How many worlds could there be? David Lewis and advanced modalizing

Advanced modalizing, viz. possibilities and necessities concerning modal space itself, is problematic for a Lewis-style analysis of modality. A popular solution, proposed by Divers, postulates explicit semantic clauses for a collapse of advanced modalizing, to the conclusion that all such matters are, if true in the first place, both possible and necessary. But this is problematic: Divers’s solution not only leaves no room for ’advanced’ contingency, but also renders alternative approaches to Lewisian metaphysics not merely false or metaphysically impossible, but analytically false. In this paper, we propose a new framework for advanced modalizing that introduces two novel modal operators, which evaluate sentences not at worlds, but at galaxies. This move avoids the collapse of modality and potentially restores a measure of contingency to advanced modal discourse. A key strength of our approach is that it enables the expression of alternative metaphysical positions within a unified modal framework.