Personal Identity

1
Personal Identity
2
What is Identity?

• Identity is etymologically related to
  identical Two things are identical means that
  they are in fact one and the same.
  
• Identity is a very important relation it is
  commonly denoted by the mathematical sign .

3
Three Features of Identity

• The identity relation is
• 1. Reflexive A thing must be identical to
  itself.
  
• 2. Symmetrical If A is identical to B, then B is
  identical to A, and vice versa.
  
• 3. Transitive If A is identical to B, and B to
  C, then A is identical to C.

4
Criteria of Identity

• A is identical to B if and only if A and B have
  exactly the same set of properties or features.
  
• But how useful is the above specification?

5
Qualitative and Numerical Identity

• Note that there are two notions of identity
  qualitative and numerical.
  
• Philosophers primarily deal with numerical
  identity.
  
• Two different things, for example the two copies
  of the same textbook, can be exactly alike in
  most aspects. So they are qualitatively identical
  without being numerically identical.

6

• Personal identity is a particularly important
  case for our application of the broad concept of
  identity
  
• What are our basic criteria for judging who we
  are?

7
Different Criteria

• 1. Bodily
• 2. Psychological
• 3. Social
• 4. Soul

8
Bodily Criteria

• Jane has forgotten who she is because of a head
  injury. But since she still has the previous
  body, the amnesiac Jane is the previous Jane.
  
• Someone may find the bodily criteria too coarse
• Why not insist on the sameness of the brain only?
  Or, sameness of DNA?
  

9

• Of course, we allow that a body can have gradual
  changes of components over time.
  
• The bodily criterion holds so long as the change
  in our body is not abrupt.

10
Psychological Criteria

• What is the psychological?
• 1. personality
• 2. memory
• But people can have change of personality or
  become amnesiac.
  

11
Personality

• It is common for us to judge others by our
  previous knowledge of their personality.
  
• As a result, if a friend suddenly behaves in an
  expected way for a long time, we are prone to
  judge that she is not the same person.
  
• The strange thing is that from the first-personal
  point of view, no one will be surprised by
  his/her drastic changes of personality if those
  changes are genuine.

12

• Of course, if that person has good memory of her
  past personality, he/she might wonder why he/she
  has become thus. But it is rarely the case that
  that person would judge that he/she is not
  himself/herself on the evidence of the memory of
  how he/she was like.

13
Memory

• The memory criterion is historically important.
• We are personally disturbed by loss of memory.
• Again, the loss of memory cannot be abrupt and
  massive we cannot remember a lot of the things
  in the remote past but we surely can remember
  what happened to us in the past few weeks.

14

• The difference between memory and personality is
  that we are personally less troubled by an abrupt
  change of personality.
  
• Some argue that what our personality is like is
  indirectly dependent on our memory of how we were
  like.
  

15
Thought Experiments

• In philosophy, we perform a lot of thought
  experiments imagined situations that are able to
  test and refine our concepts.
  
• Concerning personal identity, we can imagine
  various possible happenings to us.
  
• For example, we ask what it would be like if
  someones memory is implanted on us.
  
• We will see many such cases in our reading of
  Parfits and Williams papers.

16
Social Criterion

• Most of us seem to care how society sees us.
• For example, it is common to hear people say that
  he/she is nobody because he/she has low social
  standing.
  
• Are you puzzled, for example, by your lack of a
  university degree such that you are not properly
  recognized as somebody?
  
• But would you be equally puzzled if you could not
  become a millionaire in your thirties?

17

• Philosophers usually care little about social
  criteria of personal identity.

18
Soul Criterion

• Even for somebody without religious affiliation,
  they understand that it might be the case that no
  matter how different we might become, we probably
  have the same soul throughout.
• In general, the soul is some substance that is
  immaterial and indivisible.

19
What Philosophers Think

• 1. The soul criterion is impossible to verify.
• 2. The soul, even if it exists, seems to be quite
  separate from the body and the mind.
  
