Abstract

Conditionals and modals work in tandem in some instances of practical reasoning, or decision making. Consider the following example :a.I want to become a mayor.b. I will become a mayor only if I go to the pub.c.Therefore, I should go to the pub.Given what the cogniser wants and the relevant circumstances, the conclusion that the cogniser goes to the pub comes out as necessary. Hence, the presence of the necessity modal should in. Indeed, given the context of, the necessity modal in is simply a reflection of the necessity of p for q, which is overtly represented by the use of the ‘only if p, q’ construction. This chapter looks into whether indirect reports of conditionals – in particular, indirect reports which involve the use of a modal verb – are sensitive to the necessity of p for q in cases where necessity is not overtly represented in a conditional, as in ‘if p, q’ formulations.We report on two online experiments into the relation between perceived necessity or sufficiency of the truth of a conditional antecedent for the truth of the consequent, and the formulation of an indirect report of a conditional with necessity or possibility modals. In Experiment 1, the ‘necessity/sufficiency of p for q’ variable was manipulated by contextually altering the number of alternative antecedents. It was found that modals used in indirect reports of ‘if p, q’ conditionals co-vary with the number of alternative antecedents in predictable ways. This suggests that modals used in indirect reports of ‘if p, q’ conditionals may be a diagnostic for biconditional versus material interpretations of conditionals. The aim of Experiment 2 was to find out whether the results of Experiment 1 could be replicated in contexts which lower/eliminate the believability of the conditionals. It was found that manipulating the believability variable has no reliable effect on the results.