Talk:Quantum suicide and immortality

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[edit] This is not in Encyclopedia format!

So, I realize that everyone here thinks they are such good physicists that they need to argue their points forever, but allow me to point out how this is absolutely NOT in any kind of encyclopedia format. I mean seriously, it's like: Point Counter-Point Counter-Counter-Point. That is obvious on this discussion page, but the whole article needs to be re-edited to remove all the internal arguing, and made a lot more fluid. -----Tobias —Preceding unsigned comment added by 129.93.65.19 (talk) 20:01, 11 April 2008 (UTC)

[edit] One Small Problem

The fairly obvious problem that seems missing from this discussion is this: Quantum suicide experiment only leads to a possible Quantum Immortality in the set of universes in which the only form of death is suicide. And presumably, if you're in such a universe, you know it, so you never conduct this experiment except in unverses as we know them. In any of these universes, the experimenter will eventually die anyway, just not always from suicide. In fact, if the subject simply sits in front of that gun indefinitely, splitting off at every branch still both shot and not shot, he'll starve on the not-shot branch, eventually. Or end the experiment.

In my opinion that is neither obvious nor a problem. The interpretation is that a conscious observer will not cease to exist because there is, in all cases, a nonzero probability that he will continue to exist, and, if this interpretation is true, thus there is a universe in which he continues to exist. However, he only observes those universes in which he exists, so he will not die in his own frame of reference. The method of suicide is irrelevant - the experiment would work the same way with a physicist being sealed into a chamber with no food and drink for long enough to induce starvation. If there is a nonzero probability (which would seem to be the case with quantum mechanics) of something miraculous happening so that he can live another moment, that event occurs in his frame of reference, because his frame of reference includes only those possibilities that he observes. Others in alternate universes would, of course, see him die. In fact, this experiment is bound to happen to every single conscious being anyway. In your frame of reference, if this interpretation of the many-worlds interpretation is true, you will not cease to exist for as long as the probability of your continued existence is nonzero, even if very small. This might also mean that you could make a bar of gold materialize in your own frame of reference by programming a computer to attempt to kill you (in a way that you are much less likely to survive or succeed in reprogramming the computer than a bar of gold is likely to materialize in front of you) unless a bar of gold appears within a finite time interval. Right?
The gold bar idea is neat, but I don't think you can use suicide threats fulfill your wishes just yet. You will survive in the event that the gold bar fails to materialize, but you will also survive in the much more likely event that the computerized suicide machine fails. Since any kind of failure is much more likely than a gold bar materializing, you're also much more likely to be alive and disappointed.
"because there is, in all cases, a nonzero probability that he will continue to exist"
The preceding quote seems to make a fantastic assumption from my end (I'm not a physicist). What is there, in the non-statistical math and assumptions of physics, that predicates non-zero statistical probability in all cases, and are these equations supported empirically in all ways in the forms necessary to guarantee non-zero probability? (I would like the statistical calculations supported as derivatives of non-statistical calculations, if possible, though lack the knowledge of the quantum equations to know whether this is possible.) What are the boundaries of the potential states in which the person would continue to exist? --Formerly the IP-Address 24.22.227.53 (talk) 12:04, 24 May 2008 (UTC)
What's the probability a low-energy electron will spontaneously become a stable atom? Is conservation of mass and energy over extended periods of time superordinate to non-zero probabilities of quantum mechanics? --Formerly the IP-Address 24.22.227.53 (talk) 12:04, 24 May 2008 (UTC)

[edit] Max or Michael?

Is this Michael Tegmark or Max Tegmark?

It's definitely Max Tegmark, the cosmologist. -- Derek Ross 20:07 Nov 16, 2002 (UTC)

[edit] "Imposible to pruve"

I hope nobudy ever dus this experement, becuse it will be imposible to pruve... -- 24.207.69.51 04:52, 2 Mar 2004 (UTC)

yeah, me wants a bag of superstring-chews...yay! (Anon)

I think it can be proven -- see "It IS possible to convince others of your findings" further down on this page. -- Parsiferon 05:46, 12 October 2007 (UTC)

But of course, while it can be proven, it won't be proven in the VAST majority of all universes if it is correct, so it is about as safe to say that from our point of reference that it won't be proven as it is to say that entropy won't ever randomly stop. Tiak (talk) 13:44, 23 November 2007 (UTC)

[edit] Free will and God

Nonetheless, if this view is admissible, then it settles the age-old controversy among Christians over the "free-will/predestination" debate, as the many-worlds conjecture allows God to know the state of the entire system of his creation -- what is happening in *ALL* of the "many-worlds". It is only when a measurement is taken, and a choice point is traversed, that the non-god observer "colapses the wave function" and travels along the trajectory to a down-stream sub-tree of the many-worlds heirarchy. The probability associated with each different choice at such a choice-point is similar to the "heuristic values" computed by the heuristic functions used to decide how to expand the search tree in classical artificial intelligence programming. Thus we as humans perceive it as an evolutionary narural selection process, but only because we have no knowledge of what is happening in other parallel worlds associated with what Robert Frost calls "The Road not Taken".

I would think that if God exists and can observe and has observed everything, his act of observing would preclude the existence of many worlds as he would have, in effect, already collapsed the wave function. -Seth Mahoney 17:09, Jul 6, 2004 (UTC)
No, there isn't any actual wave function collapse in the M.W.I., just decoherence which can give the same appearance. Yet that doesn't reduce the brilliance of the original remark about "Free will and God". I think s/he is right that God (if real) could know everything (see all paths being taken) without reducing our impression that we control our choices.
BUT, on the other hand, the MWI itself seems to kill free will! It suggests that perhaps I both did and did not write this comment, and that I wrote it both agreeing and disagreeing with you.
Max Tegmark's paper, "THE INTERPRETATION OF QUANTUM MECHANICS: MANY WORLDS OR MANY WORDS?" includes these words:
"(Everett’s brilliant insight was that the MWI does explain why we perceive randomness even though the Schroedinger equation itself is competely causal. To avoid linguistic confusion, it is crucial that we distinguish between:
• the outside view of the world (the way a mathematical thinks of it, i.e., as an evolving wavefunction), and
• the inside view, the way it is perceived from the subjective frog perspective of an observer in it."
--Parsiferon 06:13, 12 October 2007 (UTC)

[edit] I don't buy it.

