 Why are you always lying? Why did the Ancient Egyptians mummify their dead? Should Huck Finn have turned Jim in? Why is she selling her car? Questions that ask for reasons, and in particular, reasons for action, are among the commonest questions humans have. Philosophers have sought to understand the nature of such reasons. Most contemporary philosophers start by distinguishing two types of reason for action: “normative” reasons—that is, reasons which, very roughly, favour or justify an action, as judged by a well-informed, impartial observer; and “motivating” reasons—which, again roughly, are reasons the “agent” (that is, the person acting) takes to favour and justify her action and that guides her in acting. But there are, in addition, “explanatory” reasons, reasons that explain an action without necessarily justifying it and without being the reasons that motivated the agent.