Legal Theory Lexicon 039: Primary and Secondary Rules

Introduction Most law students begin to notice that there is a fundamental difference between the kinds of legal rules that come up in torts & criminal law, on the one hand, and the sorts of legal rules that arise in contracts, on the other. The rules of criminal law seem to define standards of conduct; they are about what you can and cannot do, or more precisely, rules that forbid certain conduct and then attach punishments for disobedience. The rules of contract law are different. It's true that contract remedies do provide sanctions (or prices) for breaking contracts, but most of contract law is about making contracts. In criminal law (and torts), the state makes up the rules of conduct. In contract law, the contracting parties are empowered to create their own rules of conduct.
Once you've seen this distinction, you might then become interested in what legal theorists have to say about it. One of the most important views of this distinction was advanced by the great legal philosopher H.L.A. Hart, who classified the rules of tort and criminal law as "primary rules," and the rules of contract law as "secondary rules." This post is an introduction to the Hart's distinction between primary and secondary rules. As always, the Legal Theory Lexicon is aimed at law students, especially first-year law students, with an interest in legal theory.
The Distinction Between Primary and Secondary Rules Hart's basic idea is quite simple. Primary rules are rules of conduct; they tell you what your are legally obligated to do (or refrain from) and what consequences attach to obedience or disobedience. Thus, the criminal law rules that prohibit theft, forbid certain conduct and provide for penalties for violating the prohibition. Technically, the class of secondary rules includes everything except primary rules. For example, secondary rules are legal rules that allow for the creation, extinction, and alteration of secondary rules; secondary rules are power-conferring rules. Thus, contract law empowers individuals and firms to make contracts; contracts themselves are usually collections of primary rules.
More precisely, primary rules are rules that govern conduct, and secondary rules are rules that do not. Thus, the distinction between primary and secondary rules is just a bit different than the difference between duty-imposing and power-conferring rules: duty-imposing rules impose duties, whereas power-conferring rules confer power. This leaves open the possibility that some rules can regulate other rules, but do so by imposing duties. For example, a secondary rule might impose a duty to legislate in a certain way or a prohibition on certain kinds of rule creation.
Some more examples may help:
Examples of Primary Rules
• Criminal prohibitions.
  
• Tort rules.
  
• The individual right to freedom of speech.
  
• The provisions of contracts that define the primary obligations of the parties.
  
• The environmental law rule that forbids discharge of toxic substances in rivers and streams.
Examples of Secondary Rules
• Contract law rules that enable parties to form contracts.
  
• The rules that allow testators to create a will.
  
• The constitutional rules that confer legislative powers on Congress.
  
• The statute that authorizes the Supreme Court to promulgate rules of practice and procedure for the federal courts.
The Practical Importance of Secondary Rules One of the really nifty things about Hart's introduction of the distinction between primary and secondary rules was his account as to why secondary rules are important. We can certainly imagine a system in which there were primary rules, but no secondary rules. This would be a system of customary law. Certain actions would be required; others would be taboo. But there would be no mechanism by which the set of obligations could be changed. Of course, customary law need not be completely static. It is is possible that customs might gradually change over time, but this process would require a change in social norms. It could not be legislated. Secondary rules enable relatively more rapid legal change at a lower cost. Moreover, secondary rules enable individuals to create customized primary rules that govern their private relationships or privately owned resources.
Conclusion The distinction between primary rules of conduct and other, secondary rules is a crucial member of the legal theorist's toolbox. My own experience has been that I use this distinction to understand legal problems and arguments, but that it rarely plays a direct role in my own work. Primary and secondary rules are everywhere, and you need to understand the differenced between them, but you don't necessarily need to use the distinction when you construct normative legal arguments.
One more thing. The place to go for a really thorough understanding of the distinction between primary and secondary rules is H.L.A. Hart's magnificent book, The Concept of Law--in my opinion, the most important work of legal theory in the twentieth century.