British physicist Paul Dirac had a brilliant mind, but the joys of daily life flummoxed him, discovers Robin McKie.
Werner Heisenberg
In August 1929, two of the founding fathers of quantum mechanics, Werner Heisenberg and Paul Dirac, were sailing on a cruise ship to a conference in Japan. Both still in their twenties, and unmarried, they made an odd couple. Heisenberg was a hedonist who constantly flirted and danced with women on the ship, while Dirac - "an Edwardian geek", as Graham Farmelo puts it - suffered agonies if forced into any kind of socialising or small talk. "Why do you dance?" Dirac asked his companion. "When there are nice girls, it is a pleasure," Heisenberg replied. Dirac pondered this notion, then blurted out: "But, Heisenberg, how do you know beforehand that the girls are nice?"
The remark perfectly sums up Dirac, one of the most revered - and strangest - figures in the history of science. The physicist, born in 1902, predicted the existence of anti-matter, laid down some of quantum mechanics' key equations, won a Nobel Prize in 1933 and laid the foundations for today's micro-electronics industry. He was also a misfit who lacked social skills or insight into the feelings of others. His daughter Monica never once remembered him laughing; he turned down a knighthood because he didn't want people using his first name; and when questioned about a statement made during a lecture, he merely repeated the offending sentence in a slower, louder, slightly irritated voice. He ate only the plainest of foods and, in reply to his wife Manci demanding, after a row, what he would do if she left him, looked puzzled before replying: "I would say goodbye, dear."
His close friends included Robert Oppenheimer, Heisenberg and Einstein, admirers who nevertheless found his company - and his silence - unsettling. "This balancing on the dizzying path between genius and madness is awful," Einstein once said of Dirac. For his part, Dirac blamed his frailties on his father, a Swiss immigrant who bullied his wife, chivvied his children and insisted Paul spoke only French at home, even though the Diracs lived in Bristol. "I never knew love or affection when I was a child," Dirac once said.
His work, though, was striking for the purity of his mathematical reasoning, a gift that saw him appointed Cambridge's Lucasian professor of mathematics at 29. By then, Dirac was at the height of his powers and his output included work on cosmology, uranium-enrichment and quantum mechanics. As Freeman Dyson noted: "His great discoveries were like exquisitely carved marble statues falling out of the sky."
As a result, Dirac was showered with awards and accolades. He was made a member of the Order of Merit (which meant he could continue to use his surname) and, after his death, was commemorated in Westminster Abbey's science corner. Yet Dirac today is virtually unknown in Britain or - even worse - in the city of his birth. "During my many visits to Bristol, I have met scarcely half-a-dozen people outside the university who have heard of him," notes Farmelo. Even the city's records office was perplexed by the name. By contrast, Bristol has lionised Dirac's exact contemporary Archie Leach (aka Cary Grant). Farmelo is therefore to be congratulated for reminding us of the scientist's remarkable achievements and for producing such a well-researched and insightful biography.
The book does have flaws, however, with Farmelo indulging in some odd, infelicitous turns of phrase: "He was her Elvis and she was his Colonel Parker," is his strange summing up of Dirac's marriage, while the scientist is described as the "Trotsky of theoretical physics", presumably because his work was a constant revolution of ideas. These are minor drawbacks, however, and do not undermine a magnificent biography from which Dirac emerges with sympathy, damaged but not broken and capable of love but not of expressing it.
As to the roots of his peculiar behaviour, Dirac was probably right to blame his father, though not just for his bullying. The problem lay with his genes, Farmelo argues. Both father and son had autism, to differing degrees. Hence the Nobel winner's reticence, literal-mindedness, rigid patterns of behaviour and self-centredness
However, Dirac flourished because he was a Cambridge don whose food and bed were made for him and who could work to his own tight routine. It was a fortuitous combination. As Farmelo says: "Dirac's traits as a person with autism were crucial to his success as a theoretical physicist: his ability to order information about mathematics and physics in a systematic way, his visual imagination, his self-centredness, his concentration and determination."
The divide between genius and mental fragility is indeed a fine one - a point perfectly revealed through the brilliant but perplexing mind of Paul Dirac and by this handsomely written story of his life.