Talk:Quantum suicide and immortality/Archive 3

QM principles are incorrectly applied in this thought experiment
AFAIK it is incorrect to apply the unitarity principle of the QM wave function transition to the system consisting of a man and a gun. It is not and can never be an isolated system and the unitarity principle does not work on open systems. So this thought experiment is invalid.

--Dc987 (talk) 19:25, 11 September 2009 (UTC) We have always existed since our physical bodies are comprised of atoms and molecules that have been around since beginning of our universe. Likewise when our physical body dies the atoms and molecules eventually get rearranged. My thought on "dying" is that when loose all conciousness we probably revert back state of conciousness we were in before we were born, remember that? We don't know we died, we don't know we ever lived, maybe. If alt. universes pick up our conciousness, I don't know and the rest of us can never know. Based on probabilities as we know it none of us can ever "know" anything absolutely.74.107.171.137 (talk) 20:22, 4 July 2010 (UTC)terry lyon 7-04-10

Aren't we all in a Quantum Suicide experiment right now?
The thought experiment has the experimenter surviving a near-death experience in a box. But I'm surviving my very own near-death experience right now. I am alive, and that is always a near-death experience.

Let's say I have a heart attack and drop dead when I'm 80. But there's another one of me that won't have that experience and will keep on living. I keep living, and then I get hit by a truck when I'm 90. But another one of me won't. I get killed by my great grand kids at 100. Another one of me wont. The one me that keeps on living, will keep on living forever. I don't need a Schroedinger's cat box to show that this experiment is false - I won't go on living forever! And this would be true of everyone - that everyone keeps on living forever. —Preceding unsigned comment added by Jgroub (talk • contribs) 05:47, 21 May 2009 (UTC)

You seem to be implying that there is always a branch to take at every moment in which you survive. Surely, by the time you get old enough, you will have died of old age in all possible futures. --118.90.74.223 (talk) 10:11, 18 July 2009 (UTC)

I don't know a lot about aging, or about quantum mechanics, but, on a cellular level... well, an atomic level, with the atoms making up the cells... (or something like that), there must be some non-zero probability that the atoms in the cell will not decay (that's what atoms do, right?), and the cell will not die. Expand this to cover all cells in the body, and there must be some non-zero probability that the person to whom those cells belong to will not age, and thus will not die of old age. Which, when combined with the non-zero probability that they will not die in any other way, gives you an infinitesimal probability that this person is immortal. Possibly. Am I right, people who know the slightest thing about this stuff? PopeJaimie (talk) 13:26, 28 July 2009 (UTC)

Probably not, but you will be the oldest person on Earth and so will I, except at different realities.

Yes you are right..In some universe you will not age..In the many worlds interpretation, every possible outcome will be played out, even whether you will age or not..everything will always be played out

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)


 * Agreed, I was just going to add this point, but you said it for me. phocks (talk) 05:19, 9 December 2008 (UTC)

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.

But suicide isn't a cause of death. Death is always caused by destruction of the brain, stopping of the heart. Therefore suicide as used in the experiment is just a means to the end and irrelevant to the outcome. 67.160.174.24 (talk) 12:42, 19 August 2008 (UTC)


 * 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)

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)

"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)

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)

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)


 * We live in a universe that clearly permits the suicides of others. That fact is excused by saying the would-be suicidees are still alive from their perspective. But this assumes different rules for each observer, then goes on to assume each person constitutes one observer. That seems anthropocentric, and leaves me wondering: What, exactly, is an observer?  --208.48.56.50 (talk) 18:21, 6 November 2009 (UTC)

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)

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)

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)

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&mdash;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). &mdash; 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)

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&mdash;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&mdash;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&mdash; 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. &mdash;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&mdash;say, odds of one in a googleplex, for example&mdash;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&mdash;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. &mdash;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%.

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)


 * You have an equal probability, however, of finding yourself in Hell, Hades, Avalon, and other such places, and you might find yourself talking to Zeus, Brahma, Odin, or other deities. Both the conceivable destinations and the possible deities are infinite in number (and combinations of these deities cannot be ruled out, either), and thus your the odds against you experiencing any one of those outcomes is infinity to one. It is far more probable that the gun would fail to go off a billion times in a row, and when it did go off, you'd discover that you accidentally loaded it with blanks, or a helium tank would rupture and your 10-ton magnets would break, requiring almost a year to repair (oops, that's a different quantum immortality experiment). 71.72.235.91 (talk) 12:56, 18 January 2009 (UTC)

-Shouldn't it be "Quantum invincibility" rather than "immortality" to avoid confusion - the experiment described only makes the test-subject invulnerable to a gun bullet - they don't suddenly become a vampire that never dies as long as they are in the experiment (I suppose you could argue that in some universes events might come in to play that would somehow prevent a person's biological decay over time but I dont think thats the main argument of this article...) —Preceding unsigned comment added by 87.192.248.235 (talk) 16:36, 22 July 2009 (UTC)


 * Well, I think it might be, for example if you have a heart attack, these a chance it could kill you. So with this theory, the heart attack will kill you in one universe, but you'll live in another. ~ Michael 118.90.102.127 (talk) 04:10, 15 October 2010 (UTC)


 * Even if the chance of you getting shot is 1 in 1, you still could survive, the bullet could manage to go thru your body missing all vital areas for example. And of course, there could be universes in which you didn't participate in the experiment at all to start with. --TiagoTiago (talk) 03:20, 29 October 2011 (UTC)

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&#39;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: (talk • contribs)

There's 100% chance the gun will fire, and 100% chance that it will not. It actually happens in both worlds. —Preceding unsigned comment added by 76.4.86.178 (talk) 22:20, 15 February 2011 (UTC)

Mention the Anthropic principle
http://en.wikipedia.org/wiki/Anthropic_principle

The anthropic principle is necessary for this experiment.


 * Seconded. I came here to suggest that they are similar concepts. Should put Anthropic Principle as a "related link", or mention in the description that they are similar concepts and quantum immortality would invoke the Anthropic principle. Spur (talk) 13:40, 8 July 2017 (UTC)


 * Could you please elaborate how the anthropic principle has to be assumed for the experiment? R5IJwcw2 (talk) 16:00, 8 July 2017 (UTC)

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.

