Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Critique of the quantum suicide experiment

  1. Sep 1, 2011 #1

    Demystifier

    User Avatar
    Science Advisor

    At another thread, it has been pointed out that Tegmark said the following:

    Here I want to criticize it. More precisely, I want to show that the suicidal guy cannot be objective about his own chances for survival. Therefore, since his own conclusions cannot be objective, he cannot objectively conclude that his experiment confirms the many-world interpretation.

    To understand this, for the moment forget about quantum mechanics. Instead, assume that we have a CLASSICAL gun that kills with the probability 50% (classical Russian roulette). We give that gun to a suicide person who wants to kill himself, but we do not tell him what the probability of killing himself is. We ask him to try to kill himself as many times as he wishes and ask him to tell us his conclusions. No matter how many times he tries to kill himself, he will either not exist as a person which can make any conclusion (because he will be dead), or will find out that he survives whenever he tries to kill himself. Thus, he will either conclude nothing, or will highly overestimate the probability of surviving. There is no chance for him to conclude by this experiment that the gun kills in 50% cases. If he will conclude anything, it will be that the probability of surviving is larger than 50%.

    But we know that this conclusion is wrong. So we must conclude that conclusions about probabilities for surviving found by someone who attempts suicides and survives - are unreliable. So we cannot trust even our own conclusions about our survival probabilities in our own attempted suicides. In this case, we are biased observers who cannot make objective conclusions about probabilities for survival. Subsequently, we cannot make objective conclusions about anything which otherwise could be concluded from those probabilities.

    So far I was talking about classical probabilities, but quantum probabilities are not much different. If I try suicide many times and I survive each time, I cannot objectively conclude anything about my probabilities for survival. Subsequently, I cannot objectively conclude from that experiment that the many-world interpretation is correct. If I am objective, I know that I am a biased observer, so I know that a naive conclusion that the many-world interpretation seems to be right - is in fact an invalid conclusion.

    To conclude, objective suicide persons cannot use the quantum suicide experiment to convince themselves about the validity of the many-world interpretation. That's because they are biased observers, so cannot be objective about estimating probabilities.

    In other words, the first Tegmark's statement above is incorrect.
     
    Last edited: Sep 1, 2011
  2. jcsd
  3. Sep 1, 2011 #2
    I already debunked this in the other thread.

    If some hypothetical model of MWI could be made to work, it would have Born Rule and thus the exact same probabilities as any single universe model (bohm, copenhagen, other hidden variable etc.).
    So if you try to commit a quantum suicide and you survive, this would just confirm Born Rule, not whether MWI is more likely or less likely, if that had been the case MWI would be required to not obey quantum probabilities.

    If surviving the quantum suicide is 1% and dying is 99% you surviving this would only confirm that you were extremley luckily, this would also happen 1 out of 100 times in a single universe model.
    The probabilities doesn't change, so you could do this to infinity and it would only confirm QM and Born Rule, not MWI at all.

    Jacques Mallah has also written a good paper on the whole illusion that you PERSONALLY survive a quantum suicide:
    http://arxiv.org/ftp/arxiv/papers/0902/0902.0187.pdf
    (this is a must read for anyone who believes in this fallacy, as it is potentially life threatening delusion amongst people who believe in MWI)

    I also seem to remember that Don Page retracted his belief in the validity of QS because he realized what I described above.
     
  4. Sep 2, 2011 #3

    xts

    User Avatar

    Frankly: I got a bit bored by Mallah's paper - he could present the same ideas on two pages...
    I can't agree with his argumentation. He redefines 'personality' in a way far from common meaning and from our introspective sense, by introducing strange concepts like 'total amount of consciousness' (recombining all Everett's worlds back together), while he misses major Tegmark's point:
    - in MWI there always exists some worlds with the experimenter alive;
    - in single-world interpretations, consciousness of the observer often totally ceases.

    I don't think this threat is so serious. Vast majority of people believe in some kind of afterlife immorality (usually in worlds better than ours) and only few of them is led to suicide by those religious delusions.

    You are missing the same Tegmark's point as Mallah does: MWI implies that you are always extremely lucky in death situations - your consciousness always survive. While on single world your consciousness may just stop to exist.
     
  5. Sep 2, 2011 #4

    Demystifier

    User Avatar
    Science Advisor

    Since nobody commented my argument, let me add a clarification:

    I DO think that many-world interpretation implies quantum immortality.
    Yet, I argue that a rational experimentalist conducting the quantum suicide experiment cannot conclude that the result of experiment is an evidence for the many-world interpretation.

