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.

Extant counterfactual accounts of causation (CACs) still cannot handle preemptive causation. I describe a new variety of preemption, defend its possibility, and use it to show the inadequacy of extant CACs. Imagine that it is a law of nature that the first spell cast on a given day match the enchantment that midnight.

As the ball flew towards us I leapt to my left to catch it. But it was you, reacting more rapidly than I, who caught the ball just in front of the point at which my hand was poised. Fortunate for us that you took the catch. The ball was headed on a course which, unimpeded, would have taken it through the glass window of a nearby building. Your catch prevented the window from being broken.