A wise old friend once said to me that if Christianity died out, what would come next would not be atheism but polytheism. That is, instead of worshipping one God, people would start worshipping a whole range of gods. I thought of that yesterday while watching a Brazilian shaman called Putanny Yawanawa performing a native spiritual ceremony onstage at the World Economic Forum in Davos. The leaders onstage all managed to keep a straight face — in fact, they looked deeply humbled and impressed — as Yawanawa did her incantations and blew her sacred breath into their faces. All behaved...