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Quantum Physics & Reality

  1. Aug 26, 2009 #1
    Hi,

    I'm new here and I apologise in advance for any perceived abruptness and hope I am not causing offence :)

    I am debating a guy, religious philosophy type, who claims that virtual and real universes would be indistinguishable from each other ... to some degree I suppose that is true i.e. that we cannot prove the universe we live in is real (it’s an assumption ... if it isn't real it seems to be persistent). He is has used a number of tacks including referring to solipsism (as I understand it the idea that nothing exists outside of oneself ... interesting I suppose but ultimately pointless) though I'm not quite sure what he thinks it proves.

    My basic stance is that reality is the more realistic assumption (so claims that it is not are effectively the extraordinary one) but he has advanced a claim that quantum physics somehow disproves this (that quantum physicists) and I wasn't sure what he meant by this so I went to the guys at CFI (Centre For Inquiry) who helped me compose the following reply:

    Since then (trying to avoid the twisting conversation you usually get in forum debates) he has claimed he didn't claim what he appeared to claim saying that he wasn't a quantum physicist nor am I) and that he wasn't referring to Bohmists but specifically to the Bohrists/Copenhagists. He went on further to say that was a realist which I found amusing since he believes in a deity without evidence and that what quantum mechanics showed depended on the interpretation i.e. arealist/acausalist (Copenhagen orthodoxy) or realist/causalist (Bohm). Being no specialist (just a bog standard adherent of science) I pointed out to him that quantum mechanics describes physical reality, how matter is composed of molecules & atoms and how they are composed of yet smaller particles still to which he replied:

    He also recommended a book called “Quantum Theory and the Flight From Realism: Philosophical Responses to Quantum Mechanics” noting that it was, "not representative of a standard interpretation of quantum mechanics, which involved fundamental quantum arealism, aphysicalism, unknowability outside of the unrealistic observationally modified information and even then, quantum nonlocality, quantum indeterminacy, quantum acausality, uncertainty, and other things in stark contradiction to classical, Einsteinian metaphysics, and in Einstein’s words, a 'spooky' picture of the universe."

    So I posted the above over at CFI again and further summarised with the questions:

    1. Am I presenting the classic Einsteinien view? I mean I thought I was just critiquing his view that QM disproves reality ... I think he is referring to Heisenberg and similar here, uncertainty and stuff.
    2. Who is this Bohm guy and why is he relevant? I’ve read stuff on Wiki about him but he seems to be referring to him as a major player whereas I thought the major disagreement was between the Einstein and Heisenberg camps of thought. I’ve never heard of Bohm.
    3. Is the Copenhagen interpretation as widely accepted as implied? Is that relevant?
    4. Is metaphysics of any real value ... as far as I can tell it can be used to “prove” almost anything and can be somewhat cynically defined as a means of justifying that which cannot be demonstrated empirically.

    That was when someone recommended I address this to a physics forum and explains why I am here :)

    So my questions (just above) are what I want to know about, I apologise for the long post and hope I haven't offended anyone, I'm unashamedly atheist and tend to view modern day philosophy (and especially metaphysics) in a rather poor light but, with my evidence based view of the universe, I rail against almost everything he says and I'm looking for a way to answer him.

    EDIT: Jesus! I've just been looking at some of the stuff on QM you guys have been posting and I'm wondering if I'll even understand any answers I'm given? No wonder the CFI guys couldn't take it further!

    Kyu
     
    Last edited: Aug 26, 2009
  2. jcsd
  3. Aug 26, 2009 #2
    If QM has the final say, the reality you perceive lies somewhere between not very real and totally unreal. Matter is almost entirely empty space and a certain class of weakly interacting 'partciles' - neutrinos, show us that our 'solid' world is more like a shadow through which they pass all the time(billions per second), as if nothing happened. And it doesn't matter if that's the Earth, the Moon or the Sun that they pass through. Then, concerning your argument over God(s), it's unclear what selects outcomes from superpositions of states, so that "we" always end up in environments that can be comprehended and are sensible. The problem of outcomes may not be a question that science can tackle at all. Thus, radical ideologies like hardcore atheism and fundamentalist religions lose their ground.
     