• 3. Social criteria are entirely irrelevant to our
  fundamental concerns. And, with the basic
  criteria clarified, we can derive the
  corresponding judgment on social criteria.

20

• What philosophers want are necessary and
  sufficient conditions for personal identity.
  
• This demand is commonly called a reductive
  approach to explain something in terms of some
  simpler and basic concepts.
  
• For example, you might want to ask HKU for the
  necessary and sufficient conditions for being a
  talented student.
  
• If they reply at all, it might be something like
  having IQ 130 is sufficient for being a
  talented student whereas having a high degree of
  curiosity is necessary.

21

• Some might object to the reductive approach
  because they believe that identity is the most
  basic relation we dont just call two things
  identical because there are some conditions they
  both fulfill. Rather they are identical because
  they are one thing but not two.

22
John Locke

• John Locke is a famous British philosopher in the
  17th century.
  
• He thinks that sameness of memory is necessary
  for sameness of person.
  
• He also thinks that sameness of memory is
  possibly underlain by sameness of soul.
  
• Note that Locke distinguishes between person and
  human being.

23

• A human being is like you and me, with 23 pairs
  of chromosome. Of course, we are also persons.
  
• A Martian, if there were ET, is in theory a
  person although it has biological structure
  different from us.
  
• So you may say that some intelligent robots you
  see in films qualify as persons.

24
Rebuttal against Locke Circularity

• Thomas Reid, a Scottish philosopher, regards
  Locke's memory criterion as circular.
  
• In other words, sameness of memory presupposes
  sameness of person, rather than explaining it.
  
• For example, if I claim to remember that I was
  Alexander the Great, and do give a lot of details
  of Alexanders life history, who could possibly
  prove that I am lying?
• In fact, it is not honesty that is at issue.
  Rather, whenever we claim that someone remembers
  something, we are already presupposing that the
  person who does the remembering is the person who
  had the experience being remembered.
• And, if I fail to remember what I have done one
  week ago, does it follow that I have become
  another person?

25
Transitivity

• Another Scottish philosopher, Bishop Butler,
  charges Locke of assuming wrongly the
  transitivity of memory
  
• Consider I remember now what I have done back to
  when I was twenty years old, and if the
  20-year-old me remembered up to what my
  five-year-old did, but I now completely forget
  about what I have done between my 5th and 20th
  birthdays.
• In the above case, is the present-I the same as
  the five-year-old-I?

26
Body

• If you consider what happens to our body on the
  cellular level, you should know that our body has
  constant changes in material composition every
  second.
• So, we might need to modify our bodily criteria
  to account for gradual changes in the body.
  
• But how gradual is gradual?
• Is a person who has undergone a heart transplant
  another person?
  
• Is it better to restrict our criteria to sameness
  of the brain? Nerve cells do not increase in
  number after a certain age.

27

• Why sameness of brain is more important than
  sameness of other body parts?
  
• Is it because we assume that sameness of brain
  guarantees sameness of mind?
  
• If so, aren't we also assuming that the
  psychological criteria are more important?
  
• For those who want to insist on sameness of DNA,
  think of the DNA of identical twins.
  
• In any case, it seems that criteria that are
  independent of the person's conceptual grasp are
  weird ones few people know what their DNA coding
  looks like, but most of us intuitively know who
  we are just by reflection.

28
Consciousness

• We are conscious beings. Furthermore, we are
  self-conscious beings.
  
• That a person is self-conscious implies that that
  person has a unity and this unity accounts for
  his/her continuing as one person rather than
  many.
• Some mentally deranged persons, however, are
  troubled by their having multiple personalities
  and multiple consciousness.
  
• We are also reluctant to say that an unconscious
  human being is not a person.

29
Abnormal Cases

• The issue of personal identity looks trivial
  until we encounter abnormal cases.
  
• 1. Amnesia
• 2. Human cloning
• 3. Transmigration of souls
• 4. Remembering the experience of someone else
• 5. Criminal cases where the wrongdoers have
  forgotten about their crimes, or have completely
  changed to have a nice personality.

