The Quantum Mars Teleporter: An Empirical Test Of Personal Identity Theories
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I was excited but skeptical, to hear that you could empirically test anything on the topic. And disappointed but unsurprised that you don't. There's nothing empirical about this - there is zero data you're collecting, measuring, or observing.
It will be an empirical test when you ACTUALLY have and use this teleporter.
Until then, you're just finding new ways to show that our intuitions are not consistent on esoteric and currently-impossible (and therefore irrelevant) topics.
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1This thought experiment can help us to find situations in nature when similar things have already happened. So, we don't need to perform the experiment. We just look at its result.
One example: notoriously unwelcome quantum immortality is a bad idea to test empirically. However, the fact of biological life's survival of Earth for the last 4 billion years, despite the risks of impacts, irreversible coolings and warming etc – is an event very similar to the quantum immortality. Which we observe just after the event.
This thought experiment can help us to find situations in nature when similar things have already happened.
It can? Depending on what you mean by "similar", either we can find them without this thought experiment or they don't exist and this doesn't help. Your example is absolutely not similar in the key area of individual continuity.
1For example, impossibility of sleep – a weird idea that if quantum immortality is true, I will not be able to fall asleep.
One interesting thing about the impossibility of sleep is that it doesn't work here on Earth because humans actually start having night dreams immediately as they go into sleep state. So there is no last moment of experience when I become asleep. Despite popular misconception, such dreams don't stop during deep stages of sleep, just become less complex and memorable. (Do we have dreams under general anesthesia is unclear and depends on the depth and type of anesthesia. During normal anesthesia some brain activity is preserved, but high dose barbiturates can temporarily stop it; also, an analogue of impossibility of sleep can be anesthesia awareness – under MWI it is more likely.)
It could be explained by anthropic effects: if two copies of me are born in the two otherwise identical worlds, one of which has protection from impossibility of sleep via constant dreaming – and another not, I will eventually find myself in the world with such protection as its share will grow relative to QI survivors. Such effects, if strong can be observed in advance – see our post about "future anthropic shadow".
This meta effect can be used instead of the natural experiments.
If we observe that some natural experiment is not possible because of some peculiar property of our world, it means that we somehow were naturally selected against that natural experiment.
It means that continuity of consciousness is important and the world we live in is selected to preserve it
By the nature of the experiment you know that the people on Mars will have direct, personal experience of continuity of identity across the teleport. By definition, their beliefs will be correct.
In 99.9999999999999999999999999999% of world measure no version of you is alive on Earth to say any different. In 0.0000000000000000000000000001% of world measure there is a version of you who is convinced that teleportation does not preserve personal identity, but that's excusable because extremely unlikely things actually happening can make even rational people have incorrect world models. Even in that radical outlier world, there are 10 people on Mars who know, personally, that the Earth person is wrong.
One you in the worlds with total weight of 0.001 will observe remaining on Earth, while either the exact or approximate you in the worlds with total weight of 1.000 will observe arriving on Mars. That is all that actually happens.
Then they'll start making strange proclamations about their newfound epistemic states and empirical observations from the personal observation stream relevant to theories of identity, but that's beside the point.
Your comment can be interpreted as a statement that theories of identity are meaningless. If they are meaningless, then copy=original view prevails. From the third-person point of view, there is no difference between copy and original. In that case, there is no need to perform the experiment.
There is a full explanation right there, in the description of the thought experiment. It describes all outcomes, including all observations and theoretical conclusions made by all the people-instances. We can look at this and ask whether those theoretical conclusions are correct, whether the theories the people-instances use to arrive at them are valid. You can tell what all the details of outcomes are in advance of actually doing this.
Personal experimence of people existing in the world is mediated by the physical states of their brains (or other physical hardware). So we can in principle predict what it says by asking about the physical content of the world. There are agents/people that don't have concrete instances in the world, and we can ask what they experience. They might leave the physical world, or enter it back, getting instantiated once more or for the first time. They might persistently exist outside concrete instantiation in the world, only communicating with it through reasoning about their behavior, which might be a more resource efficient way to implement a person than a mere concrete upload. But that's a different setting, not what this post describes.
They might persistently exist outside concrete instantiation in the world, only communicating with it through reasoning about their behavior, which might be a more resource efficient way to implement a person than a mere concrete upload
Interesting. Can you elaborate?
That only seems to make sense if the next instant of subjective experience is undefined in these situations (and so we have to default to a 3rd person perspective).
A 3rd person perspective is there anyway, can be used regardless, even if other perspectives are also applicable. In this case it explains everything already, so we can't learn additional things in other ways.
Does the 3rd person perspective explain if you survive a teleporter, or if you perceive yourself to black out forever (like after a car accident)?
Any "perceive yourself to X" phenomenon is something that happens within cognition of some abstract agent/person instance, whether they exist in some world or not. What kind of person instance is "perceiving themselves to black out" (that is, having blacked out)? Ghosts and afterlife seem more grounded than that. But for Earth/Mars question, both options are quite clear, and there is a you that perceives either of them in some of the possibilities, we can point to where those that perceive each of them are, and that is what would be correct for those instances to conclude about themselves, that they exist in the situations that contain them, known from the statement of the thought experiment.
What kind of person instance is "perceiving themselves to black out" (that is, having blacked out)?
It's not a person instance, it's an event that happens to the person's stream of consciousness. Either the stream of consciousness truly, objectively ends, and a same-pattern copy will appear on Mars, mistakenly believing they're the very same stream-of-consciousness as that of the original person.
Or the stream is truly, objectively preserved, and the person can calmly enter, knowing that their consciousness will continue on Mars.
I don't think a 3rd-person analysis answers this question.
(With the correct answer being, of course, that the stream is truly, objectively preserved.)
Since I don't think a 3rd person analysis answers the original problem, I also don't think it answers it in case we massively complicate it like the OP has.
(Edited for clarity.)
The 3rd person perspective assumes the existence (or at least possibility) of some observer X who knows everything and can observe how events evolve across all branches.
However, this idea assumes that this observer X will be singular and unique, will continue to exist as one entity, and will linearly collect information about unfolding events.
These assumptions clearly relate to ideas of personal identity and copying: it is assumed that X exists continuously in time and cannot be copied. Otherwise, there would be several 3rd person perspectives with different observations.
This concept can be better understood through real physical experiments: an experiment can only be performed if the experimenter exists continuously and is not replaced by another experimenter midway through.
By "3rd person perspective" I mean considering the world itself, there is no actual third person needed for it. It's the same framing as used by a physicist when talking about the early stages of the universe when humans were not yet around, or when talking about a universe with alternative laws of physics, or when talking about a small system that doesn't include any humans as its part. Or when a mathematician talks about a curve on a plane.
Knowing absolutely everything is not necessary to know the relevant things, and in this case we know all the people at all times, and the states of their minds, their remembered experiences and possible reasoning they might perform based on those experiences. Observations take time and cognition to process, they should always be considered from slightly in the future relative to when raw data enters a mind. So it's misleading to talk about a person that will experience an observation shortly, and what that experience entails, the clearer situation is looking at a person who has already experienced that observation a bit in the past and can now think about it. When a copied person looks back at their memories, or a person about to be copied considers what's about to happen, the "experience" of being copied is nowhere to be found, there is only the observation of the new situation that the future copies find themselves in, and that has nothing to do with the splitting into multiple copies of the person from the past.
I think all copies that exist will claim to be the original, regardless of how many copies there are and regardless of whether they are the original. So I don't think this experiment tells you anything, even if it were run.
all copies ... will claim to be the original ... regardless of whether they are the original
Not if they endorse Litany of Tarski and understand the thought experiment!