In Fight Club, there's a scene where Tyler Durden and the Narrator are discussing new fight club chapters, and there's one where they both deny starting it, and claim to have thought the other started it. I see three main interpretations of this scene:
The straight forward one: some other member of Fight Club started another chapter.
Tyler Durden started the chapter, but was messing with the Narrator's head.
There's actually a third personality that neither Tyler nor the Narrator is aware of.
Which is most likely the answer, based on actions by Tyler and the Narrator in the movie? If anyone can also cite book sources, I'll take that too.