As law students become more sophisticated, they begin to notice that certain debates seem to repeat themselves over and over again. Disagreements about disparate subjects--in procedure, criminal law, torts, property, and constitutional law--frequently seem to turn on the really big questions of ethics and political theory. On the one hand, the proponents of inviolate individual rights appeal to deontological premises in moral theory or liberal (or libertarian) ideas in political philosophy. On the other hand, the proponents of balancing argue from premises rooted in utilitarianism or welfarism (the economic version of utilitarian moral philosophy).
For a short time, the ability to see this pattern may be exhilarating. You begin to see big patterns that transcend courses and doctrines. But after a while, exhilaration may give way to depression. If all the great debates in legal theory boil down to debates about the deepest questions of moral and political philosophy, then the question arises, "Can we make any progress?" Because it sure doesn't look like the debates between deontology and consequentialism or between libertarians and communitarians are going to be decisively resolved any time soon.
And that is where today's Legal Theory Lexicon comes into the picture. Even if the deep debates of moral and political philosophy are irresolvable, there may be other ways to make progress in legal theory. In particular, we may be able to use the ideas of "incompletely theorized agreements" (associated with Cass Sunstein) or "overlapping consensus" (associated with John Rawls) to break the impasse on the deep questions.
The basic idea is simple. We cannot agree on the deep questions, so go shallow. Find the level at which those who disagree on the deep can nonetheless find common ground. John Rawls calls the idea of common ground by the name "overlapping consensus." Cass Sunstein calls a similar idea, "incompletely theorized agreement." But both Sunstein and Rawls express a similar intuition. When you cannot reach agreement at the deep end of the pool of ideas, head for the shallow end!
Deep and Shallow I suspect that you've already gotten it! But just to make sure, let's work through the ideas one by one. The first idea we need is the one that I have expressed by the metaphor of deep and shallow reasons. The metaphor is based on the idea that particular applications (e.g. particular questions of legal doctrine) are at the surface, they are in the shallow end of the pool of ideas. Beneath the surface of particular issues in legal doctrine and legislative policy are deeper disagreements. Disagreements about the a surface level question (e.g. the precise contours of the mailbox rule in contract law) lead to beneath-the-surface issues (e.g. the nature of offer and acceptance) and then to still-deeper issues (e.g. the basis for contractual obligation) and finally to the deepest questions (e.g. the nature of moral obligation). You might picture a chain of reasons, stretching from the surface of legal doctrine down to the depths of political and moral philosophy.
Overlapping Consensus John Rawls developed the idea of an "overlapping consensus" as part of the work that led up to his book Political Liberalism. The idea emerged as part of Rawls's work on what he called the problem of stability. In a society governed by Rawls's theory (justice as fairness), the guarantee of basic liberties would mean that individual citizens would be free to adopt their own views about morality and religion. As a result, Rawls argued, it was likely that a variety of comprehensive religious and moral doctrines would emerge. Rawls believed that this fact of pluralism posed a problem for his theory. How could justice as fairness be stable (or reproduce itself) given the plurality of viewpoints that is bound to emerge and persist under conditions of freedom? Rawls's answer to this question was based on the idea that divergent moral and religious conceptions of the good could (despite their diversity) converge on some common ground. That is, citizens who held a plurality of religious and moral beliefs could nonetheless agree on the constitutional essentials--the basic constitutional principles necessary for a society to satisfy the demands of justice as fairness.
This meant that different citizens would support justice as fairness for different reasons. Catholics might affirm justice as fairness for reasons found within the Catholic natural law tradition, while secular humanists might affirm the same (or similar) ideas about justice for different reasons. Although a deep consensus might on justice as fairness might be impossible, an "overlapping consensus," Rawls argued, is possible.
Incompletely Theorized Agreements Cass Sunstein has a related but different idea. Here is a summary from his article in the Harvard Law Review:
Incompletely theorized agreements play a pervasive role in law and society. It is rare for a person, and especially for a group, to theorize any subject completely -- that is, to accept both a highly abstract theory and a series of steps that relate the theory to a concrete conclusion. In fact, people often reach incompletely theorized agreements on a general principle. Such agreements are incompletely theorized in the sense that people who accept the principle need not agree on what it entails in particular cases. People know that murder is wrong, but they disagree about abortion. They favor racial equality, but they are divided on affirmative action. Hence there is a familiar phenomenon of a comfortable and even emphatic agreement on a general principle, accompanied by sharp disagreement about particular cases.
This sort of agreement is incompletely theorized in the sense that it is incompletely specified -- a familiar phenomenon with constitutional provisions and regulatory standards in administrative law. Incompletely specified agreements have distinctive social uses. They may permit acceptance of a general aspiration when people are unclear about what the aspiration means, and in this sense, they can maintain a measure of both stability and flexibility over time. At the same time, they can conceal the fact of large- scale social disagreement about particular cases.
There is a second and quite different kind of incompletely theorized agreement. People may agree on a mid-level principle but disagree both about the more general theory that accounts for it and about outcomes in particular cases. They may believe that government cannot discriminate on the basis of race, without settling on a large-scale theory of equality, and without agreeing whether government may enact affirmative action programs or segregate prisons when racial tensions are severe. The connections are left unclear, either in people's minds or in authoritative public documents, between the mid- level principle and general theory; the connection is equally unclear between the mid-level principle and concrete cases. So too, people may think that government may not regulate speech unless it can show a clear and present danger, but fail to settle whether this principle is founded in utilitarian or Kantian considerations, and disagree about whether the principle allows government to regulate a particular speech by members of the Ku Klux Klan.
My special interest here is in a third kind of phenomenon -- incompletely theorized agreements on particular outcomes, accompanied by agreements on the low-level principles that account for them. These terms contain some ambiguities. There is no algorithm by which to distinguish between a high-level theory and one that operates at an intermediate or low level. We might consider Kantianism and utilitarianism as conspicuous examples of high-level theories and see legal illustrations in the many (academic) efforts to understand such areas as tort law, contract law, free speech, and the law of equality to be undergirded by highly abstract theories of the right or the good. By contrast, we might think of low-level principles as including most of the ordinary material of legal doctrine -- the general class of principles and justifications that are not said to derive from any particular large theories of the right or the good, that have ambiguous relations to large theories, and that are compatible with more than one such theory. [Cass Sunstein, Incompletely Theorized Agreements, 108 Harv. L. Rev. 1733, 1739-40 (1995)]
The alternative is to see whether you can find a different level at which the dispute can be resolved. One possibility is that you can find convergence at the surface level. It seems as if deontologists and utilitarians disagree, but perhaps you can craft consequentialist arguments that converge with the arguments of fairness. Another possibility is that you will be able to find converged on what Sunstein calls "mid-level principles." For example, both consequentialists and deontologists might be able to agree that contract formation (normally) requires that both parties manifest and intention to be bound--although they would have different reasons for affirming this proposition.
Conclusion The move to "overlapping consensus" or "incompletely theorized agreements" is one of the niftiest and most useful in contemporary legal theory. Add it your personal legal theory toolbox!