The only thing that distinguishes quantum immortality from old-fashioned probabilistic immortality (play Russian roulette as much as you like, and if you survive then it turns out that you survived, duh) is the idea that all those possible-yous are real. In which case, relying on “quantum immortality” means just letting the vast majority of them die. If cryonics offers a substantial chance of greatly increasing the proportion of possible-yous that have good long happy lives, then “there’s always quantum immortality” seems to me no reason at all to pass up that chance.
Imagine that you are going to be put into a machine that will replace you with a million copies, all of them having exactly the same degree of physical and psychological continuity with your present self as you generally expect your near-future selves to have. You have (now, before going into the machine) the choice of two actions, one of which means that all but one of those million copies will die horribly tomorrow, and one of which means that only one of them will. The second choice has a moderate cost associated with it. Which way do you choose? I go for the second, for sure.
In the case of your machine, I would have a 999999/1000000 chance of experiencing death if I choose the first option, and 1/1000000 chance with the second. I would most likely choose the second.
But in the case of cryonics, the experience of death is guaranteed; the only question is how many “copies” wake up later. And I have no intuition or logical argument that a million copies of me is better than one.
Maybe I didn’t understand what you were saying about quantum immortality, then. Let’s make it a bit more explicit. To avoid confusion let’s ignore (1) other copies of you that exist merely because the universe is very large, if any, (2) simulations of you that exist for any reason at all, if any, and (3) the possibility that you might escape death without either cryonics or extreme good luck, for instance because of a technological singularity in the near future.
1. Ignoring many-worlds quantum stuff:
Without cryonics, you will almost certainly die within the next (say) 100 years, but there is an infinitesimally tiny chance that you will somehow survive much longer.
With cryonics, you will certainly “die” (that is, go through something that greatly resembles death up to and beyond the point at which you cease to be conscious), and then there’s some chance (whose size is debatable) that you will later be revived.
Comparing these two outcomes, you should decline to bother with cryonics (even if its costs are very low) if (a) you think the chance of getting revived is very tiny, or (b) what matters to you is having some chance of survival rather than having as much chance of survival as possible.
2. With many-worlds quantum stuff:
Every statement that used to be about probability now gets a reinterpretation in terms of (speaking loosely) “number of versions of you”. If you toss a coin, roughly half of your versions see it come up heads and roughly half see it come up tails. If you play Russian roulette with a six-shooter, roughly 5⁄6 of your versions live and roughly 1⁄6 die.
So you should feel exactly the same way about “proportion of versions of me for which X is true” as you do about “probability that X is true for me”.
Now:
Without cryonics, almost all your versions die within (say) 100 years. An infinitesimally tiny fraction of them get “lucky” and live much longer.
With cryonics, all your versions “die”, and then some (debatable how large) fraction get revived later.
Comparing these two outcomes, you should decline to bother with cryonics (even if its costs are very low) if (a) you think the fraction of versions-of-you that get revived is very tiny, or (b) what matters to you is having some copy of you survive rather than having as many copies survive as possible.
And, once again: if you take many-worlds seriously—which you have to, for “quantum immortality” to make any sense—then you should feel exactly the same way about this as you did about the corresponding comparison stated in terms of probabilities: because that’s what probabilities (of the “objective” sort) are. Probability of survival == fraction of Everett branches on which you survive.
If you’re happy for your survival to depend on quantum immortality, then you should also be happy for it to depend on a coin toss or the result of a game of Russian roulette. If quantum immortality doesn’t lessen your reluctance to bet your life in those ways, then it also shouldn’t make a difference to your feelings about cryonics.
The only thing that distinguishes quantum immortality from old-fashioned probabilistic immortality (play Russian roulette as much as you like, and if you survive then it turns out that you survived, duh) is the idea that all those possible-yous are real. In which case, relying on “quantum immortality” means just letting the vast majority of them die. If cryonics offers a substantial chance of greatly increasing the proportion of possible-yous that have good long happy lives, then “there’s always quantum immortality” seems to me no reason at all to pass up that chance.
Imagine that you are going to be put into a machine that will replace you with a million copies, all of them having exactly the same degree of physical and psychological continuity with your present self as you generally expect your near-future selves to have. You have (now, before going into the machine) the choice of two actions, one of which means that all but one of those million copies will die horribly tomorrow, and one of which means that only one of them will. The second choice has a moderate cost associated with it. Which way do you choose? I go for the second, for sure.
In the case of your machine, I would have a 999999/1000000 chance of experiencing death if I choose the first option, and 1/1000000 chance with the second. I would most likely choose the second.
But in the case of cryonics, the experience of death is guaranteed; the only question is how many “copies” wake up later. And I have no intuition or logical argument that a million copies of me is better than one.
Maybe I didn’t understand what you were saying about quantum immortality, then. Let’s make it a bit more explicit. To avoid confusion let’s ignore (1) other copies of you that exist merely because the universe is very large, if any, (2) simulations of you that exist for any reason at all, if any, and (3) the possibility that you might escape death without either cryonics or extreme good luck, for instance because of a technological singularity in the near future.
1. Ignoring many-worlds quantum stuff:
Without cryonics, you will almost certainly die within the next (say) 100 years, but there is an infinitesimally tiny chance that you will somehow survive much longer.
With cryonics, you will certainly “die” (that is, go through something that greatly resembles death up to and beyond the point at which you cease to be conscious), and then there’s some chance (whose size is debatable) that you will later be revived.
Comparing these two outcomes, you should decline to bother with cryonics (even if its costs are very low) if (a) you think the chance of getting revived is very tiny, or (b) what matters to you is having some chance of survival rather than having as much chance of survival as possible.
2. With many-worlds quantum stuff:
Every statement that used to be about probability now gets a reinterpretation in terms of (speaking loosely) “number of versions of you”. If you toss a coin, roughly half of your versions see it come up heads and roughly half see it come up tails. If you play Russian roulette with a six-shooter, roughly 5⁄6 of your versions live and roughly 1⁄6 die.
So you should feel exactly the same way about “proportion of versions of me for which X is true” as you do about “probability that X is true for me”.
Now:
Without cryonics, almost all your versions die within (say) 100 years. An infinitesimally tiny fraction of them get “lucky” and live much longer.
With cryonics, all your versions “die”, and then some (debatable how large) fraction get revived later.
Comparing these two outcomes, you should decline to bother with cryonics (even if its costs are very low) if (a) you think the fraction of versions-of-you that get revived is very tiny, or (b) what matters to you is having some copy of you survive rather than having as many copies survive as possible.
And, once again: if you take many-worlds seriously—which you have to, for “quantum immortality” to make any sense—then you should feel exactly the same way about this as you did about the corresponding comparison stated in terms of probabilities: because that’s what probabilities (of the “objective” sort) are. Probability of survival == fraction of Everett branches on which you survive.
If you’re happy for your survival to depend on quantum immortality, then you should also be happy for it to depend on a coin toss or the result of a game of Russian roulette. If quantum immortality doesn’t lessen your reluctance to bet your life in those ways, then it also shouldn’t make a difference to your feelings about cryonics.