See my semi-rambling objections on the Talk:Quantum immortality. In particular, any suicide is a quantum suicide, so all you have to do for an experiment is try to kill yourself (NOT RECOMMENDED!); this is totally non-falsifiable because it cannot be observed, by definition; and it assumes that, at any wave-function collape point, the mind/consciousness/soul will usually choose the most likely point (at least I must conclude that from my subjective experience), except it will always choose one in which it continues to exist. And another thought I just had; the existence of Heaven (in which I do not believe), or any other mechanism by which the mind can outlive the body, would mean that "quantum suicide" would still be permanent, regardless of the soul's insitence on continuing to exist. So I'd recommend nobody who does believe in Heaven try this at home. (Note: I'd recommend that NOBODY try this at home. Just making a point.) Glenn Willen (Talk) [[]] 21:36, 4 Aug 2004 (UTC)

You're totally right. Any suicide would do. However, it is verifiable, though only subjectively. Simply commit suicide in a way that statistically cannot fail (though I'm not advocating suicide!) several times. If you continue to live after several run-throughs, it is likely that the idea conveyed here is true. However, we don't need to go that far. Its a thought experiment, like Schroedinger's cat, not an experiment intended to be carried out in real life. We can see that this is indeed the result of a many-worlds interpretation of quantum mechanics. If you think its ridiculous (which I believe is the point), you shouldn't believe in many-worlds. -Seth Mahoney 03:56, Aug 5, 2004 (UTC)
The experiment was dreamed up by a believer in many-worlds, as a mostly hypothetical way to prove many-worlds is correct. If anything, it should discourage people from attempting suicide, by suggesting that any attempt may always be unsuccessful, that the victim may always wind up conscious even if badly injured. -Parsiferon 08:37, 12 October 2007 (UTC)

[edit] Flipping Coins ain't Quantum Suicide

You don't even need to commit suicide, just flip a coin. If the many worlds theory is correct then there must exists a world where you can get 1000 consecutive heads in a row thus proving that the many worlds theory is correct. Pity you can't send the result to the other ((2^1000) - 1 ) other worlds. -- (Anon)

Negative. The consciousness-obliterating quality of (abrupt) suicide is fundamental to the Quantum suicide thought experiment. That is, measuring random events which do not have a substantial probability of destroying the observer's consciousness (or at least, the observer's continuity of consciousness, which opens a whole other bag of superstrings) will not provide any confirmation one way or the other with regard to the veracity of either the Many Worlds interpretation or of the Quantum Suicide/Quantum immortality theories. If you work through the scenario enough, you will start to see why consciousness-disruption is fundamental here. --Ryanaxp 16:26, Nov 18, 2004 (UTC)
I've thought through the scenario quite a bit, and I've never seen any reason why the death of the experimenter is at all relevant. The same experiment could be performed with instead of killing the experimenter when radiocative decay is detected, a light is turned on when radioactive decay is detected. In some universes, the experimenter will see the light turned on quickly, in other the experimenter will see it take longer to turn on, and in others, the experimenter will never see the light tun on. Each experimenter has no access to the consciousness of the experimenters in other universes. The experiment works the same way without death being involved. -- (Anon)
The reason for the death of the experimenter being relevant, is that it is impossible for the experimenter to be aware of being dead. The experiment with the light is completely different because the experimenter can see that the light is on or off depending on the outcome of the experiment. Likewise, if the experimenter is attempting to kill other people. But if the experimenter is attempting to kill herself, the experiment does not work the same way because only one outcome can be seen by the experimenter. -- Derek Ross | Talk 00:06, 19 October 2006 (UTC)
Only one outcome can be seen by the experimenter... No. Indeed he will be quite sure he is dying. And anyway, what if? How would not been able to see the bad outcome diferentiate "many worlds" from Copenhague? --euyyn 22:23, 3 February 2007 (UTC)
The experimenter isn't necessarily going to be aware that he's dying. For instance, if the gun is behind him where he can't see it, and the bullet is supersonic and sufficiently damaging, then it will destroy his brain before the sound even reaches his ears. In fact, because of the slow speed of nerve impulses (around 100 m/s, google it) the neurons will be destroyed before any abnormal impulses from the already dead ones can reach them.

This will quickly remove the experimenter's awareness in any universe where he is killed, so the only remaining ones will be the ones where he's alive, and that's the only way he can have any significant chance of being in them (if he's in the experiment long enough). In the Copenhagen interpretation, there is only one world, and he's almost certainly not going to survive. That's the difference.

Still, we can never observe the difference between the two, since all we'll see is a dead physicist regardless: only the subject willing to do this and risk death can know the truth. I'd only recommend trying this experiment if you actually want to die... NVAFDiscoStu 05:43, 24 April 2007 (UTC)

[edit] I'm not sure the quantum suicide experiment makes any sense

While I agree one cannot experience anything once one has ceased to exist, does it really make this experiment work? What if not experiencing anything is a null experience, which, while it isn't an experience in the normal sense, is still fundamentally a valid experience. Why would a mind magically evade the null experience? --Lakefall 21:59, 10 Apr 2005 (UTC)

