My problem with time travel and teleportation

[Tyndmyr]

...actually...
you do sort of have to treat them as indistinguishable (that is you can't say the photon that was over there and the photon that was over here*).

*at least in non trivial cases

In practice, yes, uncertainty means there are some difficulties in determining exact positions of individual photons. In practice, copying people runs into the exact same problem.

But if we're handwaving that in order to discuss the theoretical sameness, well...the conclusion is obvious.

The brain injury case is interesting. We do, in dramatic circumstances, where the change is great enough, say things like "oh good, you're back" when a person recovers, or talk about losing someone, or even "they're a different person". So yes, I'd say that in some cases, at least, severe brain injury is treated as identity-changing.

[MorgromTheOrc]

My answer in regards to teleportation changes completely depending on the kind. If we're saying it disassembles you and then reassembles you using those particles elsewhere(with a 0% margin of error) I have no problem using it. Though I would wonder why we aren't just traveling in a fully assembled state instead if we clearly posses FTL technology, surely it would save a huge amount of energy and design complexity not having to disassemble then reassemble you.

There's really logically no problem with this form of teleportation because if you(theoretically) looked at a small enough span of time you would find an instant where none of your particles are interacting and are indistinguishable from if they were separate. So if you did the process in a small enough span of time you wouldn't notice any difference, and at a longer span of time it would just be as if some time was skipped.

But if we're talking about a teleporter that destroys you and then builds a copy elsewhere based on your information then there's no real situation where I would ever use it. The biggest fundamental difference in philosophy I see here between most posters in this thread and myself is that I am not my information. Information has no value. All information has always and will always exist, anything "invented" could have always and probably did somewhere exist before it was invented, and will likely again after it's forgotten.

Information is just an abstraction used to represent a possibility. And under physics as we can possibly imagine anything that ever was possible always will be. And so information really has no objective value. The only thing you could possibly claim has objective value is your experience of any given moment, the present is the only verifiable thing and no moment in the future or past can be said to be the same. We can't say for certain what consciousness is, all the empirical data we gather just points more towards its lack of measurable existence. But you do know that as long as you have physical continuity you have the experience of the present, and you know you wouldn't have that if you went through that "teleporter." So you would be throwing away the only thing you know has any objective value.

Spoiler

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On the objective value of existence versus nonexistence all I can really say is that something can always stop existing, but that existence can never truly start again, just something identical but new.

[NichG]

That is similarity, not causality. Your parents are absolutely causally connected to you.

Position is not the same for *any* of of the items between you and even an identical copy. So, even for similarity, this presents a problem. Sure, sure, it's quite similar, but you are not the same entity. If one or more perfect copies are made, yes, they are much like you, but they are not you. If the original is destroyed, you do not become any of the copies.

If your copies are fine with this, thanks to your outlook on life, cool. But that doesn't change what is.

It's causality because, if you were somehow able to go back and time and change a few bases of my parents' genomes before I was born, the exact same bases would be different in my genome. Of course we can't actually do this, but since we know that the information in my genome got there via a process which copied my parents' genomes and combined them, we can work out what would happen and estimate the causal mutual information (rather than just the correlational mutual information, which is 'similarity').

But it's not just a binary yes/no caused/not caused, it's a measure of a specific quantity of information. Different factors are responsible for different quantities of information. My parents caused some fraction of my total information content (probably more from actual interactions than from their genome, just by the numbers), but for the most part, the immediate past me causes (in the same, interventional sense that if I were to alter my immediate past self, I would expect my present self to also change) almost all of my information content.

For the teleporter, the version of me about to step through the teleporter causes (in an interventional sense) almost all of the information content of the version of me that steps out the other end. Of course we don't know how the teleporter works and probably building a deconstruct-and-reconstruct teleporter is just physically impossible, but in the same way I can posit changing my parents' genome or changing my past self and figure out what would happen by understanding an abstraction of the way that information is propagated, we can do the same thing for the teleporter. And the result is that the function of the teleporter ends up creating a causal structure which, locally to the thing being teleported, is indistinguishable from 'I take a step to the left'. Globally (that is, if we include the environment around the subject of the teleportation, etc) of course it's different, but if we use a standard of identity that lets me be the same person in my home as I am when I go to a coffee shop, we're accepting that there's at least a good enough approximation of a boundary we can use (e.g. the body in question) where in terms of identity we care about what's within the boundary and we don't count external variation as being part of the content of that person's identity.

Physical location IS a property of matter. This is just convenient shorthand for describing it.

It is not movement that presents a problem, but physical location not being identical does make two otherwise entities distinctly different. Use whichever coordinate system you please, it makes no difference.

Consider a photon. Not really a lot of properties there, you can absolutely have photons that are otherwise identical, but in different places. You cannot reasonable treat all of them as the same photon. If you attempt to do so, nothing really makes sense, and it's not a useful framework for understanding reality.

Thus, you are not the same entity as one or more teleporter made copies.

