Could SR not be built from only one postulate?

  • Context: Graduate 
  • Thread starter Thread starter guitarphysics
  • Start date Start date
  • Tags Tags
    Sr
Click For Summary

Discussion Overview

The discussion revolves around the possibility of combining the two postulates of Special Relativity (SR) into a single postulate. Participants explore the implications of such a combination and whether it can adequately encompass the original postulates, particularly in relation to Maxwell's equations and the laws of physics in inertial frames.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants propose that a single postulate stating "All the laws of physics are the same in every inertial frame of reference" could encompass both original postulates of SR.
  • Others argue that this approach requires the inclusion of Maxwell's equations as a law of physics, questioning whether it is necessary to state this explicitly.
  • A participant challenges the feasibility of deriving Maxwell's equations from the proposed single postulate.
  • Another participant mentions that there are formulations of SR that drop the second postulate, suggesting that the discussion may overlook other foundational aspects of SR.
  • Some participants assert that combining the postulates is valid, while others caution that it may lead to circular reasoning if Maxwell's equations are included without justification.
  • A later reply emphasizes that simply postulating the Lorentz transforms could be an alternative approach to reducing the number of postulates.

Areas of Agreement / Disagreement

Participants express differing views on whether the two postulates can be combined into one. While some support the idea, others maintain that it is not valid without additional assumptions or justifications. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants note that SR is based on more than just the two postulates discussed, indicating that there may be additional assumptions or principles at play that are not fully addressed in the current debate.

  • #121
WannabeNewton said:
Charge density is the time-like component of the current 4-vector and charge is a Lorentz scalar. Charge is defined as the integral of the charge density over a space-like hypersurface. The proof that charge is a Lorentz scalar is actually quite simple, given the 4-divergence of the current 4-vector. It's basically just an application of Stokes' theorem.

Yes, you're right. I can't find my copy of Jackson, so I'm not sure what the alternative theory is that reduces to Coulomb's law in the nonrelativistic limit.
 
Physics news on Phys.org
  • #123
WannabeNewton said:
Charge density is the time-like component of the current 4-vector and charge is a Lorentz scalar. Charge is defined as the integral of the charge density over a space-like hypersurface. The proof that charge is a Lorentz scalar is actually quite simple, given the 4-divergence of the current 4-vector. It's basically just an application of Stokes' theorem.
The 4D divergence theorem
 

Similar threads

Undergrad Understanding Einstein's second postulate of special relativity
  • · Replies 57 ·
2
Replies
57
Views
7K
Graduate Is the constancy of c a postulate or a derivable theorem?
  • · Replies 13 ·
Replies
13
Views
1K
High School Velocity Addn Paradox: SR Postulate Explained
  • · Replies 11 ·
Replies
11
Views
2K
Undergrad The Einstein Clock aka Light Clock
  • · Replies 34 ·
2
Replies
34
Views
3K
Undergrad SR flat Lorentzian manifold and Anderson simultaneity convention
  • · Replies 16 ·
Replies
16
Views
2K
High School Why Shouldn't I Be Skeptical About SR Postulate No.1?
  • · Replies 15 ·
Replies
15
Views
2K
Undergrad Speed of light one more time
  • · Replies 5 ·
Replies
5
Views
1K
Undergrad Postulates of Special Relativity: Speed of Light in Inertial Frames
  • · Replies 9 ·
Replies
9
Views
2K
High School Problem about postulate of the invariance of the speed of light
  • · Replies 33 ·
2
Replies
33
Views
4K
Undergrad Can two inertial frames differ by the speed of light?
  • · Replies 15 ·
Replies
15
Views
3K