University of Pennsylvania Law Review
The word "reasonable" and its cognates figure prominently in innumerable areas of the law – from antitrust and contract law to administrative and constitutional law, from the common law of nuisance to an assortment of rules in statutes and regulations. While some thinkers have equated "reasonableness" with "rationality," others have looked to "justifiability," and others still have decided that "reasonableness" means virtually nothing at all, but serves the important function of allocating decisionmaking authority. The reality is that the term "reasonable" is both vague and ambiguous, and thus plays many different roles in the law. As with terms such as "rights" and "responsibility," we will benefit from an analysis of "reasonable" that admits that different meanings take center stage in different legal contexts. This broad, ‘varietal’ analysis of reasonableness in the law comprises the first half of the article. Turning to negligence law, the second half of the article offers a broad critique of the Hand formula conception of reasonableness. The article criticizes both the Posnerian/economic interpretation of the Hand formula and the more basic idea (in the Restatement (First)) that the "unreasonableness" of risk is the core of negligence law. The breach element of negligence law is focused first and foremost not on a level of risk but on a kind of person – a reasonably prudent person or a reasonable person. By attending closely to the role of reasonableness concepts in various aspects of negligence doctrine, and comparing them to reasonableness concepts in other parts of the law, the article constructs and defends a "moderation and mutuality" conception of reasonableness in negligence law.
Reasonableness In and Out of Negligence Law, 163 U. of Pa. L. Rev. 2131
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