" We perceive – we inhabit – one arrangement of the set of events. But why should that arrangement be unique? There’s no reason to believe that the pattern we’ve found is the only coherent way of ordering the dust. There must be billions of other universes coexisting with us, made of the very same stuff – just differently arranged. If I can perceive events thousands of kilometers and hundreds of seconds apart to be side-by-side and simultaneous, there could be worlds, and creatures, built up from what we’d think of as points in space-time scattered all over the galaxy, all over the universe. We’re one possible solution to a giant cosmic anagram … but it would be ludicrous to believe that we’re the only one. "

― Greg Egan , Permutation City (Subjective Cosmology #2)