Introduction to Personal Identity

1. Introduction to Personal Identity Lecture 7

2. Dan Turton • Office: MY715 • Office Hour: Thurs 2:10-3:00pm • Email: dan.turton@vuw.ac.nz • Phone: 04 463 5233 x 8651

3. Personal Identity Essay Question • What is the best theory of personal identity and why? • Explain and evaluate at least two common philosophical theories about personal identity, including ‘psychological continuity theory’. • Apply these theories to at least one ‘whacky’ thought experiment and the real-life split-brain experiments as part of your evaluation.

4. Personal Identity • Who am I? • What makes me the same person through time? • What happens to me if I’m copied? • What about people who have their brains chopped in half!?! • Hard questions, even if we have all of the facts

5. Terminology • Numerical Identity • A (literally) unique thing • Qualitative identity • Looks, feels, tastes (etc) identical • Essential properties • Required for numerical identity • Accidental properties • Can change without affecting numerical identity

6. Personal Identity & the Afterlife • It can comfort us to think that our loved ones live on somehow after death • But what would that really entail?

7. Reincarnation • You are reborn into a new body after death • PROBLEM: Reincarnations don’t seem to be the same person

8. Resurrection • You (and your body) come back to life after you die • PROBLEM: • Need an earth-like place to go to • If we’re recreated exactly the same, we’ll just die again

9. Soul Liberation • When we die, our soul leaves our body to live on somewhere else • PROBLEMS: • What, exactly, is a soul? • If the soul is just the mental, then how can it live on? • Is my soul (without my body) human enough to be me?

10. Cryogenics • Being frozen until medical advances can fix all your ailments • PROBLEMS: • Technological risk • The brain may be too damaged

11. Cyborgs • Use technology to keep us alive! • PROBLEMS: • Will it ever work? • How will we know?

12. Personal Identity & the Accident Victim • Brain damage and amnesia could drastically change what a person is like • But, would it change who they are?

13. COMINS • Continuity of the Mental Is Necessary for Survival • VERDICT: Mr Edward’s son has not survived the accident • PROBLEM: • How much and what type of ‘the mental’ has to continue and how must it continue?

14. CEBINS • Continued Existence of the Body Is Necessary for Survival • VERDICT: Mr Edward’s son has survived the accident • PROBLEM: • This may be necessary, but is it sufficient for a person to survive?

15. CESINS • Continued Existence of the Soul Is Necessary for Survival • VERDICT: Mr Edward’s son has survived the accident • PROBLEM: • If it’s not the body or the mental… what, exactly, is the soul again?

16. Take Home Lessons • Please don’t do any life-after-death experiments when you get home! • He’s our best bet for life after death, so start saving now! • The beauty of youth is fleeting – enjoy it while you can!

17. For Next Time • Read: • Baggini, Julian: The Elusive I (p8) • Law, Stephen: Brain Transplants, ‘Teleportation’ and the Puzzle of Personal Identity (pp9-14) • Get ready to discuss: • Two promising theories and the ‘whacky’ thought experiments that seem to refute them

18. Bodily Continuity vs Psychological Continuity Lecture 8

19. Personal Identity Essay Question • MAIN QUESTION: What is the best theory of personal identity and why? • INSTRUCTIONS: Explain and evaluate at least two common philosophical theories about personal identity, including ‘psychological continuity theory’. • INSTRUCTIONS: Apply these theories to at least one ‘whacky’ thought experiment and the real-life split-brain experiments as part of your evaluation.

20. Personal Identity • We want our theory to be able to provide answers to questions like these: • What makes me me? • What makes me the same person through time? • What happens to me if I’m copied? • What about people who have their brains chopped in half!?!

21. The elusive ‘I’ • Who here thinks they exist? • Cogito ergo sum • Meditation time • Lets ‘find ourselves’ • Where am ‘I’ ?!?!

22. Sci-Fi Disclaimer • The following ‘whacky’ thought experiments may never be possible in real life • But, then again, they might! • Regardless, a good theory of personal identity should be able to answer theoretically possible as well as actually possible problem cases

23. Animal Theory • In essence, each person is a living animal • What essentially makes me me through time is that I am the very same living creature as the one in the photos

24. Brain Transplant Case • A brother and sister have their brains swapped while they slept one night • Problem for the Animal Theory

25. Brain Theory • In essence, each person is their unique living brain • What essentially makes me me through time is that I have the very same brain as the ‘me’s in the photos

26. Brain Recorder Case • This device re-splices the existing brain bits so that a pre-recorded personality (etc) can be downloaded into the (same) old brain • Problem for the Brain Theory

27. Stream Theory • AKA: Psychological Continuity Theory • In essence, each person is (the right kind of) continuation of psychological properties • E.g. What MIGHT essentially makes me me through time is that my memories are psychologically continuous

28. The Reduplication Case • This device makes perfect copies of anything put in cubicle A (in c. B) but the original is vaporized • A new model also makes a duplicate in cubicle C • Problem for the Stream Theory?

