An idea · Nineteenth Century · first attested 1859
The Harm Principle
The only legitimate use of power against an individual is to prevent harm to others.
Mill in On Liberty. Society may not coerce a person merely because it disapproves of their lifestyle, beliefs, or choices, so long as they harm no one else. The principle is the philosophical core of classical liberalism and the perennial battleground of contemporary political philosophy: what counts as harm? does offense count? what about future selves?