 Beginning with a series of articles in the 1950s and culminating in their massive book of 1959, Causation in the Law, second edition 1985, Herbert Hart and Tony Honoré sought to describe the idea of intervening causation that they saw the law adopting from everyday causal idioms. One can see their concept most easily in three steps. First, presuppose some version of the counterfactual analysis: a cause is at least a necessary condition for its effect, or perhaps a NESS condition (Honoré 1997). Second, a cause is not just any necessary condition; rather, out of the plethora of conditions necessary for the happening of any event, only two sorts are eligible to be causes rather than mere “background conditions:” free, informed, voluntary human actions, and those abnormal conjunctions of natural events we colloquially refer to as “coincidences”. Third, such voluntary human action and abnormal natural events cause a given effect only if some other voluntary human action or abnormal natural event does not intervene between the first such event and its putative effect. Such salient events, in other words, are breakers of causal chains (“intervening causes”) as much as they are initiators of causal chains, so if they do intervene they relegate all earlier such events to the status of mere background conditions.