It is usually assumed that, as an approach to religion, or to culture in general, functionalism is passé. Functionalism has been superseded by structuralism, poststructuralism, and postmodernism. Yet the appeal of functionalism as an explanation of the existence or persistence of religion has meant the continuing appearance of functionalist works on religion, which hail mainly from the social sciences. This article focuses on the philosophical problems posed by functionalism. Some of those problems are hoary. Others, while already recognized, were presented in their classic form in 1959 by Carl Hempel. Only those social scientists with philosophical proclivities were ever affected by Hempel’s challenge. Their unanimous response has been to try to meet the challenge, and the fate of functionalism has been assumed to rest with the response to Hempel. This article presents responses by philosophers themselves to Hempel. It concentrates on the response by Robert Cummins, who defends functionalism in biology and, by implication, social science by recharacterizing it—and in turn making Hempel’s challenge irrelevant. What a functionalist approach to religion guided by Cummins’ depiction of functionalism would look like is offered.