Heraclitus??:? You could not step twice into the same river; for other waters are ever flowing on to you. ?

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• Heraclitus??? You could not step twice into the
  same river for other waters are ever flowing on
  to you. ?
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????(Personal Identity)

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• ??Personal Identity,???????????

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• What does it take for a person to persist from
  one time to anotherthat is, for the same person
  to exist at different times?
• What sorts of adventures could you possibly
  survive, in the broadest sense of the word
  possible, and what sort of event would
  necessarily bring your existence to an end?
• What determines which past or future being is
  you? Suppose you point to a child in an old class
  photograph and say, That's me. What makes you
  that one, rather than one of the others? What is
  it about the way she relates then to you as you
  are now that makes her you? For that matter, what
  makes it the case that anyone at all who existed
  back then is you?
• This is the question of personal identity over
  time. An answer to it is an account of our
  persistence conditions, or a criterion of
  personal identity over time.

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• Historically this question often arises out of
  the hope (or fear) that we might continue to
  exist after we diePlato's Phaedo is a famous
  example. Whether this could happen depends on
  whether biological death necessarily brings one's
  existence to an end.
• Imagine that after your death there really will
  be someone, in the next world or in this one, who
  resembles you in certain ways. How would that
  being have to relate to you as you are now in
  order to be you, rather than someone else? What
  would the Higher Powers have to do to keep you in
  existence after your death? Or is there anything
  they could do? The answer to these questions
  depends on the answer to the Persistence
  Question.

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• Scientists tell you that instead of having to
  travel by rocket, which would take many years,
  you can step into their machine here on earth and
  (so they claim) step out of a similar machine on
  the colonized planet a few hours later. What the
  machine does is conduct a complete scan of the
  state of every cell in your body, recording all
  this information on a computer (the nature of the
  scan being such that the cells are all destroyed
  by the process). The information is then
  transmitted in the form of a radio signal to a
  machine on the colonized planet, which will build
  a replica of you which is exact right down to the
  last details.

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?????????

• In the film Here Comes Mr. Jordan, a
  prize-fighter is taken to heaven because of a
  mistake in the heavenly records. His body has
  been crushed beyond repair in a plane crash, and
  he demands a new body so that he can continue his
  career. He is supplied with another body no one
  recognizes him, of course, but his own memories
  are intact, and he fulfills his dream of becoming
  world champion. All this is fantasy, to be
  surebut wouldnt you be as certain as the movie
  audience that it is still the same person with a
  different body? And even if you werent sure, he
  is sureand he knows, doesnt he?

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?????????

• Suppose when you awoke this morning your body
  looked quite unlike your body of yesterday. You
  now have an extra leg and feathers sprouting all
  over, and can emit only a few ostrich-like
  screeches and no words. Of course, nobody
  recognizes you everyone thinks youre someone
  (or something) else. But dont you know its
  still you, in spite of this unexpected
  transformation?

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Numerical identity

• The persistence question is about numerical
  identity. To say that this and that are
  numerically identical is to say that they are one
  and the same one thing rather than two.
• This is different from qualitative identity.
  Things are qualitatively identical when they are
  exactly similar. Identical twins may be
  qualitatively identicalthere may be no telling
  them apartbut not numerically identical, as
  there are two of them thats what makes them
  twins.

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• A past or future person need not be, at that past
  or future time, exactly like you are now in order
  to be youthat is, in order to be numerically
  identical with you. You dont remain
  qualitatively the same throughout your life. You
  change you get bigger or smaller you learn new
  things and forget others and so on. So the
  question is not what it takes for a past or
  future being to be qualitatively just like you,
  but what it takes for a past or future being to
  be you, as opposed to someone or something other
  than you.

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An insidious misunderstanding

• Many people try to state the Persistence Question
  like this
• (1) Under what possible circumstances is a person
  existing at one time identical with a person
  existing at another time?
• In other words, what does it take for past or
  future person to be you? We have a person
  existing at one time and a person existing at
  another, and the question is what is necessary
  and sufficient for them to be one person rather
  than two.

