In his original paper of 1905, "On the Electrodynamics of Moving Bodies", Einstein described a procedure for synchronizing distant clocks at rest in any inertial system K. Clocks thus synchronized may be said to be in standard signal synchrony in K. It has often been claimed that there are no logical or physical reasons for preferring standard signal synchronizations to any of a range of possible non-standard ones. In this paper, the range of consistent non-standard signal synchronizations, first for any (...) one inertial system, and second for any set of such systems, is investigated, and it is shown that the requirement of consistency leaves much less room for choice than is commonly supposed. Nevertheless consistent non-standard signal synchronizations appear to be possible. However, it is also shown that good physical reasons for preferring standard signal synchronizations exist, if the Special Theory of Relativity yields correct predictions. The thesis of the conventionality of distant simultaneity espoused particularly by Reichenbach and Grunbaum is thus either trivialized or refuted. (shrink)

The objective of this article is to provide a formalism to deal with the special theory of relativity (STR, in short) as riewed by Reichenbach, according to which STR involves an ineradicableconventionality of simultaneity. One of the two postulates of STR asserts that, in empty space, the one-way speed of light relative to inertial frames is constant. Experimental evidence, however, is related to the constancy of the round-trip speed of light and has no bearing on one-way speeds. Following Reichenbach's viewpoint, (...) we relax the second postulate of STR, abandoning the constancy of the one-way speed of light to the more realistic one asserting the constancy of the round-trip speed of light. This, in turn, results in a formalism to deal with Reichenbach's special theory of relativity (RSTR, in short) in which the two one-way speeds of light in empty space, C±, in the two senses of a round-trip are arbitrarily selected in such a way that their harmonic mean is the measurable round-trip speed of light, c. Experimentally, RSTR and STR are indistinguishable and, hence, represent the same physical theory. It is only the formalism that we use to deal with STR which is extended in RSTR to accommodate the immeasurability of one-way velocities. The usefulness of the proposed formalism to study special relativity is demonstrated. (shrink)