Lectures: Perry

I. The problem of personal identity

• Remember that the founders of analytic philosophy wanted to get away without doing metaphysics; they wanted only to do science
• But it turned out that this was impossible. They needed to account for a lot of things that traditional metaphysics did.
• Remember the notion of a substance from Descartes. The wax itself—the substance—is what remains throughout the changes.
• Even modern scientists need something like that. They need to be able to explain what makes the butterfly "the same thing" or "the same organism" as the catterpillar—as opposed to saying that the caterpillar died and a new organism was born. They don’t necessarily have to explain this in terms of substances, but they have to have some account of identity over time.
• To say that things are identical is to say that they are the same. But there are two meanings of same. (1) being one and the same thing, or (2) being exactly similar, i.e., having all properties in common.
• This is the difference between numerical and qualitative identity. Identical twins are qualitatively identical; they are exactly alike. But they are not one and the same thing. On the other hand, I am numerically identical to the person I was when I was four. This means that I am one and the same person. But notice that I'm not qualitatively identical to who I was then.
• The notion of identity of time is thus a notion of numerical identity. A lot of interesting questions are raised when we apply this to people.
• The question of personal identity is a question of the conditions of the numerical identity of persons, i.e. it is about what makes this time-slice of me the same as earlier and later time slices of me.
• PERSONAL IDENTITY IS NOT ABOUT QUALITATIVE IDENTITY. PERIOD.
• PERSONAL IDENTITY IS NOT ABOUT A PERSON’S "SELF-IMAGE" OR "IDENTITY" IN THE SENSE IN WHICH IT'S OFTEN TALKED ABOUT IN ORDINARY DISCOURSE.

II. The Set-up to the Dialogues

• Three characters: Gretchen Weirob, philosophy professor, Dave Cohen, one of her students, and Sam Miller, college chaplain and friend.
• Gretchen has been badly hurt in motorcycle accident. Only has a few days to live.
• Sam seems relatively unconcerned about Gretchen’s imminent death. This is because he, unlike her, has a strong belief in life after death.
• They decide to engage in a discussion about the possibility of life after death. They admit from the outset that Sam will never convince Gretchen that it's probable that there is life after death, but she says she'll accept an argument to the effect that it's even possible—that is, imaginable—that there could be life after death, given the inevitable facts.
• It should be easy to see how this relates to the problem of personal identity. The question of my life after death is the question of whether there could be a being numerically identical to me, who lives after my death.
• So you can see why she dismisses the "merger with being" hypothesis. Survival after death means survival of the self. I don't survive death unless there is a being which is uniquely me after death.

III. The Kleenex box

• Sam says its easy to imagine the two of them meeting sometime in the future in a very different place
• Gretchen uses the analogy of the kleenex box to call this into question: but I will rot in a few days. How can, after I rot, the same person suddenly exist somewhere else. It's as if I burned this kleenex box to ashes and you told me the very same one was sitting at home on the self! Wouldn’t that be absurd?
• Sam says there could be an exactly similar box, but Gretchen says this is not relevant. It needs to be one and the same box. I can't anticipate having the experiences of someone just because she's exactly like me.
• Focus on key concept of anticipation--I must be able to anticipate the experiences of future temporal parts of myself. I need to be able to remember and be able to feel proud of what past temporal parts of myself have done.

IV. Sam's first theory: Personal identity is based on the sameness of immaterial soul.

• Refers to the work of Descartes: the soul is not the same as the body. It is an invisible, intangible, inaudible and immaterial substance that in principle can exist separate from the body. It's true that her body will rot, but not her soul, and that's what's important.
• Gretchen asks about how he can then make personal identity judgements. How does he know she is the same person he ate lunch week last week? He has to be able to know that her body is inhabited by the same immaterial soul.
• But how does he know he’s not talking to Barbara Walters or Mark Spitz? Perhaps by some strange turn of events, one of their souls came to inhabit her body.
• Sam: I use the principle "same body, same self (same soul)".

V. Problems with "Same body, same self"

• The problem that is if you also apply this principle to heaven, it becomes impossible for someone to survive after death of the body.
• Sam responds that "same body, same self" is a rule of thumb only applicable on this earth, where it is a well-confirmed regularity.
• But then it cannot be known a priori, because it's not a necessary conceptual claim.
• But how can it come to be known through experience? We don't experience other people’s souls. How can we confirm this regularity?
• Box of chocolates example.
• Gretchen: Therefore, since we have no way of knowing "same body, same self", our personal identity judgments would be groundless and silly. But they obviously are not groundless or silly, so there must be something wrong with your theory.

VI. Knowledge via Psychology

• Sam: Although I can't see your soul, I do have a way of "biting into the chocolate" so to speak. When I talk to you, I recognize your psychological traits. The way you think, reason and choose to behave are all properties of your soul, not of your body, and I do have access to them. If you acted very differently, I would conclude you were someone else. But since you act like you, I know it's still you with your body.
• Gretchen responds with the Blue River example: Sameness is characteristics does not require sameness of substance. It could be the same substance "flowing through the same spot" or through the same body, in her case.

