Counterfactual Contamination

Many defend the thesis that when someone knows p, they couldn’t easily have been wrong about p. But notion of easy possibility in play is relatively under-theorized. One structural idea literature, principle Counterfactual Closure (CC), connects with counterfactuals: if it could happened and p were case then q would be case, follows q. We first argue that, while CC false, there a true restriction to cases involving counterfactual dependence on coin flip. The failure falsifies model where possibilities are counterfactually similar actuality. Next, we show extant normality models, sufficiently normal ones, incompatible restricted flips. develop new kind theory can accommodate version CC. This introduces Contamination, which says, roughly, any world fairly abnormal at very events depend Finally, explain why flips other related special status. A central take-home lesson correct vicinity Safety importantly normality-theoretic rather than (as usually conceived) similarity-theoretic.