Lacunae in the philosophical foundations of special relativity

Abstract Based on the two postulates of the invariance of both the laws of physics and light speed in inertial frames, Einstein revolutionised the prevalent conceptions of space and time in the Special Theory of Relativity, which is not however without difficulties, due to gaping holes in its philosophical foundations. The first postulate is an unjustified and clumsily drafted extension of Galilean Relativity, while the second postulate, if interpreted as meaning that the speed of light will not be altered by a moving frame, does not lead to Lorentz transformations, but just reveals that a light ray is not transported by a moving frame. Reference frames involving light propagation do not exhibit the equivalence inherent in inertial frames, and hence could be classified as seemingly-inertial, being some category of non-inertial frames. Either equivalence, including simultaneity in both moving and stationary frames, is a defining characteristic of inertial frames, or else if inertial frames allow inequivalence, then they are not indistinguishable, which is a contradiction. All along, the definitions of “frames of reference,” “inertial frames,” and “simultaneity” and the “legal” drafting of the two postulates play a crucial role in the development and consistency of the Theory, almost as much as the thought experiments and the mathematics.