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MWI and Human death

  1. Jul 14, 2008 #1
    Please correct me if i am wrong.

    As per MWI,when an observer open the box,schrodinger cat will be alive in
    one world and the same cat will be dead in other world. If we replace the cat with human,then the dead human and alive human will be different worlds.so,my curious question is does this mean even for normal death after we are old,the dead human will be in one
    world and the other alive human will be other world? so MWI says that there is life after death in other world? since we are in one world,we are able to see only the dead human and couldnt see the alive human who lives in other world?
  2. jcsd
  3. Jul 14, 2008 #2


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    Well, I'm out of my depth here to be honest, but my ignorant understanding of MWI is that each possible instance of a fundamental process is played out in a different universe, such that at every possible juncture where there are mutiple possible paths each one is played out in a seperate universe. The upshot being that for every decision you make there are an infinite other "yous" in an infinite number of other universes living out all the alternative possible decision combinations.

    Hence if you decide not to J-walk across a motorway, then another you will decide to J-walk and get killed, hence you may be alive in one universe and dead in another.

    MWI does not say that there is life after death, as for the guy that died, he is still dead. It depends how you view the "you" in each universe. Up untill that crucial life or death decision you were exactly equivalent objects, but after the decision the universe "splits" and you are entirely separate non-equivalent objects. Please correct me if I've misunderstood.

    As for Schrodinger's cat analogy that is all that it is; an analogy. The cat is analagous to a non-macroscopic (quantum) system that is in a quantum superposition of states, such that observation causes it to collapse into one state or the other. This is not a property of macroscopic systems (such as cats or humans). In MWI it is this property of quantum systems that means that quantum processes (which must surely underly the macroscopic world) exist in an "apparant" superposition where each state of the superposition exists throughout the multiverse. This means that the unfavourable idea of wavefunction collapse is replaced by another unfavourable idea of a multiverse, although the multiverse concept is also proposed in other non related areas of Cosmology and the like.
    Last edited: Jul 14, 2008
  4. Jul 14, 2008 #3
    absolutely not, human death has nothing to do with superstate.
  5. Jul 14, 2008 #4
    Fascinating stuff. I suspect you've already read this, but here's the Wikipedia article on MWI in regards to the Quantum Suicide experiment:


  6. Jul 14, 2008 #5


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    Sorry, I've made a silly mistake on my previous post. When I was talking about Schrodinger's cat I was incorrect. Ignore what I said. I actually forgot the set-up of the experiment where the death is caused by radioactive decay. In the proper sense therefore of course, schrodinger's cat, or indeed a human in the box can be dead in one universe and alive in another, just as the J-walker lives and dies in different universes
  7. Jul 14, 2008 #6
    The question is what possibilities can be realized? In your example you have two universes: one where a person j-walks and the other does not (dead/live). However, push the point closer to where we have a j-walker getting hit by a bus. In one universe he dies and in the other universes he survives. From the surviving one we then have a multitude of variations of his injuries -- from paralyzed, to broken bones, to bruises, to mysteriously uninjured? If MWI is correct, then all possible scenarios will play out.

    Like the quantum suicuide thought experiment, I had another that would allow you to "easily" win the lottery:

    Make a machine that will kill you if you do not possess the winning numbers on your lottery ticket. Since the losing "yous" will all be terminated, the only surviving "yous" will be the ones that won the lottery. Since the winning numbers are determined randomly and HAVE to be affected by quantum uncertainty on SOME scale -- it would stand to reason that every possible winning combination is realized thus allowing at least one of "you" to win.
  8. Jul 14, 2008 #7


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    I don't know why you've introduced a machine gun into the equation; whether you kill yourself or not the same number of yous will win and loose. The machine gun doesn't affect the probabilities. If you die in one universe you don't then become yourself in another universe.

    Just buy a lottery ticket don't try and be clever about it, you'll hurt/kill/maim/blind yourself all at once
  9. Jul 14, 2008 #8
    Actually, you would. Remember, we're talking about the moment in time the branching takes place -- when the machine determines if you won or lost the lottery depending on your numbers. By killing the "yous" that lost (thus ending your consciousness) the only active consciousnesses are the ones that won. If the transition is smooth (as in you aren't laying there bleeding to death) then, from your point of view, you come out of the machine a millionaire.
  10. Jul 14, 2008 #9
    is the normal death also a quantum event,if so, then there should be an alive human in another universe...
    i heard that worlds cannot communicate because of linearity..is there anyway that different worlds can communicate...
  11. Jul 15, 2008 #10
    The thing you have to remember about MWI is that "you" are irrelevant. What matters are the states of your particles. In some states (worlds) your particles will be arranged in such a way as to make a live organism. In others, they won't be. This roughly can be thought of as multiple copies of "you" but not in any form that you could ever interact with or be conscious of.

