Summary
Chapter I: Introductory
Mill defines the subject as civil or social liberty: the limits of collective power over individuals. Representative government does not eliminate oppression because a majority can impose its preferences through law and public opinion.
He proposes the harm principle. Coercion against a competent adult is justified only to prevent harm to others. A person’s own good permits persuasion and warning, but the individual remains sovereign over body and mind. The principle does not apply in the same way to children or societies Mill regards as not yet capable of free discussion, a limitation modern readers should examine critically.
Chapter II: Liberty of Thought and Discussion
Silencing an opinion assumes infallibility. The rejected view may be true, and even a unanimous society has no greater right to silence one dissenter than that dissenter would have to silence everyone else.
If the conventional opinion is true, challenge still has value. Beliefs protected from argument become prejudices whose reasons are forgotten. If opposing positions each contain part of the truth, open discussion is required to correct one-sidedness and reach a fuller understanding.
Chapter III: Individuality
Mill argues that individuality is an ingredient of well-being, not merely an instrument for producing social discoveries. Choice exercises perception, judgement, discrimination, self-control and moral preference. A person who follows custom without reflection fails to develop these capacities.
Original people introduce new practices and prevent social life from becoming uniform. Mill does not recommend eccentricity for its own sake; he defends room for different characters and plans wherever they do not harm others.
Chapter IV: Society’s Authority
Individuals owe duties not to injure the recognised interests of others and may be held responsible for failing to perform a fair share of common burdens. Society may express dislike of self-regarding conduct, but inconvenience or moral offence alone does not establish a right to punish.
Mill answers objections involving bad example and indirect social effects. When conduct violates a definite duty or causes identifiable harm, it enters the social sphere. Where consequences fall chiefly upon the agent, compulsory moral improvement remains illegitimate.
Chapter V: Applications
Mill applies the doctrine without pretending that every case is simple. Trade is social and may be regulated against fraud; dangerous goods may require warnings; and conduct creating a direct risk to others can be restrained.
Contracts, intoxication, education and family responsibilities reveal differences between choosing risk for oneself and placing others in danger. Mill also opposes unnecessary state control, arguing that voluntary association and local initiative educate citizens in practical freedom.