 Here are four reasons philosophers examine what it is to be a law of nature: First, as indicated above, laws at least appear to have a central role in scientific practice. Second, laws are important to many other philosophical issues. For example, sparked by the account of counterfactuals defended by Chisholm (1946, 1955) and Goodman (1947), and also prompted by Hempel and Oppenheim’s (1948) deductive-nomological model of explanation, philosophers have wondered what makes counterfactual and explanatory claims true, have thought that laws play some part, and so also have wondered what distinguishes laws from nonlaws. Third, Goodman famously suggested that there is a connection between lawhood and confirmability by an inductive inference. So, some sympathetic to Goodman’s idea come to the problem of laws as a result of their interest in the problem of induction. Fourth, philosophers love a good puzzle. Suppose that everyone here is seated (cf., Langford 1941, 67). Then, trivially, that everyone here is seated is true. Though true, this generalization does not seem to be a law. It is just too accidental. Einstein’s principle that no signals travel faster than light is also a true generalization but, in contrast, it is thought to be a law; it is not nearly so accidental. What makes the difference?