Permutation City

by Greg Egan

So long as the flesh-and-blood man had no way of knowing the truth, it was meaningless to talk about ‘two different people’ in ‘two different worlds’. The two patterns of thoughts and perceptions had effectively merged into one. If the Copy had been allowed to keep on running after the visitor had learnt that he was flesh and blood, their two paths would have diverged again. But the Copy had been shut down; it had no future at all in its original world, no separate life to live. So the two subjective histories remained as one. Paul had been a visitor believing he was a Copy. And he’d also been the Copy itself. The patterns had merged seamlessly; there could be no way of saying that one history was true and the other false. Both explanations were equally valid. Once, preparing to be scanned, he’d had two futures. Now he had two pasts.