I think this is the correct answer to the branch-line case. Any "one" who is me, yet occupied different atoms and extracts difference resources from the environment to maintain homeostatis, and occupies a different "moment' in space, cannot be me. — AmadeusD

But why? What is it that your specific atoms contain that hold your "essence"?
And how many such atoms need to be moved across for you to still be alive? Will 95% do it? 99%?

I think this is a really stupid 'paradox' personally. A ship is "that ship" because of what people call it. There isn't, that I can see, a physical boundary to the identity of a utility/object. — AmadeusD

Agreed, I hate the ship of Thesus. It's only a marginally interesting paradox in its own right, and though it is invoked for good faith reasons, I think it actually derails this topic. Because, as I said upthread, the problem of personal identity chiefly concerns the first-person perspective -- what it is, and under what circumstances it is preserved. The ship of thesus gets us immediately thinking of the third person perspective, and making a completely arbitrary judgement that doesn't actually matter.
Whether my first-person perspective still exists or not matters a hell of a lot to me! It's not like ship of thesus.

Spatiotemporal continuity (with me).
— bongo fury

Why does that matter? — Mijin

It seems crucial to the viability and identity of an organism, at least? Pre-sci-fi, of course.

And how, precisely, do we define it? — Mijin

Mereologically? Topological closure? :yikes:

whether I as an organism have spatiotemporal continuity with an entity at a past state of the universe is something less clear. — Mijin

Really? I suppose there are edge cases, like that of conjoined twins? But generally we, like the ship of Theseus, maintain our personal identity by losing and replacing a few planks at a time. Whereas, we lose it by being rebuilt from scratch. That produces only copies. More or less different: perhaps identical. But spatiotemporally non-overlapping. Lacking the spatiotemporal continuity that connects the "time-slices" of you.

Maybe we attach too much importance to this kind of identity? Perhaps we should regard our biological relatives, or our Star Trek duplicates, as equally entitled to our memories?

And I deserve Napoleon's?

It seems crucial to the viability and identity of an organism, at least? Pre-sci-fi, of course. — bongo fury

But that's my question. When I ask why spatio-temporal continuity matters, I mean why is it critical to whether consciousness persists or not? If we believe that there is some persistence of consciousness from moment to moment then it is a valid question of what is required for this persistence. If the key thing is that it's the same atoms, why is that necessary?

Really? I suppose there are edge cases, like that of conjoined twins? But generally we, like the ship of Theseus, maintain our personal identity by losing and replacing a few planks at a time. — bongo fury

Yes that is the case today but I am not talking about only what is biologically or technologically possible today. If that were a requirement for topics here, then 99% of threads on philosophy forums can be shut down right now.
I am talking about hypothetically copying entire brains, swapping out atoms etc to test a given position or model of personal identity.

If we believe that there is some persistence of consciousness from moment to moment then — Mijin

It seems more realistic to infer episodes of relative coherence among otherwise fleeting and unconnected moments of consciousness?

They deserve identifying with (or as) one person because they arose in that particular (spatiotemporally continuous) brain and body.

My memory of Waterloo, however vivid and historically accurate, did not.

@Mijin If spatial-temporal continuity is required to maintain identity, then your case adds nothing, the subject is killed no matter what.
If it is not required, then your case reduces to, "How much damage can someone sustain before becoming a new person?"

But why? What is it that your specific atoms contain that hold your "essence"? — Mijin

I didn't content they did. Not sure where this is coming from.

And how many such atoms need to be moved across for you to still be alive? Will 95% do it? 99%? — Mijin

This doesn't have much relevance to my position, or the claim, to be clear. For sake of discussion, there will be no specific amount. You can lose both legs and still be alive, and you. It's a silly question, in context. That's not the belittle it. It just has no reasonable avenue to a response.

Whether my first-person perspective still exists or not matters a hell of a lot to me! — Mijin

Yes, indeed. And this is why my response to the branch line case is attractive to me. It removes the potential for my first-person to disappear, but someone to still be me. Which seems ridiculous and intuitively hogwash.

It seems more realistic to infer episodes of relative coherence among otherwise fleeting and unconnected moments of consciousness? — bongo fury

This seems to be alluding to different levels of consciousness. Sure, there are different levels of alertness largely corresponding to brainwave states. This seems a different topic though to personal identity.

They deserve identifying with (or as) one person because they arose in that particular (spatiotemporally continuous) brain and body. — bongo fury

This is just asserting the position of bodily continuity. I'll ask again: what makes the particular atoms that you are made of special, and how many of your own atoms need to be incorporated into an entity for you to survive in any form?