29. Modified Stream Theory • In essence, each person is (the right kind of) continuation of psychological properties • Except when two or more people are psychologically continuous (in the right kind of way) from one person • In which case, none of those later people are the same person as the original person

30. The Duplicator Gun Case • This device makes a perfect copy of anything shot with it but it doesn’t destroy the primary target • Problem for the Modified Stream Theory

31. They All Seem Wrong! • The Animal Theory • Gets the brain transplant and recorder cases wrong • The Brain theory • Gets the brain recorder case wrong • The Stream Theory (AKA the Psychological Continuity Theory) • Gets the reduplication and duplicator gun cases wrong • The Modified Stream Theory • Gets the duplicator gun cases wrong

32. The Teletransporter Case • You have been ‘teletransporting’ to work (on a very distant planet) for 3 years • You are at work when you are informed that the ‘teletransporter’ really works like the reduplicator (it copies & kills you) • Do you get in and ‘teletransport’ home? Why? Why not?

33. Take Home Lessons • This course is about tackling the big questions, not necessarily the relevant ones • If you do something stupid quickly get soo drunk you lose your memory of it – then it wasn’t you who did it • With a duplicator gun we could win the world cup

34. For Next Time • Read: • Nozick, Robert: Personal Identity through Time (pp15-26) • Get ready to discuss: • Nozick’s more complex views on this topic

35. The Closest Continuer Theory Lecture 9

36. Some Theories of P.I. • CEBINS: Continued Existence of the Body Is Necessary for Survival • E.g. The Brain Theory • CESINS: Continued Existence of the Soul Is Necessary for Survival • E.g. The Soul-Pellet Theory • COMINS: Continuity of the Mental Is Necessary for Survival • E.g. Psychological Continuity/Stream Theory • E.g. You have to remember being your previous self (and that previous self has to remember being a more-previous self and so on)

37. Nozick: Personal Identity through Time • Bernard Williams’ main Principle for P.I.: • The numerical identity of something cannot depend on facts about other things • Because what makes you uniquely you is not dictated by facts about things other than you

38. The Vienna Circle (TVC) • 3 of the 20 original members continued meeting in Istanbul • Later, they hear that all of the other TVC members are dead and considered themselves as ‘TVC’ • Later still, they hear that 9 other members have been meeting in New York the whole time and realised that they were just an offshoot of the real TVC in NY • Thus Williams’ principle is false

39. Closest Continuer Theory (CCT) • What essentially makes me me through time is that I am always the (one) closest continuer of the previous me • And that the closest continuer (CC) is close enough • I.e. too dramatic a change of an essential property (even) in the cc will mean that the cc is not numerically identical with the original

40. The Vienna Circle (TVC) • Later, the 3 hear that all of the other TVC members are dead and considered themselves as ‘TVC’ • Because they are the closest continuer of TVC • Later still, they hear that 9 other members have been meeting in New York the whole time and realised that they were just an offshoot of the real TVC in NY • Because they are not the closest continuer of TVC

41. The Ship Theseus • A repaired ship is the CC of the original • Until the old parts are all put together in ship B A B

42. More Specific on the CCT • Being the closest continuer needn’t involve being qualitatively similar • Although it often will • More important is that the CC is causally dependant (in the right kind of way) on the original • E.g. The CC has grown or developed out of the original (or maybe) was caused by it • There can be many factors that are relevant to being the CC, but they needn’t all be necessary (essential)

43. How Do We Discover the Dimensions of Closeness? • Nozick: Introspect • We have intuitions about whether something is numerically identical with something else • We must analyse these intuitions to discover what makes something ‘closest’ to the original in each particular case • PROBLEM: Intuitions might track accidental properties

44. The Duplicator Gun Case • This device makes a perfect copy of anything shot with it but it doesn’t destroy the primary target • CCT seems to work in this case

45. Modified Brain Transplant Case • You’re dying of a heart attack, but your brain is transplanted into a healthy clone of your body • The old body dies as the new one comes to life • CCT says that the clone with your brain is now the real you

46. Conflicting Judgements • What if our intuitions are different? • What if we disagree about what the dimensions of closeness (the important properties) are? • Nozick thinks we can eliminate most disagreement by comparing cases and going for consistency • But maybe the CCT is too flexible

47. Brain Splitting Case • You have ½ of your brain transplanted into a clone of yourself • Both you and the clone live on with full psychological continuity • CCT says that you are still you and the clone is a different person

48. Random Cosmic Occurrence Case • A random chemical reaction on a distant planet creates a perfect copy of you exactly as you die • But not caused by you in any way • CCT says it’s not you because it isn’t caused by you

49. Teletransporter Case Revisited • You’ve been teletransporting to work (on a very distant planet) for 3 years • Nozick: teletransporting probably destroys you because if Person A was not destroyed then Person B would not be the Closest Continuer • So on the CCT, Person B is probably not close enough to Person A to be numerically identical to them

50. Mono-Relatedness & Jumping • More specifically, CCT entails that numerical identity can only pass between pairs of closest continuer and closest predecessor • Strangely, this allows ‘jumping’ if being temporally connected is not set as a dimension of closeness A' A'' A''' Teletransporting A B' B'' B''' Time 1 2 3 4