    Last edited: Aug 26, 2009
  4. Aug 26, 2009 #3
    The argument doesn't need to be about defining reality or what QM tells us or doesn't. In fact I don't believe it actually is. The guy seems to be arguing for a "Matrix"-like virtuality. That's computationalism, not physics.

    I'd ask him if he likes Nick Bostrom's Transhumanism, or Ray Kurzweil's dogmatics about the Singularity. Ask him if he wants to be downloaded to a CD or whatever so he'll never die (Kurzweil actually believes that stuff). Your opponent's religious? You should dig ole Ray rhapsodizing about the joys of virtual sex. It's reminiscent of back-of-the-magazine adverts for swingers' clubs. Your opponent might even be able to have sex with historical religious figures of his choice. If that idea offends him, remind him that there are probably plenty of people it doesn't.

    Just a thought.
     
  5. Aug 26, 2009 #4

    dx

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    He's talking bogus. Quantum Mechanics does not "disprove reality". On the contrary, it gives us an astonishingly accurate picture of it.
     
  6. Aug 26, 2009 #5

    Especially of Time and Space. But you were joking, right?

    I presume that you are aware that because of this "astonishingly accurate picture" of reality, we are in need of a drastically new theory of space and time which will be compatible with the laws of quantum mechanics as we know them, and somehow allow a theory of quantum gravity to exist.
     
    Last edited: Aug 26, 2009
  7. Aug 26, 2009 #6

    DrChinese

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    Welcome to PhysicsForums, Kyu!

    You will find plenty of discussion of the above here. I might make a few recommendations before you go much further. First, take some time to learn about some of the key issues and players in the debate about the nature of reality. Then follow some of the other threads here on the Interpretations of Quantum Mechanics and Entanglement. Quickly you will get familiar with the buzzwords.

    1. EPR (Einstein Podolsky Rosen), 1935
    2. David Bohm's work on Pilot Wave theory, which is usually referred to as the Bohmian Interpretation.
    3. Bell's Theorem, 1965
    4. Aspect's experiments, 1981

    I maintain a couple of pages on my own web site about several of these: you can read 1, 3, and 4 at: EPR, Bell & Aspect: The Original References (in PDF Format)

    Basically, the accepted view is that you must abandon either a) classical notions of reality; or b) the speed of light as a fundamental "speed limit" for the propagation of cause and effect. Einstein was opposed to abandoning either (you would expect that) but died before 3. and 4. above appeared on the scene.

    The questions about Heisenberg's Uncertainty Principle - which go to the roots of realism - and Bohm - which go to the roots of locality - will mostly be answered in these papers. They are readable although the math will likely elude you. Just focus on the discussion and you should be able to follow. It is easy to get pulled off track and many discussions tend to become semantic questions. It helps to get to the point where you understand the good and bad points on each side.

    -DrC
     
  8. Aug 26, 2009 #7
    Since Time appears to be such a fundamental concept in our macro realm of reality, it's also definitely worth checking out Wheeler's Delayed Choice Experiement(on cosmological scales).
     
  9. Aug 27, 2009 #8
    Solipsism is a useful thought experiment when one is dealing with 'what we can know' (epistemology) about the world (Descartes), but as a theory of what actually exists (ontology), it fails on almost every level.

    'Virtual reality' or brain-in-a-vat type arguements are not actually solipsism. They are used to question one's ability to 'know' the external world. Solipsism, on the question of existence, really only deals with the mind or self existing. Virtual reality demands hardware to run on, that is, a vat, of some sort.
    Kant's phenomenology, and his idea of 'thing-in-itself', describe a kind of virtual reality.
    I very much enjoy modern philosophy, and I am thoroughly atheist. The problem as I see it is that most people, if they are exposed to philosophy at all, its either via a first year course, or via pseudo-philosophical mysticism, like you find in the Matrix movies.

