Who Are You?

By Sean Carroll | December 15, 2009 10:12 am

Last week I Twittered/Facebooked some provocative results from a poll of philosophers. In particular, this little tidbit:

Teletransporter (new matter): survival or death?

Accept or lean toward: survival 337 / 931 (36.1%)
Other 304 / 931 (32.6%)
Accept or lean toward: death 290 / 931 (31.1%)

Yes, that’s all the detail presented in the question: “Teletransporter (new matter): survival or death?” As a professional philosopher, you’re supposed to be familiar with the issue, which I reconstruct as follows. Imagine that someone has invented a working teleportation device. You step in the box, lights flash and sparks fly, and “you” rematerialize in another box, exactly the same in every way, but constructed out of a completely new collection of atoms. The original version of you is destroyed. Did you die? (And then, what if a million years passed in between the two events?)

It would probably be annoying to real philosophers, but I personally put this question in the category of “Not that hard.” And I would phrase my answer as: “Who cares?” What we should care about is how well the teleporter actually works — is the reconstructed person really in exactly the same quantum state as the original one was in? Same memories, feelings, etc? That’s an interesting technology question.

But there’s no interesting question associated with “Did you really die when you were teleported?”, or “Are you really the same person after being teleported?” These are just bad questions. They assume a certain way of looking at the world that ceases to be useful once we’ve invented teleportation. Namely, they assume that there’s a certain “essence of you-ness” that is (somehow) associated with your physical body and continues through time. That’s a perfectly sensible way of talking in the real world, where we don’t have access to duplicator devices or transporter machines. But if we did, that conception would no longer be very useful. There is a person who stepped into the first box, and a person who stepped out of the second box, and obviously they have a lot in common. But to sit down and demand that we decide whether they are “really” the same person is just a waste of time — there is no such “really.”

Which isn’t to say there aren’t interesting questions along these lines, but they are operational questions — how should I actually act, or what should I actually expect to happen, in these situations? — rather than arid metaphysical ones. What if you murdered someone, and then teleported — would the reconstructed person still be guilty of murder? That’s not quite the right question, because it still relies on the slippery essence of continuous personhood, but there’s a closely related sensible question — should we treat the reconstructed person as if they had committed murder? And it seems to me that the answer is clearly “yes” — whatever good reasons we had for treating the pre-teleportation person in a certain way, those reasons should still apply to the post-teleportation person.

The issue of duplication seems much thornier to me than the issue of teleportation. If someone made an exact copy of a known murderer, should we treat both the original and the copy as murderers? (I vote “yes.”) Fine, but what about the view from the inside? Let’s say you have an offer to get paid $100 if you let yourself be copied, with the proviso that after being copied one of the two of you will randomly be chosen for immediate painless execution. Do you take that deal?

I think problems like that are legitimately interesting, although to a great extent their mystery relies on the inadequacy of our conceptions of death. Most of us don’t want to die, at least not right away. But if we did die, we’d be gone, and wouldn’t have any wants or desires any more — but it’s very hard to consistently reason that way. Note that if we replaced “immediate painless execution” with “prolonged torture,” it seems like a much more straightforward question.

This showed up in our long-ago discussion of the quantum suicide experiment. In the many-worlds interpretation of quantum mechanics, you can make measurements that split the wave function of the universe into distinct branches. In some sense, then, you really do have a duplicator machine — it’s just that the whole universe gets duplicated, not just you. Some folks have tried to argue against this idea by pushing adherents into a logical cul de sac. You shouldn’t (to make a long story short) be averse to bargains that leave you dead with large probability, as long as there exist branches of the wave function where you are alive and flourishing — after all, in the branches where you are dead you don’t care any more, right?

My point in that earlier post — a point I somehow managed to completely obscure — was that these are misleading thought experiments, because very few of us would take seriously the corresponding classical suicide experiment. “Here, I’ll flip a coin, and give you $100 if it’s heads and shoot you instantly dead if it’s tails. Deal?” Very little temptation to take that offer. But the logic is essentially the same — if you’re dead you don’t care, right? (For purposes of these thought experiments we always assume you have no friends or loved ones who would miss you; it’s just part of the philosophical game, not a comment on your actual social situation.)

At some point in thinking about the many-worlds interpretation, issues like this inevitably do come up. That’s what David Albert and I talked about a bit on Bloggingheads. There might be a certain measurement that yields result A 10% of the time, and result B 90% of the time. But in the MWI, the measurement splits the universe into two branches, and you end up either in the branch where you saw A or the branch where you saw B. What does it mean to say that you had a “10% chance of measuring A”? You either did or you didn’t — there is no ensemble of millions of you all doing the same experiment. People have made progress on these questions — here’s a talk by David Wallace on his work with David Deutsch in attacking this problem. (Don’t ask me why everyone who thinks about these issues is named “David.”) I haven’t ever looked at this work closely enough to have an informed opinion.

