I don’t have an answer for the question, but I note that the hypothetical raises the possibility of an anthropic explanation for twenty-first century recessions. So if you believe that the Fed is run by idiots who should have , consider the possibility that in branches where the Fed did in fact , the world now consists of computronium.
I find this especially compelling in light of Japan’s two “lost decades” combined with all the robotics research for which Japan is famous. Obviously the anthropic hypothesis requires the most stagnation in nations which are good at robots and AI.
Can we put a lid on this conflation of subjective probability with objective quantum branching please? A deterministic fair coin does not split the world, and neither would a deterministic economic cycle. Or are we taking seriously the possibility that the course of the economy is largely driven by quantum randomness?
EDIT: actually I just noticed that small quantum fluctuations from long ago can result in large differences between branches today. At that point I’m confused about what the anthropics implies we should see, so please excuse my overconfidence above.
This comment was banned, which looked to me like a probable accident with a moderator click, so I unbanned it. If I am in error can whichever mod PM me after rebanning it?
Naturally if this was an accident, it must have been a quantum random one.
Can we put a lid on this conflation of subjective probability with objective quantum branching please? A deterministic fair coin does not split the world, and neither would a deterministic economic cycle. Or are we taking seriously the possibility that the course of the economy is largely driven by quantum randomness?
I’m certainly taking it seriously, and am somewhat surprised that you’re not. Some ways small-sized effects (most likely to “depend” of quantum randomness) can eventually have large-scale impacts:
Whether or not quantum randomness drives the course of the economy it’s still a really good idea to stop conflating subjective probability and the corresponding notion of possible worlds with quantum/inflationary/whatever many world theories. Rolf’s comment doesn’t actually do this: I read him as speaking entirely about the anthropic issue. Eliezer, on the other hand, totally is conflating them in the original post.
I understand that there are reasons to think anthropic issues play an essential role in the assignment of subjective probabilities, especially at a decision theoretic level. But given a) subjective uncertainty over whether or not many-worlds is correct, b) our ignorance of how the Born probability rule figures into the relationship and c) the way anthropics skews anticipated experiences I am really suspicious that anyone here is able to answer the question:
“Do you think Everett branches with 4% or 1% RGDP growth have a better chance of getting FAI before UFAI”?
People are actually answering
“Do you think possible worlds with 4% or 1% RGDP growth have a better chance of getting FAI before UFAI”?
Whether or not quantum randomness drives the course of the economy it’s still a really good idea to stop conflating subjective probability and the corresponding notion of possible worlds with quantum/inflationary/whatever many world theories.
why Alan Turing never published his work on the theory of computation
why all the projects in the 1950s aimed at making general-purpose computers got cancelled for complex political reasons no one understood
why that big earthquake killed everyone at the Dartmouth Conference, tragically wiping out almost the entire nascent field of AI
why all attempts at constructing integrated circuits mysteriously failed
why progress abruptly stopped following Moore’s law in the early 1980s
why no one has ever been able to make computer systems capable of beating grandmasters at chess, questioning Jeopardy answers, searching huge databases of information, etc.
All of which are true in other possible worlds, which for all we know may have a greater amplitude than ours. That we are alive does not give us any information on how probable we are, because we can’t observe the reference class. For all we know, we’re one of those worlds that skate very, very close to the edge of disaster, and the two recessions of the aughts are the only thing that have kept us alive; but those recessions were actually extremely unlikely, and the “mainline” branches of humanity, the most probable ones, are alive because the Cuban War of 1963 set the economy back to steam and horses. (To be sure, they have their problems, but UFAI isn’t among them.)
Note that, if you take many-worlds seriously, then in branches where UFAI is developed, there will still be some probability of survival due to five cosmic rays with exactly the right energies hitting the central CPU at just the right times and places, causing SkyNet to divide by zero instead of three. But the ones who survive due to that event won’t be very probable humans. :)
If most copies of me died in the shooting but I survived, I should expect to find that I survived for only one reason, not for multiple independent reasons. Perhaps the killer’s gun jammed at the crucial moment, or perhaps I found a good place to hide, but not both.
On the other hand, if you are being shot at repeatedly and survive a long time, you should expect there to be lots of reasons (or one reason with very broad scope—maybe everyone’s guns were sabotaged in a single operation, or maybe they’ve been told to let you live, or a god is looking out for you). And it’s only in that sort of situation that anthropic “explanations” would be in any way sensible.