You have to be careful when talking about pairs of things. If I take two photons and 'paint' them with virtual indices #1 and #2, it turns out that quantum mechanics is equivariant under an exchange of those photons (so long as I exchange them properly, meaning I not only swap their positions but also their momenta). I can swap them back and forth as much as I like, in any pattern that I like, and there is not only no observable difference, there is no underlying mathematical difference. So those virtual indices that track identity do not couple with anything - there are no interactions or physical processes which care. Swap(x) = x.

If I'm swapping electrons, I do pick up a mathematical difference, but not an observable one - swapping a pair of electrons (or any fermions) introduces a 180 degree phase shift of the wavefunction: Swap(x) = -x. However, the global phase of the wavefunction is much like the choice of coordinate system when doing classical mechanics - it has to have a value, but the value is arbitrary and doesn't matter. So even though there's a mathematical change, if all I do is swap those two electrons, its still unobservable - it makes no change in any probabilities which follow. The minus sign has implications if you're doing something like a 'partial' swap and then combining the resulting wavefunctions, and in the end that's how you end up getting the Pauli exclusion principle, but a uniformly applied swap doesn't change anything.

Anyhow, the 'having an uninterrupted spacetime continuum' isn't a property, but rather its a heuristic that generally speaking lets you make a pretty good guess about sameness. But just because something is an effective heuristic in day to day life doesn't mean it's the only way to obtain a result, nor that it's a guarantee of the result you expect to see. Most of the time, the thing most responsible for causing the future at a certain location is generally its immediate, local past looking backwards in its direction of travel. So generally it's a good heuristic to assume that if e.g. you look at someone, look away for a second, and look back then if they're still there it's probably the same person. But if we posit a device which extends that over space and time distances, we're explicitly exploring a case for which that heuristic fails.

Information is just an abstraction used to represent a possibility. And under physics as we can possibly imagine anything that ever was possible always will be. And so information really has no objective value.

Information is exactly the part of things that can be lost - it's the index which identifies you out of the distribution of randomly generated outcomes. The distribution itself can't be lost, but the distribution for the most part is comprised of lumps of cold rock and widely separated hydrogen atoms and things like that. Once information has been lost, there's no way to get it back - it's the only thing that can be lost, really.

[MorgromTheOrc]

Information is exactly the part of things that can be lost - it's the index which identifies you out of the distribution of randomly generated outcomes. The distribution itself can't be lost, but the distribution for the most part is comprised of lumps of cold rock and widely separated hydrogen atoms and things like that. Once information has been lost, there's no way to get it back - it's the only thing that can be lost, really.

I won't claim to know whether or not information can be lost practically(no evidence of things like multiverse theory or anything else that could theoretically cause a repeat of the universe) but theoretically the information very much still has the same value after it's "lost" because it could theoretically exist again. I'm not going to in any way dispute that a literally perfect duplication would contain the same information(sans maybe location but you're already debating that) because under the given example it can't have lost any information and still be perfect. What I will say is that the most important, most valuable part of you, your actual continuity of experience would not carry over. And that is what I see as the actual self since anything else can be copied.

If I refer to the comic on sleeping we don't have any solid reason to believe we die when we lose consciousness, as someone in the thread has already said we can observe unconscious brains and they're still active. But I'll admit there's no way to verify that the continuity we think we have is real and we aren't technically dead one moment of experience to the next, however if that was the case we should probably change our definition of "living." Medically you would most certainly be temporarily dead with either method of teleportation

On a separate note I forgot to say anything about time travel. There's only really two logical questions you need to ask with time travel paradoxes. 1:Is the mechanism part of the continuity being affected? If yes then you have a paradox, the mechanism activating then reversing time until it disables itself, ad infinitum. If no then all's good and you can move onto question two. 2:Is the traveler part of the continuity being affected? If yes then they would be reversed the same as everything else just like the OP proposed and there would be no way to verify anything happened in universe. No paradoxes though because the traveler couldn't change anything and even if quantum shenanigans messes with things the mechanism can't be affected by the traveler not activating it since it's outside the continuity. If the traveler isn't part of the continuity then you still get no paradoxes no matter what they do or how far back they travel because changes in that continuity can't affect them or the mechanism. They could kill they're parents before they were born and there would be no(non-moral) consequences. This all of course assumes you're able to solve the conservation of mass and energy problems that would come with reversing time while you're outside the continuity, otherwise the time it reverses to wouldn't be right.

[NichG]

I won't claim to know whether or not information can be lost practically(no evidence of things like multiverse theory or anything else that could theoretically cause a repeat of the universe) but theoretically the information very much still has the same value after it's "lost" because it could theoretically exist again.

The state can potentially be visited again, but when the information is lost what you've lost isn't the state but rather the fact that the state occurs with higher probability than the underlying distribution would suggest. That's the thing that makes it informative - even knowing what all the possibilities could be, having information lets you know that it happens to be a specific one and not all of the others.

If we're talking about very low information content systems like coin flips or oscillators near equilibrium, you don't lose very much by erasing the state - the difference between a 50/50 chance and a 100% chance isn't a huge deal. But if we're talking about a billion bits, it's the difference between a 2^(-10^9) probability and a 100% chance. That's why if a species goes extinct, even if it could exist again we will never see it no matter how long we wait - the universe will end before it would exist again from random sampling. And that's just talking about genomes, which are, relatively speaking, a fairly small quantity of information.

