 Kim argues that Hempel is a paradigm example of an explanatory internalist (Kim 1994 [2010]; cf. 1999 [2010]). For instance, suppose that one wants to explain and hence understand why a particular bar of metal began to rust (McCain 2016: ch. 9). A good Hempelian explanation would be one in which a sentence describing the rusting follows inferentially from (a) a statement of the initial conditions (the moisture in the air, the constitution of the bar) and (b) a further law-like statement connecting the moisture, the constitution of the bar, and the onset of rust.