Xavier Morales Zayes (St. John’s College): 'A Critique of the Thesis that Simultaneity is Conventional in Special Relativity'
Abstract: It has been argued, since its first formulation in 1905, that the Special Theory of Relativity shows that simultaneity is conventional. Call this thesis, which holds that within Special Relativity there are no facts of the matter about whether two distant events are simultaneous, the Conventionality of Simultaneity Thesis (CST). In this talk, I will first clarify the CST by identifying three senses in which simultaneity may be said to be conventional, only one of which would confirm the CST. I will then show that while there is no good reason to believe the CST is true, there is some reason to believe it is false. The CST is most often motivated by demonstrating that it is impossible to empirically determine whether two events are simultaneous. I grant this epistemic premise but deny the usual inference to an ontological conclusion that simultaneity is conventional in a non-trivial sense. This step distinguishes my approach from that of past anti-conventionalist arguments, whose strategy has often seemed to involve providing a proof that identifies which simultaneity convention is the correct one. Having thus shown that the usual argument for the CST is insufficient, I will proceed to offer two direct arguments against the thesis. One shows that the metaphysical picture CST theorists must endorse is conceptually problematic. The other, which assumes a neo-Kantian view of physical theories, argues that simultaneity might best be understood as a constitutive a priori principle of special relativity—a presupposition required for the theory to be capable of making sense of our sensory experience. In the course of developing both of these arguments, I will consider and reject possible objections an advocate of the CST might seek to press. My conclusion will be that, given the current state of play, there are compelling reasons to reject the CST.
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Philosophy of Physics Graduate Lunch Seminar Convenors: Paolo Faglia, Gregor Gajic and Rachel Pederson
