This excellent, semi-technical account includes a review of classical physics (origin of space and time measurements, Ptolemaic and Copernican astronomy, laws of motion, inertia, and more) and coverage of Einstein’s special and general theories of relativity, discussing the concept of simultaneity, kinematics, Einstein’s mechanics and dynamics, and more.

The Reichenbach-Grunbaum thesis of the conventionality of simultaneity is clarified and defended by developing the consequences of the Special Theory when assumptions are not made concerning the one-way speed of light. It is first shown that the conventionality of simultaneity leads immediately to the conventionality of all relative speeds. From this result, the general-length-contraction and time-dilation relations are then derived. Next, the place of time-dilation and length-contraction effects within the Special Theory is examined in the light of the conventionality thesis. (...) The slow-transport method of synchrony is then examined in the light of these results and is shown not to provide an adequate method of uniquely determining the one-way speed of light. Finally, the general ε -Lorentz transformations for events along the x-axis are derived from three principles: the round-trip light principle, the principle of equal passage times, and the linearity principle. These principles are shown to be independent of one-way velocity assumptions, and thus may form the basis of a Special Theory of Relativity without distant simultaneity assumptions. (shrink)

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 Conventionality of Simultaneity espoused by Reichenbach, Grunbaum, Edwards, and Winnie is herein extended to mechanics and electrodynamics. The extension is seen to be a special case of a generally covariant formulation of physics, and therefore consistent with Special Relativity as the geometry of flat space-time. Many of the quantities of classical physics, such as mass, charge density, and force, are found to be synchronization dependent in this formulation and, therefore, in Reichenbach's terminology, "metrogenic." The relationship of these quantities to (...) 4-vectors and their physical significance is discussed. (shrink)

After describing a new method of synchronizing spatially separated clocks by means of clock transport, this paper discusses the philosophical import of the existence of such methods, including those of Ellis and Bowman and of Bridgman, with special reference to the Ellis-Bowman claim that "the thesis of the coventionality of distant simultaneity... is thus either trivialized or refuted." I argue that the physical facts do not support this philosophical conclusion, and that a substantial part of their argument against Reichenbach, in (...) particular, is misdirected. Finally, I suggest that Ellis and Bowman employ seriously unclear notions of triviality and "good physical reasons" that tend to obscure rather than clarify the basic philosophical issues. An objective criterion of nontriviality of conventions is advanced. (shrink)

In this paper we examine Ellis and Bowman's argument, that simultaneity in inertial frames of reference is not conventional, from the axiomatic point of view. In Part I we examine the role of conventions in an axiomatic physical theory, and in Part II the relation of simultaneity in Reichenbach's axiomatization of the space-time theory of special relativity.