On Measuring the Possibility of Selection Function-Based Conditionals, General Updates, and Qualitative Capacities
摘要
This paper investigates updating methods for possibility measures and their logical representation through conditional operators. We introduce a general possible worlds semantics equipped with selection functions (or equivalently, Boolean algebras with binary conditional operators). This provides a unified framework for various conditionals, including those studied by Stalnaker and Lewis. Building on our recent triviality result—which shows standard conditionalization for possibility measures cannot be represented as the possibility of a given conditional—we explore how alternative updating methods for possibility measures can be represented as the possibility of conditionals within our framework. Specifically, we define novel updating methods for possibility measures based on these selection functions. These methods, unlike standard conditionalization, exhibit a direct correspondence with the possibility of conditionals. In particular, we prove the possibility of selection function-based conditionals directly aligns with updated qualitative capacities, as defined by Dubois et al. Furthermore, we delineate the specific conditions under which the possibility of such conditionals precisely coincides with a general update of the original possibility measure.