GR or QM: which is more 'fundamental'?

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Discussion Overview

The discussion centers on the question of which theory, General Relativity (GR) or Quantum Mechanics (QM), is more 'fundamental' in the context of a potential theory that could extend beyond the Standard Model (SM). Participants explore the implications of each theory's foundational role in physics, considering their relationships to spacetime and matter.

Discussion Character

  • Debate/contested
  • Exploratory
  • Conceptual clarification

Main Points Raised

  • Some participants propose that QM is more fundamental because it does not rely on hidden determinism, suggesting that GR represents a limit of deterministic field theories.
  • Others argue that GR is fundamentally about geometry interacting with matter, implying that any future theory must address this interaction as a core aspect.
  • A participant questions the framing of the question itself, suggesting that asking which theory is more fundamental may not be the right approach, as it implies a binary classification that may not capture the complexities involved.
  • One participant references historical debates between Einstein and Bohr, suggesting that both may have been incorrect in their assessments, which they argue supports the view that QM is more fundamental than GR.

Areas of Agreement / Disagreement

Participants express differing views on the fundamental nature of GR and QM, with no consensus reached on which theory is ultimately more foundational. The discussion remains unresolved, with multiple competing perspectives presented.

Contextual Notes

Participants acknowledge the limitations of current theories and the potential for deeper, non-deterministic formulations that could emerge, but these ideas remain speculative and are not fully developed within the discussion.

Aidyan
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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?
 
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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,
 
Aidyan said:
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?
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.
 
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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:
http://xxx.lanl.gov/abs/1203.1139

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

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