Prescriptive legal theories have a tendency to cannibalize themselves. As they develop into schools of thought, they become not only increasingly complicated but also increasingly compromised, by their own normative lights. Maturation breeds adulteration. The theories work themselves impure.

This Article identifies and diagnoses this evolutionary phenomenon. We develop a stylized model to explain the life cycle of certain particularly influential legal theories. We illustrate this life cycle through case studies of originalism, textualism, popular constitutionalism, and cost-benefit analysis, as well as a comparison with leading accounts of organizational and theoretical change in politics and science. And we argue that an appreciation of the life cycle counsels a reorientation of legal advocacy and critique. The most significant threats posed by a new legal theory do not come from its neglect of significant first-order values—the usual focus of criticism—for those values are apt to be incorporated into the theory. Rather, the deeper threats lie in the second- and third-order social, political, and ideological effects that the adulterated theory’s persistence may foster down the line.


When originalism burst onto the scene in the 1970s and 1980s, it promised to stabilize constitutional law and rein in judges by tying interpretation to the Framers’ “original intentions.” Critics complained that this approach slighted the Constitution’s popular character and could justify intolerable outcomes, such as racially segregated schools. Originalism subsequently reoriented itself around “original public meaning” and the interpretation/construction distinction—blunting some of the earlier criticisms and broadening the theory’s appeal, but at significant cost to its motivating principles of certainty and constraint.1

When cost-benefit analysis (CBA) burst back onto the scene in the 1980s, it promised to rationalize the regulatory state and rein in administrators by demanding adherence to a scientifically informed, quantitative methodology. Critics complained that this approach slighted the importance of nonwelfarist concerns and could justify intolerable outcomes, such as gross violations of human dignity. CBA subsequently incorporated deontological and distributive elements—blunting some of the earlier criticisms and broadening the theory’s appeal, but at significant cost to its motivating principles of efficiency and expertise.2

When popular constitutionalism burst onto the scene in the 2000s, it promised to democratize constitutional law by displacing the court-centered perspective of judges and scholars and returning the Constitution to the people. Critics complained that this approach slighted the role of courts in protecting minority rights and could justify intolerable outcomes, such as mob rule. Popular constitutionalism subsequently shifted its focus from ordinary citizens to government institutions—blunting some of the earlier criticisms and broadening the theory’s appeal, but at significant cost to its motivating principles of lay participation and control.3

In this Article, we argue that these episodes reflect a general tendency of prescriptive legal theories, when they blossom into intellectual movements or schools of thought, to shed many of the core commitments that made the theories attractive in the first place. As they develop over time, that is, these theories become not only increasingly complicated but also increasingly compromised, by their own normative lights. Maturation breeds adulteration. The theories work themselves impure.

The tendency of prescriptive legal theories4 to work themselves impure mirrors the tendency of legal rules to evolve into standards.5 It also has analogues in political science and the history and philosophy of science.6 Yet while we will suggest that the process of impurification can affect nearly all prescriptive projects (and many ostensibly descriptive projects) to some extent,7 there is a subset of legal theories that are especially likely to work themselves very impure: those theories that seek to negotiate highly politicized legal conflicts through the introduction of decision-
making frameworks that abstract away from the central values in contention. Thus, originalism appealed to the authority of a univocal constitutional text in response to the conflict sparked by the Warren and Burger Courts’ expansion of the rights of minorities, women, criminal defendants, and the poor. CBA turned to the language of economics in response to the conflict sparked by the activism of agencies tasked with protecting health, safety, and the environment. And popular constitutionalism heralded the emergence of a demotic formalism—“the people themselves”—in response to the conflict sparked by the Rehnquist Court’s rollback of federal regulatory power.

We submit that the prescriptive legal theories that have gained the broadest support in public law fields over the past several decades have shared these features of abstraction and proceduralism, together with a common life cycle:8

Birth—At T1, the theory9 introduces a decision procedure or criterion for judgment that seeks to resolve a highly politicized legal conflict in terms that are relatively alien to the main points of political contention; in so doing, the theory differentiates itself from preexisting legal theories used to negotiate the conflict.

Critique—At T2, critics of the theory highlight its failure to secure certain values that gave rise to the conflict in the first place.

Reformulation—At T3, the theory responds to these critiques by internalizing them—supplementing or modifying its approach so as to better serve the initially ignored values. As a result, the theory’s constituency expands, but at the price of normative and conceptual purity.

Iteration—At T4, this process of criticism and response recurs.

