To date, there have been 639 episodes of The Simpsons. That sounds like a hell of a lot of TV to keep track of: character arcs, relationships, continuity, on-going narratives, and that’s before you even get into timelines and chronology. Luckily, for the most part, The Simpsons ignores all of those things – most episodes end up right back where they started, characters learn nothing and experiences are quickly forgotten, all in order to create a light, fun, uncomplicated 22-minute comedy. However, not everything that happens on The Simpsons is disposable: some story elements stay put. So what’s the deal? Is there an official Simpsons canon or not?