The value that is lost is that knowing where you are in an infinite space is something that can never be recovered just by exploring all the space. What 'could' exist and what 'will' exist become infinitely separated from each-other.

The things that when you lose them, you always end up finding them again - those are the things that don't contain any information, so in that case there's nothing to lose.

[Wardog]

Let's assume a purely magical teleportation. A person is in some place, then is in another place. They're whole the entire time. Do you consider the person to still be the original? Why/why not?

Now if we then turn to the (still magical) sci-fi version of teleportation. A person is in some place, then is in another place, but we posit that information has been moved from the first place to the other. Is there a difference to the first scenario? Why/why not?

In the first case, as far as I can tell from your description, the person is simply being magically moved from one place to another, so there is no reason not to consider them to be the same person.

In the second case, I'm not quite sure, becasue its not clear what exactly is involved. Are you talking transmitting information, and then about scratch-building a new person (and erasing the original)? Because in that case it is clearly not the original original (who will cease to exist and never have any experience of being in the new place). Or about disintergrating the person, and then transmitting both their original components and the information to rebuild them? In that case, I would say it is the original person - you've just killed* them and then brought them back to life in a different place.

*Subject to definitions - if you define death as permenant by definition, then anything that can be recovered from, including disintegration, isn't really death. I suppose you could compare it to the old Batman the Movie where the villains capture the Un delegates by "dehydrating" them and turning theminto powder, which Batman later restores by carefully rehydrating them. (Although in that case there were... complications... due to accidental mixing of powders, so I'm not sure if you could really say you got the original people back).

[Manga Shoggoth]

Spoiler: This video(s) may explain better

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That - and the video it references - was interesting. Thanks for posting it.

[veti]

In the first case, as far as I can tell from your description, the person is simply being magically moved from one place to another, so there is no reason not to consider them to be the same person.

In the second case, I'm not quite sure, becasue its not clear what exactly is involved. Are you talking transmitting information, and then about scratch-building a new person (and erasing the original)? Because in that case it is clearly not the original original (who will cease to exist and never have any experience of being in the new place). Or about disintergrating the person, and then transmitting both their original components and the information to rebuild them? In that case, I would say it is the original person - you've just killed* them and then brought them back to life in a different place.

I'm still not on board with this "clearly not the original" part.

It seems to me that you're saying that humans have some property that I can only describe as "magical", that can't be detected, or even defined, in any way whatsoever, but this property would be destroyed by teleportation just because obviously it would.

And again this fixation with "original components". Why is that so important? Given that the cells of our bodies are constantly renewing anyway, what exactly is the big deal about doing the whole lot all at once in a single operation? (I mean - sure it's a big deal in the sense of an impressive feat of technology, but why would it be qualitatively different from the normal, natural process?)

[Manga Shoggoth]

And again this fixation with "original components". Why is that so important? Given that the cells of our bodies are constantly renewing anyway, what exactly is the big deal about doing the whole lot all at once in a single operation? (I mean - sure it's a big deal in the sense of an impressive feat of technology, but why would it be qualitatively different from the normal, natural process?)

If you haven't already done it, look at the video linked to the one linked earlier (The Trouble with Transporters). It goes in to a lot of details including the Ship of Theseus that you are referencing here.

The short answer is this: Continuity. The original person is clearly you (I assume we can all agree on that?).

A person who is not teleporting is changing in small increments all the time. Nobody is disputing that. However there is a clear continuity across that person's existance. Even with breaks in conscious perception (Sleep, surgery) the body itself is the same thing.

Introducing the teleportation removes that continuity and inserts a discontinuity: the transport itself. At the start and the end of the process there is a person who is convinced that they are the real person.

The question is, are they? Have you disintegrated person A and created person B (in which case you have killed person A, regardless of the rhetoric you use to cover it up) or have you genuinely transferred person A to Location B.

Either way you will have someone at the other end that is convinced they are the genuine thing. It's just that in one case they are wrong.

This is part of the reason that the exact process being used is so important. The linked video (Transporters and Quantum Teleportation) gives one possible answer to the question about accidental copies, but does not address the central problem.

[NichG]

I disagree that the teleporter introduces a discontinuity in any meaningful way (or, perhaps, that 'discontinuity' is at all a meaningful concept applied this way). That would require there to be some physical trace which would be left by being the one with a discontinuity in it's history.

[Bohandas]

If you haven't already done it, look at the video linked to the one linked earlier (The Trouble with Transporters). It goes in to a lot of details including the Ship of Theseus that you are referencing here.

The short answer is this: Continuity. The original person is clearly you (I assume we can all agree on that?).

A person who is not teleporting is changing in small increments all the time. Nobody is disputing that. However there is a clear continuity across that person's existance. Even with breaks in conscious perception (Sleep, surgery) the body itself is the same thing.

Introducing the teleportation removes that continuity and inserts a discontinuity: the transport itself. At the start and the end of the process there is a person who is convinced that they are the real person.

The question is, are they? Have you disintegrated person A and created person B (in which case you have killed person A, regardless of the rhetoric you use to cover it up) or have you genuinely transferred person A to Location B.