All I know is that being able to teleport around would be really cool.

CATEGORIZED UNDER: Philosophy
  • http://orbum.net/mark Mark

    Knowing what we know of consciousness, you’ll never know until you try it. And even then, you might not.

  • Haelfix

    Well theres the thorny problem that you cant duplicate information exactly. The no cloning/zerox theorem of quantum mechanics forbids this.

    You can get it kinda close to within some accuracy, if you stick enough energy in, and for all intents and purposes you can clone the classical side (which is the one of most relevance for biological processes). So if you are satisfied with close enough, then in principle its possible.

    Also problematic. How do you measure the state of the human body, down to electrical currents et al, all at the same time with no error?

  • DaveH

    Most of the polled philosophers are atheists and realists IIRC, yet the whole idea of “survival” seems to depend on the concept of a soul. That is, as you say, an essence of you-ness. It’s the same thing.

  • Sam C

    The usual problem that gets raised about this picture is one you mention: duplicates. You say ‘The issue of duplication seems much thornier to me than the issue of teleportation’ – but they’re apparently the same issue. Teleporter A produces just one copy of Sam C in the receiver, and we perhaps want to say that Sam C after transportation IS Sam C before, where IS = identity. Transporter B produces two copies, one on Earth and one on the Moon. In the B case, do we want to say:
    1) both Sam-afters ARE Sam-before? But 2 things (2 Sam-afters – we know they’re 2 things because they’re in 2 different places) can’t be identical with one thing (Sam-before).
    2) neither Sam-after IS Sam-before? But how can a double success be a failure?
    3) just one of the Sam-afters IS Sam-before? But they’re identical, so it’s completely ad hoc to pick one over the other.

    Your answer is quite close to Derek Parfit’s in *Reasons and Persons*: the interesting question isn’t the (unanswerable?) one about whether the essense-of-you is teleported, it’s the question: is the person who comes out of the receiver *similar enough to* the person who went in to the sender to count as the original’s survival? ‘Survival’ here means rather less than IS as in ‘is identical with’.

    Parfit suggests that we think of the survival of persons as like the survival of nations or clubs: sometimes their survival is obvious (Scotland tomorrow is ‘the same country’ as Scotland today); sometimes there’s no answer to the question (is Scotland now the same country as Scotland under James I? Well, it covers most of the same territory, it has some related customs and cultures, its cities contain some of the same buildings and institutions, etc., but there’s no further ‘essence of Scotland’ which either is or isn’t still there). What this amounts to is denying that the IS of identity applies to persons over time. I’m not identical with Sam C last year, I’m just the closest survivor of him.

    Some philosophers – including me – are sympathetic to this. Others think we can’t do without the concept of identity of persons in the strong, logical sense of identity.

  • Sam C

    DaveH said: ‘the whole idea of “survival” seems to depend on the concept of a soul. That is, as you say, an essence of you-ness. It’s the same thing.’

    I don’t think so. A soul (i.e. a simple, non-material thing which is you) would be one way to guarantee identity through teleportation (assuming that the soul moves to the nearest appropriate body, and why assume that?). ‘Essence of you’ would be whatever property/ies are required to preserve logical identity (i.e. 1-1, transitive, all-or-nothing identity). Some philiosophers (e.g. Bernard Williams) have argued that the relevant property is ‘having the same body’, where sameness of body requires a continuous history through time and space (so, no teleportation, no uploads, no body swaps).

    In general, views on this problem (usually called the problem of personal identity by philosophers) cut across the theist/atheist divide. The Parfit solution I sketched above is based on the work of John Locke, who was a christian.

  • http://www.savory.de/blog.htm Eunoia

    Teleportation?
    If I jumped (Jumper was on TV here yestreen) to the other side of the world,
    surely classical momentum would have me going at Mach 1+ relative to the surface?
    What happens to conservation of mass, momentum etc?

  • Kerub

    I would have voted as “both death and resurrection”

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    I like Parfit’s analogy with countries, hadn’t heard that one before.

  • Alex

    Sean there is so much going on here that it is hard to know where to start.

    First: you are right to turn your focus on the duplication problem, since that is what suggests that the person who steps out of the transporter is not the person who steps in. [Imagine the transporter breaks… flash of light. “You’re” still on Earth, and “you” step out on Mars… now there are two persons… since the one can be punched in the face, while the other remains unpunched, they are not numerically identical. At most one of them can be the person who stepped in.]

