Forthcoming in Henk de Regt, Samir Okasha, and Stephan Hartmann (eds.), Proceedings of the Second European Philosophy of Science Association Meeting, Amsterdam, October 2009, Berlin: Springer.
Online available at the Pitt PhilSci Archive (penultimate draft).
Here is the abstract:
This paper argues that recent arguments to the effect that the debate between presentism and eternalism lacks any metaphysical substance ultimately fail, although important lessons can be gleaned from them in how to formulate a non-vacuous version of presentism. It suggests that presentism can best be characterized in the context of spacetime theories. The resulting position is an ersatzist version of presentism that admits merely non-present entities as abstracta deprived of physical existence. Ersatzist presentism both escapes the charges of triviality and promises to offer a route to solving the grounding problem which befalls its more traditional cousins.