VII. Abstracting from one's own case.

• Sam says he knows from his own case that his body goes with his soul. It may be kind of an inductive leap, but since there is no reason to think otherwise, he assumes the same is true of everyone else.
• Gretchen: but you don't really know about your own case. Perhaps exactly 5 years ago the soul in your body then vanished unnoticeably and a new one took over with all the same memories and psychological traits as before. It remembers being the old one. It does not know that it is not the same soul.
• Suppose that happens every five years, or every five minutes, or continually. The Blue River example also applies to you.
• Gretchen is very skeptical about the very idea of souls, because she thinks it's impossible to say what "soul identity" consists in. But the real problem is that if personal identity is based on identity of souls, then our personal identity judgments are completely groundless.

VIII. Objections to Gretchen's theory

• At the end of the first dialogue, Gretchen claims that her own belief is that a person is just a live human body. Personal identity is therefore based on sameness of the physical body.
• Sam doesn't quite know how to keep arguing for the idea that sameness of self is based on sameness of an immaterial substance, but he does think Gretchen's positions works either.
• His counter-example is that of waking up in the morning. A person could tell who she was without looking around. This means that a person does not need to look to see if she has the same body to tell if she is the same person.
• You can even imagine yourself waking up with a different body--the body of someone else, or even a cockroach. So obviously the theory that personal identity is based on sameness of body is not true, or else we couldn't imagine this.
• Where does this leave us? Sam has given arguments for why personal identity can't be based on the sameness of physical substance. Gretchen has argued that it isn't based on the sameness of immaterial substance. The conclusion? Personal identity is not based on the sameness of a substance at all!
• When we make personality identity judgments, we are not claiming that there is any thing that is the same. We are only judging that the person is the same, but the survival of a person over time does not mean survival of any thing.
• Leads into memory theory.

IX. The Memory Theory

• Sam again talks about the Blue River. He asks us to imagine seeing two different parts of the same river. What makes the two parts parts of the same river? It's not because we are seeing the same substance at all. Rather, we are seeing certain substances that are connected in some way. Specifically, in this case, they are connected by stretches of water.
• Another analogy: doubleheader. Stupid to ask "Is this game the same game as itself?" But it makes sense to ask "Is this the same game as it was before I went for hotdogs?" But what is "the same game"? Again, it's not some substance, but about how what you're seeing now is connected by what was before.
• A person is a "stream of consciousness"--a collection of different states. To say that I am the same person I was when I was four is to say that Kevin here and little Kevin are two parts of the same stream of consciousness.
• But what is the relationship between these person-stages that unite them into a stream of consciousness?
• We can extend our consciousness forward and backward in time.
• Locke: extending backward in time. That we exist in the same stream of consciousness as we did is why we can remember having certain experiences.
• This theory basically states that person-stage X and person-stage Y are part of the same stream of consciousness, and thus the same person, iff X can remember being Y or Y can remember being X.
• So here we can see how survival after death is possible, for there may be being who remember being us, whose consciousness is continuous with our own.

X. Actually remembering and seeming to remember

• Gretchen's response: There are such things as false memories. Some people claim to remember being Napoleon. Surely, such people are not the same person as Napoleon.
• Therefore, there must be a distinction between actually remembering and only seeming to remember, and the memory theory must state that X and Y are the same only if one of them actually remembers being the other.
• The question is: how do we explain the difference?
• Hypnotist example.
• Sam's response: the person actually remembering is the person who actually had the experience.
• Problem: that involves a personal identity judgment... you need to say that the person actually remembering is the same person as the person who actually had the experience, but the person who is only seeming to remember is a different person .
• But then we need personal identity to explain actually remembering, but we also need actually remembering to explain personal identity. This is circular in a bad way.

XI. The Caused-in-the-right-way Hypothesis

• In order to avoid the problem of circularity, Dave (who has been silent so far), suggests that instead of explaining the difference between actually remembering and seeming to remember in terms of whether or not that same person performed the thing remembered (and thus involving personal identity), Dave suggests that the difference between real memory and apparent memory should be explained in terms of the memory being caused the right way.
• When the causation is all internal to the brain, it's probably the right sort of causation, but if it involved other people--like the hypnotist, then obviously we don't have the right sort of causation.
• "a person is a sort of causal process"
• The question then becomes how to describe "the right sort of causation". Does it necessarily have to be all internal to the brain? If so, then this theory doesn't allow for life after death.
• But if we allow causation via God to count, then there are other problems. God could conceivably create 2 or 4 or 6 people who remember having my experiences. But these people can't all be identical to me, because they're not identical to each other.
• Dave points out that God could create just one. It's only a problem if God create mores than one, and all we're looking for here is the possibility of survival.
• Gretchen: but this really amounts to a change in your view. Now memory alone isn't enough for personal identity, but rather memory plus "lack of competition"
• And this is an absurd theory. Why would I be able to anticipate having a being's experiences only until God creates another one? The being in heaven wouldn't even know who she was unless she knows what God has done. Finally, God could create another Gretchen in Albuquerque, thus killing her right then.
• She's not saying that God would do such things, but that their theory is absurd for saying that if God did, she would cease to exist.