    In fact, if you are immortal (for whatever reason you are so, which may have nothing to do with many worlds), you cannot prove it to yourself by a Russian-roulette experiment, provided that you are rational and understand the theory of probability and sampling.
     
    Last edited: Sep 2, 2011
  6. Sep 2, 2011 #5

    xts

    User Avatar

    Yes, and no. You can't prove it with absolute certainity. But you can do it with any marginal error you like. Just perform the suicidal attempt with this marginally low chance to survive.

    The paradox is opposite: you cannot prove to yourself that you are mortal!
     
  7. Sep 2, 2011 #6
    Well, if you didn't get it in that many pages I doubt 2 would do the trick....

    Ok let us break it down in simple terms if MWI had been true, you would be like a amoeba always "splitting" into new versions of yourself, all of which are the "original" in a sense.
    Now imagine that they did some sort of experiment where 9 of the future splittings of the "original" amoeba will die and 1 will live.
    9 actually ****ing dies and 1 survives.
    It is really that simple. The consciousness of these amoebas do not magically transfer over to the surviving amoeba, so 9 will infact DIE just like in a single universe model and 1 will survive, get it?

    If I had a flash light and conducted an experiment where in 9 out of the 10 worlds the flashlight would go out of battery and thus stop shining the photons will not magically jump into this single universe where the flash light still works.
    it is THAT simple.

    A single last example: if MWI had been true this would be true for everything.
    If in another universe right now a brick forms right over your head and falls on top of your head, YOU in this Universe does not experience that pain, because it doesn't happen to YOU, it happened to your twin.
    Just like death in a parallel universe!
    People need to stop thinking that consciousness is a soul that could just jump from universe to universe....


    Because in most religions suicide is also what they call a "sin", a guaranteed into whatever made up hell they believe in.
    If you believe that MWI is true and that it implies quantum immortality for you personally, there is no reason for you not to play quantum lottery and continue killing yourself until you end up in a branch where you are a billionaire...
    So yes QS/QI belief (which is a fallacy) is dangerous....

    A consciousness survives, not YOUR consciousness survives.
    Consciousness is nothing but interactions in a ****ing brain, it's not a soul that magically jumps to the next universe.

    Luckily MWI is most likely wrong and people are finally starting to realize this so this falsehood will most likely die out before it claims too many lives.
     
  8. Sep 2, 2011 #7

    xts

    User Avatar

    In MWI consciousness is not 'jumping' but 'splitting' or 'forking'. No consciousness ever dies. It sometimes forks, and sometimes does not fork. Even in an example with heavy wound as an outcome of russian roulette, in some worlds the medical help comes quickly enough to stop bleeding. Of course - heavy wound leading to spending the rest of your (still immortal) life on a wheelchair - is definitely not a desired (but possible) outcome of russian roulette experiment in MW.


    Fortunately, religious and metaphysical beliefs are not so dangerous. Except of few fanatics of various religions, majority uses common sense rather than follow logical implications of their beliefs.

    ADDED:
    By end of 19th century it was quite popular to bet the whole property on horse racings and shot himself in case the bet failed. Do you think all of them were MWI precursors?
     
    Last edited: Sep 2, 2011
  9. Sep 2, 2011 #8
    I don't even understand how you don't understand it...
    That puzzles me more than this whole QS puzzle.
    There is nothing "magical" about life, it's just processes, they can stop and then you are dead, consciousness does not jump over to the other branches.

    If I conduct a quantum blind-myself experiment, sure there will be branches where successors of me will against all odds not go blind, but there is still a huge chance that I will become blind on one eye, I wont jump over to the branch where I'm not blind....

    Another comment by Tegmark on this whole thing seems to suggest even he isn't 100% sure you are guaranteed immortality.

    In response to questions about "subjective immortality", Max Tegmark made some brief comments: He acknowledged the argument that "everyone will be immortal" should follow if a survivor outcome is possible for all life-threatening events. The flaw in that argument, he suggests, is that dying is rarely a binary event; it is a progressive process. The quantum suicide thought experiment attempts to isolate all possible outcomes for the duration of the thought experiment. That isolation delays decoherence in such a way that the subjective experience of the superposition is illustrated. It is only within the confines of such an abstract quantum scenario that an observer finds they defy all odds.[6]



    Lol, no :P
    Very very few actually believe in MWI at all

    By the way, you should send a email to jacques mallah (email on top of the paper I linked you to earlier in the thread) and have him participate in this debate and explain his paper in more detail.
     