I suppose the answer to your thought experiment (and supposition of a null experience) lies in the nature of consciousness, and is likely an unresolved question. I think this also has to do with the "individuality" of consciousnesses--that is, what exactly separates your consciousness from mine? Why isn't there only a single "overconsciousness" that experiences everything in the universe? If consciousnesses were not "unique" or "distinguishable" in such a way as to permit you and I to have our respective private consciousnesses, then I think the possibility of a "null experience" would be important.
Of course this is moot if the solipsists are correct, and only my own consciousness truly exists :).
Assuming there are more than one "unique" consciousnesses in the universe, that implies to me that there is an important distinction between experience and non-experience, such that the "null experience" you suggested would be sufficiently separate and distinct from "actual experience" which consciousnesses undergo.
Of course, some non-dispositive evidence might be gleaned from our experience of sleep: as for me at least, the timeline of my memory spans only the moments I was undergoing mental experiences, of either the fully conscious or sub-conscious (dreaming) varieties. Our mental timeline mimics a continuous series, and elides any moments of true non-experience as if it had never happened, regardless of how much actual time elapsed (for example, in the stage after dozing off but before the onset of dreaming; or during true unconsciousness such as from a head injury).
Another way to analogize the continuity of consciousness is to think of putting a PC into hibernation mode. When you tell your operating system to put the computer to hibernation, the "state information" of the PC is stored to non-volatile storage and the fictional "running consciousness" of the PC ceases for the duration of the sleep. Once you "wake" the PC back from sleep mode, the "state information" is restored and the PC resumes running as though it never had been halted (at least in old versions of Windows 98, I remember that the clock of a recently-awakened PC would reflect time as though no shutdown had occured, for example). If you imagine a human consciousness as similar to the running PC, you can see that both the PC and human consciousness would have "experienced" only the time periods of "running," despite the fact that eons might have elapsed between the time of hibernation and the awakening.
--Ryanaxp 05:30, Apr 11, 2005 (UTC)
"I suppose the answer to your thought experiment (and supposition of a null experience) lies in the nature of consciousness, and is likely an unresolved question."
If it is indeed an unresolved question, then the thought experiment described in the article is based on an assumption, which may be incorrect. That was my point.
"there is an important distinction between experience and non-experience, such that the "null experience" you suggested would be sufficiently separate and distinct from "actual experience" which consciousnesses undergo"
I don't agree with "sufficiently" in this case. Is zero a number? Have you ever seen zero apples? Let's say you have five apples and you eat them all whole. How many apples do you have left? The answer is one or more, because you got into an alternate universe where you didn't eat all the apples in the first place, because having any number apples is definitely separate and distinct from not having any apples. Wait, I think that's a wrong answer. So, is zero a number? It doesn't matter. Whether we call it a number or not, you can still have zero apples. I bet you are carrying them right now. ;-)
"If you imagine a human consciousness as similar to the running PC, you can see that both the PC and human consciousness would have "experienced" only the time periods of "running," despite the fact that eons might have elapsed between the time of hibernation and the awakening."
The "null experience" I was referring to is an experience in the same sense a pile of zero apples is a pile of apples. A pile of zero apples doesn't have any apples in it and you can't even locate it, because it's not there. The time periods of not running describe the null experience pretty well. Saying the null experience is not an experience and therefore cannot occur is the same as saying a pile of zero apples does not exist and therefore I will always have at least one apple.
However IMO there *can* be a null experience as opposed to no experience at all. For example, in deep (dreamless) sleep you have no experience at all (you're not even aware that time is passing). Instead, if you are fully awake lying in a totally dark, totally silent room you are a good approx of a null experience, that is you have few external perceptions, but you'll still be aware that you exist, that time is passing etc... In principle afterlife could well be something like that. (notice that in the real-life example you will still have perceptions from inside your body but out of your mind, eg your breath, your heart beating etc., but it's meant to be just an approx.) --Army1987 19:39, 16 Jun 2005 (UTC)
I disagree. If you are fully awake lying in a totally dark, totally silent room you are still experiencing (in addition to gravity and feeling the floor) your own thoughts. Also seeing darkness is not necessarily the same thing as not seeing anything as your brain is still probably receiving some kind of signal from your eyes. BTW, if we'll do the experiment you are suggesting right, you'll be hallucinating in a relatively short time as the human brain doesn't handle total lack of input (while awake, at least) very gracefully. So you may end up experiencing quite a lot. There have been experiments where the subjects senses have been bloked nearly completely (they were floating in water etc.), but I don't know what these experiments are called in English and can't find anything about them with googling. --Lakefall 16:05, 15 July 2005 (UTC)
This is called sensory deprivation. I'd link the appropriate wiki page but unfortunately it is of extremely poor quality. JGW 15:19, 5 August 2005 (CET)
That was supposed to be an example. (As for the thoughts, they could be included into the etc. of "you'll still be aware that you exist, that time is passing etc..." above.) In the afterlife you don't have a brain like the one you have now, then it's not sure you'd get hallucinations. It's quite possible that, in the afterlife, you experience total lack of input and yet stay conscious. However, my aim was to show the difference between an empty experience and no experience at all, and it seems you understood it (when you pointed out the difference between seeing darkness and seeing nothing at all), the concept I mean is quite similar.--Army1987 20:53, 19 July 2005 (UTC)
In fact I think a mind is a second class citizen in a quantum mechanical sense, because it is not physical in the same sense software is not physical. Some people seem to assume the "observer" in quantum mechanics is a mind. It is not. I think a mind cannot be an observer in that sense, because it isn't a physical entity. If this is correct, I think it completely invalidates the thought experiment described in this article.
--Lakefall 19:41, 12 Apr 2005 (UTC)

There is another flaw in this thought experiment. Whether there are multiple universes or not, this experiment cannot fail! If we assume a mind is a valid observer in quantum mechanical sense and the only observer in this case, it doesn't in any case measure a negative result even if there is only one universe. That is because the mind ceases to exist before it gets any result. It's like measuring something with a device, which can only return true or blow up. Either you get a positive result or a null result. Negative result is not possible. --Lakefall 19:41, 12 Apr 2005 (UTC)

This point of mine souds kind of stupid as read it now. What I meant was that as you cannot ever find out you failed, the idea behind the quantum suicide experiment isn't falsifiable and thus isn't scientific from anyone's point of view. --Lakefall 16:05, 15 July 2005 (UTC)

[edit] Individuality is the fallacy underlying this paradox

I believe that questioning the individuality of consciousness is indeed the solution to this paradox. If you enforce individuality rigorously, no one is the same as they were a minute or an hour ago, let alone over the course of years as most of the atoms in their body are exchanged for new ones. So quantum immortality would dictate that each moment's "self" should verge into a parallel universe where nothing ever changes; our memories of a past are just an illusion. I'd say the opposite - in the suicide-universe consciousness continues, so does it matter "whose"? There is just a change in the conformation of matter and memory between moments, as usual.

