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Quantum immortality

  1. Mar 20, 2006 #1
    I'm not certain if, strictly, this should be in the general discussion forum but the idea is based on quantum ideas so I have put it here. If I am mistaken, please, move it.

    I stumbled upon this idea when I was reading through lots of different interrelated articles on Wikipedia (it can be very addictive). Basically, it suggests that, if the many worlds interpretation of quantum mechanics is correct, that any observer will perceive their own life to continue in any situation in which it is physically possible (no matter how unlikely) for them to survive.

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

    I have thought about the idea for a few days now and I am actually a little uncomfortable with it having at first been pleased with the concept.

    Are there any thoughts about this idea?
     
  2. jcsd
  3. Mar 20, 2006 #2
    If you assume that, then you have to assume "you" are constantly dying in alternate realities all the time, and somehow, each time that happens, something about "you" (in this reality) changes. There should, I assume, be a measurable change in "you" in this reality.
     
  4. Mar 20, 2006 #3
    The MWI is an artificial solution to the measurement problem in quantum mechanics. It's just a metaphysical fiction which doesn't help in understanding, say, the movements of electrons and photons in double-slit systems. It doesn't help in understanding what electrons and photons correspond to in some underlying reality.

    Do you really think it makes any sense at all to say that an instrument pointer is in no definite position or that a detector both clicked and didn't click at the end of an experimental trial, or that there are an infinite number of you's or me's, or an infinite number of universes all existing simultaneously?

    If you do, then good luck in playing the MWI word games. If you don't, then you don't have to worry about the immortality thing, and you can prepare for your eventual death.:smile:
     
  5. Mar 20, 2006 #4

    loseyourname

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    This is pretty poorly thought out. Even if one experienced reality in such a way that one always lived as long as physically possible (which is idiotic if you ask me, but there's obviously no way for me to prove this doesn't happen or even argue against it), there is still a physical limit to how long the human body can remain alive. Even if every one of us maxed out our potential lifespan, it wouldn't make any of us immortal.
     
  6. Mar 20, 2006 #5

    vanesch

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    There is indeed some speculation about this, but I find it a far stretch. If you want to read another article about it, look up "quantum suicide" on the arxiv (in the quantum physics part). There was a fun article concerning a spicy party :smile:

    It is not impossible of course in the MWI interpretation, given that each time there might be a small (or big) amplitude for a "livable body" to continue to exist. But the entire question is of HOW subjective experience is linked to your body: does the Born rule select only from "livable bodies" or can it also select from "dead bodies" ? In the last case, your subjective experience has a finite probability to "die" of course. Nevertheless, these considerations are a good exercise in "MWI thinking" - although they are of course making a lot of assumptions beyond what's experimentally established!

    To LYN: there is always a small amplitude that your old body undergoes exactly those transformations that it continues to be livable - again - in principle.

    To Sherlock: the only objection to the MWI view I've ever seen is like your reply: "naah, just too crazy".
     
  7. Mar 21, 2006 #6
    To me, the MWI interpretation seems much like the ID position on evolution. How can life evolved after such amazing odds? We don't know! Hence, ID is correct. :)
    The MWI Interpretation is a solipsist's dream theory....completely unprovable one way or another.
     
  8. Mar 21, 2006 #7
    RVBuckeye
    I see what you mean but, without any predictions about what should change, it can't really be held up as evidence that the idea is wrong.

    Sherlock
    You are very dismissive. I am not necessarily a believer in the MWI but the idea provides a certain symmetry don't you think?
    I agree that it is not really helpful to furthering our understanding but I started the thread more to see if people thought that the quantum immortality idea was possible if the MWI is accepted.

    loseyourname
    It is my understanding that biology is progressing in such a way that the causes of ageing may be preventable in the future. This suggests that there may be a non-zero probability that life can continue indefinitely if treated correctly. How can you rule anything out if you accept the MWI?

    vanesch
    Good post. It is perhaps fanciful to think of such things such a distance beyond experimental verification but it is just a bit of fun at the end of the day. I will look up the article.
    I wonder if there is another universe with a more open minded poster on here call sherlock :smile:

    LnGrrrR
    It isn't completely unproveable. If you are still alive on your 900th birthday, you may consider it proven.
    I didn't intend this thread to be about the likelihood of the MWI (I suspect that, if I had, it would not have been moved here) but I am not at a stage in my thinking where I can confidently rule it out as some on here seem to be.
     
