Saturday, April 03, 2004

Judge Posner on "Rules of Law"

This may be off-topic, but we can't help ourselves.

In the course of legal research, we have stumbled across the following bit of wisdom by Judge Posner in AM Int'l, Inc. v. Graphic Management Associates, Inc., 44 F.3d 572, 575 (7th Cir. 1995):

Rules of law are rarely as clean and strict as statements of them make
them seem. So varied and unpredictable are the circumstances in which they are
applied that more often than not the summary statement of a rule -- the terse
formula that judges employ as a necessary shorthand to prevent judicial
opinions from turning into treatises -- is better regarded as a generalization
than as the premise of a syllogism.
Like many insights that seem obvious once stated, Judge Posner's remark may have the ring of a truism. But in the heat of advocacy, its truth is often disregarded. It even seems to us that disregarding it has become something of a trend -- and one for which computer-assisted legal research may be partly to blame.

Syllogistic reasoning is valid enough, within systems constructed in such a way that well-formed propositions legitimately employing the universal quantifier can serve as the major syllogistic premise. Mathematics is widely assumed to be one example of such a system, and that very assumption shapes the interpretation legitimately to be placed on mathematical utterances. When a geometer says that the area of a circle is given by multiplying the square of the radius times pi, he or she is not saying that this formula is a helpful rule of thumb, applicable on the heavy preponderance of everyday occasions. The geometer is claiming that the formula enjoys perfect generality, with no Euclidean counterexamples. In some disciplines, such as physics, it is even the goal to formulate universally quantified statements that can survive the crucible of empirical testing, and which can, to that extent, be regarded as "laws" to which the physical universe unstintingly conforms.

But as Judge Posner reminds us, legal discourse, for the most part, is not, and is not intended to be, such an idiom. To be sure, there may be pockets of legal discourse where syllogistic reasoning may be validly and harmlessly employed. Certain bedrock principles are true almost as a matter of legal definition. All contracts have more than one party. Other legal propositions are true because the law so ordains, with sufficient universality unto the day. No one can libel the dead. But in the main, legal propositions obey a logic of rule-and-exception, rule-with-qualification, rule-for-these-purposes, rule-as-generalization. Limits on the scope of legal propositions often go unstated, because the fact pattern under consideration may not require a precise determination of where those limits may fall. But although legal principles may often be stated in a grammar reminiscent of universal quantification, a claim of perfect generality is not usually intended, and usually could not be sustained.

That helps to explain why law must draw on hermeneutic tools beyond formal logic. It also explains what is frequently wrong with legal briefs that string together a series of judicial quotations, stating abstract legal "principles," in a syllogistic chain. Every litigator has probably had the experience of receiving just such a brief and wondering how his or her client might survive in the face of so many Immutable Principles, only to discover, upon cracking the books, that the first Immutable Principle in the chain comes from an admiralty precedent, the second from a decision about quartering troops in peacetime, and the third from a case involving an extradition treaty with Uruguay. To us, that experience seems to have grown more common.

Certainly it aids and abets the practitioners of such spuriously syllogistic legal reasoning that a vast corpus of judicial utterances can now be searched almost effortlessly for whatever quotation is required. Everyone knows the story about the six monkeys, sitting at their six typewriters, who will eventually inscribe every sentence of arbitrarily finite length that it is syntactically possible to utter. So enormous is the volume of searchable legal prose now publicly available, that the American legal community could easily be thought to be conducting precisely the same experiment. Even if the uneven quality of this tsunami of authority were left to one side, there would still be the matter of the temptations afforded by modes of legal research making it almost effortless to locate statements possessing the requisite verbal form, regardless of what their original context might imply about their intended conceptual content.

We're not saying it's time to cancel the Lexis subscription and turn off the computers. Not just yet. But as Judge Posner's remarks should help us to remember, excessive inferential circumspection is not the most prevalent legal vice. The next time we stumble across that irresistible quotation in the reporters (or on the computer screen) -- the one that announces some Hallowed Legal Principle dating back to the Magna Carta -- maybe we should take a moment to see whether its context suggests limits on its scope.
Fed. R. Evid. 702: If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.