=
===========
 * 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)

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)

I've read some books related to the topic that develop it just as a possible scenario of the multiple interpretations of QM, and in one of them I find a reference of a Moravec's Essay about consciousness. Hope it helps.

http://www.frc.ri.cmu.edu/~hpm/project.archive/general.articles/1998/SimConEx.98.html

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)

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)

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)


 * Let it be. Disillusioned people will always find new ways of escaping death.


 * But the point is that death has nothing to do with it. You could replace being shot with a lobotomy, or being punched in the face, or a light turning on. It won't change the fact that this is a deterministic system.
 * DarkEther (talk) 01:36, 11 March 2010 (UTC)

-there is a nobel prize waiting for you if you can prove QM is deterministic. — Preceding unsigned comment added by 93.63.137.34 (talk) 19:41, 31 May 2011 (UTC)

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


 * In quantum mechanics, you can't mix up observation with measurement because they are the same thing. You're confused by an ambiguity in the English language.  The most important part of your quote of me is "When physicists uses . . . ".  This was meant to alleviate that ambiguity.  In retrospect, I could have done a better job.  From another wikipedia page: Observer_(special_relativity)
 * In quantum mechanics, "observation" is synonymous with quantum measurement and "observer" with a measurement apparatus and observable with what can be measured.
 * I hate to reference wiki to make an argument about wiki, but I'm tired.


 * DarkEther (talk) 01:13, 11 March 2010 (UTC)

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)

Unlikely (though not impossible) things happen in our universe as well. You would be surprised by the number of people who fail to kill themselves with a gun. I agree with you that death is a process and not a single moment though and we aren't sure of how much it takes for someone to be dead. If there is indeed a specific moment when someone stops being alive and this experiment is correct, there will always be a universe where the subject survives by halting near the brink of the abyss. And yes, you would most likely end up in bad shape. — Preceding unsigned comment added by 93.63.137.34 (talk) 19:51, 31 May 2011 (UTC)

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


 * Schrödinger said that the device to detect decay and kill/not kill the cat "must be secured against direct interference by the cat." (See the wiki on Schrödinger's thought experiment)--Jakebathman (talk) 04:45, 28 February 2009 (UTC)

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)

Wouldn't any statistical anomaly serve as proof that it is real then? Killing someone is just to take things to the extreme, there oughtta be an universe where someone will always get heads with the flip of any coin whatsoever that does have a heads side for example, that is the exact same thing as many-worlds immortality. --TiagoTiago (talk) 03:30, 29 October 2011 (UTC)

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)


 * From your point of view, there are no other yous, either you're still alive and can observe your own existence and therefore your survival, or you're not alive and isn't there to care about it. You, while still being you, are always the one that survives. --TiagoTiago (talk) 03:36, 29 October 2011 (UTC)

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. —Preceding unsigned comment added by 81.153.90.137 (talk) 20:58, 5 November 2007 (UTC)

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)


 * There is no paradox. There should not be more Boltzmann Brains than normal brains, but less - infinitely less, in fact: almost, but not quite zero probability. Imagine the old thought experiment of monkeys banging on typewriters. Given an infinite number of universes, one of those monkeys would type the complete works of Shakespeare. And there would be an infinite number of such copies. But not all infinities are the same size. There are an infinite number of integers, for example, but an even larger infinity of real numbers. If you selected a real number at random, the odds of picking an integer are virtually zero. So, if you could peek into other universes to see how the monkeys are doing, even though there would be an infinite number of copies of Shakespeare, you would never find a monkey who had written one. It's the same way with the Boltzmann Brains. There might be an infinite number of them in the multiverse, but they would be as rare or rarer than monkey-typed copies of Shakespeare.--RLent (talk) 21:27, 17 September 2010 (UTC)


 * Umm.. no. It is simply impossible to make a random selection from an infinite set, even with the axiom of choice. Or, put another way: The number of real numbers that can be expressed meaningfully is finite (assuming that all integers greater than the number of quanta in the universe cannot be meaningfully expressed); therefore the odds of a random real number having the quality: "Able to be expressed meaningfully" is zero. To disprove the quatam immortality question, you only need to find someone who tried to prove it to themselves and was killed, and who can tell you firsthand. Another way would be to have some kind of significance to the multiple worlds theory; postulating something that by definition cannot interact in any way at all with the observable universe isn't exactly science. Treedel (talk) 22:04, 4 November 2010 (UTC)


 * When you see others dieing, according to this theory, you just happen to not be in the universe where that person survived; millions of years from now, you could be the only remaining human still alive, it's possible that everyone that ever existed and will exist, will eventually each in their own universes be the last human. --TiagoTiago (talk) 03:41, 29 October 2011 (UTC)

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)
 * No, The Prestige is definitely relevant. It's almost exactly the same scenario. —Preceding unsigned comment added by 69.88.46.242 (talk) 00:18, 20 August 2008 (UTC)
 * It's not the same scenario at all. With quantum suicide, you're traveling from one universe to another in such a way there's only one you there at the same time. in The Prestige, two yous exist in the same universe, which is nothing like the concept of quantum suicide at all. --2003:EF:13C1:CE34:A02D:4BDC:F77F:7E48 (talk) 22:40, 13 October 2018 (UTC)

Larry Niven 1971 "All the Myriad Ways"
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)


 * That idea of choice splitting universes is just a simplification, at each plack tick (or perhaps even small than that) each universe split into as many universes as there are combinations of states of all subparticles and things like that that exist inside plus all that can pop into existence (virtual particles and things like that). --TiagoTiago (talk) 03:45, 29 October 2011 (UTC)

Not implied by all many-world theories
If you believe Robin Hanson's account of MW, 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. &mdash; ciphergoth 09:57, 27 April 2008 (UTC)

QS and QI as tautology?
Reading the article, the idea of Quantum Immorality sounds a lot like a tautology. Basically, being hooked up to a machine that will cause instant death, which here is assumed to be the cessation of consciousness, here assumed to be the ability to perceive. Then the situation becomes "as long as the device does not kill the experimenter then the experimenter will never experience his own death". This would come quite literally because no one could perceive their own death. In order to experience death, or perceive death, one would have to continue perception and experience after death. Under the presumption of an after-life (let's assume a Christian-like one, where your consciousness continues only elsewhere) then one would have the chance to experience and perceive their own death, however under this same assumption the experimenter would be capable in all worlds of experiencing the outcome of each event, until such time as he is transfered to the "elsewhere". As it has been so widely taught "cogito ergo sum", the metaphysics of reality is that the absolute skeptic cannot doubt that he exists. To doubt his existence is to prove his existence. The mere fact that we are able to think proves to each one of us individually of our existence. Such a definitive meta-physical statement cannot be said for anything, anything else at all (due to veil of perception). Thus, defining the end of our existence is simply "when we stop perceiving ourselves". Faced with such an end of existence (not "death", which might have an after-life, this is guaranteed to be the End for you) we could never experience it, or perceive it. Such an event will never be known to us, because once the End comes, we will have stopped being able to perceive even the most definitive thing in the universe, ourself.