Mijin If spatial-temporal continuity is required to maintain identity, then your case adds nothing, the subject is killed no matter what. — hypericin

Can we know that? What if the transporter functions by firing your actual atoms across space? If assembling your own atoms back into the configuration that they were in isn't you, then what is missing?

If it is not required, then your case reduces to, "How much damage can someone sustain before becoming a new person?"

From the third person perspective yes that's what it boils down to. The question is what about the first-person perspective of the person that entered the transporter. Is he gone entirely?

I didn't content they did. Not sure where this is coming from. — AmadeusD

Because I am trying to get your meaning. You're alluding to bodily continuity, so I am asking follow up questions of why bodily continuity is critical.

This doesn't have much relevance to my position, or the claim, to be clear. For sake of discussion, there will be no specific amount. You can lose both legs and still be alive, and you. It's a silly question, in context. That's not the belittle it. It just has no reasonable avenue to a response. — AmadeusD

Hard disagree.
Look, in daily life we all implicitly subscribe to some form of bodily continuity. I have Mijin's memories and I assume that I am one and the same entity as Mijin. If I were to suffer an accident and have brain damage, then that is a damaged Mijin.
The problems for bodily continuity come with hypotheticals like the transporter problem and the follow up questions that I have summarized in this thread. It's much easier of course to insist that we keep our focus only on how personal identity works in daily and handwave questions like the imperfect transporter. But if we have a good model of personal identity we shouldn't need to dodge; we should be able to apply our model.

It removes the potential for my first-person to disappear, but someone to still be me. Which seems ridiculous and intuitively hogwash. — AmadeusD

This is why the terminology is important here. Another entity could be qualitatively identical to me, but if he is not numerically identical to me, then he's arguably Mijin but not me. If you stick a pin in him, I don't feel a thing. And when I'm lights out, I have no reason to believe I will suddenly have his conscious experiences.

Exactly. The only unanswered question isn't: "is a facsimile an original?" It's: "is a person's self defined by more than it's physical body and it's memories?".

I call it "radical lastthursdayism".

Lastthursdayism tells you, you should be skeptical that your entire existence didn't start last Thursday, with all your memories implanted but they didn't actually happen to you.

Radical Lastthursdayism says, that's constantly true, all the time - your existence is being renewed every moment and your memories are effectively implanted.

I'll ask again: what makes the particular atoms that you are made of special, — Mijin

I'll answer again: nothing; only my continued corporeal integrity matters.

and how many of your own atoms need to be incorporated into an entity for you to survive in any form? — Mijin

And so, all of them would be not enough, if you rebuild me from scratch.

If assembling your own atoms back into the configuration that they were in isn't you, then what is missing? — Mijin

I.e. Why isn't

a facsimile an original?" — LuckyR

??

Another entity could be qualitatively identical to me, but if he is not numerically identical to me, then he's arguably Mijin but not me. If you stick a pin in him, I don't feel a thing. And when I'm lights out, I have no reason to believe I will suddenly have his conscious experiences. — Mijin

Exactly. Perhaps arguing that he is Mijin doesn't add clarity. "Mijin 2" better.

Radical Lastthursdayism says, that's constantly true, all the time - your existence is being renewed every moment and your memories are effectively implanted. — flannel jesus

Indeed. In fact, even talking of "your existence" being "renewed" could be misleading here, as what we're actually positing is that every instance of consciousness is essentially a new entity that just happens to inherit the memories of that body. And then its existence ends in an instant.

It's not a pleasant conception, but as I say, it's immune to the strong counter arguments to the two more obvious positions on the transporter problem. In fact, I've never heard any argument against it (but I've generally not heard this position discussed very much at all -- most people in this debate implicitly assume continuous existence).

I'll answer again: nothing; only my continued corporeal integrity matters. — bongo fury

Your answers are basically just asserting your position again.
What I am trying to get at, is why. And to also tease out the answers to questions that are problematic for bodily continuity, like why it would make a difference if I move your atoms from point A to point B in one piece or separated for a nanosecond. What was lost in that second scenario?

Your answers are basically just asserting your position again. — Mijin

If the question is

what makes the particular atoms that you are made of special, — Mijin

then how is "nothing" not an answer? Perhaps you meant,

assuming there is something special (and sufficient!) about the particular atoms that you are made of (or at least, something special about their physical configuration), such that putting them together (or correctly putting together any others) creates a continuation of (a part of) the original, rather than a facsimile, then what is that?

Is that what you meant? There must be something special (and sufficient) but what is it?

What I am trying to get at, is why. — Mijin

Why is there nothing special? Or, why is the special thing special?

like why it would make a difference if I move your atoms from point A to point B in one piece or separated for a nanosecond. — Mijin

Like why bother distinguish between different tokens of a linguistic type? Between original and facsimile?

