As secularism grows, atheists and agnostics are trying to expand and diversify their ranks. More people than ever before are identifying as atheist, agnostic, or otherwise nonreligious, with potentially world-changing effects. You don’t usually think of churches as going out of business, but it happens. In March, driven by parishioner deaths and lack of interest, the U.K. Mennonites held their last collective service. It might seem easy to predict that plain-dressing Anabaptists—who follow a