A curious corollary concerns the fate of the universe as entropy increases. If the universe is torn apart to widely separated cold atoms, as many physicists predict, there is no material seat for conscious thought; yet the quantum immortality paradox dictates that the only relevant possibilities are those that can be experienced. This demands either that the second law of thermodynamics must fail in the future, or else that consciousness can continue to exist in an essentially "empty" universe. In this way the Universe can be perceived as a scientific experiment that is actually capable of proving the existence of God (or spirits, etc) ... though not, of course, to a non-supernatural conscious observer! Well, either that or you decide that if the universe tore apart and there was nobody there to see it, it never really happened.

(The problem with our comments, alas, is that they are somewhere past the far side of "original research", so some corroborating source has to be dug up before we can decorate the article with them) 70.15.116.59 (talk) 19:19, 10 December 2007 (UTC)

[edit] Edits by 80.14.70.148 on April 29, 2005

80.14.70.148 wrote:

However in this theory you have to suppose that the phusicist's observing mind will allways end up in the world in which he is alive, and therefore you are supposing that the physicist cannot die which makes the whole experiment pointless since you are supposing your result is correct.

I removed this text foremost because the above-written assertion is demonstrably not the case, and also because it is not appropriately placed or phrased. For one thing, the experiment does not assume that the physicist's observing mind ends up in a world in which he is alive—in fact, the fact that this is not assumed is what makes the Quantum suicide experiment an experiment in the first place. Of course, the experimenter who attempts such an experiment at all is taking the risk that, indeed, his consciousness may well cease to exist in any world (or that in fact there is only one "stream" of reality, thus falsifying the Many-worlds interpretation). — Ryanaxp 17:16, Apr 29, 2005 (UTC)

And how exactly could the experimenter discern if there is only one "stream" of reality or not? I agree with the anonymous editor that the experiment is a sillyness, although it's not up to us to point it in the article... --euyyn 22:30, 3 February 2007 (UTC)

[edit] It seems a bit wrong to me

I don't know much about QM or it's interpretations, but this description sounds a bit wrong to me. Whether the gun fires or not is not the direct cause of death/life. Even if the gun fires - you will still live untill the bullet reaches your brain and does whatever causes you to die. There is no reason you should be experiencing only what happened when the gun didn't fire (because not firing is not what REALLY makes you stay alive). This thought experiment should focus on the final and direct cause for completely loosing consciousness, and perhaps when the bullet reaches a certain stage (and the person is still not dead) there isn't any probability left that it won't kill him, meaning he will die anyway.

Well, firstly, what a lawyer might call the proximate cause of death is the gunshot. All we need to do is assume that there is zero probability that the gun, if triggered, will fail to fire; zero probability the bullet will miss, and zero probability that the bullet will fail to cause fatal damage. If the gun fires, the physicist dies. If the gun does not fire, the physicist lives. With those assumptions in place (and with a high-quality, well-maintained weapon and a suitable aimpoint, they're not at all out of kilter with reality), the experiment leaves us solely with the probability involved in whether or not the weapon will be triggered. As I understand it, hypothetically speaking, when a probability collapses, or branches, or whatever, it takes with it everything that's inconsistent with the remaining branch - so the surviving physicist wouldn't remember seeing the gun fire, wouldn't remember feeling the bullet touch their head, and that's assuming that the the human nervous system would have had chance to register these things in the fractions of a second involved anyway.
If, for whatever reason, there is no circumstance in which the experiment will not kill the physicist, then there is no probability that s/he will not die, and the experiment is therefore moot, because there will be no branching alternative world in which s/he lives. But in that case, the experiment becomes meaningless just as Schrodinger's Cat would become meaningless if there is no probability that the cat can live.
The big problem with this experiment in 'real' terms is that there is no circumstance in which it can be tested. The physicist will sense no 'shift'; no discontinuity - the one who ends up in the world where s/he lived cannot report anything other than that the weapon did not fire. The others cannot report anything at all. If the experiment is repeated a thousand times, the physicist remaining alive in their own universe will probably be credited by colleagues as the luckiest person in history - and perhaps after a time, THEY will be able to conclude that this is what is probably happening. But each success would leave one dead physicist and a set of bereft colleagues and friends and family, and it would thoroughly unethical to allow a thousand people (albeit technically the same person) to die just so that one remaining iteration in some distant universe can conclude that there might be something in it after all. - Shrivenzale 11:09, 13 July 2007 (UTC)
Actually there may be plenty of volunteers: anyone who is going to die soon anyway who has a burning interest in this central question of physics. Some of these individuals might even give part of their life savings to fund the experiment. A more pleasant means of execution would be used if possible. After the experiment, the surviving volunteer(s) could be rewarded in some way. Before anyone considers actually doing this, though, nonlethal variants of the experiment should be considered: not everyone agrees that lethality is required to get the answer. Also the entire idea of the experiment should be reviewed more carefully: not everyone agrees that "the answer" would be meaningful or even possible to obtain. To avoid ever having to repeat the experiment in the world(s) where a volunteer winds up alive or even dead but with significant results, the experiment should be structured to provide everyone compelling evidence of what happened. (See "It IS possible to convince others of your findings", below, for proposals on how to do that.) -Parsiferon 19:15, 12 October 2007 (UTC)
It's pedagogical, there's no need to nit-pick. The model is simple: if the gun fires, the physicist dies instantly. If it does not fire, he lives. A simple model lends itself to simple analysis. There's no need to get into the messy specifics of what constitutes consciousness and what causes it to end. In this model, consciousness is simply the thing that allows a measurement to be made. -- Tim Starling 02:05, July 22, 2005 (UTC)
But then it simply ignores reality. A physical model has no value if its presumptions do not correspond with what happens in real life. "Gun fires = you die" is a model which simply isn't true. How can you hope to learn something about reality if you use a fallacious model?
Well, that is the inherent limitation of all thought-experiments: they are always in danger of losing touch with a reality of physics, whether because the thought-experimenter never learned or forgot a particular physical rule, or erroneously applies it, or there is some yet-undiscovered law that the experiment violates, or what have you. This is a danger that plagues many such disciplines, such as the construction of rigorous mathematical proofs, yet which does not remove all value from them—recall, for example, that Einstein discovered and then communicated the theory of general relativity through use of thought-experiments.

