Multiple Personality Disorder appears very bizzarre.  If, however, we interpret it in straightforward P-world terms, some parts of the P-world are simply inaccessible from others.  Those are fault lines.  We don’t have to answer the question of how many people there are.  There is just one, divided, P-world.  The division doesn’t even have to be all or nothing, and it rarely is.  Nobody ever seems to think of the in-between cases, where the selves blend.  Isn’t that a good picture of many of us (Louise?).