Utilitarianism

While Mill didn't invent the term "utilitarianism," his book did much to popularize the moral philosophy. Utilitarian ethics play a supporting role in many of Mill's other works, and in this book Mill writes a lucid and vigorous defense of his system of thought. Mill begins by dispelling some myths about how utilitarian ethics work, and then presents a clear definition of the philosophy with the famous "greatest happiness" principle: the right action is invariably that which results in the greatest amount of overall happiness. In addition to Mill advocating the use of utilitarian ethics in one's personal life, he suggests that legislative bodies consider the amount of pleasure or pain that would be caused by proposed legislation—a radical notion in his day.