In this case, feel free to substitute any appropriate device for the gun—for example, it may be appropriate to simplify the experiment to the black box level by stating that there is a simple, instantaneous on/off switch for the experimenter's consciousness. It bears mentioning that of course any results from such a though experiment bear the risk of running counter to physical reality, which may be significant (or may indeed be a fundamental property of consciousness— that it is necessarily continuous in the mathematical sense by nature and simply cannot be instantaneously switched on or turned off). However, maybe valid exploration of the implications of this theory can be made even if the rules of physics are "bent"; then again, maybe not. That's the beauty of philosophy and metaphysics, eh? heh. —Ryanaxp 17:41, July 22, 2005 (UTC)

The original poster wrote:

This thought experiment should focus on the final and direct cause for completely loosing consciousness, and perhaps when the bullet reaches a certain stage (and the person is still not dead) there isn't any probability left that it won't kill him, meaning he will die anyway.

The portion I emphasized in your quote leads to the crux of the Quantum Suicide exercise: According to the theory of Quantum Electrodynamics, there is never a scenario in which something has exactly zero probability. A particular future event might have a vanishingly infinitesimal probability of occurring—say, odds of one in a googleplex, for example—but that probability still is non-zero. Therefore, if the many-worlds interpretation of QED is accurate, then there is always some universe in which even that incredibly unlikely event occurs. That is the powerful and sobering (not to mention seemingly absurd) implication of the many-worlds interpretation of QED.

You're implying that the Copenhaguen interpretation is false in assigning to that event a non-zero probability. In your view, the wave function, except for many-worlds, is cut abruptly to zero when its modulus squared becomes "incredibly" small, so in Copenhague "incredibly unlikely" events do never happen. And exactly when is then an event incredibly unlikely? 0.0001? 10^-1000? 5*10^-1001?
If you get an incredibly unlikely result, it could be because you are in a fortunate universe as well as because you are fortunate yourself. The first is many-worlds interpretation and the second is Copenhague's. I personally see no way to differentiate both with this experiment. --euyyn 22:46, 3 February 2007 (UTC)

So, for instance, while it is extraordinarily improbable that a bar of pure gold will materialize out of empty space and drop onto my desk—nonetheless if in fact MW is correct, then in some universe I'll be celebrating my newfound wealth. By the same token, while it's very unlikely that a bullet could liquify 99% of the Quantum Suicide experimenter's brain and yet he still survive (to make it even more far-fetched, let's say with full consciousness and no permanent effects), nevertheless this thought-experiment asserts that at least in some universe(s) the experimenter does in fact live, and that his "awareness of being" will of course continue only in those universes. —Ryanaxp 17:29, July 22, 2005 (UTC)

Replace the gun with an atomic bomb. The bomb is right next to the physicist and if one of the radioactive atoms decay, the physicist dies. But, in an alternate world(s) the physicist still lives and doesn't experience death. So the physicist never dies in one scenario or another, but the physcist also ends up dying in other scenarios. How many times he/she dies depends on the probability of the atom decaying. So if there is a 50-50 chance the scientist will die in half of the worlds and live in another half. In this case you cannot say that the physicist won't die because if an atoic bomb explodes let's say 2 feet from a person the chance of death is 99.999%.

[edit] what about death

Doesn't this idea assume that death is the end of conciousness?

I don't think that is relevant. The split will supposedly still occur and you will live on in one universe. In the universe that you die in you may end up in heaven watering pot plants and talking to God however. It does raise the interesting point as to weather Consciousness (or should I say: Sentience) is 'special' or purely just a bi-product of the brain.

The experiment does assume death is the end of consciousness. If your consciousness doesn't permanently end but you end up in Heaven, then you will with high probability find yourself in Heaven after a few rounds, whether Many Worlds is true or not. Spgrk 09:20, 10 June 2007 (UTC)

[edit] Not a categorical proof?

I do not see how this is a categorical proof of multiple universes.

Say, during the first round the observer survives. Now there are two possibilites:

1> He/she is dead in an alternate universe. 2> He/she survived, as the probability of survival was 1/2.

Now, after the second round the two above statements would still hold true except that the probability would change to 1/4. We can continue almost* ad infinitum. So, my question is, how does the survivor know which of the two cases it is? The notion that he/she will EVENTUALLY die is disturbing. After any given number of finite rounds, there exists a probability of >0 that the observer would survive(in a Copenhagen world). It does get highly improbable, but it is possible. So, in my opinion the observer can never say with surity whether he/she has survived by luck or is he/she living in an alternate universe and dead in several others. Hence, it is not a categorical proof.

  • I am not considering the case where there are infinite rounds, in which case the observer would indeed die as the probability of survival would be (1/2)^infinity = 0. The reason being that the observer would die of natural causes before that.

