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Bernard d'Espagnat Quote

  1. Mar 16, 2009 #1
    Hi everyone,

    I've always thought that the idea of a relationship between consciousness and wave function collapse (or any other quantum phenomenon) was just a common laymans misunderstanding.

    But then I read this quote:

    "The doctrine that the world is made up of objects whose existence is independent of human consciousness turns out to be in conflict with quantum mechanics and with facts established by experiment."

    Bernard d'Espagnat said it and as far as I know he is a well respected phsicist!

    Does anyone know what he is reffering to?
  2. jcsd
  3. Mar 16, 2009 #2
    I have to take issue with the "... independent of human consciousness" part. What about other creatures? Chimps can't be observers? You have to have a certain intelligence, or something? Seems far fetched. If this statement has any truth to it then IMO it must have more to do with whatever it is that defines life that what defines consciousness. I'm curious to hear what someone who actually knows something thinks though!!
  4. Mar 16, 2009 #3
    It's his own interpretation of quantum mechanics. If you were inclined to follow the logical chain to this conclusion, I'm sure you could shoot plenty of holes in it.
  5. Mar 16, 2009 #4
  6. Apr 23, 2009 #5

    He reffers to the usual (widely used) conception of realism which postulate that a Mind Independent Reality is at least in principle knowable, in the sense that it is possible to "describe it in precise words and details". Yet he can be seen as being still a supporter of a form of ontological realism (weak) for in his view the independent reality is 'veiled' but we can still catch an indirect glimpse of its existence (he "does not a priori dismiss the view that the great mathematical laws of physics may let us catch some glimpses on the true structures of Mind-Independent Reality"). See more details here.

    Personally I prefer a form of sophisticated realism much closer to the usual conception of realism taking in account the valuable parts of instrumentalism (we can know the independent Reality at least partially but we must always remain open to non-trivial paradigm shifts here). Let's hope that the 'deep' Reality is not so 'veiled' as d'Espagnat argues and that it will not remain, if it exists, 'forever God's secret'*. Anyway there is still hope that modifications at the level of the basic postulates of QM - around which the existing interpretations are built - could make an 'objective' difference between the various interpretations of QM and that the 'winner' is clearly realist in nature. Although we are far from such a result we certainly do not have the right to underestimate it.

    *I tend (as a provisional, fallible, personal preference) towards a hidden variables interpretation, realist in nature (a contextual one, involving 'observer influenced Reality', opposed to 'observer created Reality' or Einstein's noncontextualism). Remain to be seen its final form, there is still plenty of room in spite of Zeilinger's experiments (de Broglie-Bohm-Vigier non-local interpretations are only some possibilities, the only ones that 'work' - to some extent - at this moment in time); hidden variables interpretations are not even necessarily causal, they are compatible with the existence of a few uncaused events
    Last edited: Apr 23, 2009
  7. Apr 23, 2009 #6


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    Quantum and classical models are like oil and water. Clearly both are successful as models, but they don't mix. It seems they cannot both make sense within the same interpretive frame.

    So some people say you have to believe it is "quantum reality" all the way up. Because it seems impossible to insert an "epistemic cut" - a wave function collapse - at any classical point, there is a regress all the way to the mind of the human observer. Very mystical and unlikely, but "logical" if you take the model as being also "the real".

    Then there is the opposite reaction. The one that leads to a belief in hidden variables. Now it is about pushing the classical viewpoint all the way down. Once we get into quantum terrain, we argue that there must be classical reality - and we just can't see it yet.

    Another pathological response that results is the many worlds interpretation - actually very popular among top theorists. Because classical reality must be the truth all the way down, we have to believe there is a crisp forking of classical histories concealed behind what we view in our splintered reality as a quantum uncertainty.

    I started a separate thread on vagueness which is perhaps a way to resolve all this.


    The basic idea is that interpretation problems arise because quantum level and classical level descriptions of reality are both treated as "crisp existence". Actual and definite states - even though QM is a bit weird as a state. So this sets up a boundary problem as there has to be a sudden binary transition as you cross from one realm to the other.

    But an alternative view is one where such a transition is soft or gradual. A change that develops. Where one realm is a "state" of potential. Then the potential gets shaped up to be something more crisply actual - decohered in QM jargon. Though really it would be more like the incoherent (the vague) being made coherent (crisply developed).
  8. Apr 26, 2009 #7
    Thanks for the great replies metacristi and apeiron!
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