    And also keep in mind that "you" will be dead in every world eventually because even quantum randomness cannot make someone live forever. But from a quantum perspective, all that means is that your molecules are no longer interacting in such a way as to support life. They're just in different states.

    Since consciousness is likewise a function of chemistry, the same analysis applies. In some worlds the electrons in your brain are working together to make a consciousness, in others they're not.

    Sorry if this sounds particularly secular or solipsist. No quantum interpretation can address the soul, so there's no point in trying to work it in. :)
  12. Jul 15, 2008 #11
  13. Jul 16, 2008 #12
  14. Jul 16, 2008 #13
    Well, please don't confuse mainstream MWI with thus "quantum suicide" nonsense. There's solid math behind MWI and legitimate research. The quantum suicide thing is 100% speculation.
  15. Jul 17, 2008 #14
    No offense, but how is it people treat MWI as a religion, it got no upper hand in the "competition" of interpretations.

    "MWI gives some bizarre results but seems to be valid", please show me what exactly make it seem anymore valid than RQM/BOHM/TI etc.?
    Infact, everything we can observe (which is where we get ALL our external information about the external world from: aka source of the science) is not pointing towards splitting, but rather a single universe.

    Many Worlds is just getting the most hype because it fits people's scifi fantasies, like the Quantum Suicide "thought experiment" that will fail.

    One thing I've noticed among MWI proponents it got all the nutjobs, thinking it advocates all type of pseudoscience.
    + Everyone insists it's correct, like a religion, which makes me pretty sure even it's proponents are very very unsure of it themselves or they'd let the interpretation speak for them.
  16. Jul 17, 2008 #15
    No offense, but ... ? *sheesh* First post eh?
    what a lame phrase, used in attempt to excuse a person from being offensive, as they proceed to be offensive.
    please show me what exactly make it seem any less valid than RQM/BOHM/TI etc.?
  17. Jul 17, 2008 #16
    I would not go as far as QMecca, but i think he does have a point about qm interpretations in general.

    They are all different philosophical explanations for the same physical phenomenom - qm.

    However i dont think its right to call anyone a nutjob just because of their favoured qm interpretation, which is just an intepretation after all, and it does not challenge the maths which i believe all versions agree on, more or less.

    Of course i also think there are some perfectly rational objections to MWI which have never been satisfactorily resolved.
  18. Jul 17, 2008 #17


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  19. Jul 17, 2008 #18
    I agree that the thought of the universe continuously splitting into all probable possibilities sounds ridiculous. But is it any more ridiculous than waveform collapse being dependent on an observer?

    What other mainstream interpretations exist besides Copenhagen and MWI that explain the phenomena we observe?
  20. Jul 17, 2008 #19
    In my opinion Copenhagen (with 1 universe) can be seen to explain collapse in one of two ways: a)obseveration/measurement or b) interaction between the microcopic and macroscopic. So this is why i think it still remains popular because it allows different philosophical implications depending on one's favoured view.

    There are other more specific interpretations such a "Transactional" or for instance "Conciousness causes collapse" which is actually just like Copenhagen but its making a further philosophical leap. I'm not sure but i believe Zurek's "decoherence" works in conjunction with MWI as the causation for branch universe splits.

    I think they are all "ridiculous" to some extent but that's not surprising since qm itself presents us with some shocking paradoxes, compared to how we use to think the universe worked under the classical/newtonian mindset.

    However, i would say that even though i am highly skeptical about MWI; i can admit that it appears to be the most rational explanation in the context of Schrodinger's cat where we are asked to believe that the cat is entangled with the atomic decay superposition. In that case, if the cat really is entangled it presents a real paradox about what it is like to be the cat before we've looked in the box. Forget the observer because its more important to understand this issue from the point of view of the cat. What is going on with it? Is it non-existent? Is it both alive and dead in some weird physical state? Or as MWI would have us believe it exists in both an alive and dead universe. So for all pratical purposes the cat experiences death and life but in different realities.

    I find the MWI explanation easier to believe, but then again i prefer Copenhagen on the whole because i do suspect an observer plays a sort of defining role in the universe. I would prefer an observer-essential MWI where its the observer's choices shunting him from one reality to the next.

    Of course i am talking about what i think would be a more pleasing outcome philosophically. I could be a nut-job as they say :)
  21. Jul 17, 2008 #20
    - Bohmian Mechanics (in short, particles surf waves like in Baja)
    - Transactional (a total mess, but nonetheless "mainstream", I guess - in short, the particles give each other a wave "handshake" first followed by the actual force, all happening forward and backward in time)
    - Ensenble Interpretation (it's all just statistics - though that doesn't really explain much).
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