Ok, analogy here with D&D. If I kill a character and then I cast resurrection on them, are they still the same person? Because that's what's going on in scenario 1.

[Manga Shoggoth]

I disagree that the teleporter introduces a discontinuity in any meaningful way (or, perhaps, that 'discontinuity' is at all a meaningful concept applied this way). That would require there to be some physical trace which would be left by being the one with a discontinuity in it's history.

You have a transferral process - the body is converted to something, transmitted and rebuilt somewhere else. This is in itself a discontinuity, and the process is not the same as - say - walking there.

As to there being no physical trace: Location is a measurable physical property, and quite an important one. There is a big difference between being teleported across the room (discontinuous) and walking across the room (continuous).

The question here whether the introduction of a discontinuity has an effect or not (and works towards the real issue, what happens to the Original). You don't think so, and I am ... less certian, to say the least. I'm happy to disagree, provided we are actually clear where the issue is - it's not like this is ever going to be a real problem.

This is why I think The Ship of Theseus is a bit of a red herring - while it is a genuine thought experiment on the idea of identity, it is based on a an object going through a continuous process of change. Teleportation is a discontinuity in such a process. One wonders how Plutarch, Hera****us and Plato would have reacted if the idea of teleportation was current then.

Second, as I mentioned earlier, in real life we would have such joys as transmission losses and artifacts and the uncertianty principle, which puts a limit on what we can measure in the first place.

Edit:

Ok, analogy here with D&D. If I kill a character and then I cast resurrection on them, are they still the same person? Because that's what's going on in scenario 1.

In D&D? A completely fictional environment where magic reigns? Because of a magic spell? Yes, because magic! If you try to do the same thing without magic you will run into a few practical problems.

Frankly, I'm disappointed. While I think your previous analogies (Paramecium division, Dismantled Bicycle) were missing the point they were at least reasonable issues to bring up and were connected to reality.

[Millstone85]

Ok, analogy here with D&D. If I kill a character and then I cast resurrection on them, are they still the same person? Because that's what's going on in scenario 1.

In D&D, casting resurrection explicitly calls a soul back from the afterlife. You are not so much reassembling the person as you are merely reassembling their earthly vessel. The soul assures the continuity of the self. It is pretty much what souls are for, when they are not treated as mystical fuel.

[NichG]

You have a transferral process - the body is converted to something, transmitted and rebuilt somewhere else. This is in itself a discontinuity, and the process is not the same as - say - walking there.

As to there being no physical trace: Location is a measurable physical property, and quite an important one. There is a big difference between being teleported across the room (discontinuous) and walking across the room (continuous).

What is the actual difference though? This is just saying 'it is because I say it is', but there's nothing in physics that would suggest that if you were to slowly move a collection of matter from A to B, jump it suddenly from A to B while exactly maintaining its shape, or construct an identical copy of it at B, there is any way for a difference to occur in what happens next. Absolute location isn't actually a measurable physical property, only relative location. So if we have a person in universe empty of all things but that person, and we change the coordinates of that person (and all their emitted fields, etc) by a billion meters in some random direction, there's no way to tell that anything happened.

Of course if we teleport a person, the person moves but the environment doesn't - so if your claim is that identity is stored in the relationship between the person's body and their environment more so than it's stored in the person themselves, that would be consistent. But that claim would correspondingly mean that, for example, driving to work each morning kills you and replaces you with a different person (or at the least, driving to work 'sufficiently fast' does this). There's certainly no evidence for that though.

The question here whether the introduction of a discontinuity has an effect or not (and works towards the real issue, what happens to the Original). You don't think so, and I am ... less certian, to say the least. I'm happy to disagree, provided we are actually clear where the issue is - it's not like this is ever going to be a real problem.

I think the question is deeper - whether the concept of a discontinuity in this sense is even capable of being meaningful at all. It's not 'does it have an effect?', but rather 'is it even possible for it to have an effect?'. Even putting physics aside, the issue has to do with the setup of the premise - that a person walks through the teleporter and the person who walks out is indistinguishable in any way from the original. If that's the case, then there is no room in the premise itself for there to be a measurable effect. What that leaves is that there is an effect, but that the effect is impossible to measure.

Here's the root of our disagreement I think: I would say that only things which actually change the outcome can be called 'effects'. If you have defined something so that it is definitionally affected, but nothing at all changes about the outcome, I would claim that the definition itself is in error. So I take the assumed element of the premise that the copy is absolutely indistinguishable from the original in any way to be absolute proof that there is actually no effect - in any universe where teleporters don't change peoples' personalities or memories, they must necessarily preserve people's identities as well, inasmuch as the 'identity' we're talking about is a real thing.

It may well be that you can't build a teleporter in this universe that does not change someone's personality. But I would say that if you observe that it doesn't, assuming that you're still not safe is at least not 'rational' in the way that you've claimed, because you've also made that decision in a way that denies the possibility of any evidence influencing your belief on the matter.

