Sure, but the difference is that the experience of me and the copy appearing before me can’t be contiguous, while that of a copy appearing somewhere after I’ve been snuffed may be; i. e. that copy might have as a last memory being about to be hit by a bus. And if you need anything beyond contiguity of experience (note that I’m not saying continuity, as we don’t have that: we sleep), then it’s difficult to say how you, tomorrow, are the same as you, today—you’re not made of the same particles (indeed, quantum mechanically, particles don’t have any individual identity), and you’re not an uninterrupted stream of consciousness. Indeed, suppose we were to exchange every particle in your body with an identical copy while you slept: you’d still be you in the morning. Suppose we’d do so while you’re in transit to somewhere else: you’d still be you. Suppose we would put those particles together somewhere else: what’s changed then? Suppose we didn’t put them together immediately: what’s the difference?
Anyway, there is significant philosophical debate on this point, but the quantum immortality debate doesn’t depend on any of it. The point is simply that there’s always a nonzero chance of surviving anything. What exact story you choose to make that point is immaterial.
Yes, of course there’s significant philosophical debates on the subject of how we define a single continuous entity. (And for the record, I don’t think I’ve ever heard anybody seriously propose “he’s got a copy of your memories” as being the determining factor.)
And of course the argument for quantum immortality depends on these sorts of arguments. Quantum immortality claims that there’s a way to get out of any situation unscathed. Which is, of course, a patently absurd claim, so increasingly absurd arguments for how a person could survive are emerging - up to and apparently including “after the shockwaves die down you just suddenly pop back into existence…somewhere far away where the environment is still conducive to human life”.
Oh, and for complete disclosure, I’m pretty sure the actual proposed survival method is, “There’s a version of you that started building a spaceship at the age of four and fled the planet long ago.” Which is of course why I skipped directly to things like the heat death of the universe - when you’re trying to swat an elusive fly, you bring a big swatter.
It’s the most generally accepted resolution, going back to Parfit’s discussion:
And note that I didn’t simply say ‘copy’ of your memories, but rather, contiguity of experience.
What you consider absurd doesn’t play into it, unfortunately. As long as there’s a term in the resulting superposition in which the observer still is alive, if the MWI is true, they’ll continue to live, from their own subjective experience.
No, that’s completely besides the point of the thought experiment. While there will be, of course, branches in which there’s a version of ‘you’ that diverged from you some time ago and aren’t now faced with immediate doom, you wouldn’t continue as those copies—as soon as they diverged from you, you became different entities. No, the intent of the argument is very much that for each proposed method of death you’re faced with right now, there’s a branch with you surviving afterwards, and that’s the one you’ll experience—hence, you’ll always find yourself surviving.
Right, and there’s two ways of having a contiguity of experience: contiguity of existence, or a copy.
Wait, seriously? The argument is that a dinosaur staring up at the Chicxulub meteor has an ongoing theoretical chance of survival no matter how far into the process of getting squished/incinerated it is?
No wonder you’re resorting to “no, wait, that guy over there is me!” arguments. The position is indefensible.
You might’ve noticed I’ve actually argued that the quantum immortality-argument is wrong; it’s just that the arguments you propose either don’t address it, or fall flat.
Quantum immortality is a natural extension of many worlds. If MWI is true, I think quantum immortality would have to be true as well.
And I have no idea why anybody would want quantum immortality to be true. If they do, they don’t understand quantum immortality at all. Quantum immortality says that you’ll end up as some endlessly sick, aging, quadripeligic, suffering blob for thousands, millions, billions, trillions, and eventually quadrillions of years. You’d survive the extinction of humanity (except for you), new ice ages, the sun becoming a red giant, the destruction of earth, etc. Once earth gets destroyed, I guess you’d end up floating in space for eternity.
What you’re describing seems to be the Boltzman Brain. That’s not at all quantum immortality.
Quantum immortality means that your whole body survives forever. You never die at any point. For example, you might get a cancer that has a 99.9% chance of killing you, but you end up in a branch where you survive. The next year, you end up with a heart attack that has a 99.9% of killing you, but you survive that too. So on, forever, with things that should kill you. Both your body and your mind never die.
Boltzman brains, which seems to be what you’re describing, means that particles from your dead brain will randomly recombine at some point after your death and basically form a new brain. Your body never forms again, but your brain imagines it’s in a body just to make sense of the whole situation. The Boltzman Brain definitely doesn’t last forever-it only lasts a few seconds before dying from lack of oxygen.
The arguments that we on earth are really a Boltzmann brain center around the idea that Boltzman brains perceive a few seconds as lasting decades.
No, it means that your experience continues. You don’t necessarily need a body for that. There will always be a spectrum of possobilities, i. e. a plurality of branches, which contain experiences that follow from yours just before, say, you pulled the trigger on your quantum suicide device.
Boltzmann brains are a logically possible way for continuing your experience. They’re very, very unlikely, but crucially, not impossible. It might be that whatever’s threatening your continued existence leaves the option of your current body continuing to exist sufficiently unlikely that your next moment of experience is more likely to be that of a Boltzmann brain.
Of course, the whole scenario is already misguided, as I argued before. But if you believe in the possibility of quantum immortality, you’ll have to take the possibility of going on as a Boltzmann brain into account.
If the possibility exists of living forever and enjoying it, versus living forever and not enjoying it, then doesn’t Many Worlds imply that at both will happen in one universe or another?
I’d feel awfully guilty if I were living happily ever after, knowing that in some universe somewhere I’m also living miserably ever after.
There’s no real continuous existence with Boltzmann brains. Brains, including Boltzmann brains, can only survive without oxygen for about 5 seconds or something. If Boltzmann brains keep reforming from your dead brain every million years, that would mean that after death, your mind (and not your body) would live again for 5 seconds every million years.
It’s not at all like quantum immortality, where your whole body will be alive for all million of those million years.
That doesn’t mean the events would happen with remotely similar frequency. The miserable universes would probably outnumber the non miserable universes by a ratio of something like a googleplex to one.
That isn’t a problem, so long as you accept that the important part of your experience is the continuous existence of the mind’s pattern of data.
But accepting that the pattern is more important than continuity opens the door to many more possibilities, all of which are highly debatable. For instance, in an infinite universe, your mind’s pattern is presumably replicated exactly an infinite number of times, all of which are thinking the exact same thing as you are right now, and have all the same memories. Max Tegmark has even worked out how far away these copies are (they would be way outside the Hubble Volume).
Some of those infinite copies of you would presumably not die in any future accident, and exist continuously to become a shapeless blob of living tissue. would that count? There is no more contiguous-ness between you and a Boltzmann brain in the far future and between you and your Tegmark-clone a googleplex light-years away.
Whatever people mean by “quantum immortality”, it does not mean you cannot in fact die, as has been explained above. (And, I would glibly add, as any number of people would attest, except they can’t because they are dead.)
Everett’s daughter definitely believed in quantum immortality, although she didn’t have a very good understanding of it. She committed suicide about 15 years after her dad died. Her suicide note outright said she was committing suicide because she believed she’d end up in another universe where her dad was still alive.
Really, quantum immortality would suggest that she ended up in a universe where she had a gunshot wound, might have ended up brain damaged, and her dad was still dead.
Anyway, if she believed in quantum immortality, it’s pretty safe to say her dad did too. Although he may have had a poor understanding of it, just like his daughter.
ETA since you have mentioned Everett, I should emphasize that that “many worlds” stuff is merely an interpretation/way of visualizing simple quantum mechanics. In particular, by definition you cannot travel to a different “world”, so Russian Roulette won’t help you do so.