The Temporal Asymmetry of Chance

Alison Fernandes (University of Warwick)

Abstract: Explanations in science appeal to probabilities. We explain why smoke in a closed room disperses by appealing to the fact that it has a high probability of doing so. Such explanations seem to make use of objective worldly probabilities (chances). But some have argued that if the fundamental laws are deterministic, there can be no non-trivial chances (Popper, Lewis, Schaffer). Scientific probabilities are merely epistemic, or otherwise less real than dynamic chances. I’ll argue that denials of ‘deterministic chance’ have been driven by a temporally asymmetric picture according to which the past produces the future. According to this picture, chance is intrinsically temporally asymmetric: it is part of the nature of chance that the past is ‘fixed’, and that only the future has a chance of being otherwise than it is. I’ll articulate a more minimal view. Chances are compatible with determinism. Moreover, temporal asymmetries in chance are contingent, and explainable in scientific terms. Once we understand why we come to think of the past as fixed, we’ll see the past can be chancy after all.