30
Prince/Cobbler Scenario

• Locke asks us to consider a hypothetical case
  where the soul of the prince and the soul of the
  cobbler have switched bodies. So who is the
  prince?
• He thinks that since it is the cobbler's body who
  has the prince's mind and soul, he concludes that
  the person of the prince has the look and body of
  the cobbler. This is quite consistent with folk's
  judgment.

31

• Locke also thinks that a criminal who has
  genuinely forgotten about his/her wrongdoings
  should not be punished by the law it is
  pointless to punish someone who has no idea of
  what he/she has done.
• It seems to follow that a criminal can also seek
  pardon by agreeing to some kind of brainwashing.
  
• If you want to see a movie about reforming a
  criminal by changing his memory or character, you
  should see Clockwork Orange.

32

• Lockeans can also claim that punishing the body
  is inhumane if it is not accompanied by punishing
  the mind and the soul of whom the wrongdoings are
  attached to.
• Do you know the principles of legal punishment?
• 1. Preventive to detain the dangerous person so
  that he/she wont harm others.
  
• 2. Deterrence to intimidate others to reduce
  similar crimes.
  
• 3. Retributive to seek revenge.

33

• So, can punishing a criminal without the memory
  fulfill any of the above three functions of
  punishment?

34
Who do you want to be?

• Suppose Andy Lau is your idol and you want very
  much to be him. How would you choose between the
  following?
  
• 1. You can have Andy Lau's body except his
  brain.
  
• 2. You can have Andy Lau's mind.
• 3. You can have Andy Lau's social standing and
  wealth.
  
• 4. You can have everything Andy Lau has.

35
Just have Andy Laus Body

• Case one is like when you have a plastic
  surgery.
  
• It seems that you are still the same you, but
  with a new face.
  
• Your friends will probably admire you but if
  they are Andy Laus fans, they will hate you for
  your behaviour.

36
Having Andy Laus Mind

• Case two is like Andy Lau waking up finding
  himself having a different face yours.
  
• He would be very angry with the change and most
  of his fans will abandon him.

37
Having Andy Laus Wealth and Social Standing

• Case three is like you becoming a wealthy and
  important person overnight. It is quite similar
  to winning Mark Six.

38
You Have Everything Andy Lau Has

• Case four is just like nothing has happened.

39

• In describing the four cases, I have deliberately
  left out how you and Andy Lau will be treated in
  the process.
  
• I have also focused on describing what happens to
  one person without mentioning the other.
  
• Try to think about what happens to a pair of
  persons in the four cases and then decide whether
  your previous verdict will be affected by it.
  
• Can you also suggest what particular problem one
  will encounter in each case?
  
• How would such consideration affect your previous
  judgment of the four cases?
  
• I will talk about these when we review Bernard
  Williams paper (our supplementary reading).

40
More Thought Experiments

• Fission
• If you can divide into two identical selves like
  amoeba does
  

41

• Fusion
• If you can fuse with another person to become a
  person with two minds, or a person with one new
  mind.
  
• Do you remember the famous fusion?
• http//hk.video.yahoo.com/video/video.html?id3863
  89ptv
  

42

• I think most of us are not that uncomfortable
  with imaginary cases of fission and fusion.
  
• It is because we have read many comic books and
  animations which take for granted the
  intuitiveness of fission and fusion.
  
• Consider Naruto, Dragon Ball Z, etc.

43
Memory Transplant

• Can you imagine what it would be like to have
  your memory deleted and replaced by someone
  else's?
  
• Can you imagine what it would be like to plug in
  a memory card with the fictitious experience of a
  vacation in Japan?
  
• Watch the movie Total Recall to understand the
  above situation.

44

• There is a famous hypothetical question
• Why should you not prefer to be plugged to a
  machine giving you endless pleasurable
  experiences such as being a CEO?
  
• This is the question facing Neo in Matrix.
• People say that this is an ethical question
  whats wrong with preferring to have ready-made
  good experiences that are allowed by the law?
  
