Is Einstein’s procedure for the synchronization of clocks in Special Relativity merely a convention about the one-way speed of light? This issue was first raised in the 1920s by H. Reichenbach, who argued that the standard synchronization involves circular reasoning, and that a nonstandard synchronization convention can be adopted, with unequal values of the speed of light in opposite directions. This “conventionalist thesis” has been widely discussed by physicists and philosophers in the context of kinematics, but not in the context of dynamics. We will show that an examination of the laws of dynamics resolves all ambiguities in synchronization. The nonstandard Reichenbach synchronization introduces pseudoforces into the equation of motion, and these pseudoforces are fingerprints of the nonstandard synchronization, just as the centrifugal and Coriolis pseudoforces are fingerprints of a rotating reference frame. In an inertial reference frame, the nonstandard synchronization is forbidden.

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Also called Einstein convention; see C. Audoin and B. Guinot, The Measurement of Time (Cambridge U.P., Cambridge, 2001).
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See Ref. 1, p. 113.
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My notation differs from that of Anderson et al., who use κ / c instead of k. Although this has the advantage of making κ dimensionless, it has the very serious disadvantage of introducing gratuitous factors of c into the equations, and these factors of c create the impression that the term κ / c is a relativistic effect, which in the present context it is not.
17.
Unfortunately, the equations given by Anderson et al. contain a slew of misprints.
18.
There is no violation of causality from this. With k<1/c, the extra time k⋅(xsx) is always smaller than the light travel time, so the events in question are outside the light cone.
19.
In the relativistic case, with high-speed motion, the interparticle forces are altered, and the relativistic length contraction can be calculated from the alteration of the forces; that is, the relativistic length contraction can be given a dynamical interpretation. Such a calculation was done by J. S. Bell on the basis of a naïve Bohr model of the atom [reprinted in J. S. Bell, Speakable and Unspeakable in Quantum Mechanics (Cambridge U.P., Cambridge, 1987), Chapter 9]. But it is not hard to calculate the length contraction for a hydrogen atom by exact solution of the Dirac equation for an electron bound to a high-speed proton. The historical and logical role of such a dynamical interpretation of the length contraction in relativity is incisively discussed by H. R. Brown, in Physics Meets Philosophy at the Planck Scale, edited by C. Callender and N. Huggett (Cambridge U.P., Cambridge, 2000).
20.
In this calculation we did not need to take into account the standard retardation of electromagnetic effects. For uniform translational motion, the electromagnetic fields “anticipate” the motion of the charged particles, and the electric force is directed toward the actual position of the particle, rather than toward its retarded position.
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