John Stuart Mill (20 May 1806 – 8 May 1873) was an English philosopher, political economist and civil servant. One of the most influential thinkers in the history of liberalism, he contributed widely to social theory, political theory and political economy. He has been called "the most influential English-speaking philosopher of the nineteenth century."
Mill's conception of liberty justified the freedom of the individual in opposition to unlimited state control.
Mill was a proponent of utilitarianism, an ethical theory developed by his predecessor Jeremy Bentham, and contributed significantly to the theory of the scientific method.
Mill's On Liberty addresses the nature and limits of the power that can be legitimately exercised by society over the individual. However Mill is clear that his concern for liberty does not extend to all individuals and all societies. He states that "Despotism is a legitimate mode of government in dealing with barbarians".
Mill states that it is acceptable to harm oneself as long as the person doing so is not harming others. He also argues that individuals should be prevented from doing lasting, serious harm to themselves or their property by the harm principle. Because no one exists in isolation, harm done to oneself may also harm others, and destroying property deprives the community as well as oneself. Mill excuses those who are "incapable of self-government" from this principle, such as young children or those living in "backward states of society".
Though this principle seems clear, there are a number of complications. For example, Mill explicitly states that "harms" may include acts of omission as well as acts of commission. Thus, failing to rescue a drowning child counts as a harmful act, as does failing to pay taxes, or failing to appear as a witness in court. All such harmful omissions may be regulated, according to Mill. By contrast, it does not count as harming someone if – without force or fraud – the affected individual consents to assume the risk: thus one may permissibly offer unsafe employment to others, provided there is no deception involved. (Mill does, however, recognise one limit to consent: society should not permit people to sell themselves into slavery). In these and other cases, it is important to bear in mind that the arguments in On Liberty are grounded on the principle of Utility, and not on appeals to natural rights.
The question of what counts as a self-regarding action and what actions, whether of omission or commission, constitute harmful actions subject to regulation, continues to exercise interpreters of Mill. It is important to emphasise that Mill did not consider giving offence to constitute "harm"; an action could not be restricted because it violated the conventions or morals of a given society.