This concept of Quantum Immortality and this article itself reflect no different a notion to me other than the tautological statement: "I'm immortal until I die". --Puellanivis (talk) 23:28, 20 June 2008 (UTC)

1.5 The universe may be a false vacuum
What has this got to do with the article? Sure, it's related to quantum physics in general, but has nothing to do with quantum suicide or immortality. I'm removing it; if someone has a good reason to add it back in, undo my edit after posting the reason. 86.135.97.226 (talk) 15:46, 28 June 2008 (UTC)

The nature of immortality
Well, I know the talk page is to discuss ways to improve the article and not for questions, but the explanation leads me to several questions. In some world(s), there would exist an immortal observer, but does that mean that each time we die our conscious is forced to move to a 'surviving' state? How does the nature of the existence of consciousness relate to the MWI in the first place? Maybe I missed something in the article but why is ceasing to exist not a state, is conscious separate from the physical brain? I'd appreciate if someone could explain that in plain English (and without getting into philosophy or religion) Something Edible (talk) 18:46, 12 July 2008 (UTC)
 * No one is aware of being no-existent, so the assumption is that your consciousness is "squeezed" into the worlds where "you" do have some physical existence (and, yes, this does assume that consciousness is not separate from the physical brain -- i.e. no afterlife etc).--Michael C. Price talk 21:45, 12 July 2008 (UTC)

What about dying to get to a parallel universe? There is a lot of discussion about going to the next closest (however that is measured) parallel universe at death, but why should that be the case? Could this not be a means of accessing your own (subjective) heaven and hell? How one would direct which universe you would go to is beyond me, but this seems like the key to happiness for some of the more suicidal folk. Ghostface26 (talk) 07:14, 3 December 2008 (UTC)


 * Quantum suicide is the method. This basically works by setting up a situation where something kills you if things are on the brink (and I mean the absolute instant) of turning out the way that you don't want. Of course this is all theoretical stuff; there's no guarantee that it works and you only have one life, so I strongly advise against trying it out. -- Derek Ross | Talk 20:26, 3 December 2008 (UTC)

No kidding. But thus far this seems like the only method this side of a Level II civilization that I can think of that allows universe hopping. And that`s not much of a difference if it only affects the absolute instant.

What of David Ambrose`s `The Man Who Turned Into Himself?` Okay, it`s fiction, but in it our protagonist`s consciousness essentially gets transported into a new universe of him, but with most of the world different. Even he`s a different person, with new memories and all. Is there some mechanism that allows for that? I`m also reminded of Ken Grimwood`s `Replay`, where the protagonist dies and is suddenly alive in his 18 year old body (from age 43). Ghostface26 (talk) 22:54, 3 December 2008 (UTC)


 * Not to mention the grand-daddy of them all, A.E. van Vogt's 'The World of ~A', of course -- or Kurt Vonnegut's 'Slaughterhouse 5'. Trouble is that we don't currently have a method of carrying out any of the transfers described in those books. So they remain in the realm of fiction. -- Derek Ross | Talk 18:21, 4 December 2008 (UTC)


 * Slaughterhouse-Five has nothing to do at all with quantum theory or the MWI. It's basically Gödel metric aka a block universe. --2003:EF:13C1:CE34:A02D:4BDC:F77F:7E48 (talk) 22:46, 13 October 2018 (UTC)

Your conscience doesn't get moved into your surviving body, it was with it all along. --TiagoTiago (talk) 03:49, 29 October 2011 (UTC)

Quantum Immortality = Travel Between Universes?
I`ve no idea how someone would go about navigating or directing the travel, but does it not stand to reason that, should quantum immortality hold true (admittedly a big if), then one could use that as a way to get to a better (or far worse!) universe? Could this effectively amount to time travel? I mean, if in the multiverse, all times are happening `now`(ie: the snapshot hypothesis of reality, that each instant is its own `now`), and your mind `carried over` to those worlds, would that not for all intents and purposes BE time travel?

Thanks!

Ghostface26 (talk) 17:51, 3 December 2008 (UTC)


 * Well, we're all time travellers. As we speak we are moving forward in time at the rate of just under 1 second per second. So it is an implication but you are very restricted as to the set of universes that you can visit. For instance you can buy a lottery ticket which gives you a small chance of visiting those universes in which you have won the next lottery draw. However there is no way that you can visit the universes where you won the previous lottery draw. Basically for a universe to be visitable it has to be in the future and there must be some course of actions which could take you from the present to that future. -- Derek Ross | Talk 20:13, 3 December 2008 (UTC)

But why must that be? If the theory implies that consciousness can`t be extinguished, then why not just have my consciousness transferred (or whatever the term is) to any other world than the one immediately in the future? How come we can interact with just some but not others? It seems to me that that`s a double standard. If all moments exist at the same `now`, then subjectively they are all in the future. If there was some independent observer who witnessed that transaction,they would think you`d leapt into the future, even if that future was a snapshot of the past.Ghostface26 (talk) 22:41, 3 December 2008 (UTC)


 * Why must that be ? Because we don't know of any practical method of doing it at the moment except for the boring one that I outlined. It may well be true to say that all moments exist at the same 'now' but that doesn't change the fact that some are much easier to reach than others from the moment that you are currently experiencing-- Derek Ross | Talk 18:12, 4 December 2008 (UTC)

Is Many Worlds/Quantum Immortality even scientific?
According to Dictionary.com, science is: 1. 	a branch of knowledge or study dealing with a body of facts or truths systematically arranged and showing the operation of general laws: the mathematical sciences. 2. 	systematic knowledge of the physical or material world gained through observation and experimentation.

