Liam Murphy's What Makes Law: An Introduction to the Philosophy of Law is offered as an “advanced introduction” to some central questions in general jurisprudence. Murphy, who holds faculty lines in both law and philosophy at New York University, has provided us with a lucid, thoughtfully organized, and tightly focused exploration of key debates in contemporary legal philosophy. Murphy's analysis is expert and skillfully deployed throughout; key thinkers from the Anglo-American jurisprudential tradition are drawn upon and their arguments engaged. However, in the course of this analysis, Murphy also reveals what might be characterized as an underlying disciplinary anxiety, an anxiety that can be located in at least some of the current scholarly literature—and, although he does not name it as such, this anxiety can be understood to serve as an organizational reference point for the development of Murphy's own argument.

Writing more than 70 years ago, the English legal scholar Glanville Williams, assessed the then current state of scholarship on one of the fundamental questions of general jurisprudence—the question, what is law? He observed that “[t]he amount of printed matter on the meaning of the word ‘law’ is enormous…. [And] any attempt to define this word leads us into a maze of metaphysical literature, perhaps larger than has ever surrounded any other symbol in the history of the world” (Reference WilliamsWilliams 1945: 146). The path to escape from the “maze” that this jurisprudential controversy had created could only be seen, according to Williams, once it was recognized that such controversies are mere “verbal disputes” and, therefore, should be thought of as “wholly unreal.” Once understood as such, disputes that previously had been understood as fundamental now could be set aside to allow for progress on more substantive questions. Although somewhat dated, Williams’ essay makes a cameo appearance in What Makes Law (p. 61), to serve as an example of the kind of approach to dealing with fundamental disagreement in legal philosophy that Murphy wants to push back against. For Murphy, questions such as what makes law? continue to matter because law itself matters.

As Murphy notes, “[d]ifferent kinds of philosophical questions can be asked about law.” Here he is interested with that core set of questions concerning the very nature of law itself. “When we ask what makes law, we may have in mind the question of how we determine the content of the law in force. This is the question of the grounds of law” (p. 1). From this starting point, the “ancient issue” emerges: “whether moral considerations are ever relevant when we are trying to find out what the law is, as opposed to what it ought to be” (p. 2). Those who deny the relevance of such moral considerations go by the name of “positivists.” And, in Murphy's rendering, those for whom moral considerations are always relevant are referred to as “nonpositivists” (a somewhat inelegant name, but it allows him to avoid some of the confusions attendant to the concept of ‘natural law’). Murphy devotes the first six chapters of his book to unpacking this basic question and summarizing the work of key contributors to its resolution from both positivist and nonpositivist camps. A second question—“what makes a normative order an order of law, rather than something else”—provides the subject matter for the last two substantive chapters of the book (Chapters Seven and Eight).

Unsurprisingly, Murphy turns to the work of H.L.A. Hart and Ronald Dworkin to represent the positivist and nonpositivist positions, respectively. The “Hart-Dworkin” debate has dominated philosophical discussions of law for the past half-century. By now, the arguments of the principals are well known. In Chapters Three and Four, Murphy does an excellent job explicating the central claims of each thinker, along with helpful analyses of the increasingly sophisticated elaborations of positivist and nonpositivist arguments provided by contemporary theorists sympathetic to one or the other traditions of thought. By what criteria might we choose which tradition of thought offers the better argument? Can we choose? Should we even try? What are the implications either way for legal actors and others? The “big problem,” as Murphy frames it, is that “the two camps represent two fundamentally opposed visions of the kind of thing law is, and that nothing so much as an argument is likely to move either side closer to the other” (p. 3). Unpersuaded, and perhaps unpersuadable, adherents of each camp move along their own path, with every reiteration of the basic position simply cutting the same path a little deeper. “For positivists, law is grounded in fact alone. For nonpositivists, though law connects with social and political fact, it is also in its nature something good, or at least potentially so…” (p. 3).

The apparent intractability of these debates—a theoretical “standoff” in Murphy's words—suggests grounds for a growing frustration with the inability to move forward, persuading the other side, or reconciling the competing positions in some way (the source of the aforementioned “anxiety”). The seemingly “endless” quality of the engagements also gives support for the view, shared by some at least (see, e.g., Reference WilliamsWilliams 1945), that the entire endeavor is “empty and pointless” (p. 3). It is a view Murphy rejects outright, “since it could only not matter how we determine the content of law if it doesn't matter what the law is” (p. 3). In Chapter 6, Murphy rejects an “eliminativist” option as well—a position that holds that we don't need to know the content or grounds of law; rather, we can set those questions aside, in order to pursue other substantive questions on which we can make progress (see, especially, pp. 88–103). For Murphy, the grounds of law matter, and they matter, he says, because “law has great everyday importance for all of us” (p. 77). He supports this claim at some length in Chapter 7, where he turns his attention to the duty of individuals and states to obey the law, and the normative force of law. Murphy concludes by extending his analysis to international law in Chapter Eight.

Murphy provides a sophisticated yet accessible introduction to the philosophy of law through a careful examination of one of its central and most enduring debates, and by helping us to think what it might mean that that debate exists in the form it does. Moreover, he provides a detailed and compelling set of arguments in support of the activity of legal philosophy itself. Certainly, one might quibble over selection or coverage issues (e.g. more Kelsen or Finnis; something about realism, etc.), but what is addressed is dealt with thoughtfully and thoroughly.