Not all deductive inference rules are created equal. Consider a rule allowing a reasoner to infer Fermat’s Last Theorem directly from the Peano Axioms. It is natural to think that this unusual rule differs importantly from familiar rules like modus ponens. A tempting way to capture this difference is to distinguish between basic and non-basic inference rules. With this distinction in place, a question naturally arises: Why are some deductive inference rules basic, while other rules are not? I examine several answers to this question. In particular, I consider intuition-based theories, Paul Boghossian’s theory of blameless deductive inference, and David Enoch and Joshua Schechter’s justification for basic methods of belief formation. I argue that each of these accounts fails to explain why a select few deductive inference rules are basic. I end by exploring a novel solution that draws on simplicity considerations to distinguish basic and non-basic rules.