The Bactra Review   Wizard and Glass
There is a logical problem with the idea, not uncommon in fantasy, that all the parallel universes share a common center --- King's Dark Tower, Zelazny's Amber, and the like. Since they embrace all possible worlds, they would have to include all possible versions of and variations on that center; and then it's not the center any more. (Egan's ``hypothesis of the dust'' in Permutation City is not so afflicted.) This is reminiscent of the paradoxes into which Socrates is lead by Parmenides in the dialogue bearing the latter's name; also of Peirce's dictum that ``one measures a circle, beginning anywhere.'' But let us return to our horses.