    Second: the idea that there are answers to these questions doesn’t depend on the idea that there must be slippery essences of selfhood (perhaps you have immaterial souls in mind, or some such). The problem (as far as I can tell) derives from the discontinuity of the change. We might well run the thought experiment with non-human objects like tables — th0ugh the answers would be much harder to care about, since we’re (rationally or otherwise) more interested in our own survival than in the survival of tables. We don’t often care much about the diachronic identity of non-human objects. However, I take it that the reasons for thinking I would not survive the transporter are reasons for thinking that this table would not survive the transporter. [See the duplication problem.]

    Third: from a marketing point of view, defending a view by resting it on the premise that death is not in itself bad for the person who dies, is not a promising tactic.

    At any rate, even if the dead do not mind being dead (since they mind nothing), it is true that most deaths make it true that the person who dies has less of a very good thing than she would have had — had she not then died. That an event makes this kind of thing true is a reason for thinking its occurrence is a bad thing for the person who is deprived of the very good thing.

  • http://scienceontap.blogspot.com ARJ

    Part of this reminds me of a late night debate some high school friends and I had decades ago: if medical science learns to do brain transplants (and that will probably happen before teleportation), then would they really be doing brain transplants or would it in fact be body transplants???

  • Stan

    For a fun sci-fi read on this topic, you should check out Kiln People, by David Brin. It explores the social and psychological implications of technology which enables short term duplication of consciousness. You really have to stretch your imagination to keep up with the author. (The topic of the novel bears a superficial similarity to the recent movie, Surrogates, but sounds like it is much better done.)

  • Arrow

    The most interesting question regarding duplication is this one:

    You are subjected to duplication – a perfectly identical material copy is created in another perfectly identical room located in some other facility, both rooms have a camera and there are observers watching you and your copy on their screens.

    The question is who do you control? For example let’s say you decide to scratch your head, will the observers see your copy also scratch his head? Will both copies act exactly the same as long as their atomic composition and their surroundings are exactly the same? If someone punched the copy will you fell anything?

    Another problem – there would be no way to tell your original self from your copy if you had a chance to mix together, both of you would claim you are the original and deserve what past, family and material belongings you had before the duplication.

  • Davis

    I actually find it very useful to view me-in-the-past, me-in-the-present, and me-in-the-future as different persons who have significant overlap in traits, experiences, and interests. This view allows for the natural answer to the suicide question: if present actions should benefit future-me, and a current action has a high likelihood of leaving no future-me to benefit, then that action has low utility (anyone so inclined can probably rephrase this in terms of utility functions and expectation values and whatnot).

    This seems somewhat in line with Parfit’s view as described above, and suggests the same answer to the teleporter question: if the person who comes out of the teleporter is sufficiently similar to be considered future-me, then it’s not a problem.

  • DaveH

    sameness of body requires a continuous history through time and space

    Isn’t the ability to infer a continuous history how we actually (re-)identify individuals?
    Even in QED.

    We can infer a continuous history for the body because we have (for the purposes of the thought experiment) a mechanism, teleportation, which explains how the body got from A to B.

    What I’m saying is that the assumption the question is interesting requires more to “survival” than mere identification of the body.

    I see why Sean answered it “who cares?” now.

  • http://togroklife.com greg

    Yeah, the teleporter/duplicates idea is a fairly interesting one. There are different formulations of it, but generally speaking it’s a modern version of the Ship of Theseus.

  • Michael Albert

    Further discussions/uses of this issue in literature/film: “The Prestige”.

  • George Musser

    Has anyone ever calculated how long it takes for all the atoms in our body to be turned over — that is, to be excreted and replaced with atoms from the air or food? (Like the ship of Theseus.)
    George

  • Davis

    The question is who do you control? For example let’s say you decide to scratch your head, will the observers see your copy also scratch his head? Will both copies act exactly the same as long as their atomic composition and their surroundings are exactly the same? If someone punched the copy will you fell anything?

    Doesn’t this presume a “you” that exists independently of the copies, and thus beg the question? I think if you dig deeper the interesting question is, can you turn these into interesting questions without independently assuming an essential self?

    Under my view (in my previous comment), the first question does not make sense: I see them as two mes-in-the-future, so “I” don’t control either one. The second and third questions can be rephrased as “when will the behaviors of the copies begin to diverge, and why,” which under my view is more of a biological question, and so not philosophically exciting. And the last question is easy after removing the presumption that one of them is “me”: they’re two separate people, so clearly one would not feel the other’s pain.

