1. Descartes I am essentially rational, only accidentally an animal ‘essentially’ = logically necessarily ‘essentially’ = logically necessarily Strictly speaking, I’m not even accidentally an animal, for I’m not an animal at all; I’m (contingently) embodied Strictly speaking, I’m not even accidentally an animal, for I’m not an animal at all; I’m (contingently) embodied The demon thought experiment shows that I could (logically possibly) exist without my body, so I am not identical with my body

2. John Perry “A Dialogue on Personal Identity and Immortality” Possibility of survival after death as entrée to thinking about identity of persons Possibility of survival after death as entrée to thinking about identity of persons Logical possibility, not probability Logical possibility, not probability

3. Qualitative Identity: Being exactly similar Being exactly similar Numerical Identity: Being one and the same Being one and the same “She’s not the same person since her religious conversion….”

4. The Soul Theory: I am my soul x and y are the same person iff x has (is) the same soul as y Soul=mind?

5. Problem with the soul theory 1. Souls are immaterial, so we have no evidence for reidentification of souls 2. But we do have evidence for reidentification of persons 3. Therefore, persons are not identical with souls

6. Argument for premise 1: 1. Souls perceived only indirectly, by assumption of same-soul-same-body principle 2. This principle cannot be a priori, since it isn’t necessary 3. It cannot be a posteriori, since there’s no empirical evidence for it (and couldn’t be!) 4. Therefore, there’s no evidence for the principle

7. The Body Theory: I am my body x and y are the same person iff x has (is) the same body as y Conditions for sameness of body? (Ship of Theseus)

8. Arguments against the Body Theory: You wake up and you know who you are, without having identified your body yet. Mind transfers Mind transfers

12. John Locke: (1632-1704) I am a sequence of causally connected experiences

13. Psychological Continuity Theory x and y are the same person iff the psychological states of x are appropriately linked to the psychological states of y ‘appropriately linked’? ‘appropriately linked’? Locke: memory: x = y iff the later of the two can remember the experiences of the earlier

17. Teletransportation Person is disassembled, reassembled elsewhere

18. Teletransportation Person is disassembled, reassembled elsewhere

19. Teletransportation Person is disassembled, reassembled elsewhere

20. Possibilities: A. Matter is transferred

21. Possibilities: A. Matter is transferred

22. Possibilities: B. Only information is transferred

23. Possibilities: B. Only information is transferred

24. Argument against Psychological Continuity Theory: If you can replicate one, you can replicate two. Since they aren’t both identical with me, it seems that neither is So teletransportation is suicide So teletransportation is suicide

27. Personal Identity redux Soul theory Body theory Psychological continuity theory Fictionalism: strictly speaking, persons don’t endure over time; we attribute a fictional identity

28. Ego theory: underlying subject of experiences: a substance in the technical sense (usually immaterial substance)

29. Bundle theory: collection of mental events: there is (in a sense) no self

30. David Hume 1711-1776

31. No concept of enduring self 1. 1. If you can’t experience something, you can’t conceive it 2. 2. Introspection reveals only train of perceptions, no enduring subject of perceptions 3. 3. Therefore, we don’t experience an enduring self 4. 4. Therefore, an enduring self distinct from these perceptions is literally unintelligible.

32. Why do we believe in enduring things? Observing a smooth succession is very similar to observing an enduring object, so we mistake the former for the latter. We ascribe identity when: changes are proportionately small changes are gradual changes don’t alter purpose of the whole All this shows that identity is ascribed, rather than a real property of the objects

33. Parfit: argument for bundle theory 1. If ego theory is true, there should be hard and fast facts about whether x and y are the same 2. But there very often aren’t such facts 3. Therefore, the ego theory is false 4. The only alternative is the bundle theory 5. Therefore, the bundle theory is true

34. Parfit: argument for bundle theory 1. If ego theory is true, there should be hard and fast facts about whether x and y are the same 2. 2. But there very often aren’t such facts 3. Therefore, the ego theory is false 4. The only alternative is the bundle theory 5. Therefore, the bundle theory is true

35. Teletransportation with partial material preservation: 2% new matter? 2% new matter? 50% new matter? 50% new matter? 98% new matter? 98% new matter?

36. Split brains

37. Two streams of consciousness: one ego or two? Two streams of consciousness: one ego or two? 1=1+1? 1=1+1? Suppose hemispheres placed in new bodies, live separate lives. Is one of them you? Suppose hemispheres placed in new bodies, live separate lives. Is one of them you? Which one? Which one?