> I wonder why they are considered two different persons at this point. Because the system isn't well-defined in this case, which happens less than 1 in a mill

> I wonder why they are considered two different persons at this point. Because the system isn't well-defined in this case, which happens less than 1 in a million times, so isn't worth trying to fix explicitly. The simplest solution is to give them two identities and move on with life having a little oddity -- as a pragmatic solution, it seems like the one that would end in the least litigation, as it confers an advantage not a disadvantage on the person(s) in question and can't possibly disenfranchise anyone. It's not like you can't already create extra 'selves' (in most senses; eg voting is different) legally at the cost of $200 a pop -- what does it really matter if less than 1 in a million people happens to have two for what is otherwise going to be a very hard and likely short life? That said -- I agree with you that it's not really well-defined here, because our notion of 'identity' is already highly problematic. Edit: This is a strange thought: what is the impact on someone with multiple personalities if you allow each personality to incorporate an LLC, all owned by a parent LLC (obviously, all legally owned by the 'person') -- ie, create an external legal framework that parallels the structure of the internal mental one, that all of the personalities should be able to view? I'm honestly not sure if that's helpful for providing a lens to see the interaction play out or harmful for legitimizing the split. (And to some degree, all of us possess such multiple personalities -- we're rarely entirely the same person at work as at home or church or... whatever. I'd just argue that 'healthy' adults understand the interaction better.)