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N00b question

  1. Nov 9, 2008 #1
    What exactly are the philosophical implications of quantum ‘superposition’? If an atom can both be in a ‘yes’ and ‘no’ configuration, is dualism a "scientifically proven" illusion? Is it a self imposed reality?

    What about quantum decoherance? If it is impossible, fundamentally impossible to separate a quantum system from the outside world, then it is equally as fundamentally impossible to make measurements on it without affecting it – that is to say, make measurements that do not “choose” values but rather “observe” them as they actually are. Does this mean nothing yet everything exists until we observe it?

    If a tree falls in the forest and no one is around does it both make and not make a sound?


    Thanks,

    LB
     
  2. jcsd
  3. Nov 9, 2008 #2
    1) we don't know
    2) a.dualism in a very specific sense is proven b. it depends on your idea of an illusion
    3) how would that be possible
    4) it leads to probabilities instead of wavefunctions which is still not what we observe
    5) no
    6) existence is a bad word in quantum mechanics
    7) it doesn't make a sound. <-- now prove this wrong. This is a dancing angles on a pinhead question

    It seems we don't have the concepts yet to clarify the collapse of the wave function. I suspect it will ultimately be less a question of reality but a question about the mind.
     
  4. Nov 9, 2008 #3
    These answers are as useless as a screendoor on a battleship.

    for example, the reply to 1 we don't know. Who is we? Don't put me in the same category as you. How about existence being a bad word? What kind of an answer is this. QM is exactly about determining what exists? What the heck else are scientists doing?

    i'd rather spend my time figuring things out than asking people who know less than me. Poster, you are not a noob and these are great questions. In case you haven't figured it out here people are more interesting in giving you an answer than thinking about your question.
     
  5. Nov 9, 2008 #4

    Fredrik

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    Someone's in a bad mood :rolleyes:

    I would say that there are no philosophical implications of superpositions. There are interpretations and speculations, but no implications.

    The impossibility of isolating a system from its environment doesn't really have anything to do with the fact that a measurement disturbs the system. The latter is just a consequence of the fact that a measurement is by definition an interaction between the system and its environment. Interactions always affect both of the systems that participate in it. The reason why the disturbance is more severe in QM than in classical physics can be seen almost immediately from the postulates of QM.

    I agree that "existence" is a bad word here. This is because science is about finding theories that predict probabilities of possibilities, and doing experiments to find out how accurate those predictions are. I don't see a meaningful way to fit the concept of "existence" into that framework. (I tried in this thread. Maybe you should check it out).
     
  6. Nov 9, 2008 #5
    Maybe one has to abandon the visual picture of reality that our brain creates for us when we grow up. Therefore dealing with complex probability wavefunctions might be less intuitive, but actual "reality". The catch is that no-one is genius enough to do QM in his head.
    Just as for some it may seem weird that special relativity says that moving things age slower. But actually it's not hard to imagine.

    As for your superposition question: It's not hard to image that a system is in either one state or another (maybe defined but unknown or maybe fluctuating between both) until we observe it. What's harder to imagine is how correlated/entangled systems have also undefined parts, but on observation these part have correlated outcomes.
     
  7. Nov 9, 2008 #6

    Fredrik

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    You do know about Bell inequalities, right? If we assume that the system is in one of the states or the other, this leads to predictions about the results of experiments that have been proven wrong.
     
  8. Nov 9, 2008 #7
    It's about two states. That's why I said if we didn't have entangled states, it would be easy.

    Actually Bell's inequality doesn't exclude the fluctuating picture, i.e. the state of the system is well-defined but constantly changing with time until it is observed. I wrote that in a thread once
    https://www.physicsforums.com/showthread.php?t=104644&page=2
    but I think I didn't get useful response to that.
     
