This isn’t how I see survival of personal identity. I don’t think there exists any “line” that could be ‘known’ beyond our own deciding.
(edit) I’m saying the “line” cannot be known, it’s decided.
Sure; and you’re fine to take whatever position you like, but I feel there’s a conflation between numerical and qualitative identity behind your position.
Whether a third party wants to consider you the same person or not, is a situation where there can be discretion. It’s arbitrary, like whether we call the Ship of Theseus the same ship or not.
Whether you are still alive though, whether your consciousness is continuing, or whether the entity is no more you than Barack Obama is you, matters and is not merely a choice. We can’t just “choose” to be alive. We can’t say that star trek teleporters are safe as long as you choose to be the person that walks out at the destination.
Ok. You believe there’s a a fact of the matter independent of what anyone believes, I don’t. I don’t think there’s any more I can add.
Yes: whether I am alive or dead.
I would quite like to see what the world is like in 2100, but as someone already 47 years old, this seems unlikely.
Or is it that when the year 2100 rolls round, it’s, like, interpretation whether I am seeing it?
In making the original post, I certainly didn’t expect that a conclusive verdict could be made one way or the other. After all, psychological continuity can only be proven by the person who dies and is cloned. And I suppose the question could not be definitively proven in the negative since if a person’s conciousness does not continue then there is no one to process that proof.
The main aspect of this hypothetical I found interesting is the fact that, over a certain amount of time, we actually DO become made up of mostly differet atoms. Patterner’s point that a perfect copy of you could not be you because “you” could exist at the same time seems sensible to me, and I’ve thought along the same logic myself. On the other hand, the change in our “substance” that happens as we age indicates that a “you” largely made up of different atoms still doesn’t “break off” from the previous state of conciousness. I would suggest there are two possible ways to solve this:
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a stream of conciousess “defaults” to whatever version is most probable to follow from the previous moment
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whatever atoms are contiuously retained in us since birth is where our subjective identity is stored.
Are there any other possibe solutions to this question?
It is certainly possible that I am not understanding these definitions and/or premises of these hypotheticals. As far as I can tell, there are two aspects to all this. 1) The nature and relationship of the two physical bodies. 2) The nature and relationship of the identities/personalities of the two people.
I do not believe these two things can be separated. I have been discussing both, starting with the physical bodies, including what I think the connection is.
I honestly have no idea what you are discussing, but it’s obviously not these things, or you would not keep responding the way you are. I am entirely willing to take the blame for the miscommunication, since I’m very ignorant of various concepts and terminology, not having read remotely as much as most people here. i’m getting the same responses from the other person here. I’m baffled. But it doesn’t seem I’m going to catch on to what you guys are saying. So it’s been fun, and thanks for all the fishes. 
Consciousness means that you are seeing, talking, thinking, listening, writing, feeling, and sensing with facial expressions and gestures. You also make decisions and do things for you interacting with the world and with other folks around you.
Even if no one knows you are conscious, because you are not interacting for a few hours, you know you are conscious.
No one needs to find out you are conscious. Because you know you are.
That’s what consciousness is. You will not find it anywhere else in the whole world or universe apart from the living biological beings.
I don’t know what Mijin and Hyper are talking about, so don’t know why they are reacting to my posts the way they are.
But I am more sure of what you and I disagree on. Which is the very definition and understanding of consciousness. And that’s fine, I am coming to understand your view, despite not agreeing with it. At least I understand our disagreement. Lol
I have not been following you and the other interlocutors postings, so I cannot comment.
But I am aware of our discussions on the topic. And certainly we had disagreement on the point. That is totally fine. I have not been trying to change your views or forcing to agree with my view.
My point was purely from the observations on the world, and realistic methodology for making up the arguments.
But I am glad that you are now seeing my points. That is great. That is all I was hoping for. 
I think the suspicion is that this “fact” of whether you are still you, over and above the fact of seeming to be still you, is not a real fact at all. It is vacuous.
This was well illustrated by the comic in your imperfect transporter thread about the guy convinced that every time he woke up, then later at every fraction of a second, he was obliterated and replaced by someone else. If we grant that whether or not he is right is a fact about the world, it must have some observable consequence. But it does not. The world looks identical whether or not this fact is true. And so, it is not really a fact at all, it is an empty pseudo fact.
Also note that, for B to seem to be continuous to A, for A, requires BC and PC.
But I think there’s a bit of inconsistency there.
Because on the one hand, (a), you are suggesting that the possibility of making a simultaneous duplicate of you using different atoms implies that your “self” cannot be moved into a different substrate. Fine.
On the other hand, (b), you are taking the fact that we feel as if we are the same entity throughout our lives as entailing that we are.
But…a duplicate of you would also feel as if he was the same entity that has lived 30 years (or whatever your age is), and be wrong, in your view, according to (a).
It’s not possible to hold that the reasoning of (a) and (b) both necessarily follow. One has to be dropped.
Is the suggestion here that numerical identity == qualitative identity?
Otherwise I am not following you.
A fundamental question has not been addressed (unless I missed it): what (if any) objective criteria distinguishes an individual identity?
There a subjective basis: I know I am me; I have a unique history and a set of memories; I feel that I am (essentially) the same person I was yesterday, last year, and 70 years ago. I regard this a subjective sense of my own personal identity (me-ness).
If my mind were cloned into multiple copies, each copy (including the original) would have a subjective sense of me-ness. And yet, these would be distinct individuals- so this can’t establish a specific individual identity in any objective sense.
These distinct individuals are objectively distinguished by having a unique, physical history.
