Religion in America is undergoing a revolution. In 1972, 90% of Americans were self-professed Christians. Now, that number is about 64%. There are now large and growing populations of non-Christians, as well as many who have no particular religious beliefs. Such a time of change has made it an exciting time to be a scholar of religion, charged with making sense of the shifting landscape of American religious experience. For today’s conversation, Zach Davis sat down with one of those scholars,...