I am building off the fact from something I said in an earlier post. If we were to be able to change the past, then we would be the same people, just with different personalities, different parents, possibly even different "souls", if you will. If this is true, then that means we must all be equal and the same at birth. Depending on who our parents are and what genes they passed on to us.
With that in mind... is the idea of multiple personalities possible? If the mind is not stable or if someone has gone under severe trauma or if they just born like this, then can two different people inhabit the same body and use it at infrequent intervals? Have different names? Different likes and dislikes? Different preferences to the world? I have watched loads of Criminal Minds episodes concerning this and looked up on it a bit, and it's usually looked as either a mental disorder or proven that the person is faking it. But... just for the sake of asking, what do you think it would be like to be bipolar and have extreme mood shifts? Or to have another personality/person be in 'there' with you?
I would not likes it.