• Of course, the law does not allow this at
  present. But the point is that we feel that there
  is something wrong with such a choice so that we
  legally forbid it. I am not saying that
  technology at present is so advanced. Think of
  why we forbid people taking drugs to have
  pleasurable experiences.

45

• Is it okay to buy a memory card with all the
  knowledge you will get from a Harvard degree the
  card is supposed to be part of your body just
  like your spectacles.
• Wont this save time to learn in the university?
• I think the use of calculator nowadays is
  somewhat like that kind of implantable memory
  card.

46
Cloning

• Persons are supposed to be unique even though
  they look alike and have roughly the same
  mentality.
  
• How would human cloning threaten our sense of
  identity?
  
• Would you allow scientists to clone you in order
  that you can always be replaced by your clone
  when needed?
  
• You can watch Tom Cruises Vanilla Sky or Arnold
  Schwarzenaggers Sixth Day to appreciate some
  ethical and psychological consequences of
  cloning.
• But is the clone the same you, from your
  perspective?
  
• Would you be jealous of the fact that your clone
  will inherit everything you have right now?

47
Derek Parfit

• Parfit is a contemporary philosopher who is
  famous for his revolutionary view on personal
  identity.
  
• His book Reasons and Persons is a landmark on how
  personal identity and morality are to be properly
  understood.

48
Connectedness of Person-stages

• According to Parfit, the traditional emphasis on
  personal identity is misplaced.
  
• Do you really insist on some future you being
  identical to you when you think about what you
  should do now as an investment on the future?
  
• I am more concerned with the welfare of the
  person who is continuous with me two weeks hence
  than with the one twenty years hence.
  
• I am more concerned with the welfare of my
  parents than the welfare of a distant relative.

49
Time-slice

• According to some scientists, I am all the
  moments of me bound together.
  
• Each moment of me is called a time-slice (or
  person-stage) of me.
  
• This is what scientist calls a four-dimensional
  concept of a thing.
  
• Traditional three-dimensional view sees a person
  as travelling wholly through time in existence.
  This is called the endurance view.
  
• For four-dimensional view, a person perdures
  through time by having distinct time slices.

50

• To apply the above ideas to Parfit's view, we may
  say that the present time-slice of me is less
  related to the distant time-slices of me.
  
• Parfit's rejection of the traditional view is
  also motivated by the conceptual possibility of
  fission if the split persons B and C are not
  identical to each other, then the original person
  is also not identical to either B or C (to say
  that A is identical to B but not to C is just
  arbitrary).
• But that also means that A ceases to exist after
  fission.

51
Survival

• Similarly, a person who has undergone some
  significant psychological or bodily changes will
  also be considered to have ceased to exist.
  
• But this view is counterintuitive.
• So Parfit thinks that personal survival is more
  important than personal identity.
  
• To survive is to have some future persons who are
  related to me in relevant ways but I need not be
  identical to each of those persons.

52
One-one and One-many Connections

• Hence, survival is a matter of degree whereas
  identity is all-or-nothing.
  
• Each person-stage of mine is connected by some
  kind of relation rather than identity.
  
• Connectedness does not presuppose transitivity A
  can be connected to B and B to C without A being
  connected to C.
  
• Connectedness need not be one-to-one A can be
  simultaneously connected to both B and C.

53
Quasi-memory

• Memory presupposes that the person who remembers
  experience x must be the person who has undergone
  x in the past.
  
• Quasi-memory, on the other hand, allows that the
  one who remembers x is not the one who has
  experienced x.

54
Conditions of Quasi-memory (Q-memory)

• I quasi-remember (q-remember) having an
  experience if and only if
  
• 1. I have a belief about a past experience which
  seems in itself like a memory belief.
  
• 2. Someone really did have this past experience.
• 3. My belief is dependent on this experience in
  the same way in which a memory of an experience
  is dependent on it.

55

• So, having q-memory of the past is having the
  right kind of psychological connection with the
  past self to constitute the unity of a person in
  terms of the two stages.
• In theory, two or more person-stages can
  q-remember a past experience such that they are
  both the future stages of that past person-stage.

