It is a virtual axiom in the world of law that legal norms come in two prototypes: rules and standards. The accepted lore suggests that rules should be formulated to regulate recurrent and frequent behaviors, whose contours can be defined with sufficient precision. Standards, by contrast, should be employed to address complex, variegated behaviors that require the weighing of multiple variables. Rules rely on an ex ante perspective and are therefore considered the domain of the legislature; standards embody a preference for ex post, ad hoc analysis and are therefore considered the domain of courts. The rules/standards dichotomy has become a staple in economic analysis of the law, as well as in legal theory in general.

This Essay seeks to contribute to the jurisprudential literature by unveiling a new form of legal command: the catalog. A catalog, as we define it, is a legal command comprising a specific enumeration of behaviors, prohibitions, or items that share a salient common denominator and a residual category—often denoted by the words “and the like” or “such as”—that empowers courts to add other unenumerated instances. This Essay demonstrates that the catalog formation is often socially preferable to both rules and standards and can better enhance the foundational values of the legal system. In particular, catalogs are capable of providing certainty to actors at a lower cost than rules, while avoiding the costs of inconsistency and unbridled discretion inimical to standards. Moreover, the use of catalogs leads to a better institutional balance of powers between the legislature and the courts by preserving the integrity and autonomy of both institutions. This Essay shows that these results hold in a variety of legal contexts, including bankruptcy, intellectual property, criminal law, torts, constitutional law, and tax law.