Abstract

Epistemic modals have long been thought to display severe restrictions in their embedding potential. In addition, when they do embed it is often thought that the outer modal is vacuous – so that “It must be possible that it’s raining” just means “It’s possible that it’s raining”. Recently Moss (2015) has observed that, in certain carefully elaborated contexts, constructions with multiple epistemics like “It must be probable that …” are intuitively acceptable and seem to express higher-order uncertainty. I’ll present some recent work examining the range and interpretation of such constructions in corpora, and use the result to motivate a new probabilistic semantics that improves on both the classical interpretation from modal logic and Moss’ proposal. This approach has interesting points of connection with the use of causal models in psychology and with the question of how people represent (higher-order) uncertainty, which I’ll discuss briefly in conclusion.