Henry Sheffer

Sheffer was a Polish Jew who emigrated with his family to the United States in 1892 and earned his doctorate in philosophy at Harvard under Josiah Royce. In 1913 he proved that the whole of Boolean algebra and propositional logic can be built from a single binary operation, 'not both' — now called the Sheffer stroke or NAND — a result that later became foundational to digital circuit design. He taught logic at Harvard until 1952.