The more interesting problem is that of personal identity. Is the Eva on Mars (let’s call her Eva2 ) the same person as Eva1 (the Eva still in London)? It’s tempting to say, yes, she is: Eva2 would feel in every way as Eva1 would have felt had she actually been transported instantaneously from London to Mars. What seems to matter for this kind of personal identity is psychological continuity, not physical continuity.* But then if Eva1 has not been vaporized, which is the real Eva? I think the correct—but admittedly strange—answer is that both are the real Eva.
