Why Precedent in Law (and Elsewhere) is Not Totally (or Even Substantially) About Analogy

Cognitive scientists who conduct research on analogical reasoning often claim that precedent in law is an application of reasoning by analogy. In fact, however, law's principle of precedent, as well as the use of precedent in ordinary argument, is quite different. The typical use of analogy in law, including analogies to earlier decisions, involves retrieval of a source analog (or exemplar) from multiple candidates in order to help make the best decision now. But the legal principle of precedent requires that a prior decision be treated as binding even if the current decision maker disagrees with that decision. When the identity between a prior decision and the current question is obvious and inescapable, precedent thus imposes a constraint different from the effect of a typical argument by analogy. The importance of distinguishing analogy from precedent is not so much in showing that a common claim in the psychological literature is mistaken, but that making decisions under the constraints of binding precedent is an important form of decision deserving to be researched in its own right and that it has been ignored because of the erroneous conflation of constraint by precedent with reasoning by analogy.