The chapter analyzes the rise of Jewish scientific materialism in the 1870s. Inspired by both the revolutionary politics of the Russian intelligentsia and the German popular science movement, scientific materialists educated Jews about the laws of nature, technological inventions, and, most important, how God and the Jewish people could be understood through biological and chemical processes. Though often overlooked by historians, their views prefigured the major debates in the twentieth century over the scientific and biological basis of Jewish nationalist and cosmopolitan politics.