Maturity—At T5, the theory has come to reflect the conflict-ridden political and theoretical field it had promised to transcend. To the extent the theory ever posed a direct threat to particular participants in the underlying conflict, that danger has dwindled.

Death or Adulterated Persistence—At T6, the theory either falls out of favor with mainstream legal actors, at least for the time being, or persists in substantially adulterated form.10

If this life cycle model accurately captures the developmental history of some of the most influential public law theories in recent memory—including not only originalism, CBA, and popular constitutionalism but also the new textualism and possibly others—then a number of conclusions follow. First, legal theory entrepreneurs are, in general, too optimistic about the transformative power of their theories. Theories of the sort we describe are unlikely to escape the horizon of the conflicts in which they intervene. Instead, the theories are likely to be transformed by the conflicts, eventually recapitulating rather than resolving the underlying political disputes.

Second, critics of new prescriptive legal theories are, in general, too pessimistic about the impact such theories will have. Any theory that successfully attracts a large number of adherents is liable to undergo a process of refinement and revision, if not outright appropriation, that will come over time to undermine its formative goals. An appreciation of these dynamics clarifies connections between legal theorizing and other types of theorizing, and it might help to lower the temperature of some of the legal academy’s most heated debates.

Third, the belief that law can “work itself pure” ironically underwrites the contradictions and compromises of prescriptive legal theories.11 Those theories that suggest that a divisive legal practice can be redeemed, and political debate quieted, through the adoption of proper decisionmaking techniques always already contain the seeds of their own decay. There may be an inescapable trade-off between a legal theory’s ambition to transcend social conflict and its susceptibility to impurification.

And fourth, the persistence of ever-more-adulterated legal theories cannot be explained by broad acceptance of their initial normative commitments, for the price of persistence is the unraveling of those commitments. When such theories endure, we can expect to find them serving interests or ideals exogenous to their stated aims. The continuing bipartisan embrace of originalism, for instance, may be bolstered by its tendency to enhance the political prestige of lawyers or the moral prestige of American nationalism. In any event, the real basis for the persistence of an adulterated prescriptive legal theory—and the real stakes of that theory’s persistence—will be only dimly illuminated by the theory itself.

In making these claims, we are aware that theories are not conscious agents with goals, motivations, or the like. Public law scholars frequently anthropomorphize the ideas and institutions they study,12 so to a certain extent our association of legal theories with intentional states simply follows common parlance. But given that our life cycle model places special emphasis on a theory’s departure from “its own” earlier-in-time commitments, some further clarification is in order. The life cycle model depends on the empirical claim, defended in Part III, that participants in early debates on originalism, textualism, popular constitutionalism, and CBA shared common understandings regarding what the theories were about: the reasons they were introduced and the reforms they would entail. Proponents and opponents of these theories disputed a great deal, but they agreed on the theories’ central purposes and prescriptions. That agreement is what made debates over the theories’ merits intelligible. Such common understandings about a theory in its formative years can be recovered and held up to scrutiny in light of subsequent developments.

We are also keenly aware that the evolutionary process we describe may produce benefits for law and knowledge, a point addressed in Part V. In light of these potential benefits, the language of “impurity” may strike some readers as unduly pejorative. But we do not contend that impure theories are bad theories. We use the language of impurity, instead, to invite the comparison with accounts of the common law working itself pure and to underscore the loss of normative and decisional clarity that attends theoretical maturation. A theory that has become impure in our sense, with an increasingly complex decision procedure and contested normative valence, may well be more attractive than its “purer” predecessors. Alloys are often stronger than base metals. It is nonetheless important to keep track of what gets lost over the course of this progression if prescriptive legal theorists are to understand the structure of the practice in which they are engaged.

