Delineating A- and B-Time: Against the Indistinguishability of the A- and B-Theories

This essay sets out to refute the indistinguishability thesis (IT), which states that there is no substantive disagreement between the metaphysics of the A-theory of time and its alleged antithesis, the B-theory of time. It begins with an overview of the dichotomies historically taken as defining the contrast between A-time and B-time. Part I appraises IT’s success at undermining the first of these, the dichotomy between tensed and tenseless time, which is interpreted as the dispute between a metaphysics comprised solely of temporary (temporal) facts and one comprised solely of permanent (temporal) facts. It is argued that (a) IT fails to evidence any intertheoretical equivalence, and (b) there exists an alternative position that does succeed in deflating the permanent-temporary fact contrast. Part II then appraises IT’s success at undermining the second defining dichotomy of A- and B-time, i.e. as a dispute between dynamic and static models. The at-issue content here is whether time contains ‘passage’ or ‘transition’. After addressing some terminological concerns, two arguments to establish that all conceptions of time tacitly accept transition are pacified: one claims that without transition temporal extension would be indiscernible from spatial extension, the other claims that without transition we would be ‘stuck at a given time’. The latter half of Part II demonstrates that the ‘stuck’ counterfactual is coherent but ambiguous between theories of persistence, which when probed further implies another point of distinguishability between A- and B-time in their respective ways of coping with persistence-related challenges. The account set forth in Parts I and II actively excludes an increasingly prevalent view called presentism – Part III vindicates this dismissal by arguing that presentism is insufficiently motivated, on the grounds of its being causally unintuitive and, although ontologically more parsimonious, no more theoretically virtuous than vying doctrines