Great viewpoint. Basically is there a difference between experiencing last Wednesday in real time (on Wednesday) and remembering Wednesday on Saturday? I say there is, that is living life is more than your memories at time X.

ironically though, it turns out studies from neuroscience tell us that our experience of "the present" is constructed with a slight lag, and so your present ACTUALLY IS composed of some memories - things that happened to you at least a few moments ago, but which you still perceive as "effectively now".

Though that's still obviously very different from memories from a few days ago. You're not confusing your "smeared present" with memories from last Wednesday unless you have serious neurological problems.

Why? Because of the definitions of the words. Perhaps you're proposing at a certain point a facsimile becomes indistinguishable from an original.

Yes, the lag is real, but if you think about it a non-lag situation is essentially impossible. It's more about the size of the lag.

I'm not equating lag with the classic understanding of memories. Or to put it another way, the definition of the term "real time" is from the perspective of the individual, not a third person observer with a stopwatch.

Why? Because of the definitions of the words. — LuckyR

Agreed.

Perhaps you're proposing at a certain point a facsimile becomes indistinguishable from an original. — LuckyR

Yikes, not me.

More to the point, though, I'm denying that at any point the facsimile becomes a part or continuation of the original.

I'm not equating lag with the classic understanding of memories. Or to put it another way, the definition of the term "real time" is from the perspective of the individual, not a third person observer with a stopwatch. — LuckyR

Sure, and I think that makes sense as well

The point is, the measure of our understanding of a phenomenon is what predictions and/or inferences we can make about it.

When it comes to your position on personal identity, a position that I think is basically the bodily continuity position, it seems it doesn't enable you to answer questions like the kind that I have posed; about a mixture of continuous and discontinous material, or of being discontinuous on a time frame far quicker than mental events.
And I've asked why we would take the position that bodily continuity matters, because that might give a clue about how we'll go about answering such questions. But you haven't given an answer why, you've tended to just repeat your position.

I don't want any of this to sound like snark, or as if I am accusing you of bad faith. I'm just saying it seems pretty pointless.
If I were to say that what defines an instance of consciousness is the mojo, but not answer any questions on what the mojo is, how I think this might work in practice, or what led me to think it was the mojo in the first place...then all anyone can say is "good for you". End of debate, nothing learned.

No worries. I wonder if you are equally (or differently, or not at all) non-plussed by this:

Well, if the transporter didn't kill you when you entered at the source (such that now there are two "yous"), everyone would call the machine a people fax instead of a transporter and you would be the original and the person at the destination would be the facsimile. Thus the "transporter" isn't a transporter at all, it's a fax machine that destroys originals. — LuckyR

?

Indeed. The question of what happens if the person at source is not deleted is a common objection to the idea that you are teleported. The common answer is that you have now become two people; not that you are linked now, but basically your existence is branched.

If you find this problematic, so do I. The imperfect transporter I think is a pretty good counter against this position.

But I also find bodily continuity problematic when it comes to questions of how much continuity is sufficient and/or how exactly we define continuity.

The best, though most unfortunate, explanation is simply that there's never really continuity. It's an illusion.

The best, though most unfortunate, explanation is simply that there's never really continuity. It's an illusion. — Mijin

Why unfortunate?

because it kinda means you're constantly dying

Well a new person starts and ends their life at every instance under that hypothesis, there's not even a singular person constantly dying.

The common answer — Mijin

Can you edit this to clarify which position is answering which, and what you mean by "existence is branched"?

Yes no problem.
When it comes to the transporter problem (also called the teletransporter problem) there are two major positions*, let's call them Sent (your consciousness is transported) and Copied (the person on Mars or wherever, is a new instance of consciousness).

I summarized one argument against Sent in the OP, but another common argument against the Sent position is what if the person at the source location is not killed? In such a situation it would be absurd to claim the consciousness has both been sent and retained in the original. They clearly aren't a singular instance of consciousness because I can stick a pin in one person and the other is not going to flinch.

Having been in transporter debates many times, I am familiar with the counter-argument that most Sent proponents will say. They will say that the consciousness was branched. Only for the instance of time that the two mental states were identical could the consciousness be said to be in two places. As soon as their experiences differ, they are two people.
I tried to find the formal name for the position that, essentially, being qualitatively identical entails being a singular instance of consciousness (the philosophical underpinnings of the Sent position), but all I could find was https://en.wikipedia.org/wiki/Personal_identity#Locke's_conception.

* And a third position, which I've already alluded and I won't expand on in this post to keep things clear.