  9. Mar 21, 2006 #8
    Theoretician,

    Well, given your criteria for 'proving' MWI...do you know of any 900 year old people? Or any who have played Russian roulette and won a few hundred times in a row? :)

    MWI MAY be true...and I also might be a brain in a jar. I'm not going to think either are true without some positive evidence though ;)
     
  10. Mar 22, 2006 #9

    vanesch

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    First of all, MWI doesn't claim this survival to be true, it opens the theoretical possibility, that's all. As I said, if the link between subjective experience and bodystates includes dead bodystates, then the subjective experience is probably over too.

    Many people seem to think that someone INVENTED parallel worlds in order to tell a story about quantum theory, but that's not true. MWI is *suggested* by the formalism, and you have to explicitly TAKE ACTION for MWI *not* to be the natural interpretation of quantum theory ; moreover, any action taken is "formally ugly" in that it introduces inconsistencies, and a clash with special relativity.

    The story goes as follows:
    in Newtonian physics, it is postulated that a system is described by point particles in an Euclidean space, and are evolving according to a dynamical law with a quantity called time. That dynamical law is given by forces, and they are supposed to act at a distance, and a link between forces and geometry, which is Newton's law: m.a = F.

    In Newtonian physics, these point particles, and the Euclidean space, and the forces, are taken to REALLY EXIST.

    In Electrodynamics, it is postulated that there is an electromagnetic field all over space, with two components, namely an E and a B field, which follow certain dynamical equations (Maxwell's equations) and which induce Newtonian forces, given by the Lorentz force.

    Again, in electrodynamics, these fields E and B are taken to REALLY exist.

    In special relativity, space and time are seen as 2 aspects of a single geometrical entity, which is called Minkowski space (4-dim spacetime). Again, this Minkowski spacetime is taken to REALLY exist.

    In general relativity, space and time are seen as 2 local aspects of a single geometrical entity, called the spacetime manifold. The curvature of this spacetime manifold is taken to result in effects we call gravity. Again, this spacetime manifold is taken to REALLY EXIST.

    And now we come to quantum theory. In quantum theory, it is postulated that nature is described by a vector in hilbert space, with a unitary dynamics on it. AND THIS TIME, THIS VECTOR IS NOT TAKEN TO EXIST REALLY :bugeye: ... unless you adhere to MWI. MWI just says that this vector really exists, just as the other fundamental concepts in other physical theories were taken to exist.
    IF you take this vector to really exist, and the corresponding unitary evolution too, then you arrive at MWI.

    Mind you, just as you cannot *prove* that the 4-dim manifold in GR really exists, or that the E and B fields really exist, you cannot prove that the vector in hilbert space really exists. But we've never done such a thing before in a theory: to assume that what the theory postulates to describe nature doesn't "really exist"...
     
  11. Mar 22, 2006 #10
    You miss the point LnGrrrR. There are no 900 year old people in 'my' universe because the conditions that ensure my survival are extremely unlikely to do so for someone else for such a length of time. So it goes, any person to have ever existed (or, indeed, any person that could have possibly ever existed) continues to do so in their own frame (or their 'own' universe if you like) but they die before that in mine.
     
  12. Mar 22, 2006 #11
    Theoretician,

    So do you know of anyone, in history, that has survived ridiculously long odds and repeated them over and over again? :)

    Mayhaps the fact that there's been one or two people to get struck by lightning multiple times is evidence enough? ;)

    I'm being somewhat facetious here, but really....a different universe for every single 'choice' made in the universe by any quantum reaction? Maybe I just hav eproblems with it because it seems so...crazy? Perhaps I just have to open up my mind more...but for now, the Copenhagen interpretation seems to make more 'sense'. Not that QM is about making sense, of course...
     
  13. Mar 22, 2006 #12

    vanesch

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    You missed the point again, as Theoretician pointed out. You cannot observe anybody ELSE to be 900 years old (it has a very low probability in YOUR branch), but it might be that YOU will observe your body to still be alive 900 years from now, in an ever stranger-looking universe. Again, on the caveat that you will not branch in one of your "dead body" states...

    Have a look at:
    http://arxiv.org/abs/quant-ph/9709032
     
  14. Mar 22, 2006 #13
    Vanesch,

    Yes, I will observe my body to be 900 years old. But certainly, those in the same 'multi-verse' with me would observe that as well, or could do tests to prove that?

    Ok, I know you can say, "Well, our universe doesn't have 900 year old beings, but one out there might." I guess my answer to that question is, Why don't we see these ridiculously crazy things in OUR multiverse? Wouldn't the chance of something 'crazy' like this happening in our world be rather good? If there's a multiverse for every decision made, why does our multiverse seem not to have people with these 'superheroic' like qualities? Luck of the draw?

    I will read the link though, and post again after.
     
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