Read through my thought experiment, and see what you think. - An experimenter flips a coin a thousand times, and lands heads every time. (Flipping a coin 1000 times gives you about 2^1.07150861 x 10^301 different worlds, and only one would have 1000 consecutive heads flips.) The experimenter, who accepts the many worlds hypothesis, will say: "I am in that one world in which all outcomes were heads. All other copies of myself got other results."

An uneducated observer asks him, "So it was just luck that the penny landed that way?"

"Yes", said the Physicist. "It was simply my good fortune to be in the one universe in which all outcomes are heads. Perhaps some of my copies no longer believe in many worlds."

Another observer, this time a physicist, says "So you had a 1/(2^1000) chance of being in the world that you are?"

"Yes, of course."

"I believe that the Copenhagen interpretation is correct. I'm not going to use it to explain your results; I'll use simple probability. Assuming that there are not 'many worlds', and I flip a coin, there is a 50% probability of it landing heads. 2 flips lower the odds to 25%. 1000 flips lower the odds to 1/(2^1000). If you succeed in getting 1000 consecutive heads flips, then you have simply been fortunate in defying the odds. You say you have been fortunate in being in the one world where all the flips were heads. But you have no justification for including worlds in your analysis - the odds of being in this particular world exactly equal the odds of randomly flipping heads 100 times! It could be that you were fortunate in getting 1000 heads flips without all the unfortunate other copies who didn't! These other quantum worlds, if they exist, are undetectable. This experiment simply followed the laws of probability." --

How could you respond to that? Is there any way of experimentally showing Many Worlds to be correct? If not, then it is not experimentally verifiable, or provable using empirical data, and as such as not scientific (by the above definition). It's more of a psychological idea than a scientific one.

My main problem with the article is that it is rather unfair to be criticising the points and counterpoints. Wikipedia should be unbiased! Also is counter-counter-point a good expression to use? Overall the quality of the article is rather poor. --Astropastime (talk) 17:06, 15 December 2008 (UTC)


 * in answer to your original question, MWI is scientific since it is falsifiable. Any experiment that falsifies QM falsifies MWI. --Michael C. Price talk 01:43, 13 February 2009 (UTC)

The odds are always 1:1 that you would be in the universe you are; the same holds true for all other yous. It's not a matter of luck, with infinite different universes, if somthing is possible it will be true in some; you could think that the odd of a tick in the compass being the one for 180 is 1 in 360, but the odds the 180 tick is gonna be the 180 tick is 1 in 1. --TiagoTiago (talk) 03:56, 29 October 2011 (UTC)

Section uses Copenhagen Interpretation to refute scenario
Nuclear bomb

Another example is where an experimenter detonates a nuclear bomb beside himself. In almost all parallel universes, the nuclear explosion will vaporize the experimenter. However, there should be a small set of alternative universes in which the experimenter somehow survives (i.e. the set of universes which support a "miraculous" survival scenario, or some extremely unlikely, but technically possible event occurs saving the experimenter). However this variation of a quantum suicide has one factor that automatically collapses the wave function as soon as it affects more than one observer making the experimenters probability at achieving a sound result a paradox upon affecting anyone other than oneself.

Wavefunctions only collapse in the Copenhagen Interpretation, and quantum suicide only works in the Many-Worlds Interpretation, so I don't see how one can say that one variation of a quantum suicide experiment is a paradox because of wavefunction collapse, without first assuming that MWI is false. I am going to remove the sentence beginning with "However".

71.72.235.91 (talk) 12:37, 18 January 2009 (UTC)


 * I don't think the number of people taking part in the experiment affects the concept of subjective immortality; if it's possible that the bomb wouldn't go out everyone that would've been killed by the bomb is immortal, until they die that is (however if there is any chance they would all never die, no matter how small, there is the possibility they all could remain immortal forever). — Preceding unsigned comment added by TiagoTiago (talk • contribs) 04:00, 29 October 2011 (UTC)

Quantum genie
Though the references are still too sparse for me to use for Wikipeida, people are starting to talk about the possibility of controlling reality using quantum suicide. If you have an absolutely reliable killing machine, you can simply wish for something to happen, and activate the machine if it doesn't happen. Then, only two sets of universes will exist: The set of universes in which you died (which you cannot experience), and the set of those in which you were convinced that your wish came true. So from your point of view, such a machine would function as a genie. 71.72.235.91 (talk) 13:07, 18 January 2009 (UTC)
 * The more likely conclusion might be that "an absolutely reliable killing machine" is impossible. If you wished for a million dollars to materialize in front of you, and it didn't, then the most simple outcome could be that you pushed your KILL button and the machine malfunctioned, but harmed you sufficiently so that you could not repair the machine, etc...  So you would continue to exist (as discussed in the article in the "David Lewis" section) in some awful, maimed condition, with your wish remaining un-granted. - LesPaul75 talk 07:19, 17 August 2009 (UTC)

My brain hurts
And it is not from the theory on this page... it is from this section:

http://en.wikipedia.org/wiki/Quantum_suicide_and_immortality#Max_Tegmark

I am not sure of a better way to word it, but it needs to be done. It looks like someone just decided to add a comment to the end of the section as it is barely even a sentence. SeanJA (talk) 12:00, 8 February 2009 (UTC)

I think I fixed it up a little bit... SeanJA (talk) 12:07, 8 February 2009 (UTC)

Mallah's counter argument
Recent changes have presented Mallah's arguments as the final and complete refutation to quantum suicide, along with a few strawmen tossed in for good measure. I have tried to add some NPOV to the issue. See for dialogue on the matter. --Michael C. Price talk 01:39, 13 February 2009 (UTC)

Mallah is a philosopher, is he even qualifed to talk about the subject? Mind you, I'm no expert myself but some of his arguments didn't make much sense. Ngherappa (talk) 12:55, 30 July 2010 (UTC)

David Papineau quote
David Papineau is quoted as saying

"If one outcome is valuable because it contains my future experiences, surely an alternative outcome which lacks those experiences is of lesser value, simply by comparison with the first outcome. Since expected utility calculations hinge on relative utility values rather than absolute ones, I should be concerned about death as long as the outcome where I die is given less utility than the one where I survive, whatever the absolute value."

