Mill's harm principle holds that the only legitimate ground for society or the state to coercively interfere with an individual's liberty of action is to prevent harm to others; conduct that concerns only the agent is protected as self-regarding and immune from compulsion, even where persuasion or remonstration remains permissible. Mill synthesizes this rights-based doctrine with utilitarianism by arguing that individual liberty (particularly freedom of speech and thought) is itself the mechanism by which society approaches truth through the ongoing, fallibilist contest of ideas, and that truth-seeking in turn serves the maximization of aggregate utility — an invisible-hand structure analogous to Pareto efficiency in economics. This body of theory belongs to political philosophy, specifically liberal theories of individual rights and utilitarian ethics, and represents Mill's departure from earlier Enlightenment conceptions of scientific certainty toward a fallibilist, falsification-based conception of knowledge.
Mill's harm principle holds that the only legitimate ground for society or the state to coercively interfere with an individual's liberty of action is to prevent harm to others; conduct that concerns…