In this chapter I distinguish between two types of rules: necessary and normative rules. These two types, I claim, are mutually exclusive. Normative rules that ought to be obeyed cannot be said to be necessary, and vice versa; necessary rules which cannot be broken, cannot be said to be normative. Brandom's inferential rules, however, attempt to be both normative and necessary. According to Brandom, the status of inferential rules is that of a normative necessity, i.e., rules that both ought to be followed and that must be followed. The idea of a normative necessity, I argue, represents a deep problem in the philosophical use of the concept of rule rather than solve it.