Einsteinís special theory of relativity. To explain how Einsteinís special theory of relativity can be true in a spatiomaterial world is to show that the regularities it describes can be constituted by substances of the kinds postulated by spatiomaterialism, that is, that it can correspond to aspects of space and matter as substances enduring through time.
In addition to the assumptions already made about the forms of matter and the inherent motion in space in order to explain the truth of classical physics ontologically, further assumptions about the nature of space and matter will be needed to explain special relativity. They are basically distortions of the kind that Lorentz described in fast moving material objects before Einsteinís first paper (time dilation and length contraction, though there must be compensating changes in masses and longitudinal forces as well), though something more must be said about the synchronization of clocks at a distance in order to explain the truth of all the predictions of the special theory.
In the first section, A Brief History of the Special Theory, I will give a brief history of how Einsteinís special theory of relativity was accepted in order to show that these distortions in fast-moving objects provide everything required to explain why Einsteinís theory is true.
Lorentz first described these distortions in order to explain the surprising results of the Michelson-Morley experiment, which established that it was not possible to measure the absolute rest and motion of a material object by measuring the velocity of light relative to it. But Lorentzí theory was rejected in favor of Einsteinís special theory of relativity, which took a radically different approach. That was not a mistake within physics, because Einsteinís theory was superior according to the empirical method of science of physics (that is, inferring to the best efficient-cause explanation, or by the criteria of predicting and controlling what happens). But Einsteinís theory is not the best ontological-cause explanation of the phenomena. Indeed, as we shall see when Einsteinís premises and conclusions are explained ontologically, even its apparent superiority as an efficient-cause explanation rests on an illusion.
In the second section, The Lorentz Distortions, I show how Lorentz explained the undetectability of absolute motion or rest and the other distortions that are required for all the laws of physics to hold the same way on a moving inertial reference frame.
In the third section, The Symmetry of the Lorentz Distortions, I show how Einstein's definition of simultaneity at a distance combines with the Lorentz distortions to explain the puzzling symmetry about any pair of inertial reference frames that is emphasized by Einstein in calling his theory a theory of "relativity." This symmetry implies that inertial reference frames are empirically equivalent as far as experiments that observers on each frame can perform on one another are concerned, and as we shall see, it is just an appearance that depends on the mis-synchronization of clocks on inertial frames according to Einstein's definition and how that combines with the Lorentz distortions.
In the fourth section, The Ontological Necessity of the Lorentz Distortions, I will argue that although the Lorentz distortions are new laws of physics, they have a deeper explanation given our ontological explanation of the laws of classical physics and a plausible assumption about the nature of material objects (which will be justified later as a way of explaining the truth of quantum mechanics and what physics now knows about the microstructures of material objects). But given our assumption about space being the medium of light transmission (that space has an inherent motion), that conception of the nature of material objects will make it possible to show that the Lorentz distortions are not merely ad hoc assumptions made in order to retain the belief in absolute space, as is often charged, but rather have a necessity about them.
In the end, therefore, we will see that, in making the argument for his special theory of relativity, Einstein did not discover anything about the natural world that cannot be explained by an ontology, like spatiomaterialism, that implies that space and time are absolute. But what is more, spatiomaterialism explains special relativity in a way that removes all the mysteries about spacetime and makes it possible to explain ontologically, as well, why Einsteinís general theory of relativity is true. That will solve the main theoretical problem of contemporary physics, the relationship between gravitation and the other basic forces of nature, and it also has some surprising implications for cosmology.