 This proposal, the “non-branching view”, has the surprising consequence that if your brain is divided, you will survive if only one half is preserved, but you will die if both halves are. That looks like the opposite of what we should expect: if your survival depends on the functioning of your brain (because that is what underlies psychological continuity), then the more of that organ we preserve, the greater ought to be your chance of surviving. In fact the non-branching view implies that you would perish if one of your hemispheres were transplanted and the other left in place: you can survive hemispherectomy only if the hemisphere to be removed is first destroyed. This seems mysterious. Why should an event that would normally preserve your existence bring it to an end if accompanied by a second such event—one having no causal effect on the first? If your brain is to be divided, why do we need to destroy half of it in order to save you? (For discussion, see Noonan 2003: 12–15 and ch. 7.) 