Physically locating the present: A case of reading physics as a contribution to philosophy

• An approach to presentism that respects the epistemic lessons of special relativity is offered.
• A law-constitutive approach to ontic unity is extracted from Newton’s Principia.
• Considerations of unity lead to an alternative approach to presentism within physics.
• Reading history of physics as a contribution to philosophy is shown to be important.

By means of an example, special relativity and presentism, I argue for the importance of reading history of physics as a contribution to philosophy, and for the fruitfulness of this approach to doing integrated history and philosophy of science. Within philosophy of physics, presentism is widely regarded as untenable in the light of special relativity. I argue that reading Newton's Principia as a contribution to philosophy reveals a law-constitutive approach to the unity of what there is, from which an alternative approach to presentism within physics emerges. This view respects the methodological and epistemological commitments of philosophy of physics in “taking special relativity seriously”, but proposes an alternative approach to the status of spacetime (as epistemic) and to the ground of what is real (law-constitution). While this approach to presentism does not preserve all of the contemporary presentist desiderata, it offers the possibility that the spatiotemporal extent of an existing thing is less than its entire history as represented in the block universe. I argue that the approach warrants further philosophical investigation.