An Augustinian–Edwardsian Metaphysics of Possibility for the Barcan Formula

Abstract

The Barcan formula is a theorem of quantified modal logic. Its most straightforward interpretation appears to commit one to “possibilism,” the view that merely possible things exist. Alternative systems of logic revise the formal semantics to preclude the theorem and its consequences. The crux, however, is the modal metaphysics presupposed by the formal semantics. This paper presents an alternative metaphysics of possibility that follows Augustine’s suggestion that God’s plan is only one of a range of alternative histories for a creation. The metaphysics is a version of “trace actualism”—neither pure possibilism nor pure actualism.