Spacetime Metric: Which signature is better?

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Discussion Overview

The discussion revolves around the preference for different signatures of the Minkowski spacetime metric, specifically the (-,+,+,+) versus the (+,-,-,-) signatures. Participants explore the implications of these preferences in the context of mathematics and physics, questioning whether there is any evidence that Nature favors one signature over the other.

Discussion Character

  • Debate/contested

Main Points Raised

  • Some participants note that mathematicians generally prefer the (-,+,+,+) signature while physicists tend to favor the (+,-,-,-) signature.
  • One participant argues that Nature cannot have a preference since the physics remains unchanged regardless of the signature used.
  • Another participant suggests that the preference for the (+,-,-,-) signature among physicists is due to the forward direction of time and the convenience of the four-vector formulation.
  • Conversely, a participant mentions that those working in dimensions other than four often prefer the (-,+,+,+) signature to avoid complications with sign conventions in tensor calculations.
  • One participant emphasizes that the question of Nature's preference is moot, reiterating that no physics is altered by the choice of signature.
  • A later reply echoes the sentiment that the discussion could have concluded early based on the assertion that Nature does not exhibit a preference.

Areas of Agreement / Disagreement

Participants generally agree that there is no evidence of a preference from Nature regarding the signatures, but they express differing views on the implications of this preference in mathematical and physical contexts.

Contextual Notes

Some discussions involve assumptions about the implications of signature choice on calculations and interpretations in physics and mathematics, but these assumptions are not universally accepted.

LarryS
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It seems that, in general, mathematicians prefer the (-,+,+,+) signature for the Minkowski spacetime metric while most physicists prefer the (+,-,-,-) signature. Is there any evidence that Nature actually prefers one over the other?

As usual, thanks in advance.
 
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Nature cannot have a preference since no physics is changed. The only possible answer, IMO, is the one that you will make fewer mistakes with.
 
I think physicists prefer +--- for several reasons.
Time goes forward, space can go in either direction.
The four vector (E;p,p,p) has the length^2: E ^2-p^2=m^2. -m^2 would be awkward.
 
I think pretty much anyone who works in dimensions other than 4 prefers (-+++...). There is a great benefit to not having to remember exactly how many minus signs you have to think about when working with Levi-Cività tensors, for example.
 
The question was what Nature prefers, not what physicists or mathematicians prefer. PAllen nailed it in the first sentence:
PAllen said:
Nature cannot have a preference since no physics is changed.
The thread could have been locked at that point.
 
Orodruin said:
The thread could have been locked at that point.

And now it is.
 

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