You don’t actually understand an idea until you know its history. That lesson is one that most people have been doing their level best not to learn in recent years. Their unwillingness isn’t any kind of accident. Once you know where an idea came from and what kind of vagrant wanderings it’s been through on its way from its birthplace to the present day, it stops being possible to shove that idea into the simplistic straitjacket of “true or false.” You have to come to terms with who invented it, ...