  • 1. See Part III.A.
  • 2. See Part III.D.
  • 3. See Part III.C.
  • 4. By “prescriptive,” we mean “[e]xpressing what must or should be done” by official actors in a given area of regulation, interpretation, or enforcement. Black’s Law Dictionary 1374 (West 10th ed 2014) (defining “prescriptive”). See also Part I.B (identifying conditions under which ostensibly descriptive theories may undergo the life cycle). By “legal theories,” we mean coherent groups of propositions that are put forward to guide or explain particular sets of legal practices. This understanding of theory is broader than the understandings that prevail in some other disciplines, which emphasize testability and falsifi-
    ability, but it is consistent with legal academic usage. See Lee Epstein and Gary King, The Rules of Inference, 69 U Chi L Rev 1, 61 n 188 (2002) (criticizing legal scholarship for defining theory more expansively than other disciplines). But see H.M. Collins, Changing Order: Replication and Induction in Scientific Practice 34–46 (Sage 1985) (questioning the significance of falsifiability for theorizing in the natural sciences); Peter Winch, The Idea of a Social Science and Its Relation to Philosophy 91–94 (Routledge 2d ed 1990) (questioning the significance of falsifiability for theorizing in the social sciences). We consider the relationship between legal and scientific theory development in Part IV.C.
  • 5. See Part IV.A.1.
  • 6. See Parts IV.B–C.
  • 7. Among theories with staying power, the principal exceptions either do not seek to resolve politically contentious legal debates or seek to do so directly, by offering arguments that on their face support one side of the debate or the other. We discuss these exceptions in Part I.B.
  • 8. We are grateful to John Danaher for suggesting names for the stages of the life cycle in an insightful blog post. John Danaher, The Life Cycle of Prescriptive (Legal) Theories (Philosophical Disquisitions, May 26, 2016), archived at
  • 9. “The theory” invoked here is a shorthand for the overlapping efforts of an array of theorists, whose individual arguments and motivations may differ and whose identities may change over time. We explain why this internal heterogeneity does not defeat the possibility of an overarching life cycle, and on the contrary facilitates it, in Parts I.C and II.
  • 10. In a short essay from 1982, Professor Duncan Kennedy suggested that all fundamental distinctions that “constitute the liberal way of thinking about the social world,” such as public versus private and freedom versus coercion, undergo “an invariant sequence of six stages . . . from robust good health to utter decrepitude.” Duncan Kennedy, The Stages of the Decline of the Public/Private Distinction, 130 U Pa L Rev 1349, 1349–50 (1982). We follow Kennedy in combining internalist and externalist modes of analysis to account for the transformation of legal concepts over time. For an explanation of these terms, see Mark Tushnet, Book Review, The New Deal Constitutional Revolution: Law, Politics, or What?, 66 U Chi L Rev 1061, 1061 (1999) (explaining that “[e]xternalists describe developments outside the law and the courts to explain [legal] change,” while “internalists . . . emphasize the role that reasoned distinctions . . . play”) (emphases omitted). We focus, however, on a different set of transformations and a different set of external factors. Whereas Kennedy sought to explain what he took to be the decline of the liberal legal worldview as such, our life cycle theory aims to explain the divergent fates of contemporary prescriptive legal theories—all of which operate within the tenets of the liberal legal worldview, however “decrepit” those tenets might appear from other perspectives.
  • 11. The idea that law, and the common law in particular, “works itself pure” is at least as old as Lord Mansfield’s declaration from the bench in Omychund v Barker, 26 Eng Rep 15, 23 (Ch 1744) (Mansfield) (emphasis omitted). Two centuries later, Professor Lon Fuller made this idea famous within the American legal academy. See Lon L. Fuller, The Law in Quest of Itself 140 (Foundation 1940) (“[T]he common law works itself pure and adapts itself to the needs of a new day.”). See also Frederick Schauer, Thinking like a Lawyer: A New Introduction to Legal Reasoning 105 (Harvard 2009) (noting Fuller’s influence). Fuller’s effort to incorporate legal realism’s understanding of the social function of law within a procedural account of legal autonomy has, in turn, been recognized as an important contributor to the rise of the legal process school. See Neil Duxbury, Patterns of American Jurisprudence 261 & n 383 (Clarendon 1995). As discussed in Part I.A, today’s leading public law theories have important affinities with process jurisprudence in their aspiration to resolve politically contentious legal conflicts by means of politically neutral procedural norms. Today’s theories likewise share with earlier accounts of the common law a belief in the internal rationality of law, although they break with the common-law model in seeking to fix a unified decision procedure at the outset rather than refine legal doctrine in an incremental, case-by-case fashion.
  • 12. See, for example, Barry Friedman and Scott B. Smith, The Sedimentary Constitution, 147 U Pa L Rev 1, 33 (1998) (“Originalism seeks to keep faith with our Founders, while living constitutionalism seeks to keep pace with the times.”); Douglas A. Kysar, It Might Have Been: Risk, Precaution and Opportunity Costs, 22 J Land Use & Envir L 1, 42 (2006) (“CBA aspires to achieve complete agent-neutrality.”). See also David E. Pozen, Self-Help and the Separation of Powers, 124 Yale L J 2, 13 (2014) (“[T]he anthropomorphization of the branches is a standard move in constitutional theory.”).