[Manga Shoggoth]

What is the actual difference though? This is just saying 'it is because I say it is', but there's nothing in physics that would suggest that if you were to slowly move a collection of matter from A to B, jump it suddenly from A to B while exactly maintaining its shape, or construct an identical copy of it at B, there is any way for a difference to occur in what happens next. Absolute location isn't actually a measurable physical property, only relative location. So if we have a person in universe empty of all things but that person, and we change the coordinates of that person (and all their emitted fields, etc) by a billion meters in some random direction, there's no way to tell that anything happened.

First of all, thank you for a well thought out response.

I am not claiming that personallity is linked to the location, simply that their location is a measurable physical property. The fact that we are talking about relative location does not change that. Relativity simply means that someone in a different inertial frame of reference may measure a different value, and that the value they measure is no less correct. And the relative location is still changing, no matter what frame you measure from.

As to "What is the actual difference though?": This is where the mechanics come in. So far there has been very little in the way of mechanics discussed. The process is essentially treated as "person disappears at A, reappears at B". There has to be some form of conversion and transmission, and that is where the discontinuity comes in. There is a very tangible difference between walking across a room and teleporting across the room.

I think the question is deeper - whether the concept of a discontinuity in this sense is even capable of being meaningful at all. It's not 'does it have an effect?', but rather 'is it even possible for it to have an effect?'. Even putting physics aside, the issue has to do with the setup of the premise - that a person walks through the teleporter and the person who walks out is indistinguishable in any way from the original. If that's the case, then there is no room in the premise itself for there to be a measurable effect. What that leaves is that there is an effect, but that the effect is impossible to measure.

Here's the root of our disagreement I think: I would say that only things which actually change the outcome can be called 'effects'. If you have defined something so that it is definitionally affected, but nothing at all changes about the outcome, I would claim that the definition itself is in error. So I take the assumed element of the premise that the copy is absolutely indistinguishable from the original in any way to be absolute proof that there is actually no effect - in any universe where teleporters don't change peoples' personalities or memories, they must necessarily preserve people's identities as well, inasmuch as the 'identity' we're talking about is a real thing.

It may well be that you can't build a teleporter in this universe that does not change someone's personality. But I would say that if you observe that it doesn't, assuming that you're still not safe is at least not 'rational' in the way that you've claimed, because you've also made that decision in a way that denies the possibility of any evidence influencing your belief on the matter.

It is a very complicated problem. However, the issue is not "is the person at the end a true copy of the person we started with", or even "how good is the process", but "what happened to the person we started with", and I have yet to see that addressed to my satisfaction*.

This is why the question of "What would happen if - by accident - the original person remained?" comes up in these discussions. In that event, who would be the real one?

* - I don't have to agree with the answer - I would just like one that isn't skating over the issue.

[Millstone85]

This is why the question of "What would happen if - by accident - the original person remained?" comes up in these discussions. In that event, who would be the real one?

One way to look at it would be that they are the branches of a temporal Y. They are currently two different people but they were the same person a moment ago. Like in a splitting multiverse.

I think that was the legal interpretation of a teleporter accident involving Riker in TNG. Although here both Rikers were a rematerialization of the pattern.

[Manga Shoggoth]

One way to look at it would be that they are the branches of a temporal Y. They are currently two different people but they were the same person a moment ago. Like in a splitting multiverse.

I think that was the legal interpretation of a teleporter accident involving Riker in TNG. Although here both Rikers were a rematerialization of the pattern.

It's an episode I haven't seen, but judging by the TVTropes recap it is not so much "what happens to the original" as "we now have two people, what can we morally do with them?". It is an interesting question, and I think they probably came up with the best solution they could (I do wonder who gets the pension credits in that situation), but it is about two duplicates. not what happens to the original.

In fact, apart from the fleeting mention in "Spock Must Die" I don't recall it ever being addressed in any great detail despite the huge number of transporter-related issues in the universe (does anyone with a wider knowledge of Star Trek recall such a treatment?).

[NichG]

It is a very complicated problem. However, the issue is not "is the person at the end a true copy of the person we started with", or even "how good is the process", but "what happened to the person we started with", and I have yet to see that addressed to my satisfaction*.

This is why the question of "What would happen if - by accident - the original person remained?" comes up in these discussions. In that event, who would be the real one?

* - I don't have to agree with the answer - I would just like one that isn't skating over the issue.

Well again, this is the tricky thing about definitions. We assume that the question 'who would be the real one?' is well-posed because there's an unspoken assumption that only one can be real. The trick is, where does that come from? If it's because we never experience becoming two people, well, with the teleporter that preserves the original, neither of them will experience becoming two people either - they'll each experience being just the one. So if the feeling that 'only one can be real' comes from our experience, we have to take equally seriously that both people would report that they experienced continuity of consciousness, that they both experience themselves as just a single consciousness (but don't experience the consciousness of the other), etc.

And of course, this is all within the context of a universe where teleportation demonstrably works without causing problems, so its a thought experiment where we imagine a particular outcome to the experiment and then work out the implications. In that event, in that universe, the sense that there can only be one 'real' you is just a perceptual illusion.

[Lethologica]

If we can construct an exact copy of a person somewhere else, we probably have that person's exact configuration as data. If we periodically save that configuration, and then that person dies and we reboot him from his saved state, is the reboot the same person that was saved? (It clearly isn't the same person who died.)

