Personal Identity

1
Personal Identity

• Dr. Ron Mallon

2
Why Care About Personal Identity?

• Survival (Death, Dying, Afterlife, etc.)
• Individual Change
• Responsibility

3
How shall we proceed?

• Consider various cases in which we compare two
  entities over time
• Make judgments about those cases
• Try to develop a theory that systematizes those
  judgments
• Example of an a priori approach to a
  philosophical problem

4
Possible Criteria

• Psychological Continuity (Mind)
• Bodily Continuity
• Social Continuity

5
Often times we can describe the same case in two
ways

• E.g. John Perrys The Problem of Personal
  Identity Case
• Psychological Description
• The morning of the committee vote you wake up
  Something seems strange. Puzzled, you go to the
  mirror. Staring out you see not your familiar
  clean shaven face and squatty body, but the
  strapping frame and bearded countenance of your
  enemy Peter Pressher

6
The Body Transplant

• Peters Brain goes to Your Body
• Your Brain goes to Peters Body

7
The Psychological Interpretation

• You are in Peters body, Peter is in your body.
• You are where your personality and memories go.

8
Example 1 Mind Body

• Suppose that in the future, scientists develop
  the ability to perform open brain surgery. In
  this procedure, surgeons remove a persons brain
  from that persons head in order to perform
  surgical procedures more effectively. The brain
  is then replaced, and the head closed.
• Suppose that one day two patients, Brown and
  Robinson, were having open brain surgery at the
  same hospital. Unfortunately, during the
  procedures, the surgeons became confused and
  Browns brain was placed in Robinsons head,
  while Robinsons brain was placed in Browns
  head. Due to complications, Browns body
  (containing Robinsons brain) died immediately.
  But Robinsons body (with Browns brain) lived
  on, and eventually woke up from the surgery. The
  patient was in Robinsons body, but seemed to
  have the beliefs, desires, character, and
  memories of Brown.
• For insurance purposes, the doctors must
  indicate which person has survived the operation.
  Who should they say has survived?
• Brown has survived Robinson has survived

9
Example 2 Mind Body

• Imagine that in the distant future, a skillful
  surgeon switches the brain of Eva with the brain
  of Sammy. At the completion of the operation,
  Evas body wakes up and talks as if she has no
  memories of the things Evas body has
  experienced. But she does seem to have memories
  of what Sammys body has experienced. And
  Sammys body talks as if he has memories of what
  Evas body has experienced, but no memories of
  the things Sammys body has experienced.
• Soon after they undergo the operation, it comes
  to light that several months before the
  procedure, Sammy committed a horrible murder. As
  a result, the police decide to arrest Sammy.
  Which one should the police arrest?
• Sammys body with Evas brain and memories
• Evas body with Sammys brain and memories

10
This Class
11
But wait The Physical Interpretation

• You are a Senator One morning, you wake up
  seeming to remember being Peter Pressher A man
  emerges from a bedroom who seems to remember
  being you. What actually happened is that
  two people underwent radical changes in character
  and personality, and acquired delusive memories,
  as a result of brain surgery. (Perry, 5-6)

12
Its Possible To Manipulate the Cases to Cue into
the Body

• Lack of a closer candidate
• Cued into identification with the body
• Something at stake?

13
Example 1 Body over Mind

• Simon hated dogs so much, that he used to roam
  the neighborhood and poison dogs. One day, when
  he was on his way to the store to buy more
  poison, Simon got into a bad auto accident and
  suffered a head injury. The accident caused
  Simon to lose his memories he could not remember
  his family or his childhood, and he no longer
  hated dogs. In fact, he couldnt remember
  anything from before the accident. He didnt
  even remember disliking dogs! Luckily, his
  family visited him often in the hospital, and
  eventually they brought him home and cared for
  him during his recovery.
• Shortly after he returned home from the
  hospital, the police came to Simons home.
  Apparently, someone had videotaped Simon
  poisoning dogs, and the police had come to arrest
  Simon for cruelty to animals. But when they
  arrived, Simon explained that he has no memory of
  poisoning dogs. The doctors confirm that Simon
  has no memory of the poisoning. Should Simon be
  punished for dog poisoning anyway?
• Yes No

14
Example 2 Body over Mind

• Mr. Chan has a degenerative spinal cord condition
  that requires extremely painful surgery to
  correct. Unfortunately, there is no way for
  doctors to numb the pain during this operation.
  Mr. Chan does not want to undergo the operation
  if he has to undergo the pain. The doctors
  develop a way around this problem. They give Mr.
  Chan a drug before the operation that causes him
  to lose all of his memories. After the
  operation, the doctors give him another drug that
  both restores his old memories and also causes
  him to forget the intense pain of the operation.
  The physician explains that, With these drugs,
  while it is true that my patient was in very
  intense pain during the operation, the patient
  was not Mr. Chan
• Is the doctor correct? Did Mr. Chan avoid the
  pain?
• Yes No

15
Favoring the Body?
16
What do these examples show?

• One thing they might show
• Psychological continuity is sufficient, but not
  necessary.

17
The Robot Case

• Suppose that, in the future, brain scans become
  so accurate that scientists can read a persons
  beliefs, desires, intentions, and character from
  a brain scan. And suppose that scientists can
  then transfer these mental features into a neural
  net which can then be placed into the body of
  another person or a robot.
• When Melanie dies, the scientists decide to
  go a step further. A few days after her death,
  scientists take a scan of her brain and are able
  to recover a reading of her mental states. They
  then transfer these readings into a neural net
  that they place into a humanoid robot body. The
  robot awakens, and it claims to be Melanie.
  Moreover, the robot seems to act like Melanie and
  have Melanies memories. Despite all this,
  Melanies family does not accept the robot. They
  refuse to talk with it, or to allow it into their
  home. The robot cannot even acquire Melanies
  things from the family home. This makes the
  robot very sad.
• Is the robot Melanie?
• Yes No

18
Melanie