  10. Sep 2, 2011 #9

    xts

    User Avatar

    That is an external (objective) point of view. From subjective, conscious, introspective point, you are never dead.

    I think you miss Everett's idea. I'll repeat: 'fork', not 'jump'. At every event the world splits into two (more), and all copies of me are the same ME at the very moment of split, then they start to continue their own life, inheriting my personality and my history. In case of suicidal attempt the split does not occur: my personality continues only in one branch: where the gun misfired.
    That's a huge difference to quantum-blind experiment: in this case your personality splits and one of yous may say and think: "****, I lost my eye!"

    Dying slowly is only minor problem to MWI(consciousness) QS interpretation. You just should use the killing machine acting quickly enough to be unnoticed by mind. I believe the shockwave caused by magnum .44 bullet penetrating your brain is sufficiently quick.
    Or e.g. - put yourself into the narcosis, and then apply either wake up cure or poison.
     
  11. Sep 2, 2011 #10
    You still don't understand it!
    We are talking about POST-FORKING, after the fork/branching takes place you can't jump from branch 1 to branch 15 because you died in branch 1 and survived in branch 15

    I give up... Please contact Jacques Mallah and bring him into the discussion, he will clarify way better than i can.
     
  12. Sep 2, 2011 #11

    xts

    User Avatar

    I doubt if J.Mallah can explain it, as I understand your argument, but I don't see it valid.

    From external observer view, before the experiment we have one world with my conscious presence and after the experiment we have two worlds, one with me alive, and one with him mourning over my dead body.

    From my perspective ('my' = successor of my current consciousness) before we have one world, but after we also have one world with me happy and alive.

    No "post-forking-jumps" are needed for such explanation.

    You helped me to realize, that QS experiment is convincing only for atheistic MWI believers. Religious experimenters, in many cases, would find themselves in heaven (or rather hell - punished for suicide).
     
  13. Sep 2, 2011 #12
    You make no sense.

    And that bs about "Only atheistic" wtf?
    No, sorry its the other way around, you need to postulate a magical branch jumping consciousness to make Quantum Immortality valid.

    Just contact Mallah and see what he has to say, give him a chance to defend his paper.
    I'm sure he is more than glad to defend it and answer any critique you have of it.
    It would be helpful for other people who later on read this thread too.
     
  14. Sep 2, 2011 #13

    Demystifier

    User Avatar
    Science Advisor

    No. As I explained in the first post, in that way, if you will conclude anything, you will conclude that your chances to be immortal are very high, even if in reality these chances are very low or zero. Therefore, the conclusions obtained in this way are not reliable. Therefore, if you are rational and understand this, you cannot conclude that in the first place.


    Consider also the following game. (It's a variant of the game above, but nobody dies.) You flip a coin. If it is head, the result is not shown to you and the game stops. If it is tail, the result is shown to you, after which you flip the coin again with the same rule. It is repeated, until eventually it is head in which case the result is not shown to you and the game stops. You play the whole game only once. But others can independently play the same game as well. They all tell me their final conclusions about the coin. How many of them will tell me that the coin is probably biased? How many of them will tell me that the coin is probably not biased? How many of them will not be able to tell? Whom should I believe?

    Hint: The problem with that game is that the rules are such that the OBSERVER is biased, rather than the coin.
     
    Last edited: Sep 2, 2011
  15. Sep 2, 2011 #14

    xts

    User Avatar

    @Demystifier:
    I think you think in terms of 'objective reality', where MWI must be thought of in somewhat solipsistic way.

    Conclusion are not reliable for others. Even if you meet a guy, who already survived 1000 russian roulette attempts, you'll probably (as a honest experimentalist, but cruel man) ask him to repeat it 10 times more. Then you'll probably (1023/1024) go to his funeral being convinced, that the guy was mortal. But the guy is still alive in this small branch, pretty sure that if he survived 1010 attempts, he must be immortal. If he is not quite convinced yet - he'll make another 1000 attempts. For him - he is immortal.

    Stanisław Lem wrote a story (one of "Cyberiad" series) about 'probability amplifier' - bringing even very unlikely events to reality (dragons still occured more often than fairies, as just dragons are a bit more probable). In Single World we have no way to build such "probability amplifier". In Many Worlds the suicide experiment is the only available: it filters out all those worlds, where you are not conscious, so you may purposely construct very unprobable scenario (but the only you may survive) and find yourself at its end, encountering dragons and other phenomena you may explain only as miracles. Thus: miracles proves MWI (unless someone prefers religious explanation). But in MWI it is you, who may create miracles - you don't have to rely od God's good will to organise them.

