ABSTRACT
We propose that a prerequisite for the investigation of how people object to conditional sentences consists in understanding how they object to declarative categorical (i.e., non-conditional) sentences. Given the pervasiveness of epistemic modal statements, an approach that takes into account the speaker’s and hearer’s levels of certainty seems indispensable. We do this in two steps. One, we apply Horn’s (1978) scales of certainty to categorical sentences and define the concepts of possible, probable, certain, and their external negation by probability intervals, which results in a single epistemic scale. Two, we exploit this scale within de Finetti’s (1936) theory of conditionals. Given the speaker’s conditional sentence, we determine the expected formulation of its rejection by the hearer as a function of the epistemic status of both interlocutors. This is illustrated by an experiment carried out in French and Japanese which confirms the analysis and helps explain and test the opposite claims made by the material conditional view and de Finetti’s probability theory regarding the denial of conditionals, supporting the latter theory.