As was noted by someone earlier, the physical particles of our body get replaced over time. But there is a causal link from one point in time to the next, so my identity consists of this unique causal chain. This is perdurance theory of identity: the individual identity has causally connected, temporal parts.
No, I’m not saying that. I’m saying that this is the scepticism that might lead someone to say that. That is,the claim that there is no continuity, that I’m not the same person tomorrow, or even 5 minutes from now, as I’m today, is empty.
To make this claim, it must be grounded in something concrete: the fear that I’m in fact a clone swapped in for the original, or that I suffered a stroke. That is, a failure in PC or BC. To make the bare metaphysical claim that I’m just not the same person is vacuous. It is both true and false, since both describe the same world.
And so from that realization, it might seem that only PC counts, but this is a mistake.
To be as clear as possible, my position is this list is wrong in two respects. You omit BC and PC, which I believe is the correct option. While your third possibility, let’s call it NC, is not a real possibility at all, it is vacuous.
Again, I am not advocating for NC, I am simply stating that right now it’s the position that doesn’t have known counter-arguments. And posts like yours – complaining that NC is “empty” – is tacitly agreeing with that, because it’s the kind of thing people say when they can’t find a defeater argument. It’s the same thing that people say about solipsism, or the simulation hypothesis and more.
If there was a defeater argument, you’d be posting that instead.
It’s a bit odd how you phrase some things; when you say “you omit BC and PC” do you mean what you believe we should do, rather than suggesting something that I have said?
If so, then your position is that BC and PC and NC are all incorrect.
Fine – so do you have a model of continuity, and can it be used to make specific predictions for the various hypotheticals?
How so? Pretty much everyone in this thread has agreed that it is possible to have false memories. That seems to be the only requirement for NC to be a possibility.
Again: if you think you have a defeater for NC, heck even a sound argument against it (whether it defeats the whole notion or not), I’ll venmo you money, with my sincere thanks.
I’m not hearing such an argument yet though, just complaints that you don’t like NC (nor do I).
Indeed I seem to be having a peculiar communication gap with you in particular. I’m saying that both BC and PC are necessary but individually insufficient, both are required for continuity of self. And that you have omitted this combined possibility.
Saying that “this is just the kind of thing people say” is hardly a counter.
I’m not just throwing around the word “empty”. I’m saying specifically that the world where NC is true, and the world where NC is false, describe exactly the same world. There is no observable difference between them, even in theory. Can you point to one?
Whereas, the world where you have false memories must be different from the world where you do not.
I didn’t claim that my list was exhaustive. By all means let’s hear other options.
BC + PC sounds intriguing, although, depending on how you’re defining this, it may also end up being redundant.
Because BC says the physical (neuronal matter) is sufficient, and PC says the informational / syntactic content is sufficient. If what you’re saying is that both are needed, then this boils down to plain old BC, because we have good grounds for believing information / syntax to be correlated to neural structure.
There’s nothing to counter. I’m just pointing out that it’s just a complaint rather than an argument.
Ah OK. If that’s what you mean by “empty” then I think you have a misapprehension about this topic.
Because, if what you mean by “observable difference”, is observable or testable by a third party, objectively, then none of the current models of continuity have any observable difference. They all predict that a dude called Mijin will be walking around with all my behaviours, that will believe his existence is a continuation. And that’s true with all of the hypotheticals given so far.
On the other hand, if by “observable difference” you mean to the consciousness itself, then yes, NC predicts that a particular consciousness will be dead, no longer observing the universe at all. Indeed this is also the same as PC and BC; the only difference between these positions is in which consciousness dies when.
This is an inherent difficulty of the topic itself, just as with subjective experience. It’s not an issue specific to NC.
I’m not sure this works. No matter what you choose as the “body”, be it the whole body, the brain, or even a subset of the brain, what matters is whether psychological elements (memories, personality) are intact, not neural structure.
Consider the case of the brain sustaining 5% damage and losing motor function, vs suffering that same gross amount of damage and experiencing total amnesia and loss of personality.
Or, consider cases that don’t involve organic damage at all, like some forms of mental illness. Suppose the individual experiences multiple personality disorder, where the brain is fully intact. Are they the same person while they are another personality? What if the original personality is lost for good?
Yes, good point. What I meant by observable difference is observable by anyone, either a third party or the subject. If NC is empty by this measure, then C is equally empty.
What I think we need is a criteria that excludes all observable instances of non-continuity. We need BC to exclude trivial cases of non-continuity like cloning or replication with AI. And we need PC, because it is not the atoms, not the lump of grey matter itself that is important. Continuity of psychology is what we are actually concerned with. The grey matter without the psychology is meaningless.
But this involves splitting the timeline of a conscious entity into “particular consciousnesses”, a division which may be completely nominal. What if the chair I am sitting on is a “particular chair” that exists only at t1, while it is “destroyed” at t2, even though to all appearances it is the same chair? For this judgement to be more than nominal, it would seem to have to correspond with a real event. I.E., the chair at t1 really was destroyed, and swapped with a reproduction.
The “body” in the context of this topic means the neuronal structure, yes. But didn’t you say, just a moment ago, that your position is both BC + PC? If you’re explicitly saying now that only psychological elements matter, then that’s PC.
These are all interesting hypotheticals, but I think it’s important to establish first your position on perfect copies or perfect atom swaps etc. I wrote a paper on “an imperfect transporter”, but it begins with establishing first the common positions on a perfect transporter, because this establishes whether the reader is coming from a position of BC, PC or NC.
Can I ask again: are you aware and agree with the distinction between numerical identity and qualitative identity? Because your next two paragraphs are talking about qualitative differences and (third-party) observational differences, and this misses much of the debate around the philosophical concept of personal identity, which is usually much more concerned with numerical identity.