  • Sto

    Here is a video illustration of the same question:
    http://www.youtube.com/watch?v=pdxucpPq6Lc

  • http://jacobrussellsbarkingdog.blogspot.com Jacob Russell

    How could duplication be possible without also duplicating the physical environment–space time the whole shebang? The instant the ‘duplicate’ and ‘original’ begin to interact with and adapt to their respective environments, they would no longer be the same. More like monozygotic twins..

  • Aaron

    We know that subatomic particles have no identity. The answer is not “who cares”, but that there is no difference between a state that has been teleported exactly, and one that moves via some other method.

  • Zwirko

    The Star Trek transporters convert the object to be transported into steam of particles known as the “matter stream” – so you are reconstructed from the same atoms (I think). And don’t forget the Heisenberg compensators…

  • http://togroklife.com greg

    @Jacob Russell (#20) and @Michael Albert (#16) – you might also want to check out Algis Budrys’ Rogue Moon. It involves the repeat duplication of an individual and how the original and duplicate interact and identity is maintained (the original is put into a sensory-deprivation chamber and is able to maintain a mental connection with the duplicate, until the duplicate is killed.)

  • Arrow

    Davis: “Doesn’t this presume a “you” that exists independently of the copies…”

    The first question is really about the nature and origin of consciousness.

    “You” means your consciousness, the question does not presume it is independent. The whole point is that now you experience and control your body and your body only, but what is it that ties your consciousness to this particular body and not the other?

    If your body will be perfectly duplicated will your consciousness extend to the new copy (making you aware of two bodies at the same time which seems rather unlikely but who knows) or will the new consciousness be created as a result of duplication? And if the later what will be the factor determining which body your original consciousness can control knowing that there are no differences between the bodies?

    The second question is about free will, if both copies will act exactly the same in the exact same situation there is no free will.

  • Matt

    It seems to me that all this boils down to timing. For the teleportation problem, George (#17) points out something important: Physically, none of us are exactly the same person as we were yesterday. We have new atoms incorporated into ourselves, and older ones have been discarded. Would anyone argue that I die every time I lose an atom, and a new me is born because I have a different atomic identity? Hardly. Now, to fully change out my atoms takes a long time, and no doubt during that time I will be a significantly different person, but that’s a matter of timing. Let’s say that I was able to fully reconstruct myself in an instant, without invoking teleportation. I flip a switch, and every one of my atoms is switched out for an identical but different atom. Am I a different person? Would I be absolved of my crimes of honor-bar candy theft? I think not.

    Now mix in a little teleportation. I flip a switch, and the reconstituted me ends up a couple of inches to the right. Same me – a change in location and a change in physical make up does not imply a change in identity.

    As for the duplication problem (?) Sean, I gotta disagree that the logic between the classical and quantum suicide problems (as you’ve identified them) is the same logic. In the classical, you have a 50/50 chance of survival when the game is completed. In the quantum game, you (the you before duplication) has a 100% survival rate.

    Here’s the more relevant question: If I offered to make an exact copy of you, then pay you $100 and make you watch yourself get offed, would you care?

  • http://lablemminglounge.blogspot.com/ Lab Lemming

    “Now, to fully change out my atoms takes a long time”

    Not really. Soft tissues change over on a weeks to months timescale, and even bones exhibit significant exchange on the decadal scale. The only atoms that really stay put are in your teeth.

  • g

    Followup question for philosophers who answered “death”: David is sentenced to death for a murder. David then walks into a teletransporter and David Prime walks out the other side. Is David Prime free to go?

  • Maledict

    As soon as I can verify the existence of angels, and ascertain the minimum amount of real estate it takes for each of them to be able to dance, I’m sure I’ll be able to answer the question concerning how many can dance on the head of a pin with at least some authority.

    Similarly, just as soon as someone develops a supportable hypothesis as to how teleportation or copying of human beings might take place I’m reasonably sure there will be some viable clues in the hypothesis as to the identity of the copies or teleportee. Until at least that time, I’d just as soon the legal and political systems–or “philosophers”– didn’t spend effort determining who is responsible for any crimes that may have occurred prior to teleport/copying activities. Can’t you guys speculate on how to develop an inexhaustible, safe, non-polluting, and easily transportable form of energy?

  • Tom

    Knee jerk reaction makes me believe it will not be me, no matter how close to the original it is. By the same token, I am not ok with the concept of some kind of “soul” to some way guarantee a single unique me.
    If we extent the concept to more mundane example… someone knocks you out, you lose all consciousness for some hours. The process of waking from this lapsed consciousness may be akin to what would happen if my “self” was faithfully reconstructed. However where does *me* reside if the glitch that keeps the original occur?
    Diving off the deeper end here…
    In fact, death may be nothing more than a permanent lapse in consciousness, so to lose consciousness may be akin to an impermanent death…
    Even sleep may count… in which case night’s sleep may be a death/rebirth.

