Abstract

Scholarship in experimental jurisprudence has reported surprising findings about various concepts of legal significance: _acting intentionally_, _causation_, _consent_, _knowledge, recklessness_, _reasonableness,_ and _law_ itself. Often, these studies examine laypeople’s ordinary concepts and draw broader conclusions about legal experts’ concepts. This Article questions such inferences, from empirical findings about ordinary concepts to conclusions about the concepts of those with legal expertise. It presents a case study concerning what it means to act _intentionally._ An experiment examines intentionality judgments across four populations (N = 774): laypeople, law students, non-law students, and United States judges. Legal training affected judgments in three ways that are consistent with the acquisition of a distinctive legal concept. This case study supports the Article’s broader claim: Laypeople’s ordinary concepts are not equivalent to experts’ legal concepts. The acquisition of legal concepts is an important form of legal expertise.