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Is Quantum Physics an Epistemology or an Ontology?

  1. Dec 8, 2007 #1
    "The conception of objective reality of the elementary particles has thus evaporated not into the cloud of some obscure new reality concept but into the transparent clarity of a mathematics that represents no longer the behaviour of particles but rather our knowledge of this behaviour.'' (Werner Heisenberg)

    I would like to know if modern physicists today suscribe to this statement,as it seems to me that,at least,the so called mainstream physics does not take this literally,to say the least?

    I am just a physics "aficionado",trying to make some sense of the reputed weirdness of quantum physics,any comments appreciated.

  2. jcsd
  3. Dec 8, 2007 #2


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    Well, considering the definition of epistemology and ontology -

    epistemology - the study or a theory of the nature and grounds of knowledge especially with reference to its limits and validity

    ontology - a particular theory about the nature of being or the kinds of things that have existence

    then QM is more ontology than epistemology.

    I believe what Heisenberg was alluding to was the fact that we cannot 'see' atoms and subatomic particles, but we observe their interactions with other matter. We construct mathematical models based on the observations of the interactions and if we can correctly predict expected behavior, then we have confidence that that models are correct.
  4. Dec 8, 2007 #3
    Thanks for your answer Astronuc:smile:

    However,what I understood from this statement of Heisenberg,is that Physics had abandoned the hope for explaining the nature of reality (ontology),and resigned to a mere " our knowledge of reality" (epistemology).
    There are many physicists,among them Henry Stapp,who apparently suscribe to this view of Physics.

    So,what I thought was that Modern Physics had renounced to find "the nature of reality",in favor of the only alternative,"our knowledge of reality" (our perception of it?)

    Is this correct to you?

  5. Dec 8, 2007 #4


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    Well I would disagree with this. Modern physics, i.e. that of the last 100-200 years, has done a very good job of describing the reality of nature, simply based upon the theories that explain what we observe, and on the results of experiments which show that the predictions of theory are correct.

    On the other hand, I don't think we finished learning or developing an understanding the universe. And perhaps there are things like the initial conditions that we may never understand - certainly not in my lifetime.

    As for our 'perception' of reality - that's an exercise in philosophy :biggrin"
  6. Dec 8, 2007 #5
    I think that QT, epsitemologically speaking, deals with the knowledge "that exists", and not with the knowledge "how that exists". In other words, there is something missing. In that respect, it has no ontology to explain 'how that exists'.

    From a philosophical perspective, if there is no quantum model, then how QT treats the electron (both statistically and mathematically) becomes a twisted ontology, and quantum physicists would argue that this is the basis for their own special philosophy of science.

    I would say, in my opinion, that Quantum theory is neither an ontology or an epistemology, and that is why it is so hard to grasp.
  7. Dec 8, 2007 #6
    As it stands in my opinion, QM is a curvefitting mechnism. By mere coincidence theorists have discovered mathematical formalisms that fit the data. There is no explanation offered as to why that particular formalism works, it just does. So it is all ontology and no epistemology.

    We would have to find some fundamental principle that gives rise to QM before we could say that QM is founded on some epistemological principle. Perhaps we are not too far from that.
  8. Dec 8, 2007 #7
    Let me quote a few comments about this:

    Wigner (1961): "the laws of quantum mechanics cannot be formulated...without recourse to the concept of consciousness".

    Bohr (1934): "In our description of nature the purpose is not to disclose the real essence of phenomena but only to track down as far as possible relations between the multifold aspects of our experience.''

    "What we observe as material bodies and forces are nothing but shapes and variations in the structure of space. Particles are just schaumkommen (appearances).The world is given to me only once, not one existing and one perceived. Subject and object are only one. The barrier between them cannot be said to have broken down as a result of recent experience in the physical sciences, for this barrier does not exist".(Erwin Schrödinger on Quantum Wave Mechanics)

    Hendry (science historian) says: "Dirac, in discussion, insisted on the restriction of the theory's application to our knowledge of a system, and on its lack of ontological content.'' Hendry summarized the concordance by saying: "On this interpretation it was agreed that, as Dirac explained, the wave function represented our knowledge of the system, and the reduced wave packets our more precise knowledge after measurement.''

    "These quotations make it clear that, in direct contrast to the ideas of classical physical theory, quantum theory is about “our knowledge.” We, and in particular our mental aspects, have entered into the structure of basic physical theory" (Henry Stapp)

    It seems to me that these people are not doing any "exercise in philosophy",how would you respond to that?

    Last edited: Dec 8, 2007
  9. Dec 8, 2007 #8
    Hi Friend:

    I'm not an expert, but I have suspected that there is a degree of 'overfitting' within QM.

    For instance, Bohr was able to describe the spectra of Hydrogen rather well, within experimental error. In that respect it was a successful theory, mathematically. It did predict and reproduce empirical facts for Hydrogen-like systems. The problem was that it failed to do the same for elements with two electrons.

    I know that QT was initially able to reproduce the spectra of Helium, even though I've never actually seen it done, to an accuracy around 20-30%. That is certainly not acceptible. It follows that other methods, mathematical formalisms were introduced (perhaps that is what you mean by 'curve fitting) that reached better accuracy...

    The question is whether these formalisms constitute an ontology, a theory really, that can be traced back in a sense to first principles? Next, are these really principles? If QT is based upon what can be qualified as first principles then it is an ontology. If it cannot, and if it is just a mathematical formalism, as it appears you suggest, then it is not an ontology.

    I don't have the answer, yet. It is something that I am trying to figure out...
  10. Dec 8, 2007 #9
    It's a bit like we're waking up to a realisation that there's something important about the world that we haven't grasped yet. There's a whole lot of connections and math trying to describe it all, we aren't exactly shrugging our shoulders, but we still have to admit, we don't know what it is yet. Quantum 'behaviour' and its wave-like nature somehow "arrive" on our classical viewscreen.
    Something to do with observation and how we 'see' it. Or how it 'sees' us, maybe. Or something like that.
  11. Dec 9, 2007 #10
    So know of some who seem to derive QT from nothing more than a requirement of consistency between facts (whatever they are). But this seems to be a work in progress and is not fully developed yet. Is that the kind of first principles that would make QT an epistemology?
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