What if you save him just once, at thirty years old, and then boot him after the original dies of old age?

What if the configuration is constantly synced to the person's current state, except in case of fatal injury, in which case a new copy is created? Is that the same person as the person who died just because the match is better?

If we go further we start getting into Altered Carbon territory where the consciousness can be virtualized and the value of any particular body is much reduced.

[Manga Shoggoth]

Well again, this is the tricky thing about definitions. We assume that the question 'who would be the real one?' is well-posed because there's an unspoken assumption that only one can be real. The trick is, where does that come from? If it's because we never experience becoming two people, well, with the teleporter that preserves the original, neither of them will experience becoming two people either - they'll each experience being just the one. So if the feeling that 'only one can be real' comes from our experience, we have to take equally seriously that both people would report that they experienced continuity of consciousness, that they both experience themselves as just a single consciousness (but don't experience the consciousness of the other), etc.

A good point about assumptions, and that is why Location is an issue. If it is possible for the original to not dematerialise and yet a copy appear at the other end, then this demonstrates that the person at the other end - no matter what their perception is - is a copy and not the original person (not, you understand, that I am in favouring of picking one and shooting them to resolve the issue).

If it is impossible for your teleport process to leave a body behind then there is a possibility that the original/copy issue does not exist. As I have said several times, a lot of this depends on the process.

And of course, this is all within the context of a universe where teleportation demonstrably works without causing problems, so its a thought experiment where we imagine a particular outcome to the experiment and then work out the implications. In that event, in that universe, the sense that there can only be one 'real' you is just a perceptual illusion.

If you are talking about the Star Trek universe then they have no end of transporter issues. Just - oddly - not the one we are talking about in this thread.

(Actually, it's not surprising that they have never really addressed the issue - the writers would have no choice but to give the transporter a clean bill of health, and would then get accused of doging the issue. At the end of the day Star Trek is science fantasy rather than science fiction.)

However, even then, it wouldn't be the first time that a moral issue has been ignored for the greater convenience - especially when the (supposed) victim literally has no voice because they no longer exist.

If you are talking about the real world, all that has been done so far is transmitting bits of information via quantum states.

Although the name is inspired by the teleportation commonly used in fiction, there is no relationship outside the name, because quantum teleportation concerns only the transfer of information. Quantum teleportation is not a form of transport, but of communication; it provides a way of transporting a qubit from one location to another, without having to move a physical particle along with it.

[Bohandas]

Well again, this is the tricky thing about definitions. We assume that the question 'who would be the real one?' is well-posed because there's an unspoken assumption that only one can be real. The trick is, where does that come from?

I don't think it comes from anywhere; it's an arbitrary manifestation of human stupidity and inability to think things through

EDIT:
Oh, and it's probably in some way related to the naturalistic fallacy; the superstition that artificial things are somehow less real than naturally occurring ones

[Bohandas]

This is why the question of "What would happen if - by accident - the original person remained?" comes up in these discussions. In that event, who would be the real one?

Assuming a world where the first law of thermodynamics implies this is a logical impossibility. By analogy you can;t take a bicycle apart an then both put the pieces togeher somewhere else AND at the same time also put those same pieces back together in the place you started*; there aren't enough pieces. Or you can't eat an entire cake and then have someone else eat that very same entire cake**

*Or, at least, you can't be observed to do so. I suppose that if you were in a closed system and the location where you reassembled it was determined by some indeterminate quantum process you could, but as soon as the system was opened and observed by an outsider it would resolve into a single history with a single bicycle in a single location.

**Unless you're one of the two girls from that shock video.

[Wardog]

I'm still not on board with this "clearly not the original" part.

It seems to me that you're saying that humans have some property that I can only describe as "magical", that can't be detected, or even defined, in any way whatsoever, but this property would be destroyed by teleportation just because obviously it would.

I'm not (at least not intentionally) implying any magical property - just the meanings of words. If you make a copy of something, the copy isn't the original by definition, even if it is a perfect and indistinguishable copy.
http://smbc-comics.com/index.php?db=...&id=1879#comic

You could have a slightly different version of the scenario: transmitting information, and then scratch-building a new person (and not erasing the original). In such a case, the copy obviously isn't the original, because the original is still present, and different. And while the copy will have all the memories of being the original, stepping into the transporter, and appearing somewhere else, the original won't. As far as they are concerned, they stepped into the transporter, and didn't go anywhere. The original scenario is the same - except the transport works correctly and kills the person who got into it.

[Bohandas]

In D&D, casting resurrection explicitly calls a soul back from the afterlife. You are not so much reassembling the person as you are merely reassembling their earthly vessel. The soul assures the continuity of the self. It is pretty much what souls are for, when they are not treated as mystical fuel.

revive outsider then. Or resurrection via a wish cast within pholgistonic space

[NichG]

A good point about assumptions, and that is why Location is an issue. If it is possible for the original to not dematerialise and yet a copy appear at the other end, then this demonstrates that the person at the other end - no matter what their perception is - is a copy and not the original person (not, you understand, that I am in favouring of picking one and shooting them to resolve the issue).