    Now the tricky part… even if you DID do this experiment… how would you answer the question?

  • skoonz

    Requisite xkcd strip here.

    So if you have two lego houses, made with the exact same design, are they the same house?

  • http://www.7duniverse.com Samuel A. (Sam) Cox

    George Musser Says:
    December 15th, 2009 at 11:39 am
    Has anyone ever calculated how long it takes for all the atoms in our body to be turned over — that is, to be excreted and replaced with atoms from the air or food? (Like the ship of Theseus.)
    George

    First, I thought Sean’s treatment of this subject was pretty good.

    Now, do we really CARE that every atom and molecule in our body is replaced periodically? We just know factually that they are and can measure the processes involved.

    I’m not at all sure this question of teleportation is all that philosophical. Rather, in a universe where all information is permanently embedded in the manifold and where time is an illusion…well, we exist as ourselves permanently…we just observe and experience ourselves over and over again.

    I agree with Sean’s intuition. A murderer is a murderer, is a murderer. What we are is what we are- forever. The number of “readings” (presumably a near infinite number) we make of the information doesn’t change what is in place within the manifold.

    We are instinctively interested in this kind of subject not just because of idle philospohical curiosity, but our scientific aquaintence with current scientific cosmological models…models, some of which imply continuity in the existience of everything in the universe- including us.

  • Kennric

    To my mind, the duplication question makes it pretty clear that the person stepping out of the transporter on the other end is -not- the person who stepped in. It is an identical copy, and will surely -think- it is the same. It may not be distinguishable from the original, but if, as stated, the only difference between teleportation and duplication is the destruction of the original, how does the destruction (or not) of the original alter the identity of the teleported?

    The teleportation creates a new person if the old person may or may not be destroyed. The legal ramifications, of course, are a matter for the lawyers, but the teleported will feel like a continuation of the teleportee and the teleportee will insist that he hasn’t gone anywhere at all. The instant the two exist in different points in space, they are two different objects. If the destruction of the original is a necessary part of the teleportation, that just means we don’t have a dissenting opinion on the identity of the teleported. If the teleportation actually moves the teleportee from one point to another bit by bit, then there is no potential for duplication, at no point could the singular become multiple objects, and the situation is equal to moving the person via spaceship (Theseus’ spaceship, presumably).

    Identity isn’t really well defined here, it seems to either rely on the opinion of the identified, or be a purely empircal external measurement – but if you can measure that well, you’ll measure the difference of opinion, no?

    It’s the human aspect that gets people – if someone told you to go into a little room and be destroyed, but don’t worry, a person who thinks they are you will step out on mars, would you do it? If you went to sleep and woke up to find another you, the one who stayed up all night and therefore thinks he is the real you, what would you do?

    Side question: if 8 electrons are all identical, are they all the same electron? If four are arranged in a square formation, and the other four are arranged in the same formation elsewhere, are the squares identical? Are they the same square?

  • Kennric

    PS: Atoms, shmatoms, it’s the macroscopic configuration of molecules and the emergent dynamics of my brain that makes me (think I am) me, not the specific carbon atoms.

  • Low Math, Meekly Interacting

    Perhaps I’m missing something here, but, assuming the teleporter renders a duplicate that is physically indistinguishable from the person who was duplicated, that “duplicate” IS the person, correct? If you can’t physically tell him or her apart from the “original”, it makes as much sense to call that person a copy as it would if they walked across the room, no? If there’s no physical difference, there’s NO difference. Maybe this is what Sean is getting at, but isn’t the question “If you’re teleported, are you killed?” simply a non sequitur? If I walk across the room, no one asks about my soul, so why should they if I’m teleported? If every atom in my body is copied exactly, precisely nothing happened to me but a change in location. No other means of distinguishing my before and after states are possible, even in principle, right? So where’s the puzzle?

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  • http://www.7duniverse.com Samuel A. (Sam) Cox

    A PS to post 17,

    The periodic replacement of every atom in our bodies without changing our identities might well be dimensionally projective of our possible continuing existence within a higher dimensional structure.

    Our day to day lives in that scenario are a 4D cross section of reality, and we can see interesting hints about the true nature of our eternally existing selves when we carefully observe phenomena in the 4D world around us…Platonism…a universe in a marginally closed spherical geometry.

    Thanks George!

  • Wanu

    Sean–

    Let me blow all of your minds: When you zoom in on any electron or quark in your body, you’ll find that it’s in a sea of indistinguishable virtual particles that are constantly switching places with it. (Through the magic of renormalization, the effect of these processes averages away at larger scales.)

