Is Black hole complementarity incompatible with Block Time?

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Discussion Overview

The discussion centers on the compatibility of black hole complementarity with the concept of block time, exploring theoretical implications and challenges. Participants also touch upon the Second Law of Thermodynamics in the context of General Relativity (GR) and curved spacetime.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants propose that black hole complementarity presents two distinct narratives for observers, which may conflict with the block time perspective that suggests a static universe where all histories are consistent.
  • Others agree that black hole complementarity is incompatible with block time, referencing specific academic articles to support their views.
  • One participant raises a concern about the implications of block time on the concept of a "conscious observer," suggesting that without block time, the observer's role becomes problematic.
  • A participant questions the applicability of the Second Law of Thermodynamics in GR, particularly in curved spacetime, suggesting that the definition of conservation may be problematic in such contexts.
  • Another participant challenges the notion that the Second Law is problematic in GR, seeking clarification on the reasoning behind this concern.
  • A later reply emphasizes that if conservation is not well defined, then the concept of something "never decreasing" also becomes ambiguous, particularly in relation to time in curved spacetime.

Areas of Agreement / Disagreement

Participants generally agree that black hole complementarity and block time are incompatible, but the discussion regarding the Second Law of Thermodynamics remains unresolved, with differing viewpoints on its applicability in GR.

Contextual Notes

Limitations include the potential ambiguity in defining conservation laws in curved spacetime and the implications of time's smoothness on thermodynamic principles. The discussion does not resolve these complexities.

Dmitry67
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As I understand, complementarity approach claims that there are 2 different stories, for an infalling observer and an observer @ infinity, they are different, but no observer can confirm both.

But it violates the Block Time/Eternalism, where time is a dimension, the whole world is a static solution, so all histories must be consistent (even if physically observers can't verify some aspects of it).

Also, infalling observer has some extra time inside the horizon, she or he can decide to commit suicide while being inside the black hole but before the terrible death by spagettification. For an external observer, all information is radiated from the horizon, but how it might include information about the potential suicide?
 
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Thank you.
Good to know - because without Block time we add (once again!) the "conscious observer".
 
Additional question, after looking at your articles.
What's about Second Law of Thermodynamics in GR, specifically in curved spacetime?

I know that there are issues with Conservation of Energy in GR, mostly not because it is not conserved, but because sometimes it is impossible to define what is "to be conserved" in strongly curved spacetime. I expect the Second Law to suffer from the same problem in GR. Am I right?
 
I don't see any problem with second law of thermodynamics in GR. Why exactly do you think it's a problem? Or perhaps you meant the first law?
 
No, I meant the Second law.
If "something is conserved" (=const) is not well defined, then "something never decreases" is also not well defined. "Never decreases" means "never decreases in time", assuming that time is smooth enough, so moments "now" and "then" are well defined. Do you agree?

For example, what's about Second law in Goedel Universe?
 

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