But location is only an issue external to the person themselves, so we're back to assuming that identity is somehow stored outside the body, which doesn't match up with evidence (e.g. you don't stop being you because you drove to work).

If we put a box around the whole process, and someone walks into the box but two of them walk out, and within the box some unknown number of teleportation exchanges, copying processes, and destruction of copies took place (it could be that one of them was destroyed and recreated a billion times, then two copies made, or any such combinations) - by observing the people themselves there is no way to tell.

So 'location' and 'which is the original' is just a matter of external convention here, its not intrinsic to the subject of the teleportation. It's reliable only in that we didn't lie to people about the function of the teleporter, but within the context of the teleporter scenario it would be entirely possible for the 'original' to have been teleported in-place (e.g. destroyed and recreated at the entrance to the teleporter), or any other number of deceptive configurations. Whether one or the other is considered the original after that is entirely a matter of some external observer (who can be tricked) making a declaration that defines one as the original in what is essentially an arbitrary way that has nothing to do with what actually is.

It's the equivalent of legislating pi=3. You can say those words, and human society can agree to treat them as true, but it doesn't change the ratio of a circle's perimeter to its area. If the question is whether 'you' will die if you walk into the machine, rather than whether society will consider you dead, the thing that matters is what's actually different to the universe, not virtual properties created by convention (unless again we go back to the 'identity is outside the body' view with in particular identity being defined more by consensus agreement that you are you than anything about your body itself - so I suppose, if that's the claim, its self-consistent but again where's the evidence?).

I'm not (at least not intentionally) implying any magical property - just the meanings of words. If you make a copy of something, the copy isn't the original by definition, even if it is a perfect and indistinguishable copy.

It's entirely possible to make definitions of things that are not real. We could for example, define some property of an electron that depended on e.g. its past proximity to a dog within the last year or something like that. But those definitions end up not actually coupling to reality in any way - there's no experiment you can do that would tell you that this was a past-dog-adjacent electron or a non-past-dog-adjacent electron, because electrons aren't actually affected by that in any way that changes their future behavior or internal properties or whatever.

[veti]

I'm not (at least not intentionally) implying any magical property - just the meanings of words. If you make a copy of something, the copy isn't the original by definition, even if it is a perfect and indistinguishable copy.
http://smbc-comics.com/index.php?db=...&id=1879#comic

OK, but this property - "originality" - is unmeasurable and undetectable. It's destroyed "by definition" by going through a teleporter, but that same teleportation process has no other lasting effect. No matter how minutely you examine a person, there's no way of telling whether or not they've ever been teleported.

Which leads me to the conclusion that this property is wholly imaginary. Maybe it's an invented property whose sole real purpose is to scare people away from teleporters. Or maybe it's a purely linguistic construct, like "humanity", that only appears to exist because of the limitations of our vocabulary and experience, and when we come to understand the real technology, we'll realise it's as imaginary as the once-well-known tendency of things to fall vertically downward.

You could have a slightly different version of the scenario: transmitting information, and then scratch-building a new person (and not erasing the original). In such a case, the copy obviously isn't the original, because the original is still present, and different. And while the copy will have all the memories of being the original, stepping into the transporter, and appearing somewhere else, the original won't. As far as they are concerned, they stepped into the transporter, and didn't go anywhere. The original scenario is the same - except the transport works correctly and kills the person who got into it.

Again, this property of "originality". What if I step into the transporter, disappear for a moment, then reappear in the same place - and simultaneously, another copy of me appears at the teleporter's intended destination? Is the version that reappeared on the departure pad still "original"?

And why does it matter? OK, I can see obvious issues around ownership and potential conflicts of loyalty, but - let's imagine a Star Trek-like post-scarcity future, where "ownership" isn't a big deal anyway. Should the "copy" have less rights than the "original", or otherwise be treated differently somehow? If so, you'd better come up with some way of telling them apart.

[Bohandas]

Of course if we teleport a person, the person moves but the environment doesn't - so if your claim is that identity is stored in the relationship between the person's body and their environment more so than it's stored in the person themselves, that would be consistent. But that claim would correspondingly mean that, for example, driving to work each morning kills you and replaces you with a different person

I've experienced this phenomenon :(

[Tyndmyr]

I'm still not on board with this "clearly not the original" part.

It seems to me that you're saying that humans have some property that I can only describe as "magical", that can't be detected, or even defined, in any way whatsoever, but this property would be destroyed by teleportation just because obviously it would.

And again this fixation with "original components". Why is that so important? Given that the cells of our bodies are constantly renewing anyway, what exactly is the big deal about doing the whole lot all at once in a single operation? (I mean - sure it's a big deal in the sense of an impressive feat of technology, but why would it be qualitatively different from the normal, natural process?)

It's only as important as you make it. Terms like "original" and "copy" designate different, similar entities. If you don't care if you're working with an original or a copy, cool. Nobody's gonna make you care.

But sometimes it does matter. Perhaps the original painting is worth $x, and the copy is worth some fraction of $x. This is true no matter how good the copy is. So, clearly people do care.

