 In the general philosophy of science literature on  scientific explanation  there is a distinction between so-called “how-actually” and “how-possibly” explanation, where the former aims to convey how a particular outcome actually came about, and the latter aims to convey how the occurrence of an event can have been possible. That how-actually explanation actually explains is uncontroversial, but the merit (if any) of how-possibly explanation has been debated. While some view how-possibly explanation as genuinely explanatory, others have argued that how-possibly ‘explanation’ is better thought of as, at best, a merely heuristically useful exercise.