• When we talk about “reasoning,” we are never entirely clear about whether we mean to refer to internal mental processes or to public argument and justification.

• Lawyers argue conflicting points of view. Judges decide disputes and write opinions justifying their decisions in light of the prevailing legal sources (statutes, cases, scholarly commentary).

  • Both lawyers and judges engage in mental and verbal efforts properly called “legal reasoning.

  • The way a judge decides a case—the process of looking at the statute and prior cases and commentary—and comes up with a decision is also called legal reasoning. This process is supposedly neutral and objective and dispassionate.

• Arguing for a client is a particular form of reasoning—but it is partial and subjective and sometimes excessively passionate.

• The form of legal reasoning must be accessible to study and review by other judges, lawyers, and scholars.

  • Most relevant to legal studies is the written opinion, in which the judge explains and justifies the decision in the light of the relevant sources of law.

• In most European languages, the “motivation” includes the written opinion explaining and justifying the decision. The English equivalent of this Continental term would be the “rationale” of the decision.

  • Where judges have motives not recorded in the opinion—in particular, political motives—their decisions tend to lack legitimacy.

• The reasoning of judges on paper—their written opinions—are a necessary subject of study, not only in the common law but also in all national and international legal systems. Lawyers must read these opinions, which are their only source of knowledge for predicting how the court will decide in the next case.

  • Judges in inferior courts must read these opinions in order to know both how to decide their cases and how to write their opinions to avoid reversal on appeal.

• Legal reasoning is bound by a set of conventions, and these conventions are different in every legal culture. These conventions prescribe the materials that judges may cite in their opinions and that lawyers may invoke in their legal arguments.

Deduction and Analogy

• Analogical reasoning always requires a proposition of the form more like B than C. More like is a matter of degree.

  • Relationships of “more likeness” are not a matter of strict logic. Reasonable people might disagree whether an airplane is more like a bird than an automobile or vice versa. Analogies are typically subject to dispute. They are the stuff of disagreement—and dissenting opinions.

  • The important point is that the mode of argument used in a judicial opinion depends on local conventions and attitudes. As a general matter, the common law tradition prefers analogical arguments, and the Continental tradition favors deductive reasoning. But this generalization is easily overstated.

Reading Cases

• Legal cultures differ in the way their participants read and argue from prior cases.

  • German lawyers are accustomed to looking for the Rechtsatz— that is, the succinct statement of law that can be cited as though it were a statutory rule.

  • Common lawyers have cultivated a more refined way of citing precedents. This refinement brings to bear customary rules on which cases constitute precedents and how the case should be stated as precedent.

• Stare Decisis means “letting prior cases stand as binding precedents”.

  • This principle of binding precedent applies both to a single court and to all of the courts that are within the appellate jurisdiction of that court. Thus, a decision concerning a federal question rendered by the Supreme Court of the United States is binding not only upon the Supreme Court but also upon all of the state and federal courts in the United States, because a case in any of those courts could be appealed to that court.

  • A decision by the British House of Lords binds all of the courts of England and Wales, Scotland, and Northern Ireland.

  • Conversely, stare decisis does not bind courts that are not subject to appeal to a given court to follow that court’s opinions. Thus, stare decisis does not bind a court in the United States to apply a decision of the House of Lords or a court in England to apply a decision of the U.S. Supreme Court.

  • In situations in which stare decisis does not apply, the precedents of other common law courts remain “persuasive” as authority.

• The most important language in a legal opinion is the consideration of the narrowest questions of law that are logically necessary to resolve the dispute before the court. This language is sometimes called the ratio decidendi or the “reason for the decision.”

• Language or reasoning in an opinion that is thought not to have been necessary, owing either to the claims presented or to the logical evaluation of those claims, is often described as obiter dicta, or “incidental statements.”

• The necessity that a later judge must interpret the opinion of an earlier judge to determine which part of the opinion is binding upon the later case thus gives the later judge some leeway in disregarding or “interpreting away” portions of some precedents without violating the doctrine of stare decisis.

Reasoning from Statutes

• Working with statutes is not a prominent part of the first-year curriculum in most law schools.

• A maxim long in force held that statutes in derogation of the common law had to be strictly construed. This maxim reflected a certain uneasiness about legislative intervention changing the common law.

• Most statutes that alter the Common law are, at least in the years immediately following their passage, narrowly construed, or interpreted to include the fewest possible cases within the new rule.