William Graham Sumner (1840–1910), professor at Yale, was the American version of the English evolutionist Herbert Spencer (1820–1903). Sumner was a strong advocate of unrestricted capitalism. He was famous for his essay “The Man of Virtue,” which promoted self-interest as a primary duty for individuals. The industrialist Andrew Carnegie (1835–1919) built on these ideas in his “The Gospel of Wealth,” which further enshrined the “law of competition” as a natural principle of progress.