Position bias argument
From your perspective everyone else is in a different position in space than you are. Thus they are not and can not be you. There can only be one person in one place at a time. But a cidentireplica of the original will believe that he is in the same place that the original is in and everyone else will be somewhere else and thus not them. Neither the original or cidentireplica my be where they think that they are at. For example, they may think that they are out doors on earth when in fact they are in an awarepaducer in outer space, no where near a planet that has a livable outdoor environment. They may both not have a human body nor are they produced by a biological brain. The consciousness of the original and cidentireplica can be identical without it being produced identically with the same matter or produced in the identical place in space and time. Superimmortality predicts the potential multiplicity of self which means that there can be many different conscious bodies or the equivalent that produce the same ixperiencitness. Which means that the consciousness that these different bodies produce you experience exactly in the same way as you are experiencing life as you are reading this sentence, but they can be different consciousnesses. These other "you's" can seem to be the only you just like from your current perspective you seem to yourself to be the only conscious you.
See also outline