"The end of a world," ABC News called Britain's vote to leave the European Union on June 24. As if in agreement, the pound immediately racked up its biggest-ever one-day loss against the dollar. Over the next three days, the Dow Jones index fell 4.8 percent, London's FTSE 100 lost 5.6 percent, and some $2 trillion in assets evaporated. This is bad, and worse may yet follow. But is it the beginning of the end? There have been plenty of crises worse than this one in the past 100 years, but none of them ended the world. The Great Recession that erupted in 2008, the attacks of Sept. 11, 2001, the 1997-98 Asian and Russian financial meltdowns, the collapse of the Soviet Union in 1989-91, the oil spikes of 1973 and 1979 -- the list goes on, but civilization always survived. Even the material destruction of the World Wars, which claimed...