Embedded Implicatures as Pragmatic Inferences under Compositional Lexical Uncertainty

Abstract

How do comprehenders reason about pragmatically ambiguous scalar terms like some in complex syntactic contexts? In many pragmatic theories of conversational implicature, local exhaustification of such terms (‘only some’) is predicted to be difficult or impossible if the result does not entail the literal meaning, whereas grammatical accounts predict such construals to be robustly available. Recent experimental evidence supports the salience of these local enrichments, but the grammatical theories that have been argued to account for this evidence do not provide explicit mechanisms for weighting such construals against others. We propose a probabilistic model that combines previous work on pragmatic inference under ‘lexical uncertainty’ with a more detailed model of compositional semantics. We show that this model makes accurate predictions about new experimental data on embedded implicatures in both non-monotonic and downward-entailing semantic contexts. In addition, the model’s predictions can be improved by the incorporation of neo-Gricean hypotheses about lexical alternatives. This work thus contributes to a synthesis of grammatical and probabilistic views on pragmatic inference.