Georgetown University theology Professor Ariel Glucklich has written four books about religion, three focusing on the spiritual traditions of India. But the idea for his most recent work, Sacred Pain: Hurting the Body for the Sake of the Soul, didn’t emerge from his scholarly research; it sprang from something entirely different: his father’s war wound.

A retired Israeli scientist, Joseph Glucklich—who lost a leg in World War II—continues to experience phantom-limb syndrome, painful sensations that seem to emanate from his former extremity. Over the years, “we’d talk about the nature of pain,” the younger Glucklich says. “So I decided I would look into that question.” His new book marries his academic specialty, the history of theology, with his new area of interest, neurobiology.

Glucklich, 48, spent six years poring over studies of religious practices and articles about the science of pain. He also interviewed people—mostly Christian and other mystics—who have hurt themselves in the name of a higher power. “The Catholic Church, since the 19th century, has discouraged causing oneself pain, but I know for a fact that priests and monks still practice it—regulated, controlled pain,” he says. “Sometimes it’s with an elastic belt around the thigh that has pins and short nails; sometimes it’s by hitting oneself with knotted ropes.” But Glucklich says that the pilgrimage—which combines a deep religious experience with physical deprivation—is the most common form of religious pain today. “Pilgrims have to walk on hot days with their bare feet, which is very, very painful,” he says.

Pain, Glucklich asserts, does strange things to an individual’s consciousness. Intentionally inflicting pain on oneself whips the nerves into a frenzy—reducing the mind’s self-awareness and allowing something else, such as religiosity, to fill the void.

Most of Glucklich’s interviewees “couldn’t understand my theory,” he says. Yet their experiences, he adds, jibed with it. “They control their own pain, and the more they hurt, the more they become otherworldly,” he says. “They say they become empty, and something else floods in.” Torture—pain inflicted by someone other than the person being hurt—does not bring the same sensation, suggesting to Glucklich that self-control is crucial.

Pious self-hurting is widespread around the globe and has been common throughout the history of religion. But pain in the service of faith declined beginning with the development of anesthetics in the 1840s. “Before that, life was constantly full of pain,” Glucklich says. “Suddenly, people were given the option of not hurting, so pain became a medical problem. People who opted to hurt themselves were stigmatized as masochist.” The Catholic Church played down pain-related customs, and, in time, the people who chose to continue practicing them went underground.

Glucklich says he could never follow the lead of the people he studied. Even the milder forms of pain tests allowed by university science departments—placing volunteers’ feet into freezing water, for example—leave him gasping. “I don’t think I would make a very good mystic,” he says. “I guess I’d be more inclined to experiment if I decide to do my next project on pleasure.” #151;Louis Jacobson