Abstract This article integrates the concept of moral progress – here, moral improvement in the thinking and behavior of individuals over time – into the study of legal doctrine. The article first presents a naturalistic account of what moral progress is and describes three of its most historically and analytically important forms: (1) moral circle expansion , (2) moral domain expansion , and (3) increasing sensitivity to proportionality . The article then analyzes three historical developments in U.S. tort law that qualify as instances of moral progress: (1) the partial demise of the “suicide rule” beginning around the 1980s (according to the article, an episode of moral circle expansion), (2) the liberalization of recovery for emotional harm in the negligent infliction tort beginning around the 1970s (moral domain expansion), and (3) the near-total replacement of contributory negligence by comparative negligence throughout the twentieth century (increasing sensitivity to proportionality). The article ends by outlining three legal scholarly implications of the analysis. (1) Legal scholars may be able to use the concept of moral progress as a criterion for making internal as opposed to external criticisms of tort law. (2) Attending to historical moral progress in an area of law facilitates sounder assessment of the area’s present-day moral value. (3) Studying moral progress in legal doctrine can identify open legal historical questions about historical legal actors’ motives. More generally, this article can inform legal scholars who seek to analyze morally progressive or regressive change in any area of law.
Philip Petrov (2026) studied this question.