What about multiple personality disorder? Are there 2 of you time-sharing a body? I don't see how you can distinguish "different brain-states that are still me

What about multiple personality disorder? Are there 2 of you time-sharing a body? I don't see how you can distinguish "different brain-states that are still me", and "different brain-states that are not me" other than by looking at the data in these brain-states. If the data is the same - what makes it ok to say "these 2 brainstates are the same person, and these 2 are not"? > We don't say people become no one, or someone else when they sleep. We say a lot of things that are wrong or simplified, it's not an argument anymore than the word "sunrise" is an argument for geocentrism. > I don't categorically dismiss the idea that there exists an "I" outside of my natural body. I agree that existence of souls would change things, but it's untestable and unnessesary to explain all phenomena we experience, so I consider it a waste of time to discuss these.