Reasoning under rules
Under the rule model of common law reasoning, courts treat rules announced by prior courts as authoritative in later cases that fall within the terms of the rule. The rule model does not exclude natural reasoning: if no court has announced a rule that covers the current case, the current court must engage in moral and empirical reasoning to settle on an outcome and possibly announce a rule for future cases.
In other cases, a prior court may have announced a relatively indeterminate standard of decision to govern conduct and future decisions. If so, the current court must engage in moral and empirical reasoning within the zone designated by the prior court, subject to whatever limits the standard places on acceptable reasons to consider. If, however, the case is governed by a precedent rule, the court must set aside moral and empirical reasoning and turn instead to interpretation and deductive reasoning in order to apply the rule to the case at hand.To understand how the rule model works, it is useful to compare the role that rules play under a natural model of decision-making. Following rules has various benefits that a good natural reasoner will take into account in her decision-making. A rule of decision stated in a prior opinion embodies whatever expertise the prior court possessed on the subjects covered by the rule, provides a focal point for coordination by actors who need to predict what other actors are likely to do, and simplifies the process of decision-making. If disregarding the rule will cause losses that outweigh the moral costs of following the rule, then as a matter of natural reason, the current court should follow the rule. Under a natural model of decision-making, however, a prior rule has no authority: it has only the various effects just described, to the extent that the current judge takes them into account in her own assessment of reasons for her decision. Referring back to the terminology we used in Chapter 1, the current judge acts as a ‘rule-sensitive particularist', taking the various possible benefits of rules as reasons, but not conclusive reasons, to follow the rule (Schauer 1991a; 1991b).
The rule model of common law reasoning requires judges to take a different attitude toward rules stated in judicial opinions. Judicial rules are now authoritative, such that in any case that falls within a rule's terms, future judges must follow the rule without asking whether the reasons underlying the rule justify the outcome it prescribes in a particular case. If a prior judge has ruled that mortuaries in residential neighborhoods are nuisances per se, the current judge must rule against a mortuary seeking to do business in a residential neighborhood. Subject to certain qualifications we will mention later in this chapter, further inquiry into the risks, aesthetics, and social benefits of mortuaries in general, or of this mortuary in particular, is out of play.
The role of the judge also changes under a rule model. Under a natural model of the common law, judges are primarily adjudicators, attempting to determine in each case what outcome is best, all things considered. Under the rule model, judges are also lawmakers, exercising rule-making authority over future decision-makers. Traditionally, judges were reluctant to assume the role of lawmakers: their supposed task was to find the law embedded in social and legal practice and the requirements of sound reasoning (Blackstone 1765; Hale 1713; see Tubbs 2000). Modern judges, however, are more confident about assuming the role of lawmakers and more willing to embrace the rule model of judicial decision-making (see Eisenberg 1988; Cardozo 1949; Schauer 1995b; Tiersma 2005).
5.3