John Stuart Mill does not contradict himself in On Liberty with respect to the issue of piecework, contrary to Dale E. Miller's charge that he does. Miller fails to understand that the liberty principle (LP) limits society's authority to regulate trade in that society has no legitimate authority to prohibit or make unduly expensive a buyer's post-trade use of his purchased product in self-regarding ways. LP gives an employer who has purchased labor under a trade contract in a free and fair competitive labor market a right to conclude a separate mutually consensual self-regarding piecework contract with any skilled worker already in his employ.

Mill argues that, apart from the principle of utility, his utilitarianism is incompatible with absolutes. Yet in On Liberty he introduces an exceptionless anti-paternalism principle—his liberty principle. In this paper I address ‘the absolutism problem, ’ that is, whether Mill's utilitarianism can accommodate an exceptionless principle. Mill's absolute claim is not a mere bit of rhetoric. But the four main solutions to the absolutism problem are also not supported by the relevant texts. I defend a fifth solution—the competence view—that turns on his attention to decision-making structures and, in particular, on the role of expertise considerations in his account.