J. S. Mill and punishment of 'self-regarding acts'. In his famous essay On LJberty,]ohn Stuart Mill divides individual acts in two categories; acts that only harm the acting individual himself, and acts that harms other individuals. The former is called 'self-regarding acts' and the latter is called 'other-regarding acts'. There has been a long debate between famous scholars about how to interpret Mill at this point. Some argue that Mill permit that (i) only other-regarding acts could be punished, and other argue that Mill support that (ii) even self-regarding acts could be punished. I argue that Mill could not hold both of the positions at the same time, and if he does he must be guilty of a severe inconsistency. The analysis shows that interpretation (ii) is most reasonable. One conclusion that follows is that Mills liberalism is not ";radically individualistic";, it is instead a perfectionistic form of political liberalism, including both radical and communitarian ideas.