Joe Salerno

Lewis/Stalnaker semantics has it that all counterpossibles (i.e., counterfactual conditionals with impossible antecedents) are vacuously true. Non-vacuism, by contrast, says the truth-values of counterpossibles are affected by the truth-values of the consequents. Some counterpossibles are true, some false. Williamson objects to non-vacuism. He asks us to consider someone who answered ‘11’ to ‘What is 5 + 7?’ but who mistakenly believes that he answered ‘13’. For the non-vacuist, (1) is false, (2) true: (1) If 5 + 7 were 13, x would have got that sum right (2) If 5 + 7 were 13, x would have got that sum wrong Williamson is not persuaded by the initial intuitiveness of such examples: ... they tend to fall apart when thought through. For example, if 5 + 7 were 13 then 5 + 6 would be 12, and so (by another eleven steps) 0 would be 1, so if the number of right answers I gave were 0, the number of right answers I gave would be 1. (2006) That’s the whole argument—much of it implicit. Alan Baker’s critique (2007) of Brogaard and Salerno (2007) prompts us to say something less abbreviated about a less abbreviated form of Wiliamson’s argument. Then we further develop our (2007) counterfactual analysis of essense

At the center of the debate between contextualist versus relativist semantics for epistemic modal claims is an empirical question about when competent subjects judge epistemic modal disagreement to be present. John MacFarlane’s relativist claims that we judge there to be epistemic modal disagreement across the widest range of cases. We wish to dispute the robustness of his data with the results of two studies. Our primary conclusion is that the actual disagreement data is not consistent with relativist predictions, and so, that the primary motivation for relativism disappears. Our study differs from a related study by Knobe and Yalcin :1–21, 2014) in that we focus directly on the question of genuine disagreement, as opposed to a question about truth or the appropriateness of retraction. Some of our findings agree with theirs about relativism. We uncover new lessons along the way, including that there are widespread situation effects of epistemic modal discourse; idiosyncratic features of the vignettes significantly influencing judgments about epistemic modal disagreement. We reflect with mixed feelings on the prospects for contextualism to accommodate our findings.