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Whats wrong with question (1)?

• Question (1) is NOT the Persistence Question. It
  is too narrow. Why?
• We may want to know whether you were ever an
  embryo or a fetus, or whether you could survive
  in an irreversible vegetative state or as a
  corpse. These are clearly questions about what it
  takes for us to persist, and an account of our
  identity over time ought to answer them.
• Note that answers to such questions may have
  important ethical implications it matters to the
  morality of abortion, for instance, whether
  something that is an embryo or fetus at one time
  can be an adult person at another time, or
  whether the adult person is always numerically
  different from the fetus.

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Whats wrong with question (1)?

• Many philosophers define person as something
  that has certain special mental properties.
• Locke, for instance, famously said that a person
  is a thinking intelligent being, that has reason
  and reflection, and can consider itself as
  itself, the same thinking thing, in different
  times and places.
• Presumably this implies that something is a
  person at a given time if and only if it has
  those mental properties then. And neurologists
  say that early-term foetuses and human beings in
  a persistent vegetative state have no mental
  properties at all then.

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Whats wrong with question (1)?

• If anything like Locke's definition is right,
  such beings as early-term foetuses or human
  beings in a persistent vegetative state are not
  peoplenot at that time, anyway.
• In that case we cannot infer anything about
  whether you were once an embryo or could come to
  be a vegetable by discovering what it takes for a
  past or future person to be you.

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• So rather than Question (1), we ought to ask what
  it takes for any past or future being, person or
  not, to be you or I
• (2) Under what possible circumstances is a person
  who exists at one time identical with something
  that exists at another time (whether or not it is
  a person then)?
• This is the Persistence Question.

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1-23 ??????Microsoft Office 2003?????,??Microsoft??????????46?52?65?????
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2 You could not step on to you. Fragment 41 Quoted by Plato in Cratylus
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8 What does it take for a person to personal identity over time. ??Susan Schneider,Science Fiction and Philosophy From Time Travel to Superintelligence,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.68
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9 Historically this question Persistence Question. Science Fiction and Philosophy From Time Travel to Superintelligence,??Susan Schneider,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.68, ???????46?52?65?????
11 Scientists tell you that instead of ..to the last details. An Introduction to Philosophical Analysis,??John Hospers,???Routledge, 2013,p.192, ???????46?52?65?????
12 In the film Here Comes doesnt he? An Introduction to Philosophical Analysis,??John Hospers,???Routledge, 2013,p.188, ???????46?52?65?????
13 Suppose when you unexpected transformation? An Introduction to Philosophical Analysis,??John Hospers,???Routledge, 2013,p.187-188, ???????46?52?65?????
14 The persistence question what makes them twins. Science Fiction and Philosophy From Time Travel to Superintelligence,??Susan Schneider,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.72, ???????46?52?65?????
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15 A past or future person need not be,something other than you Science Fiction and Philosophy From Time Travel to Superintelligence,??Susan Schneider,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.72, ???????46?52?65?????
16 Many people try to state...person rather than two. Science Fiction and Philosophy From Time Travel to Superintelligence,??Susan Schneider,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.73, ???????46?52?65?????
17 Question (1) is NOT ...from the fetus. Science Fiction and Philosophy From Time Travel to Superintelligence,??Susan Schneider,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.73, ???????46?52?65?????
18 Many philosophers define...at all then. Science Fiction and Philosophy From Time Travel to Superintelligence,??Susan Schneider,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.73, ???????46?52?65?????
19 If anything like Locke's...person to be you. Science Fiction and Philosophy From Time Travel to Superintelligence,??Susan Schneider,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.73, ???????46?52?65?????
20 So rather than...Persistence Question. Science Fiction and Philosophy From Time Travel to Superintelligence,??Susan Schneider,???John Wiley Sons, 2010,ltPersonal Identitygt,??Eric Olson,p.73, ???????46?52?65?????