It’s always true enough to say “well, of course I find myself still alive because if I weren’t I wouldn’t be contemplating the fact that I’m still alive”. But most of the time this is really uninteresting. Perhaps it always is.
The examples given in this thread seem to me to call out for anthropic explanations to much the same extent as does the fact that I’m over 40 years old and not dead yet.
This just prompted me to try to set a subjective probability that quantum immortality works, so e.g. if I remember concluding that it was 5% likely at 35 and find myself still alive at 95, I will believe in quantum immortality (going by SSA tables).
I’m currently finding this subjective probability too creepy to actually calculate.
To me, it means expecting to experience the highest-weighted factorization of the hamiltonian that contains a conscious instantiation of me, no matter how worse-than-death that branch may be.
I think you should analyse further. Expecting conditional on still being alive? Surely you expect that even without “quantum immortality”. Expecting to find yourself still alive, and experience that? Again, what exactly do you mean by that? What does it mean to expect to find yourself still alive? (Presumably not that others will expect to find you still alive in any useful sense, because with that definition you don’t get q.i.)
I expect there are Everett branches in which you live to 120 as a result of a lot of good luck (or, depending on what state you’re in, bad luck). Almost equivalently, I expect there’s a small but nonzero probability that you live to 120 as a result of a lot of luck. { If you live to 120 / In those branches where you live to 120 } you will probably have experienced a lot of surprising things that enabled your survival. None of this is in any way dependent on quantum mechanics, still less on the many-worlds interpretation.
It seems to me that “believing in quantum immortality” is a matter of one’s own values and interpretive choices, much more than of any actual beliefs about how the world is. But I may be missing something.
I should perhaps be more clear that I’m not distinguishing between “MWI and functionalism are true” and “quantum immortality works.” That is, if “I” consciously experience dying, and my consciouness ceases, but “I” go on experiencing things in other everett branches, I’m counting that as QI.
Expecting conditional on still being alive? Surely you expect that even without “quantum immortality”...What does it mean to expect to find yourself still alive?
I’m currently making observations consistent with my own existence. If I stop making that kind of observation, I consider that no longer being alive.
Going again with the example of a 35 year old: Conditional on having been born, I have a 96% chance of still being alive. So whatever my prior on QI, that’s far less than a decibel of evidence in favor of it. Still, ceteris paribus, it’s more likely than it was at age 5.
Sure. But I’m not sure I made the point I was trying to make as clearly as I hoped, so I’ll try again.
Imagine two possible worlds. In one of them, QM works basically as currently believed, and the way it does this is exactly as described by MWI. In the other, there is at every time a single kinda-classical-ish state of the world, with Copenhagen-style collapses or something happening as required.
In either universe it is possible that you will find yourself still alive at 120 (or much more) despite having had plenty of opportunities to be killed off by accident, illness, etc. In either universe, the probability of this is very low (which in the former case means most of the measure of where we are now ends up with you dead earlier, and in the latter means whatever exactly probability means in a non-MWI world). In either universe, every observation you make will show yourself alive, however improbable that may seem.
How does observing yourself still alive at 150 count as evidence for MWI, given all that?
What you mustn’t say (so it seems to me): “The probability of finding myself alive is very low on collapse theories and high on MWI, so seeing myself still alive at 150 is evidence for MWI over collapse theories”. If you mean the probability conditional on you making the observation at age 150, it’s 1 in both cases. If you mean the probability not conditional on that, it’s tiny in both cases. (Assuming arguendo that Pr(nanotech etc. makes lots of people live to be very old by then) is negligible.) The same applies if you try to go halfway and take the probability simply conditional on you making the observation: MWI or no MWI, only a tiny fraction of observations you make will be at age 150.
In either universe it is possible that you will find yourself still alive at 120
In the MWI-universe, it is probable at near unity that I will find myself still alive at 120. In the objective collapse universe, there’s only a small fraction of a percent chance that I’ll find myself alive at 120. In the objective collapse universe, every observation I make will show myself alive—but there’s only a fraction of a percent of a chance that I’ll make an observation that shows my age as 120.
If you mean the probability conditional on you making the observation at age 150, it’s 1 in both cases.
The probability of my making the observation “I am 150 years old,” given objective collapse, is one of those probabilities so small it’s dominated by “stark raving mad” type scenarios. Nobody you’ve ever known has made that observation; neither has anybody they know. How can this not be evidence?
