In 1975, Raymond A. Moody Jr. published Life After Life, his investigation of near-death experiences. As a doctor, Moody had the opportunity to interview a number of patients who had “died”— had suffered heart failure and stopped breathing—and been resuscitated. He discovered that many revived patients tell similar stories of their dying experience. In the typical near-death experience, as described by Moody, the patient floats above his body and looks down upon the room. Next, he travels through a tunnel toward a bright light. Upon reaching the light he encounters another person, a long-departed loved one or simply a being of light, who informs him that he must return to life. The publication of Moody’s findings in Life After Life spawned a host of other near- death-experience accounts and a debate over their significance.

Moody...