Mill's harm principle in political philosophy holds that individual liberty may only be restricted to prevent conduct "calculated to produce evil to someone else," but the principle is ambiguous because it leaves unresolved who performs the calculation of harm and whether "calculated" denotes intent or a third-party judgment. This ambiguity means harm is not a single, fixed category but is treated differently across legal and social contexts, ranging along a continuum from excused harm (state-sanctioned killing) through intent-based liability (mens rea, constructive intent), negligence, and strict liability, to omission-based liability (Good Samaritan duties). Because no uniform definition of harm can span all these contexts, and because the location of the harm threshold reflects normative and political choices rather than purely scientific ones, Mill's attempt to found a single objective harm-based limit on liberty cannot be fully realized.
Mill's harm principle in political philosophy holds that individual liberty may only be restricted to prevent conduct "calculated to produce evil to someone else," but the principle is ambiguous beca…