Special Relativity and Absolute Simultaneity

Collected papers by J. H. Field MA, D.Phil

Special Relativity and
Absolute Simultaneity

Collected papers by J. H. Field MA, D.Phil

The Reciprocity Principle

We noted under Absolute Simultaneity and Invariant Lengths that John Field came to the conclusion that the Reciprocity Principle did not apply to Special Relativity. Instead, he replaced the Reciprocity Principle:

"If the velocity of an inertial frame S' relative to another such frame S is v, then the velocity of S relative to S' is -v."

With a "Kinematical Reciprocity Principle":

The velocity of an inertial frame S' relative to an inertial frame S in primary space-time experiment is equal and opposite to the velocity of S relative to S' in the reciprocal experiment.

This uses the concept of primary and reciprocal scenarios, instead of reciprocal views of the same space-time experiment. Unlike the Reciprocity Principle, this Kinematic Reciprocity Principle is actually a definition of a pair of reciprocal experiments.

Having defined `reciprocal experiments' the "Measurement Reciprocity Principle" is postulated:

Reciprocal space-time measurements of similar rulers and clocks at rest in two different inertial frames S, S', by observers at rest in S', S respectively, yield identical results.

This is the first postulate Field uses to derive the Lorentz Transformation,, as noted under The Lorentz Transformation.

John Field's paper "Primary and reciprocal space-time experiments, relativistic reciprocity relations and Einstein's train-embankment thought experiment" may be viewed or downloaded here.

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