Self‐Locating Evidence and the Metaphysics of Time

For most metaphysical debates, ordinary observational evidence seems to be irrelevant. Intuitively, ordinary observational evidence can neither confirm nor disconfirm the existence of abstract objects, the existence of tropes or universals, the existence of arbitrarily scattered mereological fusions, etc. Arguments for these views tend to be at a very abstract, theoretical level. They are rarely of the following form: conditional on metaphysical theory X, we should expect to observe O1. Conditional on ~X, we should expect to observe O2, with O1 61⁄4 O2. We have in fact observed O1, so we should raise our credence in X. The goal of this paper is to argue that ordinary observational evidence can directly confirm or disconfirm the two major positions in the metaphysics of time, Presentism and Eternalism, in exactly this way. There are cases where we should expect to observe different things depending on whether Eternalism or Presentism is true. Presentism is the view that only present things exist, and so reality is three-dimensional. Eternalism is the view that objects from both the past and the future exist just as much as present objects, and so reality is four-dimensional. I will be considering an orthodox version of Eternalism according to which no time is objectively privileged as having the primitive property of being present. I will be setting aside the Growing Block theory, according to which only past and present objects exist, and the Moving Spotlight theory, according to which all past, present, and future objects exist but a specific time, the present, is objectively privileged. If my thesis is right, that Presentism and Eternalism make different observational predictions, it puts pressure on a certain skeptical view about the entire debate between Eternalists and Presentists. According to one kind of skeptic, the debate between Eternalists and Presentists is ‘merely verbal’. Note that if ‘exists’ means ‘exists now’, then it’s trivial that, say, ‘Dinosaurs exist’ is false, contra the Eternalist. If ‘exists’ means ‘once existed or now exists or will exist’, then it’s trivial that ‘Dinosaurs exist’ is true, contra the Presentist. The skeptic then argues that it’s very unclear what ‘exists’ could possibly mean that makes the dispute over ‘Dinosaurs exist’ interesting and non-trivial. However,