. In 1937 the friends reunited at the Kapitzas’ summer house in the piney woods of Bolshevo, “with wild strawberries ripe for gathering and a fast-flowing river close by.” They arrived only “days before Stalin authorized the torture of suspected enemies of the people,” Farmelo writes. “On the roads around Bolshevo, some of the trucks marked ‘Meat’ and ‘Vegetables’ hid prisoners on their way to be shot and buried in the forests to the north of the city which Dirac admired through his binoculars.”

Farmelo handles such scenes with a refreshing, cleareyed understanding of how complicated the world actually is. Dirac did not — probably could not — know what the Soviet Union really was; he also could not know who his father really was, and his father could not really know him. These complexities and unresolvably cubist perspectives make, paradoxically, for the most satisfying and memorable biography I have read in years.

Paul Dirac