    So there is no single particle in your entire body that actually exists from moment to moment! Every particle in your body is constantly being annihilated and recreated! You’re essentially being “teleported” from one moment to the next! The metaphysical problem of teleportation is therefore entirely moot.

    As for the problem of what happens if you make two copies of a person, well, that’s impossible, as was pointed out earlier—it would violate the quantum no-cloning theorem to make an exact duplicate of another quantum state, at least not without the first state being destroyed in the process. So that problem is likewise moot.

    In your face, philosophers! Learn a little quantum mechanics, and your lives will be easier.

  • bad Jim

    It would be so handy to be duplicated! Conversation would be strained at first, since we’d start out identical, but we could split up the stack of unread books and neglected tasks and before long we’d be a team.

    I have a particular problem for which a double would be ideal, taking care of a mother with Alzheimer’s, which drastically limits my freedom. One might think that I could just foist her off on this or that sibling for a couple of weeks so that I could take a vacation, but in practice it doesn’t work very well, since I’m the one she’s used to. With two of me we could alternate and each have a better time than one could have alone.

    In terms of the work I used to do, some electronic design but mostly programming, it’s not clear how much would be improved; we might get through projects more quickly and debug more thoroughly, but we’d probably be better off working on separate problems. It would at least give us more to talk about.

  • nobody

    Questions like this, ie whether the original is dead after it is copied for the teleportation, make me like wormholes more than transporters :)

    Wormholes may have other issues but I think it would be easier to create one (or possible use an already existing?) than to copy the quantum state of a buzzilion atoms…

  • Erik

    Skoonz: “So if you have two lego houses, made with the exact same design, are they the same house?”

    Do they think they are the same house?

  • Metre

    We’ve all been dead – where were we before we were born? Physically, we did not exist before we were born; we do not exist after we die; and we do not exist while being teleported. Existence in this case means physical existence – a set of atoms arranged in a particular way and state.

    However, there is the small matter (pun intended) of information. Before I was born, there was no information about me: I did not exist in physical space or in information space. While being teleported, I no longer exist in physical space but I do exist in information space – my information is preserved and I am reconstructed from it on the other end. After I die, it should be possible (in theory) to save my information and reconstruct me later. If my information (configuration and quantum state) is lost, then I cannot be reconstructed. So there are two types of death, physical death – the body no longer can maintain itself in the steady state we call life and the atoms disperse – and information death – all information about your living configuration is lost. Information death is final.

    Of course, identity is not stored in a person’s body, it’s in the mind, which is still not a well-defined entity. If you reconstruct someone’s body but not his/her mind, you have a clone – genetically identical but a separate person. So people are not the same as the ship of theseus or a lego house; it is not the structure of the body but the mind that is important. Can a teleporter capture and reconstruct the mind? That’s the key question.

    I have to admit that it would be great to teleport at lunch and carve a few turns at my favorite ski resort, then teleport back for that afternoon meeting; and with teleportation, no lift lines!

  • Fraser

    The continuity of existence is just an illusion created by memory — we’re constantly dying, it just doesn’t feel like it, because we remember all this stuff. So the answer to whether one dies in a transporter is a very strong yes and no.

  • nobody

    “we’re constantly dying”
    @44. Fraser: That’s a very nihilistic attitude to life!

  • http://gacorley.wordpress.com GAC

    I’ve come up on this idea myself. I don’t really worry so much about my “essence of personality” or my soul. My criterion for survival is: does my own concious experience continue. I can see two possiblities:

    1) Continuous conscious experience is illusory, based on a reconstruction of one’s memories. In this case, my consciousness does continue into the new body, and I survive, since the new body has a copy of my brain and can reconstruct my past through the memories stored in it.

    2) Conscious experience ends when the brain is destroyed, therefore I am dead once the teleporter breaks down the original body. This idea scares me a little. Ultimately, no matter how perfect the copy is, this brain will be destroyed and will no longer experience qualia. Maybe the copy can be considered to have my identity, but I have still, in a sense, died.

    That doesn’t even get into the duplicate question. In a way, that can be comforting, my original brain and body are still functioning and experiencing, but then we get into the thorny identity question: Are we both the same person, or is this the original “me” and a false “me”?

  • Nameless

    This way of looking at things is actually very old and it is part of the essence of Buddhism: there’ no “you” separate from the aggregate of your body, your memories, etc. And Buddhism also takes one step further and says that nothing is permanent, because your body changes, new memories are formed, old memories are lost, … And therefore the “permanent self” or the “soul” is an illusion.

    But it’s one thing to acknowledge this formally, and it’s totally different to have a deep understanding of this by breaking the illusion. When a Buddhist achieves this deep understanding, it’s called “awakening”.

