“In many advanced democracies there is now no common debate, let alone a common narrative. People have always had different opinions. Now they have different facts. At the same time, in an information sphere without authorities--political, cultural, moral--and no trusted sources, there is no easy way to distinguish between conspiracy theories and true stories. False, partisan, and often deliberately misleading narratives now spread in digital wildfires, cascades of falsehood that move too fast for fact checkers to keep up. And even if they could, it no longer matters: a part of the public will never read or see fact-checking websites, and if they do they won't believe them.”