Jacek Wawer

Jagiellonian University, Kraków

Metaphysics of Branching Possibilities

21 June 2019, 16:00

Faculdade de Letras de Lisboa

Sala Mattos Romão (Departamento de Filosofia)

Abstract: The model of so-called Branching-Time was introduced by Saul Kripke and Arthur Prior to investigate indeterminism and temporal asymmetry between “settled” past and “open” future. The model was often adopted for various formal (primarily semantic) purposes, but the proper philosophical interpretation of the model was usually highly underdeveloped. The purpose of the paper is to fill in the interpretative gap and analyze the structure underlying the branching model. I first observe that it is highly misleading to assume that the structure represents the branching of time. Such an understanding is open to many common sense and scientific objections. I argue that it is much more reasonable to understand the elements of the structure as branching possibilities. I then propose an account of the structure in fashion of genuine (or extreme) modal realism of David Lewis – as consisting of non-modal and non-tensed events. Many claims of branching theorists suggest such non-modal account of reality. In particular, their insistence that no particular modal viewpoint is privileged – which I call modal neutrality – is readily understood within the non-modal picture of branching. I propose, however, an interpretation of the branching structure that weds modal neutrality with modal primitivism. The idea is inspired by non-standard tense realism (non-standard A-theory) proposed by Kit Fine. I also outline a potential trap inherent in such an account of branching reality: an unskilful attempt to combine modal neutrality with modal primitivism might lead to an indefensible amalgam of ideas which Nuel Belnap dubbed the Thin Red Line.