Reductive theories of modality

Abstract

Reductive theories of modality attempt to define necessity and possibility in non-modal terms to satisfy requirements of ontological parsimony and epistemic transparency. While the possible-worlds framework is the dominant contemporary analysis, most abstractionist versions, such as linguistic ersatzism and combinatorialism, suffer from circularity by presupposing modal notions to distinguish possible from impossible worlds or to define the “true in” relation. David Lewis’s concrete modal realism avoids this circularity by defining worlds as spatiotemporally isolated individuals and employing counterpart theory to account for de re modality, though it encounters challenges regarding the existence of “island universes” and the counterintuitive nature of its ontological commitments. Traditional conventionalism, which reduces necessity to analyticity or linguistic rule-following, is largely rejected because conventions cannot ground the truth of logical laws and fail to account for synthetic a posteriori necessities. However, a modified reduction remains viable if necessity is understood as a status assigned to specific classes of truth—such as logical, mathematical, or analytic—without claiming these truths are themselves products of convention. This approach preserves the distinction between the content of a proposition and its modal status while avoiding the circularity inherent in other reductive strategies. – AI-generated abstract.