Taking Times Out: Tense Logic as a Theory of Time

Ulrich Meyer’s fascinating book The Nature of Time uses a novel development of Arthur Prior’s tense logic to argue for a ‘modal’ account of time. Meyer’s metaphysical view requires tense primitivism (the view that truths are irreducibly tensed) and so, in Quine’s turn of phrase, trades ontology for ideology. Meyer’s temporal metaphysics eschews ontological commitment to temporal instants through the introduction of so-called ‘ersatz times,’ developed in analogy with the ersatz possible worlds of modal logic. In modal logic, linguistic ersatzism about possible worlds is associated with actualism (the thesis that only actual objects and events exist) so one might expect an advocate of ersatz times to endorse presentism (the thesis that only present objects and events exist). Many philosophers of physics (myself included) take presentism to be inconsistent with special relativity. Meyer, however, argues that the analogy between presentism and actualism is weak, and denies the presentist’s claim that the present is metaphysical privileged. Furthermore, Meyer claims that relativity allows for the introduction of ‘hybrid views’ that combine distinct, seemingly incompatible metaphysical accounts of time and space. In particular, Meyer advocates a metaphysics of relativistic spacetime that combines spatial substantivalism with his ‘modal’ view of time. The argument of the book follows an almost Aristotelian methodology. First, in Chapter 1, the desiderata for a theory of time are outlined. Next, rival metaphysical theories are dismissed one by one: varieties of temporal relationalism in Chapter 2, and temporal substantivalism in Chapter 3. Then the preferred theory is outlined (in Chapters 4, 6 and 8) and declared the victor, with the rest of the book devoted to showing how remaining difficulties may be accommodated. In particular, there are chapters that deal with temporal propositions and truthmakers (Chapter 5), temporal structure (Chapter 7), presentism (Chapter 9), becoming (Chapter 10), motion (Chapter 11) and relativity theory (Chapter 12).