The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom ,

Graham
Farmelo
,
Basic Books
,
New York
, 2009. $29.95 (512 pp.). ISBN 978-0-571-22278-0

When he was a boy selling raffle tickets, British physicist and biographer Graham Farmelo met a theoretical physicist who idolized Paul Dirac so much that he named one of his daughters Paula and read Dirac’s The Principles of Quantum Mechanics each Christmas, just for pleasure. Through that encounter, Farmelo became smitten with both theoretical physics and Dirac, “the theorists’ theorist.” In The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom, Farmelo has written an excellent biography of a hero of physics who lived from 1902 to 1984.

The Strangest Man is a much more personal account than Helge Kragh’s Dirac: A Scientific Biography , published in 1990 by Cambridge University Press. Farmelo describes technical developments at a level that will be accessible to nonphysicists and recounts some of the familiar events of early 20th-century physics, this time seen fresh through the trajectory of Dirac’s personal life. But the real contribution of Farmelo’s work is to uncover Dirac’s hidden life using material held in archives, correspondence held in private collections, and interviews conducted with friends, family, and colleagues.

The portrait that emerges is of a man who, on the one hand, thinks deep thoughts, calculates seemingly without error in precise handwriting, says only what needs to be said, and is utterly independent, and, on the other hand, is extremely emotionally insensitive, is often unwilling or incapable of effective communication, and, at least according to Farmelo, is likely autistic. As a child, Dirac learned to survive by speaking infrequently, eating little, and making himself independent of the need for approval or even human warmth. Fortunately for Dirac, Cambridge University would prove to be a home that was perfectly accepting of his eccentricities while providing the resources that would allow him to flourish—as he did especially from 1925 (two years after he arrived) to 1933, when he helped produce the new quantum mechanics.

Dirac brought to Cambridge his earlier education from the University of Bristol, which supplied him with engineering training that focused on getting results without getting hung up on rigor; Bristol also gave Dirac his start in physics and rigorous mathematics. His capacity to draw on both pragmatic and rigorous approaches was to be an important ingredient in his later success. In addition to providing further training in physics and mathematics, Cambridge exposed Dirac to the work of physicists such as Niels Bohr, Arnold Sommerfeld, and Werner Heisenberg. The book discusses Dirac’s work and interactions in Cambridge, Copenhagen, and Göttingen, Germany, as well as his trips to the Soviet Union. Wherever he was, Dirac kept mostly to himself and collaborated infrequently, but when he did work with others, he impressed every-one with his prowess and strangeness.

After those eight brilliant years in which he helped to define quantum mechanics, Dirac began to slow down—as did the other theorists of his time—and the thread of productive questions and revolutionary insights seemed broken. He continued to work on quantum mechanics, as well as gravity, cosmology, nuclear physics, and the effort during World War II to build a nuclear bomb. For the remainder of his life, he also started to unlearn some of his more abnormal behaviors and to open up ever so slightly, in part due to the influence of Eugene Wigner’s sister, Margit, or “Manci.” Dirac married Manci in 1937, six months after his father’s death.

The title of the book is taken from Bohr’s comment that Dirac was the strangest visitor ever to Bohr’s institute in Copenhagen. Dirac blamed his underdeveloped emotions on his parents: a severe and mean father and a doting mother who was more needy than nurturing. When his brother Felix committed suicide, Dirac expressed surprise at the intensity of his parents’ grief, saying that was when he learned that parents were supposed to care for their children. Readers may accept that recollection as strictly accurate or interpret it as his way of complaining about his parents.

But Farmelo doesn’t buy the idea that Dirac’s unhappy childhood was at the root of his peculiarities. Two of Farmelo’s interviewees, who refused to be identified, ventured that Dirac was autistic, which Farmelo believes fits Dirac’s behavior. Despite all the reservations that he expresses about the autism diagnosis, Farmelo still chooses that explanation, for which he gives only a plausibility argument. Furthermore, he does not offer evidence to support or discredit the explanation that childhood trauma could have caused Dirac’s later behavior.

Perhaps Farmelo felt the need for a narrative closure to this story of “the strangest man.” Some readers may not need to know the cause of Dirac’s behavior or believe the one Farmelo gives. Still, in The Strangest Man, we are treated to a fascinating, thoroughly researched, and well-written account of one of the most important figures of modern physics.