The special theory of relativity is widely regarded as the primary threat to the otherwise intuitive presentist worldview. In particular, both the relativity and conventionality of simultaneity within STR appear to undermine presentism and support eternalism. However, the single term ‘simultaneity’ describes multiple potentially independent concepts. By establishing the mutual independence of the relevant concepts of simultaneity, the presentist and eternalist may agree to move past the initial threat to presentism posed by STR. The subsequent debate hinges on whether presentism (...) or eternalism best accounts for the principle of relativity. The presentist is often accused of initially failing to identify the absolute present and then constructing a model that hides it using an unlikely set of premises. As a result, the eternalist Minkowski space-time interpretation appears simpler in many respects. However, it is demonstrated that on presentism one may obtain the principle of relativity by simply prohibiting instantaneous signals between distant events. Many of the objections against the presentist Neo-Lorentzian interpretation of STR are answered in light of this demonstration. The partition between the experimental evidence provided by STR and human experience is found to be unnecessary. (shrink)

U. Hoyer's argument for the linearity is discussed and a modification of the argument is proposed.

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)

The kinematical principle of Equal Passage Times (EPT) was introduced by Winnie in his 1970 derivation of the relativistic coordinate transformations compatible with arbitrary synchrony conventions in one-dimensional space. In this paper, the claim by Winnie and later Giannoni that EPT is a direct consequence of the relativity principle is questioned. It is shown that EPT, given Einstein's 1905 postulates, is equivalent to the relativistic (synchrony independent) clock retardation principle, and that for standard synchrony it reduces to an isotropy condition (...) for contraction (and dilation) effects. (shrink)

On the Linearity of the Lorentz transformations. U. Hoyer's argument for the linearity is discussed and a modification of the argument is proposed.

ABSTRACT In Einstein’s physical geometry, the geometry of space and the uniformity of time are taken to be non-conventional. However, due to the stipulation of the isotropy of the one-way speed of light in the synchronization of clocks, as it stands, Einstein’s views do not seem to apply to the whole of the Minkowski space-time. In this work we will see how Einstein’s views can be applied to the Minkowski space-time. In this way, when adopting Einstein’s views, chronogeometry is a (...) physical chronogeometry. (shrink)