The insurance function of contracts

One of the central problems in contract law is to define the frontier between legal and illegal breaches of promises. The distinction between good and bad faith is perhaps the conceptual tool most commonly used to tell one from the other. Lawyers spend a lot of energy trying to frame better definitions of the concepts of good and bad faith based on principles of ethics or justice, but often pay much less attention to theories dealing with the incentives that can engender good faith behavior in contractual relationships. By describing the economics of what Stiglitz defined as “explicit” and “implicit” insurance, I highlight the “insurance function” hidden in any promise with basically no mathematical notation. My aim is to render the subject intelligible and useful to lawyers with little familiarity with economics.