In ethics and value theory, perfectionism is the persistence of will in obtaining the optimal quality of spiritual, mental, physical, and material being. The neo-Aristotelean Thomas Hurka describes perfectionism as follows: This moral theory starts from an account of the good life, or the intrinsically desirable life. And it characterizes this life in a distinctive way. Certain properties, it says, constitute human nature or are definitive of humanity—they make humans human. The good life, it then says, develops these properties to a high degree or realizes what is central to human nature. Different versions of the theory may disagree about what the relevant properties are and so disagree about the content of the good life. But they share the foundational idea that what is good, ultimately, is the development of human nature. History Perfectionism, as a moral theory, has a long history and has been addressed by influential philosophers. Aristotle stated his conception of the good life (eudaimonia). He taught that politics and political structures should promote the good life among individuals; because the polis can best promote the good life, it should be adopted over other forms of social organization. The philosopher Stanley Cavell develops the concept of moral perfectionism as the idea that there is an unattained but attainable self that one ought to strive to reach. Moral perfectionists believe that the ancient questions such as "Am I living as I am supposed to?" make all the difference in the world and they describe the commitment we ought to have in ways that seem, but are not, impossibly demanding. We do so because it is only in the keeping such an "impossible" view in mind that one can strive for one's "unattained but attainable self." In his book Cities of Words: Pedagogical Letters on a Register of the Moral Life (2005), based on a lecture course called "Moral Perfectionism" that he first gave at Harvard University in the 1980s, Stanley Cavell characterizes moral perfectionism in general, and what he calls "Emersonian perfectionism," the form of moral perfectionism he embraces and defends, not as a theory of moral philosophy comparable to Immanuel Kant’s deontological view that there is a universal moral law (the categorical imperative) by which we can rationally determine whether an action is right or wrong, or John Stuart Mill’s utilitarian view that the good action is that which will cause the least harm, or the greatest