It seems to me that instead of "I should" he meant to say "Should I" (i.e. posing a rhetorical question). Does anyone have access to the publication to see if there's been a transcription error somewhere down the publication chain. --Michael C. Price talk 01:39, 13 February 2009 (UTC)

The idea of quantum immortality is...
The idea of quantum immortality, is not that your specific consciousness is immortal, but that a copy of it will live on in alternate realities or dimensions after your death. For better explanation, let's take 100 pennies. They are all pennies, alike and similar, fresh from the mint, same date, with impossibly perfect fabrication. We toss them violently at a sewer drain on the side of the road. Some may go down, some will ricochet and land on the cement. The pennies that did not make it, are much similar to the dead consciousness possibilities/branches. They are gone in their world. But those that ricocheted and landed on the ground, are the living ones, and continued in theirs.

Upon death you may split into either a living, or dead possibility branch.

But no matter what, you keep on living. Just not the specific consciousness that you were. You will be dead, but another "you" will go on.

The phenomenon is difficult to explain, but the "you" is who you are in every way except the consciousness is a copy.
 * This (unsigned) comment is pure speculation, as is much of this entire talk page. Please try to keep WP:NOTFORUM in mind on talk pages. - LesPaul75 talk 21:29, 29 June 2009 (UTC)
 * The conciousness that survive is not a copy, it's another original. --TiagoTiago (talk) 04:03, 29 October 2011 (UTC)

Fiction
I edited the section on works of fiction, removed "The Prestige" as it was concerned with teleportation and having multiple "copies" of a person in the same universe, not really related to the idea of "quantum suicide." I added "Anathem" as an example, because it focuses very directly on the idea of living and dying simultaneously in multiple universes. But having just one example doesn't make a very good list, so others should be added, possibly any of these: http://dic.academic.ru/dic.nsf/enwiki/8284761 - LesPaul75 talk 21:21, 29 June 2009 (UTC)

I was very excited to see the note about Anathem, because that was the first thing that came to my mind after reading this article. I vote that the Anathem note stays in! --Tibbs (talk) 03:47, 22 August 2009 (UTC)
 * Anathem is certainly appropriate for this page, but the list needs more entries, and unfortunately, I haven't read anything else that is suitable. I was hoping that someone would recognize something on that list. - LesPaul75 talk 05:10, 24 August 2009 (UTC)


 * There is another article for the fiction entries. --Michael C. Price talk 11:17, 24 August 2009 (UTC)


 * Now that the page Quantum suicide and quantum immortality in fiction has been deleted (archived at the Internet Archive), should we create an "in fiction" section? - Paul2520 (talk) 19:17, 25 December 2015 (UTC)

Why the need for death?
Why do the other copies need to die? How does it change the experiment if instead of the other copies being shot, they instead see a message on a screen, or see a light turn on? The winning copy can still draw the same conclusions about MWI regardless of whether the other copies die. —Preceding unsigned comment added by Tomfrh (talk • contribs) 09:34, 3 August 2009 (UTC)
 * Because, if you choose an experiment with two non-lethal outcomes, and MWI turns out to be true, then there will just be multiple copies of you in different universes, seeing different outcomes. For example, if you flip a coin, you see it come up heads in one universe, tails in another.  But if the experiment has two possible outcomes where one of those results in your death, then you could only perceive the one in which you do not die -- because you no longer exist (as a living, conscious being) in the universe where the lethal outcome occurred.  What I dislike about the experiment is exactly that prerequisite -- it requires the assumption to be made that your consciousness will somehow "follow" the universe(s) where you are alive.  I don't see any basis for that assumption.  It seems equally likely that in one universe, you live, and in another, you die and go to heaven (or wherever your particular religion/spiritualism/whatever dictates). - LesPaul75 talk 07:09, 17 August 2009 (UTC)


 * It is asserted that the other copies need to die, but there is no basis for this. Killing off the other copies simply gets them out of the way so they can be ignored. No copy could be aware of the state of any other copy in a different universe, so it does not matter if the copies are killed or not. You could do the experiment with any unlikely series of events: in most, the unlikely series would not take place, but in a vanishingly small percentage, the experimenter would see the unlikely series take place. Also, anyone taking comfort in quantum immortality should also note that this also implies Quantum Hell - some copies will continue to surivive, but because of highly improbable events continue to suffer unimaginable horrors for an indefinate period of time.--RLent (talk) 17:21, 11 September 2009 (UTC)

Plaigarism from HowStuffWorks
Am I correct in thinking that substantial portions of "The quantum suicide thought experiment" are plaigarised from HowStuffWorks? Brainfsck (talk) 08:17, 1 November 2009 (UTC)


 * You're right: this was added to the article by 82.93.98.87 on 20 March 2009 (diff), but has existed on the other site since at least 13 Oct 2007 (according to archive.org). I've removed the text from the article - we need to restore an older description from the page history, or write a new one. --Zundark (talk) 14:18, 1 November 2009 (UTC)

Quantum suicide is FALSE
Ok, so what qualifies someone as being as expert? If I need to be published, that's a problem. However, I do now possess a B.S. in physics.

I'll restate my argument. I'm going to play a little loose with my terminology in an attempt to avoid future semantics arguments.

1. In quantum mechanics, an observable is anything that can be measured.

2. In quantum mechanics, observation and measurement are identically the same thing.

This comes from the fact that we are dealing with elemental particles. In your everyday, macroscopic world, you know where things are because light bounces off of them. So, when you try to find your basket ball in your room, you're actually looking for the light that bounced off of it. Now, imaging what would happen if you where blindfolded and had to find your ball by bouncing other basketballs off of it. Ignoring possible property damage, the most immediate problem is that if you do happen to hit your ball with one of the test balls, it is likely to move. When trying to locate a particle in a box, the only known way to find it is to bounce something off of it. If the box is your room, the particle is a basketball and the something is alot of photons, there is no problem. The tiny amount of momentum imparted by the photons will not move the basketball in any meaningful way. If the box is a potential well, the particle is an electron and the something is a photon, the electron's position and momentum can be greatly changed. The out come is just like finding basketballs with basketballs, (or baseballs, or vollyballs,. . . the import thing is that they can impart comparable momentums on each other.)

