AbstractWhy and when should courts presumptively defer to their own past precedents? The doctrine of precedent lies at the core of American jurisprudence and legal practice, but the source of its normative force remains unclear. Consequently, its application is confused and contested. In this Article, I argue that precedent matters primarily because and to the extent that it generates reliance interests on the part of the public. The Article explores the moral and jurisprudential underpinnings of the reliance approach and considers its far-reaching theoretical and practical implications. This approach, which has both descriptive and normative features, suggests that we must limit and expand our traditional notions of what qualifies as precedent. More broadly, it upsets what I call the gravitational account of law.