    Of course, they didn’t have to worry about many-worlds, quantum teleportation & such, but it was an astute observation nonetheless.

    Another interesting related subject is memory storage. Humans can’t really hope to be 100% eternal and invulnerable – accidents do happen. But we can, in principle, create a central storage bank for all memories, where you could “back up” your consciousness before going to try to do something foolish (to explore the galaxy, perhaps, or even jump into the black hole). Then, if the word gets to the central bank that the individual got killed by an accident, the central bank simply spawns a new instance of the same individual.

  • Arrow

    Wanu: “Sean–Let me blow all of your minds: When you zoom in on any electron or quark in your body, you’ll find that it’s in a sea of indistinguishable virtual particles that are constantly switching places with it. So there is no single particle in your entire body that actually exists from moment to moment!

    So there is no single particle in your entire body that actually exists from moment to moment! Every particle in your body is constantly being annihilated and recreated! You’re essentially being “teleported” from one moment to the next! The metaphysical problem of teleportation is therefore entirely moot.”

    I don’t see why you think details of QM (which I’m pretty sure many here know quite well) somehow make “metaphysical problem of teleportation entirely moot.”

    Yes, virtual particles impinge on real ones but for most purposes the effect is negligible and since energy is conserved if you have one electron at some location it will still be roughly in the same place later. Going by the usual terminology it will be the same electron as there is no way to tell the original one from the virtual-promoted-to-real one.

    It’s also a matter of interpretation, for example I consider virtual particles nothing more then an artifact of forcing particle description on fundamental fields so to me it is always the same localized electron excitation anyway, it is just continually perturbed by vacuum fields.

    Wanu: “In your face, philosophers! Learn a little quantum mechanics, and your lives will be easier.”
    Learn even more quantum mechanics and you see it is an incomplete, inconsistent mess open to many vastly different interpretations so if anything it makes philosophy much harder not easier.

  • Fraser

    @45: How so? The word ‘dying’? Let me rephrase. We are not the same person from moment to moment. We think we are, because of all those memories telling us, but really, the situation is indistinguishable from memories which have just been created, and in any case, memory works really badly. There’s nothing wrong with this, and we certainly feel some sort of duty towards a future “I” (although I hate the way that guy is going to be enjoying himself in Australia in a few days, while I’m sitting in frozen Holland). I don’t see the nihilism myself.

  • Skeptic Tim

    This question appears to be similar to the following:
    Assume that medical science is/will be able to construct prostheses for each and every part of an individuals body – including the brain.
    If over a period of time, every part of a persons body is replaced by a prosthesis, presumably as the original organic part fails, is the resulting entity the same ‘person’ as the original organic entity? If the answer is no, then at what point does the original cease to exist?

  • Pingback: I was ‘there’ « A Man With A Ph.D.()

  • http://togroklife.com greg

    @LM,WI (#34) – what you’re “missing” is the concept of continuity. If you walk across the room, there is no break in continuity of the existence of ‘you’. However, if your physical being is destroyed after having a blueprint stored in a computer, and then reproduced from entirely different matter, there is a “break” in your physical existence (though some philosophers argue that your physical continuity is still whole, it just changed form from matter into an electrical pattern or however you describe the blueprint in the computer, and then back to matter again). And then there is the question of the continuity of the mind, which is a similar issue, unless you don’t cotton to the idea of the mind being purely physical, which makes it quite a bit more complicated.

  • Meghan

    This is a bit reductionistic for my taste. I prefer a more gestalt view of the human experience beyond the sum of the atoms that comprise us.

    …Also, I’m 90% sure that the duplicate of me would be a lot bigger jerk than I am.

  • John Wendt

    A short story from some years ago: In the sufficiently-distant future, a young couple marry and book passage on the latest thing, a teleporter that lets them spend their honeymoon on the Moon. Returning after a wonderful experience, they happily settle into discovering married life.

    Six months later she is killed in an accident. He is devastated, but eventually learns from a friend in the teleportation industry that in peak periods passengers are sometimes recorded for later transmission.

    Their records are still available; the friend pulls strings and gets her reconstituted. The groom is ecstatic, of course, but discovers that she has no memory of the honeymoon, of their time together, or of course the accident. The marriage breaks up.

    The story would have been even more poignant if they had had a three-year-old child at the time of her death.

  • Low Math, Meekly Interacting

    What does it mean to say I would be made up of “different” matter if every atom in my body had the same state as before? Also, as for continuity, what’s so special about that? I know it’s giga-highly unlikely, but every atom in my body might suddenly tunnel to another spot ten feet away. Did I die? Am I different?

  • http://sgx2.sgdragons.com Scott G.

