The command theory of law

First, with regard to the development of the command theory of law, philosophers such as Hugo Grotius (1583–1645), Francisco Suárez (1548–1617), and Samuel, baron von Pufendorf (1632–94), developed theories of what persons must be like in order to be capable of imposing and subjecting themselves to law. Although there were differences between these theorists, they shared certain common assumptions. It was agreed, for example, that law is directed at beings who are free—who have the capacity to choose among a range of available actions—intelligent, and self-directing. In other words, such beings have the capacity to recognize law as a kind of command addressed to them, to understand that fact as a reason to act (or at least to deliberate) in certain ways, and then actually to act on the basis of that recognition and deliberation. Moreover, these philosophers agreed that the content of law is determined by the content of the will of the “commander,” or the lawmaker.

That the creation of law involved some operation of the will of a person also helped to explain how law motivated its subjects to act accordingly. The legislator as commander aimed, by enacting laws, to produce behaviour of the sort reflected in the content of a law, which required an operation of the will of the subject of the sort just described. Just as one may speak metaphorically of there being a “meeting of the minds” in the context of making an agreement, these theorists thought that there must be a “meeting of the wills” in order for law to successfully guide conduct. Suárez, for example, said that the will of a legal subject must “come into direct contact” with the will of the legislator; Pufendorf likewise said that the content of a law must be “instilled into a subject’s mind” in order for the subject to be motivated to act accordingly. All these assumptions supported and formed the general view that an essential feature of law is to play a rational but decisive role in the practical reasoning of its subjects—that is, in their reasoning about what they ought to do. This view would enjoy a resurgence among philosophers of law in the late 20th century.

The common-law theory of law

The other major development of that period was the emergence in England in the early 17th century of a group of lawyers and judges who held that all law is either equivalent to or derived from the common law, which they identified as “immemorial custom.” Among those who made important contributions to this general theory were Sir Edward Coke (1552–1634), Sir Matthew Hale (1609–76), and later Sir William Blackstone (1723–80). Laws are part of the common law only if, as Hale said, “they have acquired their binding power and the force of laws by a long and immemorial usage.” The very fact of the usage of a rule by a community for years or centuries is what lends that rule authority and legitimacy. The practices of a community that extend for longer than anyone at a particular time can recall (“time out of mind”) imply and reinforce that community’s recognition and sense that such practices are reasonable and ought to be followed.

The exact nature and role of that history of practice was a matter of some debate, however. Coke held that the law of England had in fact not changed in substance since Saxon or even Roman times and that such prodigious history formed the basis of the legitimacy of the English law of his day. Hale found this claim dubious and held that the law of the present need not be identical to that of the past but only continuous with it; what is instead essential is an ongoing sense among members of the community that the present law is reasonable and appropriate for their circumstances.

Common-law theory was an important departure from the command model of law, primarily because it moved away from the statute as a paradigm and instead focused on explaining the operation of the courts and their relation to the larger community. The activities of judges and practicing lawyers were therefore, for the first time, given pride of place in constructing a philosophical theory of law. That general approach would become dominant throughout the 20th century.

As part of their philosophy of law, common-law theorists advanced what is now called a theory of adjudication: a theory of what judges do and ought to do. As the essence of the common law was immemorial custom, which transcended any single individual’s beliefs or attitudes, the judge was not and could not act as a lawmaker when settling disputes between citizens. Instead, the judge discovered or discerned the common law from relevant past cases, treatises, and common experience. Coke famously said, “Judex est lex loquens” (literally, “The judge is the law speaking”), by which he meant that the judge is a kind of expert at declaring the law that was there antecedently in the community. The judge is the “living oracle” of the law but only as its mouthpiece and not as its source. Coke’s claim also implies that with each new judicial decision based on the reasoning of past cases, and insofar as like cases should be treated alike, it is the new case itself and not the judge that extends the law. The relevant expertise of judges (and the lawyers who argued before them) was explained by Coke in terms of “artificial reason,” a special intellectual capacity of legal professionals to synthesize the customs of a community into a coherent set of common-law principles used to judge cases. “Reason is the life of the law,” Coke said, and the law “is an act which required long study and experience before that a man can attain to the cognizance of it.”

Whereas the first common-law theorists were rather parochial in their aspirations—they sought to explain the ultimate basis of the law of England—their importance has increased considerably since the middle of the 20th century. Because the political and economic power of common-law countries such as the United States and the United Kingdom have increased internationally, their legal systems, and the legal theories that justify and explain them, have correspondingly grown in influence. Moreover, international law itself has developed exponentially since the end of the World War II, and custom has long been considered to be one of its legitimate sources.