Is General Relativity Based on General Relativity or Equivalence?

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Discussion Overview

The discussion revolves around the foundational principles of general relativity, specifically questioning whether it is based on the principle of general relativity, the principle of equivalence, or both. Participants explore the implications of these principles and their significance in the context of the theory.

Discussion Character

  • Debate/contested

Main Points Raised

  • Some participants suggest that the equivalence principle, which states that a gravitational field is indistinguishable from acceleration in a sufficiently small region, is fundamental to general relativity.
  • Others express uncertainty about the existence of a distinct "principle of general relativity," instead linking it to the principle of equivalence and the principle of relativity from special relativity.
  • A participant introduces the concept of general covariance, explaining that it implies physical laws should not depend on the choice of coordinates, extending the ideas from special relativity.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether general relativity is based more on the principle of general relativity or the principle of equivalence, and there are competing views regarding the significance of each principle.

Contextual Notes

Some assumptions about the definitions of the principles are not fully explored, and the discussion does not resolve the relationship between general covariance and the principles mentioned.

eVulcanon
Is the general theory of relativity based on the principle of general relativity？or the principle of equivalence, or both of them? And if both of them, which one is more important? Thx
 
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eVulcanon said:
Is the general theory of relativity based on the principle of general relativity?

Um. Not sure about that bit, however, the equivalence principle - that in any sufficiently small reason a gravitational field is indistinguishable from acceleration - is pretty fundamental.

Here, the "sufficiently small region" takes care of eliminating the tidal forces that would allow you to distinguish the field from (linear) acceleration.
 
I don't know about any "principle of general relativity" other than the principle of equivalence...

...unless you're thinking about the principle of relativity, which underlies special relativity: that physical laws are the same in all inertial reference frames.
 
thank u guys!
 
The "General" refers to the principle of general covariance. From Wikipedia:
Wiki said:
The essential idea is that coordinates do not exist a priori in nature, but are only artifices used in describing nature, and hence should play no role in the formulation of fundamental physical laws.
That's an extension to special relativity, where physical laws look the same only in a special subset of coordinate systems - inertial frames.
 

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