If you want to slam people’s religious beliefs, call their faith a cult, its organizer a cult leader, and its buildings of worship a cult compound. The media are utterly predictable in this regard: “Members of the Idaho-based cult, whipped into a frenzy by their charismatic cult leader, have hunkered down in an isolated compound to await the end times.”

The difference between a cult and a religion in the modern world is about a hundred years. The Mormons have made the transition; for decades, hardly anyone has called the Church of Jesus Christ of Latter-Day Saints a cult. The Scientologists are about halfway there; the cult moniker is still commonly attached to them, although less often than a few years ago.

In the past, shaking off such pejoratives as cult and superstition took much longer. Critics talked for several centuries about the cult of Christianity, whose charismatic leader, Jesus of Nazareth, whipped his disciples into a frenzy. Early in the second century c.e., for example, Pliny the Younger characterized Christianity as a “contagious superstition.” Christian scholars responded by dismissing Greek and Roman religions as superstitions.

Dale B. Martin, a professor of religious studies at Yale University, traces eight centuries of these bitter wars of the words, from classical Greece to the Christianized Roman Empire. “‘Superstition’ was a category invented by ancient intellectuals, especially those we call philosophers,” he observes. “They came to believe that traditional notions about nature and divine beings could not be true, and they criticized all sorts of beliefs and practices that their contemporaries simply assumed were legitimate.”

The critiques began long before Christianity. Around the fifth century b.c., Greek philosophers derided beliefs that gods are nothing more than extensions of their human charges, or that they harm people through disease and supernatural disasters—god as superhero or Dr. Evil. Whatever a god is, the ancient philosophers argued, it must be wholly different from us. But as Martin points out in this sound, skeptical debunking of the work of earlier historians, these critiques didn’t stem from empiricism, rationalism, or new evidence. Rather, the philosophers “took these new notions to be true because they felt that they ought to be true.”

Christianity’s response to such critiques in its own time was equally nonempirical and nonrational. Among the social, economic, and political variables that contributed to the victory of Christianity over its pagan competitors in the Roman world, Martin identifies one of particular interest: daimons (demons, in modern spelling). Whereas classical philosophy maintained that “evil daimons did not exist,” he says, Christianity “offered an antidote more powerful than the poison, a drug stronger than the disease: healing and exorcism in the name of Jesus. . . . In its demonology, Christianity tapped into an assumed reality and met a need in a way classical philosophy had failed to do.”

Gradually, Martin writes, “‘Christianity the superstition’ was replaced by ‘Christianity the only true philosophy.’” With the endorsement of the new religion by the Roman emperor Constantine early in the fourth century c.e., the contest was settled. It became “‘superstitious’ (in the increasingly dominant discourse of Christianity) to worship the ‘pagan’ gods.”

Martin’s solidly researched and clearly written history is an important contribution to our understanding of the context and meaning of superstition, particularly in its application to religious beliefs, and a useful reminder that linguistic insults between religious and philosophical camps are an ancient tradition indeed.

—Michael Shermer