Are people special? Notes for November 22

Main points

Locke’s account of personal identity faces a problem: identity is a transitive relationship but remembering is not. If A is identical to B and B is identical to C, then A must be identical to C. But if A remembers what B did and B remembers what C did, it doesn’t follow that A remembers what C did. That’s what gives rise to Thomas Reid’s Brave Officer example.

Parfit’s teletransportation example suggests that the problem runs deeper. It does not arise just due to Locke’s peculiar emphasis on memory but rather plagues attempts to show that our identity consists in psychological continuity of any sort. According to those attempts, we could survive a process that does not guarantee personal identity. Teletransportation seems like a way of traveling and, obviously, you have to survive your trip in order for it to count as transportation rather than a killing machine. But it doesn’t take much imagination to realize that if you can be teletransported there could also be multiple copies at the same time.

Parfit vs. Williams

Parfit takes this sort of example to show that you can survive into the future without being the same, identical, person as anyone in the future. He calls being duplicated by the teletransporter a “double success” rather than death, even though the person who goes into the teletransporter is not identical with either of the people who come out.

Williams finds that result intolerable. His reasoning goes roughly like this. If I were duplicated, what would I see and experience on the day after duplication? If it’s what the guy on Earth sees and experiences, then I’m the guy on Earth and the guy on Mars is someone else. If it’s what the guy on Mars sees and experiences, then I’m the guy on Mars and the guy on Earth is someone else. So far, so good. It’s weird, but I understand the options.

What I can’t understand is how I could experience what both of them experience. No one alive tomorrow will simultaneously experience what the guy on Earth experiences and what the guy on Mars experiences. So I can’t either. If you tell me I’ll experience what neither of them experience, then I’m just not there at all. So where’s the double success?

We’ll talk more about the clash between these two next time.

This page was written by Michael Green for Problems of Philosophy, Philosophy 1, Fall 2010. It was posted November 29, 2010.
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