What’s the observation you’re going to make that has probability near-1 on MWI and probabilty near-0 on collapse—and probability given what?
“I’m alive at 120, here and now”—that has small probability either way. (On most branches of the wavefunction that include your present self, no version of you gets to say that. Ignoring, as usual, irrelevant details involving positive singularities, very large universes, etc.)
“90 years from now I’ll still be alive” (supposing arguendo that you’re 30 now) -- that has small probability either way.
“I’m alive at 120, conditional on my still being alive at 120”—that obviously has probability 1 either way.
“On some branch of the wavefunction I’m still alive at 120”—sure, that’s true on MWI and (more or less by definition) false on a collapse interpretation; but it’s not something you can observe. It corresponds exactly to “With nonzero probability I’m still alive at 120″, which is true on collapse.
“90 years from now I’ll still be alive” (supposing arguendo that you’re 30 now) -- that has small probability either way.
This is the closest one. However, that’s not an observation, it’s a prediction. The observation is “90 years ago, I was 30.” That’s an observation that almost certainly won’t be made in a collapse-based world; but will be made somewhere in an MWI world.
“I’m alive at 120, here and now”—that has small probability either way. (On most branches of the wavefunction that include your present self, no version of you gets to say that.)
“small probability either way” only applies if I want to locate myself precisely, within a branch as well as within a possible world. If I only care about locating myself in one possible world or the other, the observation has a large probability in MWI.
It seems to me that “believing in quantum immortality” is a matter of one’s own values and interpretive choices, much more than of any actual beliefs about how the world is.
If Charles Babbage had built his analytic engine, then that would seem to me to have gotten programming started long earlier, such that FAI work would in turn start much sooner, and so we’d have no hardware overhang to worry about. Imagine if this conversation were taking place with 1970′s technology.
I don’t mean to pick on you specifically, but the genre of vague “anthropic filter!” speculations whenever anything is said to be possibly linked even slightly to catastrophe needs to be dialed back on LW. Such speculations almost never a) designate a definite theoretical framework on which that makes sense b) make any serious effort to show a non-negligible odds ratio (e.g. more than 1%) on any (even implausible) account of anthropic reasoning.
I don’t have an answer for the question, but I note that the hypothetical raises the possibility of an anthropic explanation for twenty-first century recessions. So if you believe that the Fed is run by idiots who should have , consider the possibility that in branches where the Fed did in fact , the world now consists of computronium.
I find this especially compelling in light of Japan’s two “lost decades” combined with all the robotics research for which Japan is famous. Obviously the anthropic hypothesis requires the most stagnation in nations which are good at robots and AI.
I hope we can all agree that in discussions on LW this should by no means be regarded as a bad thing.
Can we put a lid on this conflation of subjective probability with objective quantum branching please? A deterministic fair coin does not split the world, and neither would a deterministic economic cycle. Or are we taking seriously the possibility that the course of the economy is largely driven by quantum randomness?
EDIT: actually I just noticed that small quantum fluctuations from long ago can result in large differences between branches today. At that point I’m confused about what the anthropics implies we should see, so please excuse my overconfidence above.
Isn’t everything?
This comment was banned, which looked to me like a probable accident with a moderator click, so I unbanned it. If I am in error can whichever mod PM me after rebanning it?
Naturally if this was an accident, it must have been a quantum random one.
I’m certainly taking it seriously, and am somewhat surprised that you’re not. Some ways small-sized effects (most likely to “depend” of quantum randomness) can eventually have large-scale impacts:
DNA Mutations
Which sperm gets to the egg
The weather
Soft errors from cosmic rays or thermal radiation
Whether or not quantum randomness drives the course of the economy it’s still a really good idea to stop conflating subjective probability and the corresponding notion of possible worlds with quantum/inflationary/whatever many world theories. Rolf’s comment doesn’t actually do this: I read him as speaking entirely about the anthropic issue. Eliezer, on the other hand, totally is conflating them in the original post.
I understand that there are reasons to think anthropic issues play an essential role in the assignment of subjective probabilities, especially at a decision theoretic level. But given a) subjective uncertainty over whether or not many-worlds is correct, b) our ignorance of how the Born probability rule figures into the relationship and c) the way anthropics skews anticipated experiences I am really suspicious that anyone here is able to answer the question:
People are actually answering
which is not obviously the same thing.