Another question I have is how many universes is the original universe split into? if the chance is 1/2, is it split into 2 unvierses? or 4 with 2 universes having similar outcomes? Which raises the question that how does the alternate universe thing works for irrational probabilities?

L'Umais 14:41, 14 March 2006 (UTC)

I agree with you that the experiment is bullshit. About the number of split universes, I believe the interpretation says it doesn't depend on probability, but on the number of possible outcomes, that is, the number of different states the measure can bring. So the probability of ending in each universe is what varies. But then this raises another issue when the set of possible outcomes isn't discrete but continuous (as position, momentum, energy when unbound, etc.). --euyyn 22:55, 3 February 2007 (UTC)
Personally I wouldn't have a problem with continuous splitting, but I don't think there are any truly continuous variables. Every measuring device has only a finite resolution, energy levels and momenta are always quantized by the size of the container (which can't be larger than the observable universe) etc etc. So the splitting is always a discrete process. Another way to think about it is to note that delta-Entropy = k ln (Omega), so that an infinite or continuous splitting implies infinite entropy release (which implies infinite energy), which is unphysical.--Michael C. Price talk 10:32, 24 October 2007 (UTC)

You've touched on something i was looking for comment on. Does the universe have a concept of reduced fractions? If there was a 2/3 chance of the gun firing, are 2 universes created in which the gun fires and one where the gun does not? Is there one full universe created where the gun fires and another incomplete, half universe created that limps along through time? Just something I think could be worth touching on.—Preceding unsigned comment added by [[User:{{{1}}}|{{{1}}}]] ([[User talk:{{{1}}}|talk]] • [[Special:Contributions/{{{1}}}|contribs]])

[edit] Mention the Anthropic principle

http://en.wikipedia.org/wiki/Anthropic_principle

The anthropic principle is necessary for this experiment.

[edit] Not just 'proof' to the subject.

I'm assuming that the MWI isn't a load of sh1t to start with.

But, the way I see it, this experiment isn't just 'proof' to the subject, but to an increasing number of Universes of observers to the experiment along the way.

To be brief, if the guy pulls the trigger 1000 times in a row and then stops, the observers in the Universe he ends up in will verify that he did indeed pull the trigger 1000 times in a row and not die. Naturally there will be all manner of Universes along the way (like the one just prior) where the observers saw him pull the trigger 999 times and then die on the 1000th. And such like. With each pull of the trigger there will be an increasing number of universes who are now very sure that MWI is correct.

Which then brings me back to 'proof'. Perhaps 10 pulls would be enough proof to the subject or the observer. Or maybe it would take a 100 or 1000 or a million or so to do it. etc etc.

[edit] ============
1000 consecutive suicide failures shouldn't be proof of anything at all to any observer, if (s)he truly believes that the probability of getting 1000 heads in a row is non-zero. And it is. So believe it. No proof needed of that. Anyways, I believes it.
I don't see how anyone could ever perform this experiment and survive enough times to prove anything at all to anyone. And no human would be able to observe an infinite number of runs of the experiment. It seems to me that the focus of "proof" is on the wrong point. We don't need to prove the fact that there is a nonzero probability of getting one googolplex tails in a row. But what does need proof - and what seems unproveable - is that there are two or more distinct semi-parallel universes. Luckibrian 03:40, 14 October 2007 (UTC)

[edit] Moravec+Machal citations?

Could someone provide cites for the Moravec and Machal articles? I can't find anything which fits the bill and am wondering if it's a bit of a stretch to say these people published something regarding this subject. Thanks, 68.147.56.203 05:45, 8 September 2006 (UTC)


[edit] No benefit to the physicist?

There is currently a paragraph that reads

Even if the many-worlds interpretation is correct, the measure (given in MWI by the squared norm of the wavefunction) of the surviving copies of the physicist will decrease by 50% with each run of the experiment. This is equivalent to a single-world situation in which one starts off with many copies of the physicist, and the number of surviving copies is decreased by 50% with each run. Therefore, the quantum nature of the experiment provides no benefit to the physicist; in terms of his life expectancy or rational decision making, or even in terms of his trying to decide whether the many-worlds interpretation is correct, the many-worlds interpretation gives results that are the same as that of a single-world interpretation.

but I do not see how the sentences before the "Therefore" justify the sentences after it. For instance, if MWI were true wouldn't it be quite valuable for the physicist to buy an annuity that paid her an inflation-adjusted value for as long as she lived? Sure, in the average universe the life insurance company would not lose big time and, sure her heirs might be pissed about how much she is spending on an annuity of dubious value -- but wouldn't a selfish physicist win big time in the universes she cared about? Quantling 21:19, 8 January 2007 (UTC)

Nobody assures you that you will be there to enjoy it. You perhaps (well, almost certainly) will end dead (that is, in one of the universes in which you die). So it is the same that doing it assuming there's no many-worlds: If you're extremely lucky, you'll benefit. I don't recommend to try it. --euyyn 23:01, 3 February 2007 (UTC)
The annuity concept seems valid. The experimenter gambles at very high stakes, risking her life, to learn whether the MWI is true. If she lives, she buys the annuity, reading the fine print carefully to be sure no maximum amount of money paid, or time lived, is specified. However, another reasonable approach exists: if you already believe in MWI, buy an annuity -- probably a smaller one -- and skip the experiment. For each year you live, invest any excess income into growing the annuity or to buy more annuities. This way you hedge your bet and have as long a life as possible. Albeit, if you were wrong, you have less spending money in the near term. -Parsiferon 20:39, 12 October 2007 (UTC)

[edit] Article was overly biased.

