Counterfactuals can be a lot of fun—when you are hanging out with your friends and family, debating the “what ifs” of the Kennedy assassination, or the Civil War, or the Protestant Reformation, or the Star Wars prequels, or the 1986 World Series. (I forgive you, Bill Buckner. Mostly.) I’d be happy to join you all one day for a vigorous debate on historical counterfactuals,
