Brian Leiter (University of Chicago Law School) has posted Naturalizing Jurisprudence: Three Approaches (J. Shook & P. Kurtz (eds.), THE FUTURE OF NATURALISM (Amherst, NY: Prometheus Books, 2009)). Here is the abstract:
General jurisprudence-that branch of legal philosophy concerned with the nature of law and adjudication-has been relatively unaffected by the "naturalistic" strains so evident, for example, in the epistemology, philosophy of mind and moral philosophy of the past forty years. This paper sketches three ways in which naturalism might affect jurisprudential inquiry. The paper serves as a kind of precis of the main themes in my book NATURALIZING JURISPRUDENCE: ESSAYS ON AMERICAN LEGAL REALISM AND NATURALISM IN LEGAL PHILOSOPHY (Oxford University Press, 2007).
And from the text:
Quine famously suggests that naturalism is “the recognition that it is within science itself, and not in some prior philosophy, that reality is to be identified and described.”5 In that Quinean spirit, Cummins proposes that,
We can give up on intuitions about the nature of space and time and ask instead what sorts of beasts space and time must be if current physical theory is to be true and explanatory. We can give up on intuitions about our representational content and ask instead what [mental] representations must be if current cognitive theory is to be true and explanatory.6
That Quinean version of methodological naturalism about philosophical inquiry may work well where we have bona fide sciences—for example, space-time physics or cognitive neuroscience--to turn to for guidance. But how do we fare when we turn to social scientific accounts of law?
Consider perhaps the leading predictive-explanatory theory of judicial decisions in the political science literature, Segal‟s and Spaeth‟s “Attitudinal Model.”7 Developing ideas first broached by the American Legal Realists,8 Segal and Spaeth argue that the best explanation for judicial decision-making (more precisely, decisions by the U.S. Supreme Court) is to be found in the conjunction of the “the facts of the case” and “the ideological attitudes and values of the justices.”9 Segal and Spaeth identify the “ideological attitudes” of judges based on “the judgments in newspaper editorials that characterize nominees prior to confirmation as liberal or conservative” with respect to particular issues (for example, civil rights and liberties).10 Looking at more than thirty years of search-and-seizure decisions—court decisions about the constitutionality of police practices involving the arrests of criminal suspects and searches of their cars, homes, and property--Segal and Spaeth found that their Attitudinal Model correctly predicted 71% of the votes by justices: that is, the ideological attitudes of the judge towards the underlying compare the Attitudinal Model with some alternatives--most importantly, with what they call “the Legal Model” of decision.11 On the Legal Model, it is valid sources of law, in conjunction with valid interpretive methods applied to those sources, that determine outcomes (call the valid sources and interpretive methods “the class of legal reasons”). The difficulty is that the class of legal reasons is indeterminate: it justifies more than one outcome in appellate disputes. Thus, as Segal and Spaeth write:
If various aspects of the legal model can support either side of any given dispute that comes before the Court, and the quality of these positions cannot be reliably and validly measured a priori, then the legal model hardly satisfies as an explanation of Supreme Court decisions. By being able to “explain” everything, in the end it explains nothing.12
In other words, one can generate no testable predictions from the Legal Model because the class of valid legal reasons justifies, and thus, predicts, multiple outcomes.13
Following Cummins, a naturalized jurisprudence might ask what must law be if current social-scientific theory of adjudication (namely, the Attitudinal Model) is to be true and explanatory? For the Attitudinal Model to be true and explanatory, there has to be, among other things, a clear demarcation between the ideological attitudes of judges (which are causally effective in determining the decisions) and the valid sources of law which are central to the Legal Model‟s competing explanation of judicial decision. Thus, implicit in the Attitudinal Model is quite plainly a concept of law as exhausted by authoritative texts (precedents, statutes, constitutions) which are the raw material of the competing Legal Model, and which exclude the ideological attitudes central to the Attitudinal Model. The concept of law, in turn, that vindicates this assumption is none other than Raz‟s “hard positivist” notion of a rule of recognition whose criteria of legality are exclusively ones of pedigree: a rule (or canon of interpretation) is part of the law by virtue of having a source in legislative enactments, prior court decisions or constitutional provisions. That is the view of law required by the Legal Model, and it is the view of law required to vindicate the Attitudinal Model as providing the best explanation of judicial decision. Raz‟s Hard Positivism, in short, captures what law must be if the Attitudinal Model is true and explanatory.