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"Demystifying Legal Reasoning" defends the proposition that there are no special forms of reasoning peculiar to law. Legal decisionmakers engage in the same modes of reasoning that all actors use in deciding what to do: open-ended moral reasoning, empirical reasoning, and deduction from authoritative rules. Part II (abstracted here) addresses common law reasoning, when prior judicial decisions determine the law. Part III addresses interpretation of texts. We conclude that, in both areas, the popular view that legal decisionmakers practice special forms of reasoning are false.

In Chapter 2, we propose that there are two plausible models of common law reasoning, and only two. One is the natural model, in which courts resolve disputes by deciding what outcome is best, all things considered. The other is the rule model, in which courts treat rules announced by prior courts as serious rules of decision, then revert to natural decisonmaking when rules provide no answers. Despite the inescapable flaws of serious judicial rules, the rule model of common-law decisionmaking has advantages that we believe justify courts in adopting it.

In Chapter 3, we explain why other supposed methods of legal reasoning are spurious. Analogical decisionmaking based on factual similarity between cases is either intuitive or deductive. If the process of identifying important similarities is intuitive, the precedent case does not constrain the outcome of the new case in any predictable or even detectable way. If the process is deductive, it is the rules or principles that govern similarity, rather than the outcome of the precedent.

We also reject the possibility of reasoning from legal principles. As a matter of logic, legal principles cannot operate in the way their proponents suggest, as a medium by which past decisions constrain the outcome of natural reasoning in current cases. The notion of weight is too elusive, and the criterion of fit with prior decisions is too malleable, to sustain the argument that legal principles guide judges in reaching decisions. Moreover, if legal principles could in fact effectively constrain decisionmaking, their effects would be pernicious: legal principles entrench past errors without securing the benefits associated with legal rules.

In Chapter 4, we address both the problems judges face as rulemakers and the descriptive gap between the rule model of decisionmaking we have proposed and prevailing judicial practice. Practices that appear to contradict the rule model of decisionmaking may have developed in response to the special problems that arise when a single authority must both resolve a particular dispute and also announce rules for a broader class of future cases.

Date of Authorship for this Version

January 2006


Legal reasoning

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Jurisprudence Commons