On the Gradability of Hypothetical Conditionals

This paper explores a semantic account of the gradability of conditionals, a phenomenon in which the degree of probability varies according to the types of conditionals such as present indicative conditionals (PICs), past subjunctive conditionals (PSCs), and past perfect subjunctive counterfactual conditionals (PSCCs). Observing that the degree of probability decreases from PICs to PSCs to PSCCs, this paper argues that two aspects – i.e. tense/aspect and different ordering sources – should be considered for the semantic analysis of the gradability phenomenon. Tense and aspect are what makes PICs semantically distinctive from PSCs and PSCCs. The past tense in PSCs and the pluperfect in PSCCs are involved in the exclusion feature. As a result, the likelihood of PICs is higher than that of PICs and PSCCs. The difference ordering sources are what makes a semantic distinction between PSCs from PSCCs. PSCCs presuppose that the antecedent is false, while PSCs do not. Setting up the different ordering sources based on the presupposition assists us in understanding why PSCs are more likely than PSCCs.