OK, but this property - "originality" - is unmeasurable and undetectable. It's destroyed "by definition" by going through a teleporter, but that same teleportation process has no other lasting effect. No matter how minutely you examine a person, there's no way of telling whether or not they've ever been teleported.

Okay. You have a name, yeah? Is your name measurable and detectable by someone examining your body?

Certainly not at the present time. However, nobody cares.

It's your name nevertheless. Humans routinely describe things in ways other than gross physical properties.

[Manga Shoggoth]

OK, but this property - "originality" - is unmeasurable and undetectable. It's destroyed "by definition" by going through a teleporter, but that same teleportation process has no other lasting effect. No matter how minutely you examine a person, there's no way of telling whether or not they've ever been teleported.

If the original does not disappear (the case I indicated) then the property of "originality" is immediately indicated by location.

If the whole thing takes place in a sealed box and you can't see who the copy is, well, it's unfortunate, but does not invalidate the argument. There is still an original, you just don't know which one it is.

Again, this property of "originality". What if I step into the transporter, disappear for a moment, then reappear in the same place - and simultaneously, another copy of me appears at the teleporter's intended destination? Is the version that reappeared on the departure pad still "original"?

And why does it matter? OK, I can see obvious issues around ownership and potential conflicts of loyalty, but - let's imagine a Star Trek-like post-scarcity future, where "ownership" isn't a big deal anyway. Should the "copy" have less rights than the "original", or otherwise be treated differently somehow? If so, you'd better come up with some way of telling them apart.

It matters because if you are destroying the original in the process then you are killing someone. The moral implications of that apply even if we don't see the duplication problem. Oh, but of course. You can't scientifically measure morals either. Silly me.

If you disappear and then two copies appear then you there are strong grounds for saying that the original has been destroyed.

As to the rights of the copy? Well, in a post-scarcity society there isn't an issue. But in the real world, where my pension credits have to support myself and my family, then there is a real problem. I'm not in favour of shooting the copy (or the original, for that matter), but the copy has not earned the pension credits, no matter how much they believe they have.

[Lord Joeltion]

I'm trying to say that claiming the teleporter might be unsafe because it has an error is missing the point of the thought experiment, which is to say, if everything goes exactly as planned do you, or do you not, die. Teleportation in this fashion is, insofar as we can tell, entirely impossible so we're not actually discussing technology here, we're discussing philosophy.

If we are discussing philosophy, then it means the Teleporter is (by all means and effects) a magical device. As such, we can concede it to have as many wacky theories as we desire to grant it, because, it is magical. That is why I want to avoid to mix philosophy with teleporters here, because the question of OP certainly relies on the very definition of how said teleporter works. If it works by magic, then OP's question is meaningless.

Now, if you want to discuss the Theseus Thought Experiment, I'm not really in the mood for a detailed answer. My short answer is that it's simply a paradox of language. "Identity" isn't an empirical thing, it's a metaphysical property. We can't measure it. We can't demonstrate it. We can only logically assume whether one answer or the other is correct under our definition of terminology.

The problem with people, is that we lack a method to determine whether people are self-aware or not, teleportation regardless.

Inaction is an action. Anything you do, or don't do, risks extremely improbable but also extremely bad outcomes. Why priviledge one extremely unlikely possibility over another? Unless there's some reason to think that teleportation is more likely to risk your self-awareness than a car ride or blinking or eating tacos.

"Inaction is an action" does not compute to me. I don't want to derail too much on RL, but as a matter of fact, I am an Atheist. Are you trying to convince me that my religion is Atheism? No need to answer, it's just my way of demonstrating why it "does not compute" for me.

Anyway, YES, of course there is a "higher risk" of my self-awareness being lost (any value is higher than zero, in fact), because as I said, it is unverifyable by any current method we know of. So, the only one that would realize that I "died" would be me. Except that, wait, now I am dead, I can't even realize that because the Dead lack a brain to produce any kind of synapses. Poor me. See why it's a silly risk? Why risk my self-experience unnecessarily when I already have no option but to sleep and let a doctor knock me out in case my very biology is at risk? And only for moving around? Seriously? I have Internet for Kami's sake!

Not really. The question was an attempt to get past probability and risk into certainties. If you are absolutely certain that the teleporter will kill you, you obviously shouldn't take it to escape a merely probable death. And since we're, again, positing that the teleporter does actually work exactly as described and has no chance of error, if you don't think going through the process of being turned into information and reassembled elsewhere kills you, going through it is of course the right choice.

My entire point in my first post was that the Teleporter offered me zero guarantees that my consciousness would be teleported along with my body. I don't care what third parties see or are able to "verify" because self-awareness is an entirely subjective experience impossible to demonstrate to third parties. So I may use a teleporter as a last resort, because... that's the whole point of "last resorts". Open the ultimate door when all the other doors were already closed.

OK, but this property - "originality" - is unmeasurable and undetectable. It's destroyed "by definition" by going through a teleporter, but that same teleportation process has no other lasting effect. No matter how minutely you examine a person, there's no way of telling whether or not they've ever been teleported.

I am as Nihilistic as anyone else, but good luck trying to convince people that "self-awareness" is merely an ilusion because you lack the proper tools to measure it and subsequently demonstrate it's existence to anyone else.