This is why "observation" changes a system.

The reason why measurement and observation are the same thing is because measurement amounts to counting quanta. It's like "observing" there are 5 marbles in a bag. You "measured" the number of marbles when you counted them.

3. If a system is observed in such a way that its state in know at all times, it will behave in accordance with classical models

Knowing the state of a system at all times means there is no super-positioning of states, no uncertainty of measure. That means, Newtonian. That mean, deterministic. If you doubt me, read up on the electron double slit experiment.

4. The gun fires based on the state of the system

5. In order for a the gun to know when to go off, the system needs to be observed at all times

Ok, yes, the gun doesn't "know" anything, it's not intelligent. The person who set it up is. The system needs to be observed at all times, or the gun may miss the change.

6. The mechanics of the described system are NOT statistical in nature

7. The Quantum Suicide thought experiment is invalid because it is based on a model that does not describe the mechanics of the system it sets up.

Look, general rule of thumb: If someone is talking about quantum mechanics, and they aren't describing something *much* smaller that you can possibly see, they're probably wrong.

DarkEther (talk) 20:52, 20 April 2010 (UTC)

ok, you'll have to forgive me, that last time I read the article, it was talking about radio active decay as a trigger. As it stands now, every 10 seconds the experimenter has a 50-50 chance to live. At every single moment, he knows if he's alive and what the outcome of every "flip" is, so that part is not statistical in nature. Because we are taking a random photon and measuring it, that part is probabilistic yes, but still not statistical. The random photon is functionally no different than the experimenter flipping a coin repeatedly while holding the gun himself. Just because you're measuring a spin state rather than a coin face doesn't mean that the laws of quantum mechanics apply. You might as well argue that the rules of special relativity apply because you're measuring something that's moving at the speed of light.

DarkEther (talk) 21:32, 20 April 2010 (UTC)


 * Remember that the quantum suicide idea is based on the assumption that the many-worlds interpretation is correct (that is, wavefunctions never collapse - everything is quantum and only appears classical due to decoherence). Under this assumption, the laws of quantum mechanics always apply, but macroscopic systems appear to behave classically under normal circumstances. Quantum suicide arises from an edge case where (arguably!) this appearance breaks down. --Zundark (talk) 21:40, 20 April 2010 (UTC)

Encyclopedic relevance and other issues
Hi,

I find this article to have several issues.


 * 1) It gives credit to quantum suicide to three people, but only one of them can be verified, Tegmark, and he does not quote anyone of the other two. I suggest leaving only Tegmark unless the appropriate reliable references can be given.
 * 2) Quantum immortality lacks any reference.
 * 3) Follow the reference given that claims Everett believed in the idea. The reference is a web page and not a reliable source. The web page then attributes this claim to a personal web site with a text written there, allegedly by a certain "Keith Lyn". However, even if we trust this unreliable source (Keith Lyn), the primary source itself never mentions quantum immortality. I sugesst removal of this information that cannot be verified. Potentially false.
 * 4) The quantum suicide section seems generally ok. Even without any reference, it is mostly a series of obvious statements. However, I fail to see any connection of this section to the so-called "quantum immortality" of conscious beings. It seems to be lacking any reference here to a philosophy published article that makes the connection. I can see that the personal webpage of Tegmark does have an email comment on this that came as a response to readers of a magazine article. There does not seem to be any published work that makes or elaborate such a claim. This is a clear WP:N (not relevant encyclopedic material).
 * 5) The "Dr Mallah" does not exist. It consists of a PDF sent to the arXiv.org from a random guy who just gave an Yahoo! email, but has no affiliation with a research institute or university so that we cannot track who he is, or verify what the "Dr" there stands for. It is a clear unreliable source, self-published online. Should be removed.
 * 6) The Papineau reference does exist, and he is a scholar in philosophy. However, the paper quoted has received only 4 citations (one from himself). This seems hardly relevant to the question of quantum suicide, or any scholar work at all. There does not seem to be a very good response from Papineau peers on this work. Seems WP:N to me, not encyclopedic. I believe it should be removed.
 * 7) The section on quantum immortality in fiction is vague, it should contain the information presently given in another article. I suggest they merge.
 * 8) The section "Against quantum immortality" quotes a web page and email correspondence of Tegmark to readers of a magazine. I don't see any encyclopedic relevance to this. cf. WP:N. Suggest it should be removed.

My suggestion is that this article presents the quantum suicide material, and leave the quantum immortality to the science fiction section. There does not seem to be a production in Philosophy or Physics that is relevant to this topic, even to qualify it as a metaphysical discussion in the philosophy literature (lack of any work on quantum immortality in philosophy journals seems to suggest that discussion on this topic as a metaphysical theory is completely inexistent). From 5,6,8 the whole "Against quantum immortality" section will disappear. Bode One (talk) 22:33, 30 May 2010 (UTC)


 * I don't agree. Quantum immortality is a trivial consequence of quantum suicide and therefore does not need citations to the literature. I.e., the assumptions Tegmark made that imply quantum suicide can be relaxed to imply quantum immortality.


 * The article certainly does need more work, but that means the opposite of what you are suggesing. I would suggest forgetting about trying to follow the literature closely, because of a lack of good discussions in the primary sources. Instead, one should explain the reasoning leading to quantum suicide and quantum immortalily more in detail preferably from first principles. Then the assumptions become more clear. The assumptions given in the article are not all the assumptions that one needs to make...


 * Thing is that these sort of subjects are discussed by physicists, but typically physicists do not regard philosophy as a serious science. What then happens is that you have a lot of interesting and notable topics that are discussed in the coffee rooms of theoretical physics institutions that you could include in Wikipedia, but which you cannot find in the regular philosphy journals. In fact, what you can find in there is often outright pseudoscience if the topic is physics related. Discussions that e.g. Tegmark has on some internet forum is far more reliable stuff than the contents of some peer reviewed article in a philosophical journal from the point of view of theoretical physics.


