This chapter presents a normative justification of stare decisis, that is, of a court's presumptive deference to its own prior decisions. Critics often contend that valid epistemic reasons to follow precedent-reasons based on the notion that following precedent will lead to better decisions-do not exist. The author argues, however, that a judge may have both "procedural" and "substantive" epistemic reasons to follow precedents with which she disagrees. Procedurally, a presumptive obligation to follow precedent can force a judge to confront opposing arguments and articulate strong reasons for disagreeing with them, thus improving her own decisionmaking. Substantively, the case-by-case process of generating precedent, involving the input of many judges over time, may generally be superior to ad hoc decisionmaking by a single judge or court. As a conceptual matter, the author argues, these epistemic reasons truly are reasons to follow precedent, because they might apply even when a judge believes a given precedent was decided incorrectly.