Peter van Inwagen on free will and time travel

Abstract

Peter van Inwagen’s views on free will and time travel are very influential. However, prima facie there is a contradiction between the very idea of time travel and free will. In van Inwagen’s theory, free will requires an ontologically open future. If time travel is possible and the past is closed, then ‘the future’ for time-travelers is closed, and thus, they lack free will in the past. In this article, I am going to analyze van Inwagen's views on free will and time-travel. I formulate an incoherent triad that explicates the general problem of consistency between free will and time-travel. Denying one proposition in the triad leaves two coherent residual propositions. I am going to analyze van Inwagen’s theory of time travel as an attempt to refute one proposition in the triad. Moreover, I explore the logical space of the problem by analyzing strategies of denying other propositions. I conclude that van Inwagen’s views are coherent, but they depend on a broader discussion of a general possibility to change the past, as well as on possible scientific discoveries.