Abstract

Einstein chose the absolute equivalence (i.e. symmetry) of all inertial frames, with its associated non-simultaneity, over the choice of a single absolute frame with time simultaneity. Lorentz and Poincar? were not willing to make that same positivistic choice. Acknowledging his debt to Mach, Einstein made his choice because he ?found that no measurement could provide a criterion for simultaneity that would give the same result for all observers.? Using positivistic logic, i.e. absence of proof is proof of absence, Einstein chose the absolute equivalence of all inertial frames over the Lorentz and Poincar? choice of an absolute frame. Many have justified Einstein's choice by saying that the difference is only metaphysical. But, in fact, the choice has experimental and causal implications. In this paper we explore a range of experimental phenomena which favor the alternate choice.