 A more serious worry for psychological-continuity views is that you could be psychologically continuous with two past or future people at once. If your cerebrum—the upper part of the brain largely responsible for mental features—were transplanted, the recipient would be psychologically continuous with you by anyone’s lights (even if there would also be important psychological differences). Any psychological-continuity view will imply that she would be you. If we destroyed one of your cerebral hemispheres, the resulting being would also be psychologically continuous with you. (Hemispherectomy—even the removal of the left hemisphere, which controls speech—is considered a drastic but acceptable treatment for otherwise-inoperable brain tumors: see Rigterink 1980.) What if we did both at once, destroying one hemisphere and transplanting the other? Then too, the one who got the transplanted hemisphere would be psychologically continuous with you, and would be you according to the psychological-continuity view.