Willpower triumphs over material or physical considerations. The idea is very old indeed, expressed by Virgil in the Aeneid (Mens agitat molem, “mind moves matter”), and, in an entire system of philosophy, by Britain’s Bishop George Berkeley (1685–1753), who held that nothing in the world exists unless it is perceived by the human mind. In the twentieth century, however, the cliché is most often invoked for or by someone who is carrying on normal activities despite being physically ill or otherwise incapacitated. The humorist Jack Benny quipped, “Age is strictly a case of mind over matter. If you don’t mind, it doesn’t matter” (quoted in New York Times, Feb. 15, 1974).