 * Also note that Jack Mallah does have Ph.D title. Whether or not he has an affiliation with a university is irrelevant. And not any random person can upload articles to the arXiv, this has been the case for quite a few years now. Count Iblis (talk) 03:35, 5 June 2010 (UTC)


 * Also note that the Hugh Everett article has extra references for Everett's belief in quantum immortality.--Michael C. Price talk 09:22, 5 June 2010 (UTC)

Gradual death.
I think there's some sort of subtle logical flaw in the notion of quantum immortality. Some sort of fallacy of excluded middle. Quantum immortality seems plausible when you think of abstract 'death', but when you think of gradual loss of function of the brain, it becomes a lot less plausible.

How does quantum immortality protect you from, say, succumbing to Alzheimer's ? There would be an alternative you, who never got Alzheimer's, but he diverged from you ages ago. There would be alternative you's whose alzheimer got suddenly cured stopped at different times. All of them are different people from you; there's no more reason to expect your subjective 'self' to switch into a less damaged brain than there is to expect it to switch into your neighbour. Same goes for more sudden death; the loss of consciousness is gradual. Does quantum immortality protect your neurons from dying off? Each dead neuron makes you to be very slightly less, but with no well defined boundary where you suddenly become non conscious.

In my opinion, the whole notion of quantum immortality derives from ill defined notion of 'self'. You are not the same you few seconds into the future or few seconds into the past; you are not the copy of you that diverged a few seconds ago.

It does not follow from MWI that you will subjectively survive a quantum suicide experiment. It only means that a lot of people rather similar to you will survive the experiment (vast majority of them by deciding not to perform experiment themselves and forking off early). That offers some consolation, but not immortality. It makes death less extreme in that someone very similar to you lives on somewhere else, as opposed to total loss of information. But as you don't expect your subjective experience to jump backward or forward a few seconds just because you few seconds ago are very similar to you now, you should not expect your subjective experience to somehow transition to already-branched off you.

I fainted one time in my life - no idea why - dark spots in visions, followed by whats best described as first hand experience of HAL's end in 2001 the space odyssey - being gradually switched off. I don't see how existence of parallel myselves whom are constantly forking off would prevent subjective me from experiencing this gradual sequence to it's logical limit - nothingness - just as the zeno's paradox is no reason to expect the Achilles to never catch up with tortoise.

And the entire notion that only the observers who did not die observe - well you can replace the gun with a red light, and speak of people who did not see the red light instead of people who are alive. All the people who did not see the red light did not see the red light, that's a tautology the same as all the people who are observing observe they aren't dead.

edit: or suppose for example that the number of yous is arbitrarily large but not infinite. Then the number of you's with the quantum suicide experiment is less than without, meaning that something had died. Perhaps our notion of infinity is wrong and we should use notion of something that can be arbitrarily large but not infinite (so that it, divided by 2, is not equal to itself). The whole 're-normalization' issue in quantum mechanics seem to indicate that it is the case.

78.63.245.109 (talk) 22:30, 22 August 2011 (UTC)


 * Well, 78 dot, since you're not the same person you were a few seconds ago, my condolences on your eternal demise. You may have veered towards the topic in one or two spots. I don't think we rule out something with suicide in the title as a cure for something with anything in the title, but an Alzheimer's patient might not remember their odds of survival were either somewhere between black hole bungie, and inside-out black hole bungie, or 1.


 * I was just explaining to the late late 78 how arguing that nothing ever survives anything might be like swatting a fly with one's small intestine. I too would faint, but if you read the article, it specifies an instantaneous and certain death, a conjunction of circumstances those reading this article from beyond the grave, know only too well. If by observers who did not die, you mean the subject? Yes, that would be the entire notion, full stop. If I misunderstood the meaning of tautology, I would be thankful that someone pointed it out to me, but observers who won't bother are the norm.


 * If truth is truer than fiction, a tautology barring irony, perhaps God or Tegmark have a suggestion box? —Machine Elf 1735  05:09, 23 August 2011 (UTC)


 * Speaking of a suggestion box, this article has finally taught me what a believer in the fashionable fantasy interpretation of quantum theory is, i. e. somebody who doesn't understand that Schrödinger's cat was meant only as a satirical joke at the expense of occultists who think they can invoke science as an argument that their age-old superstitions bordering on full-blown psychosis would be true somehow, simply because


 * a.) the UV desaster does not happen on account of the fact that energy consists of energy atoms called quanta instead of being continuous (the main fact exploited in quantum computing, not some imaginary "superposition"),
 * b.) because of Heisenberg fuzziness where photons mechanically bounce smaller particles out of the way, making them unobservable by means of light, and
 * c.) because Helmholtz statistics utilizing waveforms are being used for reasons of mere convenience by educated guessing (rather than any literal correspondence of the waveform to reality or the actual nature of this universe at all, or any other possible universes, for that matter) due to lacking CPU power for more precise and more realistic calculations.


 * So there: A "classical" scientist is somebody who puts people into a box when they're dead, while a quantum "scientist" is somebody who believes they can achieve immortalty by getting into the box while they're still alive, while obsessively killing kittens in it as some kind of ritual sacrifice. --2003:EF:13C1:CE34:A02D:4BDC:F77F:7E48 (talk) 23:20, 13 October 2018 (UTC)

Just added Jacques Mallah back to the Wiki page.
This wiki page use to have a section with Jack Mallah's work on it, but it got taken down because "he doesn't have an affiliation with a university." It is very important that both sides of the Quantum Immortality argument are addressed, so I added a section for Mallah. He has been arguing against Quantum Immortality and Quantum Suicide for years, and he does hold a Ph.D. — Preceding unsigned comment added by 76.1.128.18 (talk) 14:32, 11 May 2012 (UTC)
 * I agree that trying to present both sides of the Quantum Immortality argument should be attempted, but Jacques Mallah'a work 'Many-Worlds Interpretations Can Not Imply ‘Quantum Immortality’' not only lacks any sort of peer review or commentary, but is also in a field of work that he is not associated with. Even without university affiliation, the only evidence I can find of his credentials are those that he has provided himself, putting his field as, and I quote, "Bachelor's/Master's, Mechanical Engineering, Cooper Union PhD, Physics, NYU Master's, Medical Physics, UW-Madison"

- http://www.science20.com/profile/jacques_mallah This paper does not represent a source that's up to Wikipedia's quality, nor does it necessitate inclusion in this article. I move that it be removed once more. 222.147.159.195 (talk) 04:35, 26 November 2012 (UTC)

Goertzel and Bugaj

 * In their speculative work on the topic of future science and artificial intelligence, authors Goertzel and Bugaj describe a very different metaphysical notion as "quantum immortality", one they claim is applicable in all circumstances, for every "intelligent entity", and that serves as a means of "transfer" to other universes.

