On Liberty
John Stuart Mill's work on political philosophy begins in "On Liberty, On Liberty" is the most influential statement of his liberal principles. He begins by distinguishing old and new threats to liberty. The old threat to liberty is found in traditional societies in which there is rule by one (a monarchy) or a few (an aristocracy). Though one could be worried about restrictions on liberty by benevolent monarchs or aristocrats, the traditional worry is that when rulers are politically unaccountable to the governed they will rule in their own interests, rather than the interests of the governed. Mill's explicit theory of rights is introduced in Chapter V of Utilitarianism in the context of his sanction theory of duty, which is an indirect form of utilitarianism that identifies wrong actions as actions that it is useful to sanction. Mill then introduces justice as a proper part of the duty. Justice involves duties that are perfect duties—that is, duties that are correlated with rights.