  9. Nov 9, 2008 #8
    congradulations on the eyeroll. Well we all know the internet is a place where people go when they won't be heard in accepted channels. That aside, not all people here fall in to that category. If i'm not in a bad mood who will be?


    what does implications mean? The verb form is to imply. So any result of QM will imply something about the world. As science is a discipline set on investigating the world and determining what exists its finding do have implications in that they imply something. They imply something about their domain of inquiry, the physical world.

    of course it does. They two are mutually dependent. This interdependence is exactly the reason why the measurement affects the system. If they were not interdependent there would be no possibility of interaction. You should study Buddhist philosophy.

    in the beginning with galeleo you could plausably argue that physics was not involved in ontology. Beginning with newton, and growing hence, physics became involved in ontology. The introduction of the gravitational field was a big step. It was taken further by faraday's postulation of the EM field. This was really hard to accept in his day. By the 20th century there is no question physics was dealing with ontology, or at least its implications were heavily involved in it. It is possible to argue that physics per se is only concerned with experiment but any worthwhile physicist would acknowledge that curiosity about the world is a guiding principle in their work. That someone would even say 'existence' is not an appropriate word in QM is an indication that either they don't know physics or have no understanding of the history of early 20th century physics, or both. Heisenberg was a deep philosophical thinker. Many other examples follow.

    this is a huge crisis in physics today. Ever since the 1950s or so the success of experimental physics and the standard model have led to an emphasis on technology and away from deep, creative thinking. Ask yourself where are today's einsteins and feynman's?
     
  10. Nov 10, 2008 #9

    Fredrik

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    So you're not an incompetent loser like the rest of us, and a grumpy whiner is exactly what this forum needs?

    I think this calls for another one of these: :rolleyes:

    If you'd like a serious discussion, then lose the attitude.
     
  11. Nov 10, 2008 #10
    someone's got to take out the trash.

    six of one to me. If you can't refute me views i guess you attack my style.
     
  12. Nov 10, 2008 #11

    Fredrik

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    The postulates of the theory have implications in the form of predictions about the results of experiments. That's all.

    I'm not sure what the OP had in mind when he talked about "implications". When I replied I assumed that he was talking about the sort of things that are mentioned in the various interpretations of QM, and I wanted to point out that none of those things are implied by the theory.

    I'm not sure what you have in mind either. Maybe something like the statement "a particle doesn't have a well-defined position"?. The fact that there's no natural way to associate a vector in the Hilbert space of one-particle states with a unique position in space is implied by the postulates of QM, but it's a result about the mathematical model, not about the real world. It's an intermediate result in the calculation of the predictions about the the results of experiments.

    No they're not.

    No it's not, yes there would be, and you can't be serious.

    Actually it takes some philosophical thinking to realize that "existence" is a concept that requires a definition. And what's with that Heisenberg comment? It's not like I'm arguing against philosophy.

    Most of them are probably working on string theory.
     
  13. Nov 10, 2008 #12
    I'm very serious about Buddhist philosophy and unless you've done some serious study you're in no place to pass judgement. Additionally, where I come from you have to do more then say yes or no to prove your argument.

    Here is a simple yes or no question. Is an electron permanent or impermanent?
     
  14. Nov 10, 2008 #13

    Jonathan Scott

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    Yes.

    (Provided that the sets "permanent" and "impermanent" together cover all possibilities, which seems reasonable, it must be one of the two).

    Would you like to rephrase the question?
     
  15. Nov 10, 2008 #14

    Fredrik

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    I understand science well enough to know that something that isn't science, or at least philosophy about science, is irrelevant.

    Then why didn't you?

    You're the one who said that the two things depend on each other. If you're right, you can prove it just by saying how they depend on each other. What do you think I should do? List all the ways in which they don't depend on each other?
     
  16. Nov 11, 2008 #15
    I agree these questions are wide open. We all have our preferences which probably relate more to our philosophical inclinations than any demonstrable evidence.

    The fact that there are so many qm interpretations is evidence that no-one really knows why quantum mechanics behaves as it does.
     
  17. Nov 11, 2008 #16


    It just means that we are just beginning to discover who/what we are and we are mostly stumped. Perhaps it has to do with our classical, reptilian way of thinking in a world of probabilities and uncertainty. We've only recently discovered the controversy surrounding notions such as:

    Matter -- Force

    Movement -- Rest

    Existence -- Non existence

    Wave -- Particle

    ... which are somehow combined and "co-existing". But wait, the best is yet to come, when we start discovering how/why elementary partciles combine to form wonderful beings. I expect the confusion to be no less that mind-blowing, sould we reach such a stage in our development.
     
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