On Liberty

What is this book about?

Mill tries to draw a line: how far society may legitimately interfere with the individual. His harm principle holds that as long as others are not harmed, the opinions and way of life of an individual should be free from coercion — including the coercion of public opinion.

Why read it?

It shifts the question of liberty from who should rule to where the limits of power lie, a move that has shaped every subsequent debate over speech, privacy, and personal conduct. Even those who reject Mill must answer him first.

Core Ideas

• The harm principle: the only legitimate ground for restricting individual liberty is to prevent harm to others, not because an act is immoral or offensive in itself.
• Free speech matters not only for opinions already accepted but because suppressing a wrong opinion drains the vitality of the right one.
• Individuality has value in itself, and social conformity narrows the room for innovation and self-development.
• Mill concedes that the principle needs qualification for children, societies he called backward, and public duties — qualifications that became the focus of later argument.

What questions does this book try to answer?

• Under what conditions may society legitimately restrict individual liberty?
• How should the boundary between personal autonomy and social conformity be drawn?

Who should read it?

For readers of political philosophy, law, and public policy; the prose is nineteenth-century essay English with long sentences, so an annotated edition helps.