Counterfactuals and Comparative Possibility

Abstract

In the last dozen years or so, our understanding of modality has been much improved by means of possible-world semantics: the project of analyzing modal language by systematically specifying the conditions under which a modal sentence is true at a possible world. I hope to do the same for counterfactual conditionals. I write A□→C for the counterfactual conditional with antecedent A and consequent C. It may be read as ‘If it were the case that A, then it would be the case that C’ or some more idiomatic paraphrase thereof.

The theory presented in this paper is discussed more fully in my book Counterfactuals (Blackwell and Harvard University Press). My research on counterfactuals was supported by a fellowship from the American Council of Learned Societies.