1859-1924

German-born American biologist who was the leading spokesperson for the mechanistic philosophy of biology in the early twentieth century. He was primarily interested in replacing explanations of behavior that were based on instincts, which he considered vitalistic, with explanations based on chemical tropisms. Extremely well known to the public as a materialist, mechanist, and socialist, Loeb became a popular figure for other American dissenters, such as H. L. Mencken and Thorstein Veblen.