Defenses

Abstract

This chapter focuses on defenses. A considerable number of theories has grappled with the normative justification(s) for the various claims that arise in private law. This focus on the rights and powers in private law is understandable. After all, without a claim there is nothing much further to discuss. What has gone underexamined are the justifications for the various defenses that exist—the ways of resisting otherwise good claims. Defenses pose a challenge to any monist theory of private law. If private law, or a part of it, is all about efficiency or independence or utility or any other single thing, why not deal with all the elements of what justifies the plaintiff’s claim as an element of the cause of action? Why do people need defenses at all? Either the claim is justified or it is not. On the monist view of private law—that it is only concerned with One Big Thing—what is the need or role for any separate “defenses” that concern countervailing considerations? The chapter then describes what a defense is before looking at pleading and proof and distinguishing between justification and excuse. It also considers the form of reasons and details the general defenses, defenses in contract, defenses to torts, defenses in unjust enrichment, and equitable defenses.