I'm moving this here since it seems to be outside of mainstream discussion of this topic, and imho distracts and confuses if it's placed in between paragraphs describing the discussion within the physics community. --213.196.194.37 (talk) 17:58, 18 November 2012 (UTC)

As a means of gain
Assuming quantum immortality is true, it can be used to achieve virtually anything. By linking the results of an action to the hypothetical instant brain-death machine, say, whether a coin lands on heads, you must live in the universe in which you do not die (and therefore where the result you want happens). Assuming the machine had an astronomically unlikely rate of failure (orders of magnitude less likely than the result you want), you could get over the oft-mentioned problem of "maimed, but not brain dead", by programming the device to kill you if you so much as get a papercut. Sure, in the vast majority of universes people would observe you getting a papercut and then dying, but in the one in which you are conscious, you could make yourself indestructible.

Theoretically, in your own universe, you could end world hunger, stop all wars, cure all diseases, etc. this way. Pretty freaky. Silenceisgod (talk) 19:31, 20 August 2013 (UTC)
 * Or just wait till it happens by chance, somewhere. Or just off yourself by conventional means if you don't win the lottery and create world peace. You don't need quantum probability to play this game (and win!), just probability. 89.217.3.165 (talk) 00:42, 12 May 2015 (UTC)

Alastair Reynolds' short story The Real Story
Actually the story described is called Angels of Ashes, The Real Story is a Carrie Clay story, both published in the collection Zima Blue and Other Stories. There is another story called Everlasting which more directly addresses this idea. — Preceding unsigned comment added by 144.124.155.247 (talk) 09:17, 5 March 2014 (UTC)

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Reason for explanation as to why it wouldn't work
The explanation is that given by Max Tegmark, who independently originated the thought experiment some time earlier. The source given is extremely clear that it refers to this thought experiment. It is very relevant to having a neutral point of view to give reasons why it would not actually work. It is still quantum immortality, since in many-worlds a version of the experimenter will always find they defy all odds. Crossroads1 (talk) 05:39, 20 August 2018 (UTC)

Tegmark is not the originator of the thought experiment and it also doesn't make sense to include it in the main section - since it just says it won't work. I don't know if the quote is accurate, but giving the benefit of the doubt, I moved it to the section about his beliefs. Your paragraph doesn't make much sense to me, but my understanding of Max Tegmark is that he doesn't actually think quantum immortality is a real phenomena, yet he's one of the few respectable scientists to write about it. So it's fine if it's part of "his section", which is basically a criticism section. But QI implies actual immortality, so it's just wrong. Akvadrako (talk) 17:11, 20 August 2018 (UTC)

Wouldn't this lead to the most miserable kind of existence?
So, here's why I think it would be utterly awful if this turned out to be a real situation: The version of "you" which retains consciousness for the longest period of time will continually be asymptotically approaching dead. You will not know about the other "you"s, and, assuming you're conscious right now while reading this, the "you" that exists now WILL continue to be the one that's in this situation, in one universe. I won't go into detail on what I mean by "asymptotically approaching dead", but I think you can imagine - horrific injuries, paralysed, decrease mental faculties, and so on. I assume someone else has made this argument somewhere before, and I think it should be mentioned in the article somewhere. 130.63.110.250 (talk) 23:16, 14 September 2018 (UTC)

If you want to write about this, you have ample sources. David Lewis is a well known philosopher who thought the same as you did and had a number of articles published on the topic. See the end of http://andrewmbailey.com/dkl/How_Many_Lives.pdf, one of the last papers he wrote before dying in 2001. Personally I don't think you need to worry about it - I've thought about this a lot and read all the literature I can find on it. Consider not dying to be a boundary condition. Accepting that, whatever is most probable will happen. For example, it's more likely someone will cure ageing then you are currently "asymptotically approaching dead". Akvadrako (talk) 21:57, 15 September 2018 (UTC)

Actually this article used to contain references to Lewis work, but it was removed in 2010: https://en.wikipedia.org/w/index.php?title=Quantum_suicide_and_immortality&diff=prev&oldid=392880020&diffmode=source — Preceding unsigned comment added by Akvadrako (talk • contribs) 10:47, 16 September 2018 (UTC)

Error in probability of observing the experiment
The article says "Therefore, the experimenter will have a lower probability of observing a world in which they survive than the world in which they set up the experiment". Should it not be "than the world in which they don't set the experiment"? Because there are likely many more Universes where they set up the experiment than Universes where they set up the experiments and survive (given they survive in only a very tiny fraction of them). --Mati Roy (talk) 17:39, 17 February 2019 (UTC)
 * I clarified the wording now. The point is that the experimenter's measure of existence is lower after the experiment than before, and thus they have lower probability of observing it, i.e. of survival. Crossroads1 (talk) 20:47, 22 June 2019 (UTC)

In fiction
Ok, so. The "In fiction" section was removed by anonymous user. I don't see any particular discussion regarding this deletion, certainly not surrounding the time the particular section was deleted. Was there any particular prior discussion why this was supposed to be deleted elsewhere? --wwwwolf (barks/growls) 00:33, 1 June 2019 (UTC)


 * I really doubt discussion anywhere else, and as you pointed out not here. All we see is their edit summary: "section off topic". I have no opinion on this. Shenme (talk) 00:50, 1 June 2019 (UTC)
 * I am glad that section is gone, I agree with them that it is off topic. Crossroads1 (talk) 19:13, 22 June 2019 (UTC)
 * Also note another later deletion by same IP "In fiction: off topic here" with directly following revert. (sigh) Shenme (talk) 00:56, 1 June 2019 (UTC)