XII. Introduction to the Third Night

• They agree to talk about personal identity without necessarily in conjunction of seeing how it relates to the question of life after death.
• Why? What's really going here is that Dave was attracted to the theory that personal identity is based upon a certain sort of causal process internal to the brain.
• Gretchen never actually did anything to shoot down this theory. All she said was that it wouldn't allow for immortality, which shut Sam up. Dave, however, is not religious and doesn't mind the consequence.
• He thinks this theory has advantages over hers, which makes personal identity based on sameness of the body as a whole . Therefore, he gives the Julia North case as an example.

XIII. The Julia North Case (Not an actual event, but the characters pretend it is.)

• Julia North was a person who was hit by a train saving the life of child. The child's mother, Mary Frances Beaudine, had a stroke watching the scene.
• Julia's brain remained unscathed, but her body was destroyed. The opposite was true for Mary Frances, so they put Julia's brain in Mary Frances's body.
• The resulting person looked just like Mary Frances and had her body, but had the memories and psychological traits of Julia.
• Most people--including Sam and Dave--clearly think that the new person is the same person as Julia North, not Mary Frances.
• They think this proves Gretchen wrong. Personal identity cannot be based on sameness of body, or the survivor would be Mary Frances and not Julia.
• But this is exactly what Gretchen believes. Are they at an impasse?

XIV. The Supreme Court and Convention

• At this point, Dave appeals to the supreme court, which allegedly ruled that the new person is Julia North
• He points out that we normally assume personal identity goes along with both bodily identity and psychological continuity. But when these normal cases don't apply, we need to appeal to things like the Supreme Court to resolve questions of how old concepts apply to new cases.
• Gretchen's response: No, personal identity cannot be about how to apply words or the conventions adopted by any legal body.
• Aspirin example: It's only appropriate for me to anticipate the experiences of someone who is identical with me. But the supreme court can't decide whether I ought to take the aspirin. It's not a matter of convention.

XV. Supposed Advantages of Memory/Brain Theory

• They are at an impasse. But Dave says that there are two advantages to their theory
• The first is that it explains how we can know who we are without opening our eyes--it's because personal identity is based on memory and psychological continuity rather than on the body.
• Secondly, it stresses on what we take to be important about people: their psychological traits and life histories. It does not focus on the body, which we take to be less important.

XVI. Brain Rejuvenation

• Their current theory focuses on causation internal to the same brain
• Gretchen asks if it is crucial if the same brain be involved
• Suppose a new brain could be built--for likely stroke victims--in which all the memories, etc., of the old brain are duplicated, but the potential health risks avoided
• Will the person with this new brain be the same as the person whose brain it replaced?
• Problem with saying yes: Then one could create 10 such brains, and you get the same absurdity as before.
• But Gretchen also isn't happy with them saying no. Now, the very same brain is requried. But suppose they did create a new Gretchen brain, and put her current brain in another's body. Now we have Gretchen-A and Gretchen-B.
• Which is the real Gretchen? Dave has to say that's it's whichever one got the old brain, Gretchen-A.
• But can Gretchen-A and Gretchen-B know who's the real Gretchen just by thinking about it? They both remember being Gretchen. So it's not actually true on their theory that a person can tell who she is before she opens her eyes.
• It's also not true that their view tracks psychological traits--Gretchen-A and Gretchen-B have the same psychological traits. Both seem to preserve what is important about Gretchen.
• The conclusion: so much for the supposed advantages of your weird theory. Why not accept my theory--it's much simpler?

XVII. Are we even interested in personal identity?

• At the very end, before Gretchen dies, Dave very quickly suggests a different sort of theory. He never gets to elaborate but it's very interesting.
• He asks suppose you went through the procedure. Perhaps for theoretical reasons we can't say that the new person is identical to you, but the person would be happy, and we'd be happy having someone around like you.
• Maybe what we're interested in is not identity at all--where that is taken to be a transitive, symmetric, reflexive relationship--but merely survival. Perhaps it's possible for us to anticipate the experiences of beings who are not identical to us.
• Derek Parfit talks about a race of birfurcating creatures. Every few months, the race of aliens splits into two beings, each of which remembers being the old being. We can't say that either of the new beings is identical with the old one, or else they'd have to be identical with each other, but that's impossible. But perhaps it would not have been improper for the old to anticipate the experiences of the experiences of both of the new creatures. So identity is not a necessary condition for anticipation.
• Perhaps what we're interested in is survival--which needs not be transitive, reflexive and symmetric--not identity at all.

Return to course homepage.