March 23: Jewdayo’s First Mathematician

Paul J. Cohen of Stanford University, who won Fields Medal for Outstanding Mathematical Achievement in 1966 for proving that the continuum hypothesis was not provable (!), died on this date in 2007 at the age of 72. The continuum hypothesis states that there are no sets bigger than the integers and smaller than the real numbers. The question has been posed in 1880; Kurt Gödel proved that the hypothesis was not disprovable (in 1940) and Cohen proved that it was not provable (in 1963), based on known mathematics. In the course of his proof, Dr. Cohen also developed a mathematical modeling technique called “forcing” that is used to test a given hypothesis for truth or falsehood. His insights, according to Peter Sarnak of Princeton, were “courageous and truly exceptional” and opened “a floodgate of mathematical activity.” Cohen was also a linguist, fluent in Swedish, French, Spanish, German and Yiddish.

“Kurt Gödel . . . lauded Cohen’s work as ‘no doubt . . . the greatest advance in the foundations of set theory since its axiomatization.’”
—Solomon Feferman