Einstein’s Clocks, Poincaré’s Maps:Empires of Time
by Peter Galison
Norton, 389 pp., $23.95
Today the name of Einstein is known to almost everybody, the name of Poincaré to almost nobody. A hundred years ago the opposite was true. Then, Albert Einstein was a newly appointed technical expert, third class, examining patent applications in the Swiss patent office in Bern, having failed in his efforts to find an academic job, while Henri Poincaré was one of the leading figures of the French scientific establishment, famous not only as a great scientist but as the author of popular books that were translated into many languages and kept the public informed about the dramatic progress of science during the early years of the twentieth century. A hundred years ago, Einstein and Poincaré were both working hard at one of the central problems of science, trying to find a correct theory to describe how fast particles behave in electric and magnetic fields. Poincaré had published several papers on the subject which Einstein may or may not have read. Einstein had published nothing.
Two years later, in 1905, Poincaré and Einstein simultaneously arrived at a solution to the problem. Poincaré presented a summary of his results to the French Academy of Sciences in Paris, and in the same month Einstein mailed his classic paper, “Electrodynamics of Moving Bodies,” to the German journal Annalen der Physik. The two versions of the solution were in substance almost identical. Both were based on the principle of relativity, which says that the laws of nature are the same for a moving observer as they are for an observer standing still. Both agreed with the experimentally observed behavior of fast particles, and made the same predictions for the results of future experiments. How then did it happen that Einstein became world-famous as the discoverer of relativity, while Poincaré did not? Poincaré’s lasting fame, such as it is, derives from his discoveries in other areas of science and not from his work on relativity. Is the verdict of posterity, giving all the credit for relativity to Einstein and none to Poincaré, fair or unfair? I will return to these questions later.
Peter Galison is a historian and not a judge. His purpose is to understand the way in which Poincaré and Einstein arrived at their insights, not to hand out praise or blame. His book is an extended double portrait, describing their lives and times in detail. At the beginning, he complains of the unequal treatment given to them by biographers: “There are, to be sure, too many biographies of Einstein and not enough of Poincaré.” Poincaré was a great man who lived a full and many-sided life, and he deserves at least a fraction of the attention that has been lavished on Einstein. For readers who may be interested in learning more about Poincaré, I recommend a short biography by Benjamin Yandell that Galison does not mention. Yandell’s book, The Honors Class: Hilbert’s Problems and Their Solvers, is a collection of biographies of mathematicians who solved a famous list of …