Surviving a quantum death trap is a convincing argument in favor of the many-worlds hypothesis, but you’d have to be pretty risk-averse to seek it out.
I think you mean risk non-averse. Since if many worlds is wrong, you fail.
If many-worlds is right you still fail—at least if you define “self” with any sort of continuity, when you die in many-worlds you die in real life.
Cosmology is an analagous quantum death trap, and the entire human race witnessed it from the inside.
If you haven’t thought about this argument before, you should update your belief in the many-worlds interpretation radically upwards.
This is an unconvincing argument. First, you don’t know the prior probability of humanity surviving. Second, we don’t know how many observers to expect in the universe. The relevant class isn’t humans but “life intelligent enough to discuss anthropic considerations and MWI”—that class might be much larger.
Mostly agreed. Besides, the same mathematical structure exists in the Copenhagen interpretation too, though it’s labeled differently; quantum mechanics is quantum mechanics. It is however evidence for the claim that conscious people can be represented by a wavefunction that contains other possibilities, even if those other possibilities are overwhelmingly probable..
But if you only die in some of the branches, then you’ll experience yourself living.
You’re presupposing that there’s a fact of the matter about what “you” [the person you are now] will experience at a future moment. But the person you are now does not exist at any future moment. In fact, future moments merely contain people who are very similar to you—they remember everything you remember and a little bit more.
Therefore, all we can say is that in a branch where you die, there is no-one who remembers being you, but in a branch where you survive, there is a person who remembers being you. There is no such thing as a ‘you’ which is identical at different moments, no ‘thread of identity’ that connects you with your future and past selves, and which magically ‘chooses’ a branch where ‘you’ survive. In other words, there is no ‘transtemporal identity’.
Fundamentally, what you’re trying to achieve in a ‘quantum immortality’ experiment is to experience a fantastically unlikely event. But when you rephrase this in terms that don’t presuppose transtemporal identity, all you’re saying is that you want there to be a person somewhere, in some Everett branch, who experiences something fantastically unlikely. Therefore, it makes no difference whether those who fail to experience something fantastically unlikely are killed or left alone.
The real question here is simply “If you experienced something fantastically unlikely, would you take this to be evidence that MWI is true and Copenhagen is false?”
(It’s an awkward question because the Copenhagen interpretation is incoherent. We ought to ask the question above about a single-universe interpretation that actually makes sense, like Bohm’s interpretation or the GRW theory. But for now let’s just pretend that Copenhagen does make sense.)
The real question here is simply “If you experienced something fantastically unlikely, would you take this to be evidence that MWI is true and Copenhagen is false?”
And if so, does experiencing something humdrum constitute evidence that MWI is false? Surely not.
It seems to me that either (a) experiencing anything at all, regardless of how likely or unlikely it is, gives an equal amount of “anthropic evidence” in favour of MWI, whatever that means; or else (b) There is no sense whatsoever in which observations as opposed to a priori reasoning can favour MWI over Copenhagen (pretending the latter is coherent).
I don’t think (a) makes sense, because surely any theory whatsoever comes equipped with an anthropic “dimmer switch” that can be “brightened” or “dimmed” arbitrarily. For instance, to ‘brighten’ Copenhagen we could just stipulate that there are N parallel non-interacting Copenhagen universes rather than 1. We could even let N be infinite.
And if so, does experiencing something humdrum constitute evidence that MWI is false?
Could constitute observational evidence for something strange, something to follow in thinking about the future, but not in thinking about counterfactuals where quantum mechanics works.
If many-worlds is right you still fail—at least if you define “self” with any sort of continuity, when you die in many-worlds you die in real life.
Mostly agreed. Besides, the same mathematical structure exists in the Copenhagen interpretation too, though it’s labeled differently; quantum mechanics is quantum mechanics. It is however evidence for the claim that conscious people can be represented by a wavefunction that contains other possibilities, even if those other possibilities are overwhelmingly probable..
But if you only die in some of the branches, then you’ll experience yourself living.
If QI is true, then it’s when you die in ALL of the many worlds that you no longer experience anything.
You’re presupposing that there’s a fact of the matter about what “you” [the person you are now] will experience at a future moment. But the person you are now does not exist at any future moment. In fact, future moments merely contain people who are very similar to you—they remember everything you remember and a little bit more.
Therefore, all we can say is that in a branch where you die, there is no-one who remembers being you, but in a branch where you survive, there is a person who remembers being you. There is no such thing as a ‘you’ which is identical at different moments, no ‘thread of identity’ that connects you with your future and past selves, and which magically ‘chooses’ a branch where ‘you’ survive. In other words, there is no ‘transtemporal identity’.
Fundamentally, what you’re trying to achieve in a ‘quantum immortality’ experiment is to experience a fantastically unlikely event. But when you rephrase this in terms that don’t presuppose transtemporal identity, all you’re saying is that you want there to be a person somewhere, in some Everett branch, who experiences something fantastically unlikely. Therefore, it makes no difference whether those who fail to experience something fantastically unlikely are killed or left alone.
The real question here is simply “If you experienced something fantastically unlikely, would you take this to be evidence that MWI is true and Copenhagen is false?”
(It’s an awkward question because the Copenhagen interpretation is incoherent. We ought to ask the question above about a single-universe interpretation that actually makes sense, like Bohm’s interpretation or the GRW theory. But for now let’s just pretend that Copenhagen does make sense.)
And if so, does experiencing something humdrum constitute evidence that MWI is false? Surely not.
It seems to me that either (a) experiencing anything at all, regardless of how likely or unlikely it is, gives an equal amount of “anthropic evidence” in favour of MWI, whatever that means; or else (b) There is no sense whatsoever in which observations as opposed to a priori reasoning can favour MWI over Copenhagen (pretending the latter is coherent).
I don’t think (a) makes sense, because surely any theory whatsoever comes equipped with an anthropic “dimmer switch” that can be “brightened” or “dimmed” arbitrarily. For instance, to ‘brighten’ Copenhagen we could just stipulate that there are N parallel non-interacting Copenhagen universes rather than 1. We could even let N be infinite.
So that just leaves (b).
Could constitute observational evidence for something strange, something to follow in thinking about the future, but not in thinking about counterfactuals where quantum mechanics works.
No. If you die in some of the branches, in those branches you’ll experience dying, and then you won’t experience anything any more.