Many Worlds versus Thermal interpretation

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Discussion Overview

The discussion centers on the comparison between the Many Worlds Interpretation (MWI) and the Decoherent Histories (DH) approach within the context of quantum mechanics and its implications for quantum gravity. Participants explore the merits and shortcomings of each interpretation, as well as their philosophical implications.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants express that the Many Worlds Interpretation has significant support in the theoretical physics community, but others find it superficial and argue for the thermal interpretation as a more substantial alternative.
  • One participant suggests that Decoherent Histories shares the virtue of making sense of the state of the universe, similar to MWI, and is also applicable to quantum gravity.
  • There is a question raised about the relationship between Decoherent Histories and the Many Worlds Interpretation, with a participant noting that reading James B. Hartle suggests a similarity.
  • Another participant points out important differences between MWI and DH, stating that while both resolve a pure initial state into orthogonal branches, MWI posits that all histories occur, whereas DH asserts that only one history occurs.
  • A challenge is posed regarding the definition of a 'real' history in DH, questioning whether the lack of such a definition reduces the discussion to semantics.

Areas of Agreement / Disagreement

Participants express differing views on the validity and implications of MWI and DH, indicating that multiple competing interpretations remain without a consensus on which is preferable or more accurate.

Contextual Notes

Participants reference specific interpretations and their applicability to quantum gravity, but there are unresolved questions regarding the definitions and implications of 'real' histories in the context of Decoherent Histories.

A. Neumaier
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TL;DR
Points out an interesting book by Bryce DeWitt on quantum gravity and its interpretation issues
The two volume treatise
which discusses the canonical approach to dynamical quantum gravity, is probably responsible for the fact that the many worlds interpretation (MWI) of quantum mechanics has a sizable support in the theoretical physics community. His emphasis on the MWI is not to my taste and seems to me far too superficial, sweeping all the difficulties under the carpet.

But one can replace his interpretation discussion without any loss of substance by a reference to my thermal interpretation, since the latter shares the main reason why DeWitt championed MWI:

In both interpretations, the state of the universe makes sense (a necessary prerequisite of any theory of quantum gravity) , and no other covariant interpretation has this virtue.
 
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In both interpretations, the state of the universe makes sense (a necessary prerequisite of any theory of quantum gravity) , and no other covariant interpretation has this virtue.

I believe Decoherent Histories also shares this virtue, and is as readily generaliseable to quantum gravity.

https://arxiv.org/abs/1803.04605
 
Morbert said:
I believe Decoherent Histories also shares this virtue, and is as readily generaliseable to quantum gravity.

https://arxiv.org/abs/1803.04605

Isn't DH the same as Everett? Reading James B. Hartle it's hard not to conclude that
 
Quanundrum said:
Isn't DH the same as Everett? Reading James B. Hartle it's hard not to conclude that

There are important differences. E.g. Given a set of decoherent histories of a closed system, both Both MW and DH would resolve a pure initial state into orthogonal branches corresponding to the histories. But MW says all histories occur, while DH says only one history occurs.
 
Morbert said:
There are important differences. E.g. Given a set of decoherent histories of a closed system, both Both MW and DH would resolve a pure initial state into orthogonal branches corresponding to the histories. But MW says all histories occur, while DH says only one history occurs.

If it doesn't define how one 'real' history occur, then it's just semantics?
 
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