    The MWI of suicide experiment is as convincing, as explanation of happy life on Earth with the background of billions dead planets. It explains why something very unlikely to happen really happened.
     
    Last edited: Sep 2, 2011
  16. Sep 2, 2011 #15

    Demystifier

    User Avatar
    Science Advisor

    Not really. I think in terms of probability theory and biased observers, independent on quantum mechanics, objective reality, many worlds and solipsism. Please see my coin game in the previous post.
     
  17. Sep 2, 2011 #16

    xts

    User Avatar

    I fully agree with you in the following:
    1. your interpretation of the coin game - coin is not biased;
    2. full equivalence of 'quantum' and classical (revolver gun) suicide.

    But the point of QS experiment is not to show that your revolver is biased, nor that probabilities of the repetable experiments are not statistically verifiable. Its point is that you may design an experiment, whose result is a priori very unprobable, which may be extended and prolonged, but still giving subjectively more and more unprobable results.

    Mere existence of your consciousness in the world where something very unprobable happened, leads either to religious explanation (miracle - God's intervention), or to acceptance of Many Worlds. The difference between your coin experiment and MW-suicide is that even if you take all people on Earth the experiment will stop after about 1000 turns. In MW-suicide - you may continue it as long as you like, and you always get tails and tails, even as you are able to examine a coin and make test flips (which gives about 1/2 count of heads).

    In my view MWI (and suicide experiment) just exploit the paradox of infinity - every possibility mst be realized. In single world there is nobody who may say: I flipped coin 1,000,000 times and got all tails, while in MW you may become such person in one of 21,000,000 parallel worlds.
     
  18. Sep 2, 2011 #17

    Demystifier

    User Avatar
    Science Advisor

    If we accept that it is rational for the suicide guy to conclude from this experiment that MWI is probably true, then we have a paradox. The paradox is the fact that his neighbor witnessing all these unsuccessfull attempts of suicide will NOT interpret the same statistical data as evidence that MWI is probably true. How would you resolve this paradox (if not in my way by arguing that the suicide guy also should NOT conclude that MWI is probably true)?
     
  19. Sep 2, 2011 #18

    xts

    User Avatar

    Scenario: your colleague already survived 1000 shots, and you are not still convinced. So you ask him to make 10 more. Now we go to that 1/1024 world, in which you witness the guy is still alive. In this world you also saw a miracle. So you'll probably are convinced. If not - ask him to make another 20 atempts (would 106 narrowing of the margin convince you?). And again - take the world, where he survives. In this world you are now fully convinced that the miracle happened.
    The difference between your, and your colleague views is that your consciousness in vast majority of cases see his funeral, while he never sees that.
    So - in those rare small branches of many worlds, where you witness your colleague successfully playing russian roulette - you should also got convinced.

    But after the second additional test - your consciousness may get convinced with only 2-30 probability, while his - with 100%.
     
  20. Sep 2, 2011 #19

    Demystifier

    User Avatar
    Science Advisor

    No, that's totally wrong. Indeed, as indicated by the second item in the first post on this thread, the inventor of quantum suicide explicitly said the opposite. Even if the many-world interpretation is correct, it cannot offer an explanation for the colleague which would explain why the suicide guy always survives. It is still a very unprobable event for him. Hence, the colleague cannot conclude from such a result of this experiment that MWI is probably right (even if in fact it is). That's because the colleague, unlike the suicide guy, has not an a priori reason to believe that he will always be in the branch in which the suicide guy survives.
     
  21. Sep 2, 2011 #20

    xts

    User Avatar

    He may convince a collegue, if he allows him to plan the experiment.
    We may bet in less bloody way:
    You don't believe in God's intervention, so if 1,000,000 coin tosses show all tails, then you both believe we are in a so unprobable place, that only analogue of antropic principle may explain it. MWI is such analogue.
    If something like this happens (which is rather unlikely: 2-1,000,000) - you are both convinced.
    Now change the coin tossing to russian roulette. You (witness) are getting convinced again with probability 2-1,000,000. While your colleague gets convinced with 100% probability.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Critique of the quantum suicide experiment
  1. Quantum Suicide (Replies: 2)

  2. Quantum suicide (Replies: 5)

  3. Quantum suicide (Replies: 8)

Loading...