But now suppose that both hemispheres are transplanted, each into a different empty head. (We needn’t pretend that the hemispheres are exactly alike.) The two recipients—call them Lefty and Righty—will each be psychologically continuous with you. The psychological-continuity view as we have stated it implies that any future being who is psychologically continuous with you must be you. It follows that you are Lefty and also that you are Righty. But that cannot be: if you and Lefty are one and you