Abstract

The aim of this thesis is to defend a presentist metaphysics. I respond to a series of objections against presentism, including some that draw on our best physics. I also explore ways in which presentism might play an active role in interpreting and constraining physical theory, beyond merely being consistent with it. A unifying theme of this thesis is that I advocate for a reduction of presentism to its bare essentials. Within the proposed ontology, reality is three-dimensional. Time only exists in the sense that three-dimensional reality primitively changes. I reject any temporal dimension, extension, or direction. I reject any primitively tensed facts or nonpresent-tensed truths. I also reject any notion of simultaneity, beyond the mere fact that multiple entities exist in the three-dimensional world. I accept and embrace that if ontology is ‘stripped back’ to the present, then other features of metaphysics that depend on ontology should be stripped back too. The world, under this view, is a forgetful one. What we call the ‘past’ has been utterly lost from existence: there are not even any absolute facts or truths about how things once were. All that remain are records, memories, and the like, but there are no objective underlying truths to which those records correspond. This has implications for physics. In a forgetful world particles have positions, but no entire trajectories. The present may be certain and determinate, but the past and future are at best modelled using probabilistic mathematics. I believe that the world is likely to be as I describe. I will not attempt to argue, however, that this view is intuitive. Instead I will argue that it can account for our experiences and observations, including those from physics, in a simple and effective way. Most importantly, I argue that this view succeeds in the face of challenges where other versions of presentism fail.