 To the extent that there was a mid-century orthodoxy about counterfactual conditionals, it was given by the proposal in Nelson Goodman (1955). Goodman proposed that counterfactual conditionals were a particular variety of strict conditional. To a first approximation, If it were the case that p, it would be the case that q (hereafter p □→ q) is true just in case Necessarily, either p is false or q is true, i.e. □(p ⊃ q). Goodman realised that this wouldn’t work if the modal ‘necessarily’ was interpreted unrestrictedly. He first suggested that we needed to restrict attention to those possibilities where all facts ‘co-tenable’ with p were true. More formally, if S is the conjunction of all the co-tenable facts, then p □→ q is true if and only if □((p ∧ S) ⊃ q).