When I was a precocious sophomore in high school, I once barged into the office of the Capuchin priest who was in charge of our religion curriculum to inform him that I had serious intellectual reservations about the Catholic faith, and I found the answers being supplied in class unsatisfying. Father Mike Scully looked at me for a moment with what, looking back, I now recognize as a bemused smirk, and then wheeled his chair across his office and produced a thick book off his shelf: On Being a Christian by Hans Küng. “Go read this,” Scully told me, “then...