Contract Law, Default Rules, and the Philosophy of Promising

Among the topics addressed by moral philosophy is the obligation to keep one’s promises. To many philosophers, there is something strange (or, at least, something calling for explanatie1n) in the idea that moral obligations can be created simply by an individual’s saying so yet this is what seems to happen when a person makes a promise. Consequently, there is by now a large body of literature attempting to identify the exact source and nature of this moral obligation.

Part I of this article presents a more detailed survey of recent philosophical writings about promises, for the benefit of legal readers who may be unfamiliar with that literature. Part II then discusses the role of background rules in contract law, and shows why the content of those rules cannot be derived from philosophical theories based on individual liberty, or on ideals such as fidelity or truthfulness. Finally, Part III examines the writings of Charles Fried and Randy Barnett to illustrate the consequences of attempting to apply philosophy to contract law without addressing these problems. These two authors have supplied the most comprehensive attempts to give contract law a philosophical grounding, yet each falls into exactly this error.