You don’t need quantum many worlds for this kind of speculation: e.g. a spatially infinite universe would also do the trick.
As I said:
I agree, subjective uncertainty isn’t the same as quantum uncertainty!
On the other hand, there have been rumors that coinflips are not deterministic. See here.
My comment was not intended in full seriousness. :)
It is not at all clear to me that this hypothesis shouldn’t be taken seriously. It’s not clear to me that it should be, either!
It also explains why the dot com boom had to burst,
why Charles Babbage never built his Analytical Engine,
why Archimedes was killed, and Antikythera mechanism drowned in the sea,
why most children in our culture hate maths, and why internet is mostly used for chatting, games, and porn.
It unfortunately also explains
why Alan Turing never published his work on the theory of computation
why all the projects in the 1950s aimed at making general-purpose computers got cancelled for complex political reasons no one understood
why that big earthquake killed everyone at the Dartmouth Conference, tragically wiping out almost the entire nascent field of AI
why all attempts at constructing integrated circuits mysteriously failed
why progress abruptly stopped following Moore’s law in the early 1980s
why no one has ever been able to make computer systems capable of beating grandmasters at chess, questioning Jeopardy answers, searching huge databases of information, etc.
All of which are true in other possible worlds, which for all we know may have a greater amplitude than ours. That we are alive does not give us any information on how probable we are, because we can’t observe the reference class. For all we know, we’re one of those worlds that skate very, very close to the edge of disaster, and the two recessions of the aughts are the only thing that have kept us alive; but those recessions were actually extremely unlikely, and the “mainline” branches of humanity, the most probable ones, are alive because the Cuban War of 1963 set the economy back to steam and horses. (To be sure, they have their problems, but UFAI isn’t among them.)
Note that, if you take many-worlds seriously, then in branches where UFAI is developed, there will still be some probability of survival due to five cosmic rays with exactly the right energies hitting the central CPU at just the right times and places, causing SkyNet to divide by zero instead of three. But the ones who survive due to that event won’t be very probable humans. :)
If most copies of me died in the shooting but I survived, I should expect to find that I survived for only one reason, not for multiple independent reasons. Perhaps the killer’s gun jammed at the crucial moment, or perhaps I found a good place to hide, but not both.
On the other hand, if you are being shot at repeatedly and survive a long time, you should expect there to be lots of reasons (or one reason with very broad scope—maybe everyone’s guns were sabotaged in a single operation, or maybe they’ve been told to let you live, or a god is looking out for you). And it’s only in that sort of situation that anthropic “explanations” would be in any way sensible.
It’s always true enough to say “well, of course I find myself still alive because if I weren’t I wouldn’t be contemplating the fact that I’m still alive”. But most of the time this is really uninteresting. Perhaps it always is.
The examples given in this thread seem to me to call out for anthropic explanations to much the same extent as does the fact that I’m over 40 years old and not dead yet.
This just prompted me to try to set a subjective probability that quantum immortality works, so e.g. if I remember concluding that it was 5% likely at 35 and find myself still alive at 95, I will believe in quantum immortality (going by SSA tables).
I’m currently finding this subjective probability too creepy to actually calculate.
I suggest giving some thought first to exactly what “believing in quantum immortality” really amounts to.
To me, it means expecting to experience the highest-weighted factorization of the hamiltonian that contains a conscious instantiation of me, no matter how worse-than-death that branch may be.
I think you should analyse further. Expecting conditional on still being alive? Surely you expect that even without “quantum immortality”. Expecting to find yourself still alive, and experience that? Again, what exactly do you mean by that? What does it mean to expect to find yourself still alive? (Presumably not that others will expect to find you still alive in any useful sense, because with that definition you don’t get q.i.)
I expect there are Everett branches in which you live to 120 as a result of a lot of good luck (or, depending on what state you’re in, bad luck). Almost equivalently, I expect there’s a small but nonzero probability that you live to 120 as a result of a lot of luck. { If you live to 120 / In those branches where you live to 120 } you will probably have experienced a lot of surprising things that enabled your survival. None of this is in any way dependent on quantum mechanics, still less on the many-worlds interpretation.
It seems to me that “believing in quantum immortality” is a matter of one’s own values and interpretive choices, much more than of any actual beliefs about how the world is. But I may be missing something.