I found the quantum suicide article extremely biased against the thought experiment. It was overly dismissive to the pro point of view and gave the impression the issue was settled when in fact this is far from the case. I have edited it to give a less biased and more accurate picture of the debate. Jared333 03:56, 13 January 2007 (UTC)

[edit] This thought experiment is completely invalid

When physicists uses the word "observed", we don't mean, "seen with human eyes". The gun indicates the state of the system, therefore it is observed. In fact, if any kind of signal that can be seen outside the box is triggered by something inside the box, the system inside the box is being observed. Schrödinger's cat is a bit misleading because it attempts to describe the subatomic with a macroscopic system. I'm sorry, but this thought experiment is completely invalid, not because of anything remotely philosophical, but because one of it's basic assumptions is false. That being that the mechanics of the described system are statistical in nature. DarkEther 07:57, 8 February 2007 (UTC)

[edit] No it isn't

When physicists uses the word "observed", we don't mean, "seen with human eyes". The gun indicates the state of the system, therefore it is observed.

I think you are mixing observation with measurement.

Firstly, observation is a psychological function, a function of awareness. We observe what our measurment apparatus tell us. Indeed, measuring apparatus are sufficient to eradicate superpositions from our observations, but it takes an observation to see that the measurement has indeed done this.

Secondly, while this distinction makes almost no practical difference to the typical work of a quantum physicist, the Quantum Suicide experiment is designed precisely to highlight it.

Lastly, by saying we can simply see things from the point of view of the gun itself, you seem to have missed the point: We haven't asked what the gun sees, or what any surrounding human observers will see. That is given in the setup, there is a probability amplitude of -(square root of 2i) that other observers will see the you die, leading to a 50/50 chance if there is one world and a world with a live and world with a dead experimenter if the many worlds is true.

The point of the experiment is to ask what the experimenter sees, not what the gun or other observers see. That experimenter cannot possibly see themselves dead, therefore they always perceive themselves as alive. And without any negative ramifications either.

You seem to think the experiment is saying that everyone else will not see them die either. That is not what the experiement says.

Anyway, I got rid of your "This is false" statement since it lacked a neutral position, but I left in your argument, and presented a counter argument.

Jared333

[edit] this wouldn't work

As others have pointed out, the crux is the lack of any instantaneous way of causing death. If you could cease to exist in the timespan of a quantum decision, then perhaps. But instead you're going to fire the gun and for an exceedingly brief time feel the bullet rip through your skull and brain until consciousness finally ceases

Two problems that arise from this:

  • you wouldn't find yourself in a universe where the gun didn't fire, you'd find yourself in one where you lived through the ordeal with devastating(as near to death as one can get) brain damage
  • I don't believe that simply because every quantum event has a non-zero probability, that universes in which anything can happen will exist. Seems likely to be like other forms of "natural selection" - universes in which bizarre improbable things occur will wind up self-destructing due to instability. and many complex/nonsensical events will in fact not be possible - there will be no universe in which christopher columbus simply materializes beside me right now. One could imagine a universe that "forked" a long time ago and is now quite different than our own, in which Columbus is still alive. But in our universe, right at this moment, there's a "can't get there from here" problem ~ 64.80.192.218 10:23, 14 July 2007 (UTC)

[edit] Random element within the box

I have not read that Schrödinger nor any one else considers a random element within the closed box as a part of the equation. The cat has by now; (out of curiosity) opened the bottle, in all the many worlds. JohnTDanaPoint

[edit] It IS possible to convince others of your findings

Tegmark's original paper presenting the quantum suicide (QS) experiment concludes with this sentence:

Perhaps the greatest irony of quantum mechanics is that if the MWI is correct, then the situation is quite analogous if once you feel ready to die, you repeatedly attempt quantum suicide: you will experimentally convince yourself that the MWI is correct, but you can never convince anyone else!

Perhaps as a result, it is often written that the experimenter can only convince herself. But I disagree, with good cause:

(1) If I ever see you step out of one of my thousands of QS boxes (which now occupy the tunnels originally excavated for the Superconducting Supercollider, by the way), I will be very impressed. After you tell me your story, I will be even more impressed. Then I will watch and listen to the videotape from the tamper-proof recording device that was in there with you. I will hear click after click, with occasional bangs when you moved your head out of the way of the gun to test the device. By counting the clicks while your head was in place, I can convince myself of the validity of your claim.

(2) Even if you arrive in my world dead, the recording device will show us the sequence of events you experienced. If it is sufficiently long (a total of N events), then from a statistical viewpoint I will be just as impressed as if you stepped out of the box alive after N-1 events. Thus, the common assumption that only one world can get an answer is not at all correct.

(3) If you step out of a QS box after an hour, smiling and relaxed, all ready to collect your $10,000,000.00 prize, and I know you have no major psychological issues, I can ask you whether you'd be willing to step back in for another hour, to earn an extra $1000.00 bonus. If you agree and get back in, I am highly persuaded that you have become convinced that you will always remember surviving. Of course a moment later you will most likely be fatally wounded as far as my morticians can see, but that was to be expected and it doesn't reduce my belief that you are still alive elsewhere. In fact, I am then happier than ever because I know that not I, but another I, must pay you all that money. --Parsiferon 05:26, 12 October 2007 (UTC)

With trepidation, I will mention that the presence of a recording device may permit the subject to be an animal (a dying one which for its own comfort* is to be euthanized soon regardless). Can an animal be considered an observer on par with a human? Can a non-conscious machine be the subject instead of a living creature? How about just a recording device which will be "fatally" damaged if hit by a bullet? What's really needed (as usual) is to clarify what an observer is and does.
And that's interesting because in the MWI an observer does not actually cause wavefunction collapse. Perhaps, therefore, the experiment does not need a conscious entity in the box at all.
*(The whole concept of euthanasia must be rethought if the experiment works.) --Parsiferon 02:39, 13 October 2007 (UTC)
Sorry, but this doesn't make sense. The odds of the experimenter surviving, from your point of view, are the same as the odds of anyone surviving a gunshot. A Schroedinger's Cat style box is (a) not available on the open market and (b) only works until you open it, at which point there's no sign it ever did anything special. 70.15.116.59 (talk) 19:24, 10 December 2007 (UTC)

[edit] But What Am "I"?