56

• This also solves the problem of transitivity
  because a person-stage can be psychologically
  connected to an immediately previous stage and so
  on without connected to a more remote
  person-stage.
• And that series of connectedness constitutes the
  requisite psychological continuity.

57
Implications

• You work hard for your future that means you at
  present want a certain future person that has
  certain qualities to be you. But how can you be
  disappointed by yourself? Isn't you the only
  possible you in any case?
• Some claim that they want to be remembered for
  what they are 1000 years from now. But how does
  that work? I now remember how glorious the first
  emperor is. But is he really the one who can take
  personal credit just as you can benefit from my
  praises?

58

• Some parents think that their children's future
  is their future and that their children's
  children can go on to live for them and so on and
  so forth.
• Are they using Parfit's idea of personal
  survival? If not, why should they care more about
  their offspring than themselves and other
  people's offspring?

59

• In ethics, we debate about the morality of
  abortion.
  
• Can we solve the problem by clarifying what a
  person is?
  
• In other words, when we abort a foetus, are we
  killing the earlier self of a possible adult?
  
• If we can accuse people of harming the interest
  of our future, why can't we also accuse people of
  harming the future of a foetus?

60

• For most of us, having a good university degree,
  and a good job, etc. is the life goal we work
  hard for. That means we want us to be a person of
  so and so endowment. What if we are born with
  such endowment and yet with the same mentality
  and body? Are we then forced by circumstances to
  be a different person? If not, it seems that we
  can stop working hard to be someone and just be
  that someone.

61

• Parfits theory, of course, seems to cater for a
  world of cloning, brain transplant, etc.
  
• But there are some bearings on our present world
  too.
  
• Consider punishment
• Is a person less culpable twenty-years hence from
  his crime than one-year?
  
• Similarly, should we agree with Locke that a
  criminal who has lost his memory of his crime is
  not punishable?

62
Bernard Williams

• Although The Self and the Future is your
  supplementary reading, there are good points
  there worthy of my explanation in the lecture.
  
• This paper is a challenging read, for its
  arguments, imagination and writing.

63

• Williams defends the body criterion of personal
  identity.
  
• This paper is one of his early attempts.
• If one thinks that sameness of body is a
  necessary condition for sameness of person, he
  seems to be insensitive to the sci-fi scenarios
  Parfit and others have relied upon.
• Religious persons who believe in souls dont find
  our earthly bodies too important to who we are.

64

• Williams asks us to think about the values of our
  future selves.
  
• This gesture is similar to Parfits if there are
  some important principles guiding how we see our
  future selves in terms of who we want to be in
  the future, there are also similar ones telling
  us how to protect our future selves.
• Put simply, we at present want to do our best to
  avail our future selves of pain and misery.

65
The Thought Experiment

• 1. There is the technology of body-switching.
• Persons A and B enter a machine and they come out
  with bodies switched.
  
• The A-body person who walks out of the machine
  has the body of person A and the mind of person
  B.
  
• The B-body person who walks out of the machine
  has the body of person B and the mind of person
  A.
  

66

• Before the switching both were asked to decide
  which body is to receive reward and torture.
  

67
Case One

• Person A chose A-body-person to have the reward
  and B-body person to have the torture.
  
• Person B chose the same.
• Results A-body-person is glad about the outcome
  and B-body-person is unhappy.
  
• So, should A-body-person be pleased with what he
  had chosen while B-body-person be displeased with
  his choice?

68
Case Two

• This is a reverse of case one.
• Results should B-body-person be pleased with
  what he had chosen while A-body-person be
  displeased with his choice?

69

• The impression we have so far is that to care
  about what happens to me in the future is not
  necessarily to care about what happens to this
  body (the one I have now).
• Think of the body-switching in Naruto.
• Now we can even think of body-switching as an
  investment for our future after the switching, I
  might find the new body very powerful, handsome
  and clever, etc. In other words, I am now pleased
  with my new body.
• In other imaginative scenarios, people just want
  a robotic body so as to be superman-like. I think
  athletes also train their bodies for similar
  reasons.

