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GR or QM: which is more 'fundamental'?

  1. Apr 5, 2012 #1
    Which and why do you believe will turn out to be more 'fundamental' (in the sense that one will prove to be the foundation of a theory which goes beyond the SM, while the other will be explained away by it). Or maybe both, or neither?
  2. jcsd
  3. Apr 5, 2012 #2


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    Of course, you are asking about personal hunches here. Mine is that QM is more fundamental, and GR is the 'end of the Maxwell line' of continuous, deterministic, field theories. Now, what I mean by QM more fundamental is that there is no hidden determinism underneath QM (even non-local determinism). This is a hunch, that cannot be proven, at present.

    On the other hand, I think the current QFT formulation is not very fundamental, and not likely to 'last' any more than GR. Some deeper non-deterministic formulation would have spacetime, QFT, and GR as emergent phenomenon,
  4. Apr 5, 2012 #3


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    GR is a theory of geometry itself. Geometry interacting with matter is the basis of everything else.
    Everything is built on/in space/time.
    Asking "which" will turn out to be "more fundamental" is the wrong way to ask the question.
    Something is either fundamental or it's not. GR is obviously inadequate.

    What will be fundamental will be whatever theory replaces GR as our theory of spacetime itself. Its central focus will be a mathematical representation of geometry, and that picture of the world's geometry will be fully interactive with matter.

    Whatever that theory of interactive geometry turns out to be, the fields of the SM will be relocated onto it.

    It is useless to ask "which is closest?" you could say GR is closest because it is ABOUT geometry interactive with matter, and QM is not. Or you could say QM is closest because GR is not yet a quantum theory, so cannot possibly be itself part of the next basic theory assemblage.
    It's like asking someone what's their favorite color. You might learn a bit about the metric that person uses to judge by, you learn about them not about reality.
    Last edited: Apr 5, 2012
  5. Apr 6, 2012 #4


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    In 1930, Einstein attacked consistency of QM, while Bohr argued that GR saves consistency of QM. But from a modern perspective they both seem wrong, as discussed in detail here:

    I see that as another argument that QM is more fundamental than GR.
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