Just imagine all of the possible universes in your past in which you made a different decision and would still be alive and well today (although in different universes). The "you" that exists now is just one of infinitely possible copies of "you". The "me" that is typing right now shares exactly the same history and continuity with the "me" that isn't typing this. At the same time, if it were ever possible for both copies to confront one another, I would not be able to get inside the head of my alternate self any more than I'd be able to get inside the head of any other being sharing a seperate existance in my reality (though my "double" would be a little more predictable).

So, if I were to perform this experiment, why is it assured that the "I" that I think I am every morning when I wake up has priority over the other copies of me who wake up to a different morning? If the odds in the experiment are against me surviving, isn't it likely that "my" conscious existance, which is only one of many copies, would cease to exist forever, while the survivors would be my copies? It's the same hesitation I have to "mind uploading"... If you transfer my consciousness to a machine while keeping the original human "me" alive, there will be two of me in one universe. For all intents and purposes, the robot "me" would be every bit as "me" as the human, though each has its own seperate existance. That's not exactly comforting... --166.66.106.50 15:59, 24 October 2007 (UTC)

It is best to consider these questions from an operational or empirical POV, otherwise they become purely metaphysical or meaningless (to use Ayerian language). No experiment can ever demonstrate whether you "really" survive an uploading; hence it is a meaningless question. --Michael C. Price talk 18:24, 24 October 2007 (UTC)
But of course I disagree. First, upload me (please). But do it at least twice: faithfully copy everything to at least one other region of computer memory. Allow each copy to access the feelings and memories and senses and experiences of the others. Or allow the original organic brain (if not destroyed) to access the computerized versions. It's a vacation into another mind. It's like the situation portrayed in "Being John Malkovich" except that you step into another consciousness, not just another body. Experience some new events and compare how all the copies react. So, do all the copies feel similar enough to believe they are equivalent? Yes? Great. Check back in a week and a month and a year, and compare again. Are the new, unique, diverging memories consistent with how I would have perceived and reacted to things my different minds have experienced? Yes, and as time proceeds my other selves feel increasingly foreign to me, as expected. I am satisfied that there really are several autonomous mes which normally are completely separate from myself. Parsiferon 16:14, 29 October 2007 (UTC)

[edit] It was Fred Hoyle's idea. (who knows who he stole it from)

Please read the contents of the page indicated by the following url, wherein will be revealed that already in 1964 had been conceived such ideas, whereof this article purports to account a history, omissions to which ought well be corrected. [1] —Preceding unsigned comment added by 81.153.90.137 (talk) 20:58, 5 November 2007 (UTC)

[edit] Question from a novice physicist

Right, if any event has a non-zero probability, and the universe lasts forever, surely it's possible my brain will pop out of the vacuum of space infinitely many times after my death and thus my consciousness will be allowed to continue indefinitely? Isn't this idea independent of whether you use the Copenhagen or M.W.I? Thanks for any info. AnCh —Preceding unsigned comment added by 159.134.233.151 (talk) 21:44, 4 December 2007 (UTC)

Maybe? I'm not a physicist at all but I think I get what your saying. This randomly appearning brain could even be occurring before your other body dies therefor creating a form of accidental time travel? Not sure if this fits with the idea of the thought experiment though. —Preceding unsigned comment added by 70.100.23.242 (talk) 00:21, 18 January 2008 (UTC)
A brain that pops out of a thermal soup due to thermal fluctuations is sometimes called a "Boltzmann Brain". It is discussed in some scientific publications, I read something on arxiv.org/hep-th yesterday by Don Page about this. It's hard to make it precise and quantitative, but there seems to be a paradox--- if this is possible, shouldn't there be many more Boltzmann brains over the lifetime of the universe than ordinary brains? Shouldn't most of these Boltzmann brains continue your current train of thought into a far-distant future when the whole rest of the universe is in thermal equilibrium? If so, shouldn't your expectation of the future be that in the next instant you find yourself in completely different surroundings, with everything around you turned into a particle gas at thermal equilibrium? This type of paradox makes it very difficult to do "world counting" in any intuitive way and decide how your consciousnesses is going to "go" based only on laws of physics. You need a certain amount of unpleasant philosophizing, full of the usual ambiguities about what consciousness "is" and so forth to get reasonable probability distributions. In particular, I think that the business of quantum immortality can only logically come after the whole problem of the continuity of consciousness is precisely specified and resolved. I don't know any logically positive way to even formulate the question, so maybe it's meaningless.Likebox (talk) 03:07, 18 January 2008 (UTC)

[edit] The Prestige

I doubt that "The Prestige" is relevant to this article - it simply involves creating duplicates with a non-destructive teleporter. If you think it is relevant you should also include the glorious old novella, "Rogue Moon", which used similar teleports over a longer distance. 70.15.116.59 (talk) 18:56, 10 December 2007 (UTC)

[edit] Nivven 1971 "All the Myriad Ways"

[2] the short story has all the basic ideas, the universe is split each time a decision is made, there are a myriad universes, anything that can, happens in one of them. etc. et.c —Preceding unsigned comment added by Vish (talk • contribs) 10:19, 16 January 2008 (UTC)

[edit] I would like to help out.

I would like to volenteer for this to see if it is true. Does anyone know who exactly I would contact for this? Thank you bye.71.245.198.34 (talk) 11:16, 6 March 2008 (UTC)

[edit] Not implied by all many-world theories

If you believe Robin Hanson's account of MW [3], the low-measure worlds are posited to fall apart due to interference from the high-measure world. If you do this experiment, the world in which you survive may turn out to be so low-measure as to disintegrate taking you with it. — ciphergoth 09:57, 27 April 2008 (UTC)