The purpose of this Article is to describe a pluralistic model of reasoning that may be used to teach the skills of legal analysis. There are different ways to categorize legal arguments. Perhaps the most common method is to identify different legal arguments with specific schools of jurisprudence or moral philosophy. This is the standard approach followed by leading scholars such as Lon Fuller. In a classic article, Fuller illustrated how a murder case could be analyzed utilizing jurisprudential frameworks such as positivism, natural law, social contract, practical wisdom, and legal realism. Another example of this method of characterizing legal arguments was illustrated by R. Randall Kelso, who identified four schools of thought that have dominated the reasoning of the Supreme Court at different periods of American history. Identifying different types of legal arguments by their jurisprudential school is useful for showing the relationship of legal thought to classic forms of political and moral reasoning and for sketching trends of analysis over time.
Another powerful strategy for classifying legal arguments is to identify the logical structure of the underlying reasoning. Richard Posner and Vincent Wellman, for example, identify three categories of legal reasoning: formalism, analogy, and realism. The advantage of this system of classification is that the logical strength of different kinds of arguments can be compared and assessed. This system of classification is useful in evaluating the relative merits of *436 formalism and realism, as well as for inquiring into the structure of reasoning by analogy.
Over the last two decades legal scholars have developed a third method of categorizing legal arguments. This approach is primarily descriptive, in that it attempts to describe the variety of arguments that lawyers employ in the practice of law and judges use in their opinions. Akhil Amar, for example, recently observed that we interpret the Constitution: through a variety of techniques--by parsing the text of a given clause, by mining the Constitution's history, by deducing entailments of the institutional structure it outlines, by weighing the practicalities of proposed readings of it, by appealing to judicial cases decided under it, and by invoking the American ideals it embraces. Amar further states that "[t]ext, history, structure, prudence, and doctrine--these are the basic building blocks of conventional constitutional argument." This approach has been variously called "eclectic," "polycentric," and "pluralistic." Eskridge and Frickey describe their approach to statutory interpretation as an approach where "a court considers a broad range of textual, historical, and evolutive evidence when it interprets statutes" calling it "eclectic" and "polycentric." The term "pluralistic" was coined by Stephen Griffin, who defined the term as follows: "Pluralistic theories of constitutional interpretation hold that there are multiple legitimate methods of interpreting the Constitution." Michael Dorf prefers the term "eclectic" to describe theories that "recognize that courts employ a variety of forms of argument" and eschews the term "pluralistic" in order to avoid confusion with the concept of cultural pluralism and to avoid implying that there is more than one right answer to questions of constitutional law.
Part II of this Article describes a pluralistic model of law that is based upon the theories of Bobbitt, Eskridge, and Frickey. Five types of legal argument exist: text, intent, precedent, tradition, and policy. Each type of argument may be considered an information set or a category of evidence admissible to prove what the law is.
Part III describes how to measure the persuasiveness of legal arguments. There are two challenges to legal arguments: intramodal and intermodal. An intramodal challenge attacks a legal argument on its own terms, subjecting each type of argument to characteristic lines of attack. I identify twenty-five different types of intramodal challenges. Intermodal challenges attack the legitimacy or the weight of each kind of argument. Each kind of argument advances a different underlying purpose of our system of laws; the weight one assigns to each kind of argument reflects the ordering of these underlying values. The persuasiveness of a legal argument is dependent upon both its intramodal strength and the weight accorded to the kind of argument asserted.
Part IV suggests that the art of "thinking like a lawyer" consists of mastering the ability to understand, create, critique, and evaluate the five types of legal argument. In particular, I discuss how to teach students to critically evaluate policy arguments and how to make the connection between rules and policies.