Utilitarianism is a theory in normative ethics holding that the best moral action is the one that maximizes utility. Utility is defined in various ways, but is usually related to the well-being of sentient entities. Originally, Jeremy Bentham, the founder of Utilitarianism, defined utility as the aggregate pleasure after deducting suffering of all involved in any action. John Stuart Mill expanded this concept of utility to include not only the quantity, but quality of pleasure, while focusing on rules, instead of individual moral actions. Others have rejected that pleasure has positive value and have advocated negative utilitarianism, which defines utility only in terms of suffering. As opposed to this hedonistic view, some define utility with relation to preference satisfaction whereas others believe that a range of values can be included in its definition.