The law’s use of the terms “reasonable” and “unreasonable” are legion and notorious. Indeed, the law’s seemingly carefree attitude in throwing around these terms has often served Legal Realists and their descendants well in their effort to depict legal language as simply a shell through which actors exercise the widest sort of discretion to select their favored outcomes or policies. Conversely, ambitious agendas from philosophers and economists have often found that “reasonableness” provides a readily available anchor in the positive law for their normative theories. Work by moral and political philosophers devoted to analyzing “the reasonable” and work by economists, decision theorists, and game theorists on rationality understandably turn the law’s use of “reasonableness” into a magnet for legal theory. In these respects, “reasonableness” might be seen as the third “r” of legal theory. Like “rights” and “responsibility,” “reasonableness” is beloved by legal theorists and equally beloved by the skeptics who spend their time skewering those theorists.
However tempting it is to join one side or the other in these jurisprudential wars, it is useful to step back and do some legwork on the place of the reasonable within the law, and more specifically, on the variety of places that “reasonable” and its cognates are found in the law. Hohfeld and many since him have found what I might call “varietal analysis” useful in exploring the concept of rights, as did Hart within the concept of responsibility. If exploration of the varieties of reasonableness in the law were to provide even a fraction of the illumination generated by their work on the other two “r”s, the enterprise will have been worthwhile.
There is, of course, an irony in my suggested sequence of research. The word “reasonable” is a paradigmatic example of a standard in the law, and its meaning is, if nothing else, vague. And—as intimated above—that is why it is so tempting to reach to legal, philosophical, and economic theories to flesh out some content for “the reasonable” when content is needed. It thus seems odd—backwards, even—to turn to legal doctrine to try to illuminate reasonableness.
My reasons for looking at doctrine relate to a suspicion that legal scholars with a theoretical proclivity have too quickly conflated three quite different attributes of the language of reasonableness in the law: the attribute of vagueness, the attribute of meaninglessness, and the attribute of ambiguity. For a term or a phrase to fall short of clarity because of vagueness is quite different from having no meaning at all, and both are different from having multiple meanings—being ambiguous. A failure to distinguish among these features of meaning can distort our view of the relevant domain of law. Indeed, the failure to recognize the multiple ambiguity of “reasonableness” can lead to a distorted view of its vagueness and unclarity in the law.