70
Has he switched bodies several times?
71

• Now let us consider some other purposes of
  body-switching
  
• Suppose person A has anxiety that troubles him
  and B has frightful memories to get rid of.
  
• Could they possibly benefit from the
  body-switching?
  
• It would seem that nothing has changed a bit!
• This again seems to show that bodily continuity
  is not necessary for personal identity.

72

• Now Williams offers the main imaginative
  situation in order to put forth his argument.
  
• Suppose you were told that you would be tortured
  tomorrow. But you were also reassured that
  shortly before the torture, your memory of this
  announcement would be deleted from your memory.
• Does this relieve you of your fear at present?

73

• If not, what about if you were reassured that
  before the torture, not only your memory of the
  announcement will be deleted, your entire memory
  of the past will also be altered?
• I think this will not cheer you up either since
  you might as well think of this as your turning
  mad (by believing you to be Li Ka Shing, for
  example) before the torture.
• Furthermore, this is similar to the
  body-switching situation the tortured body has
  the memory and personality of another person.
  
• So, why the difference in the two judgments?

74

• Williams asks us whether the difference in
  judgment is due to one story being told in two
  different ways one correct and one misleading.
  
• It seems that the second presentation is just
  focused on one person whereas the first
  explicitly mentions two.
  
• Compare this with our Andy Lau scenarios.

75

• But does it really help if we retell the second
  story?
  
• Our fear of what happens to this body of mine in
  the future seems irrelevant to what psychological
  states happen to be in this body at the time of
  torture.
• So do I mean that my fear of the torture being
  applied to this body in the future is tantamount
  to my identifying this body as my person?

76

• Or, the question is why should who we are depend
  on our knowledge of some other persons whose
  psychological states are similar to mine?
  
• Isnt my future mine in a non-comparative sense?
• Of course, you might think that you will not be
  unhappy about not getting a university degree if
  you know that persons similar to you all fail to
  get a degree in the future.
• But our concerns with our future and ourselves
  should be at least concerns about what we really
  are and not what we are in comparison to others.

77

• Now Williams offer six variations of the
  situations for us to make judgment
  
• 1. A is made totally amnesiac before the
  torture.
  
• 2. A has complete amnesia and change of
  character.
  
• 3. A has complete amnesia and change of
  character and a set of fictitious memory is
  given to him.
  
• 4. Same as (3) but the added memory matches that
  of another person.
  
• 5. Same as (4) except that the added memory is
  duplicated from another person B who is around
  with A.
  
• 6. Same as (5) except that the same is done to
  B.

78

• As we move along from (1) to (6), there seems to
  be minor difference. If we have genuine fear for
  our body in (1), why shouldnt we have such fear
  in (6)?
• Williams answer is that we mistakenly understand
  the move from (5) to (6) as merely involving the
  addition of something happening to somebody else.
  
• What actually involves is the reintroduction of A
  as the B-body-person. So As attention is now
  directed to the B-body-person as himself and can
  forget about his original fear for the
  A-body-person.

79

• Williams also offers the contrast between
  first-personal and third-personal views.
  
• It seems that the first-personal view focuses on
  the psychological whereas the third-personal view
  on the bodily continuity.

80

• Williams himself thinks that there is strong
  common sense support for the view that ones
  fears can extend to future pain whatever
  psychological changes precede it.
• So, he concludes that unless we show why the
  above intuition is wrong, we should agree that
  if we were the person A then, if we were to
  decide selfishly, we should pass the pain to the
  B-body-person.
• Of course, being selfish is to be overly
  concerned with self interest. So if our gut
  feeling to be selfish is the best guide to who we
  are, then why is the bodily criterion of less
  importance than the psychological?

81

• Williams paper is rich and difficult. You may
  not agree with, or understand the arguments. If
  you want to be good at English, it is also your
  intention to be connected to a person-stage who
  has read through Williams essay. But you can
  only do so by using your eyes and brain at the
  present stage of technology.