That sound like an invitation to schizophrenia. I would be more in tune to thinking of it, more in terms of multidimensional planes of reality, in which another you may be living on each plane, and that each you would be experiencing different realities.
Yes, that is one theory.And there are many. Anything is possible. Where we are in our evolution as a species at this time has not allowed us to answer that question . There is an old saying that translates " The smartest person in the world is the one who has been dead 5 minutes."