Counterfactuals is David Lewis' forceful presentation of and sustained argument for a particular view about propositions which express contrary to fact conditionals, including his famous defense of realism about possible worlds and his theory of laws of nature.

Counterfactuals are typically thought--given the force of Sobel sequences--to be variably strict conditionals. I go the other way. Sobel sequences and (what I call) Hegel sequences push us to a strict conditional analysis of counterfactuals: counterfactuals amount to some necessity modal scoped over a plain material conditional, just which modal being a function of context. To make this worth saying I need to say just how counterfactuals and context interact. No easy feat, but I have something to say on the (...) matter. (shrink)

It is widely agreed that contraposition, strengthening the antecedent and hypothetical syllogism fail for subjunctive conditionals. The following putative counter-examples are frequently cited, respectively.

Berit Brogaard and Joe Salerno (Counterfactuals and Context, ANALYSIS 68 (2008): 39-46) argue that the standard Stalnaker-Lewis counterexamples to hypothetical syllogism, strengthening the antecedent, and contraposition trade on a failure to hold fixed the context in which truth values are determined for the premises and conclusion in each counterexample. I argue that no contextual fallacy is committed in the standard counterexamples, and I offer a different view of what it is for a fact to be held fixed by a counterfactual (...) antecedent. On my view, for a fact to be held fixed is an epistemological matter, not a semantic matter. (shrink)