    I made a similar (although differently-emphasized) post on my dusty blog back in January. (http://sgx2.sgdragons.com/2009/01/14/immortality/) I come down on the site of the original consciousness dies during any sort of teleportation. Sean, you think it’s a bad question to decide if the original is experiencing death or not, but I feel it’s a key question – unless and until a non-atomic consciousness (i.e., “soul”) is proven, and a mechanism for transporting such soul separately from the atoms which make up our “meat,” then the experience of the original body during any sort of teleportation is a key question.

  • http://togroklife.com greg

    What does it mean to say I would be made up of “different” matter if every atom in my body had the same state as before?

    Possibly nothing. That’s why this sort of philosophy is known as metaphysics :)

    Also, as for continuity, what’s so special about that?

    Again, possibly nothing. It is an older concept that may or may not be relevant since the development of quantum theories.

  • http://completelyfutile.blogspot.com Adam Stephanides

    To the question “who cares?” the answer is “the person being ‘teleported.'” According to the “survival” view, I walk into the teleportation booth, someone presses a button, and I step out on Mars. According to the “death” view, I walk into the teleportation booth and that’s the last thing I ever do. A duplicate will step out on Mars, but I won’t experience any of the things that duplicate experiences, because I will have been annhiliated.

    In the story “Think Like a Dinosaur” by James Patrick Kelly, there is a teleportation station which operates as follows: the person to be teleported is rendered unconscious; all the information about her is sent to her destination, where she is reconstructed; and then the original is killed, while still unconscious. The part about the original being killed is kept secret. In the story there is a screw-up and the original wakes up after being teleported, but the aliens who run the network as a whole insist that the human operator of the station kill her.

  • http://teenageelephant.blogspot.com Sam Wolk

    I’m not sure if this was said earlier in the comments (because I didn’t look at them…), but generally this problem IS viewed as the problem of duplication; the destruction of the original body is like a variation of the “coin-flip of death” (you win you get a hundred dollars, you lose you die). I completely agree that though the duplication problem is extremely interesting. It seems that if you allowed the original body to survive most people would say that that one is still “you,” simply because of continuity. I think though that body that comes out on the opposite end is also “you”; in every single way, that other body would believe itself to be “you.”
    I think a related question also is the “Ship of Theseus”: if you have a ship and once every year you replace one plank of wood or part until finally no original parts are left, is it the same ship? If you believe that it is, then you should therefore think that the “new” person is definitely “you” ,

  • http://teenageelephant.blogspot.com Sam Wolk

    I’m not sure if this was said earlier in the comments (because I didn’t look at them…), but generally this problem IS viewed as the problem of duplication; the destruction of the original body is like a variation of the “coin-flip of death” (you win you get a hundred dollars, you lose you die). I completely agree that though the duplication problem is extremely interesting. It seems that if you allowed the original body to survive most people would say that that one is still “you,” simply because of continuity. I think though that body that comes out on the opposite end is also “you”; in every single way, that other body would believe itself to be “you.”

    I think a related question also is the “Ship of Theseus”: if you have a ship and once every year you replace one plank of wood or part until finally no original parts are left, is it the same ship? If you believe that it is, then you should therefore think that the “new” person is definitely “you” , and if you think it is a new ship than you should think that the “new” person is indeed a new person. That in itself is a whole ‘nother debate though isn’t it?

    For me, it is very difficult to decide whether or not it is something you should “who cares?” about; it perhaps is not relevant, but that does not mean you should not care. In fact, that’s a whole different debate isn’t it? I think you could spend ages just debating whether or not you should. Most philosophers say they are awful at finding out the truth, just good at asking questions and I think this is a good example.

    The whole continuity of self question has so many different explanations, and some of them are definitely the religious metaphysical views… Another interesting thing to think about is the nature of the mind in this situation… whether it is the “software of the brain,” just the brain, or completely separate.

    Sorry if I was vague at all I’m pretty undecided on this one (which I think is totally fine… I think that most philosophers are undecided about most things…). I think that it is good to just lay out all the views.

    P.S. This blog is the best… How many blogs talk about astrophysics and Philosophy of the Self?
    P.P.S. Can’t wait for your book… definitely buying it.

  • http://www.philosoraptor.com zorbalee

    The topic reminds me of the movie, The Prestige, where the magician, played by Hugh Jackman, has to kill off a “copy” of himself every time he performs a very special magic trick. Of course, his first performance of the trick took his own life…uh…well, I mean…uh…his original life…oh, what difference does it make? :-)

    Great blog, Sean! And I recommend to everyone your “The Teaching Company” course on cosmology. Excellent!!

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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] cosmicvariance.com .

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