    If one is as wedded to the empiricism of science, as most scientists are, something like http://en.wikipedia.org/wiki/Methodological_naturalism" [Broken] is safe ground.

    Trying to argue for some sort of realism tends to fall apart pretty quickly.
     
    Last edited by a moderator: May 4, 2017
  10. Aug 27, 2009 #9
    Kyuu could refer his opponent to the first chapter of Putnam's Reason, Truth and History and lay the Skolem–Löwenheim theorem on him ... argue that whether or not you in fact are a brain-in-a-vat it's incoherent to say you are or might be.

    Somehow, though, it's hard to imagine that working.
     
    Last edited: Aug 27, 2009
  11. Aug 27, 2009 #10
    Reality is more realistic... Interesting.
     
  12. Aug 27, 2009 #11
    Coherence is slippery.

    To argue against an actual brain-in-a-vat scenario, as opposed to arguing against it epistemologically, occam's razor pretty good though. The simplest explanation is that we experience a reality similar to what exists. People claiming the contrary, have the onus on them, to provide evidence.
     
  13. Aug 28, 2009 #12
    Which is apparently what the guy thinks he's doing by dragging in QM. Sadly, "QM" can be spun to argue for almost anything. Even physicists ... Jack Sarfatti, Nick Herbert ... one or both of them tried communing with the spirit world via an Eccles Telegraph-type setup, a teletype machine connected to a source of quantum randomness. Okay, it was an experiment, and it didn't work, and this truth was acknowledged in a scientific ... spirit. But the fact that it was attempted ... hello ...

    We know from the hopeless MWI debates than Occam can be variously interpreted. And someone can always say, "Well, yes, your explanation is the simplest if you're just taking into account the known facts, but I'm saying there must be facts we haven't discovered yet." Which is when you discover how you simply need a drink.

    Kyu should probably challenge this ridiculous ideologue to show that there's any connection between QM and virtuality. Might keep the guy busy for a while. (Ignore "virtual particles": there you have a separate definition of "virtual". The particles are real, just extremely short-lived. Computational virtuality is a simulation, like Bugs Bunny.)
     
  14. Aug 28, 2009 #13
    Occams Razor can't be used to show that a theory with 'facts we haven't discovered yet' is better than its opposition. Why? Because that's antagonistic of Occams Razor.

    Occams Razor in a jist is used to determine which theory is better than the other by comparing the amount of postulates... So the theory that uses only facts is the superior one. This doesn't mean its more correct however and 'facts we haven't discovered yet' are alas, not facts at all, now are they?

    So IMO if you are arguing with someone and you turn to Occams Razor then your opponent uses that line BAM point conceded move to the next.
     
  15. Sep 4, 2009 #14
    I'm not quite sure which (mod?) moved this thread from the Quantum Physics forum to the philosophy forum but it must have been quite clear from my opening post that I wanted to discuss this with people that knew something about Quantum Physics and NOT (under any circumstances) with philosophers.

    Thanks anyway to those QP people who answered but I'm done.

    Kyu
     
  16. Sep 8, 2009 #15
    My naive impression is that Quantum Mechanics is a phenomenological theory of observation and does not tell us anything fundamental about the world. It does however point to deep unanswered questions.

    Currently, the measurement problem is considered to be the key gap in QM and no one knows at this point how to solve it. During a measurement, the wave function collapses. this collapse is not a solution of the Shroedinger equation and so must find its answer in a new theory.

    Attempts have been made to modify QM to explain measurement but they all have problems. One theory hypothesizes that the wave function randomly gets multiplied by a Gaussian distribution, another hypothesizes many universes in which all possible observations occur. Wigner thought that there is a spiritual world that permeates the mind which by its nature contains only definite discrete ideas. Its interaction with the world of sense causes the probability wave to collapse into a definite outcome.

    Bohm's theory returns QM to mechanics and is formally deterministic. Many Physicists believe that his theory will lead to an understanding of measurement.
     
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