An Acceptance Semantics for Stable Modal Knowledge

TL;DR

This paper introduces a new stable acceptance semantics to address linguistic puzzles involving knowledge ascriptions with epistemic modals, balancing veridicality and negative transparency while relaxing classical logic principles.

Contribution

It proposes a novel information-sensitive semantics that maintains veridicality and negative transparency by abandoning the universal validity of contraposition.

Findings

Successfully models negative transparency in epistemic modal sentences

Addresses the trade-off between classical logic and intuitive epistemic principles

Provides a critique of existing approaches to veridicality in domain semantics

Abstract

We observe some puzzling linguistic data concerning ordinary knowledge ascriptions that embed an epistemic (im)possibility claim. We conclude that it is untenable to jointly endorse both classical logic and a pair of intuitively attractive theses: the thesis that knowledge ascriptions are always veridical and a `negative transparency' thesis that reduces knowledge of a simple negated `might' claim to an epistemic claim without modal content. We motivate a strategy for answering the trade-off: preserve veridicality and (generalized) negative transparency, while abandoning the general validity of contraposition. We survey and criticize various approaches for incorporating veridicality into domain semantics, a paradigmatic `information-sensitive' framework for capturing negative transparency and, more generally, the non-classical behavior of sentences with epistemic modals. We then present a novel information-sensitive semantics that successfully executes our favored strategy: stable acceptance semantics.