Farmelo strongly suggests that Dirac was autistic, and that perhaps his father was too. The relationship between Paul and Charles was, in Farmelo's guess, doomed by nature rather than nurture: “The young Dirac was born to be a child of few words and was pitiably unable to empathize with others, including his closest family.”
Whatever the cause of Dirac's oddness, he was able to make a few close friends, including Russian physicist Peter Kapitza, and, though showing no particular interest in women, married and fathered two children.
Those who are interested in the psychology of genius will find Dirac's story, as told by Farmelo, compelling. The book is also a wonderful romp through the golden age of quantum physics. The cast of characters will be familiar by name to many readers: Einstein, Rutherford, Bohr, Schrödinger, Heisenberg, Fermi, Oppenheimer and Feynman, to name just a few. And the story is set against a background of epochal world events: the regimes of Hitler and Stalin, the Second World War and the atomic bomb.
One of the more interesting themes to run through this book is the contrast of two ways of doing physics, which might be called “bottom-up” and “top-down.” In the former, one gathers data by experiment, then looks for a mathematical theory that describes the data. In the latter, one contrives beautiful mathematical theories, then looks to see if nature conforms. Dirac was very much in the “top-down” camp. His confidence in his theories derived exclusively from their mathematical elegance.
Farmelo writes: “[W]hat is most remarkable about the story of antimatter is that human beings first understood and perceived it not through sight, smell, taste and touch, but through purely theoretical reasoning inside Dirac's head.”
The same might be said about Einstein's theory of general relativity, which was conceived in his head before any experiment indicated its necessity, and today's string theory, which is awaiting empirical verification. In the end, of course, observation is the ultimate test of any theory.
Dirac outlived almost all of his contemporaries, spending the last 13 years of his life at Florida State University, still strange, still revered as an intellectual giant of his times, but no longer at the cutting edge of his field. He died in 1984 at the age of 82, lamenting that his life was a failure. This excellent biography is worthy of its remarkable subject.
Chet Raymo is the author of a dozen books on science and nature. He resides on the Web at www.sciencemusings.com.