I should perhaps be more clear that I’m not distinguishing between “MWI and functionalism are true” and “quantum immortality works.” That is, if “I” consciously experience dying, and my consciouness ceases, but “I” go on experiencing things in other everett branches, I’m counting that as QI.
I’m currently making observations consistent with my own existence. If I stop making that kind of observation, I consider that no longer being alive.
Going again with the example of a 35 year old: Conditional on having been born, I have a 96% chance of still being alive. So whatever my prior on QI, that’s far less than a decibel of evidence in favor of it. Still, ceteris paribus, it’s more likely than it was at age 5.
Sure. But I’m not sure I made the point I was trying to make as clearly as I hoped, so I’ll try again.
Imagine two possible worlds. In one of them, QM works basically as currently believed, and the way it does this is exactly as described by MWI. In the other, there is at every time a single kinda-classical-ish state of the world, with Copenhagen-style collapses or something happening as required.
In either universe it is possible that you will find yourself still alive at 120 (or much more) despite having had plenty of opportunities to be killed off by accident, illness, etc. In either universe, the probability of this is very low (which in the former case means most of the measure of where we are now ends up with you dead earlier, and in the latter means whatever exactly probability means in a non-MWI world). In either universe, every observation you make will show yourself alive, however improbable that may seem.
How does observing yourself still alive at 150 count as evidence for MWI, given all that?
What you mustn’t say (so it seems to me): “The probability of finding myself alive is very low on collapse theories and high on MWI, so seeing myself still alive at 150 is evidence for MWI over collapse theories”. If you mean the probability conditional on you making the observation at age 150, it’s 1 in both cases. If you mean the probability not conditional on that, it’s tiny in both cases. (Assuming arguendo that Pr(nanotech etc. makes lots of people live to be very old by then) is negligible.) The same applies if you try to go halfway and take the probability simply conditional on you making the observation: MWI or no MWI, only a tiny fraction of observations you make will be at age 150.
In the MWI-universe, it is probable at near unity that I will find myself still alive at 120. In the objective collapse universe, there’s only a small fraction of a percent chance that I’ll find myself alive at 120. In the objective collapse universe, every observation I make will show myself alive—but there’s only a fraction of a percent of a chance that I’ll make an observation that shows my age as 120.
The probability of my making the observation “I am 150 years old,” given objective collapse, is one of those probabilities so small it’s dominated by “stark raving mad” type scenarios. Nobody you’ve ever known has made that observation; neither has anybody they know. How can this not be evidence?
What’s the observation you’re going to make that has probability near-1 on MWI and probabilty near-0 on collapse—and probability given what?
“I’m alive at 120, here and now”—that has small probability either way. (On most branches of the wavefunction that include your present self, no version of you gets to say that. Ignoring, as usual, irrelevant details involving positive singularities, very large universes, etc.)
“90 years from now I’ll still be alive” (supposing arguendo that you’re 30 now) -- that has small probability either way.
“I’m alive at 120, conditional on my still being alive at 120”—that obviously has probability 1 either way.
“On some branch of the wavefunction I’m still alive at 120”—sure, that’s true on MWI and (more or less by definition) false on a collapse interpretation; but it’s not something you can observe. It corresponds exactly to “With nonzero probability I’m still alive at 120″, which is true on collapse.
This is the closest one. However, that’s not an observation, it’s a prediction. The observation is “90 years ago, I was 30.” That’s an observation that almost certainly won’t be made in a collapse-based world; but will be made somewhere in an MWI world.
“small probability either way” only applies if I want to locate myself precisely, within a branch as well as within a possible world. If I only care about locating myself in one possible world or the other, the observation has a large probability in MWI.
You are correct.
If Charles Babbage had built his analytic engine, then that would seem to me to have gotten programming started long earlier, such that FAI work would in turn start much sooner, and so we’d have no hardware overhang to worry about. Imagine if this conversation were taking place with 1970′s technology.
Rolf,
I don’t mean to pick on you specifically, but the genre of vague “anthropic filter!” speculations whenever anything is said to be possibly linked even slightly to catastrophe needs to be dialed back on LW. Such speculations almost never a) designate a definite theoretical framework on which that makes sense b) make any serious effort to show a non-negligible odds ratio (e.g. more than 1%) on any (even implausible) account of anthropic reasoning.
However, they do invite a lot of nonsense.