A Relational General Relativistic A-theory

Lorenzo Lorenzetti (USI)

Abstract: It is often assumed that relativistic physics leaves no room for an A-theory of time. Special relativity seems to rule out a privileged present, while general relativity appears to undermine any physically meaningful notion of change, given diffeomorphism symmetry. We argue that this conclusion is premature. We develop a general-relativistic A-theory that avoids ad hoc privileged structure, whether local or global, and respects the symmetry structure of general relativity. Drawing on the framework of relational observables, we defend a gauge-invariant, frame-relative notion of change grounded in physical reference clocks rather than external time. We then argue that, when combined with suitably refined versions of Fine’s external relativism and fragmentalism, this yields a genuinely A-theoretic account of objective becoming. The result is a non-standard A-theory that preserves irreducible tense while remaining fully compatible with general relativity. (based on joint work with Nicola Bamonti).