Abstract: Morality: Its Nature and Justification provides an analysis of the concepts of morality, rationality and irrationality, reasons, goods and evils, moral rules, and impartiality. It uses these analyses to describe a justified moral system that includes moral rules that prohibit doing the kinds of actions that need justification so as not to be immoral; moral ideals that encourage doing the kinds of actions that, if they do not involve violations of moral rules, are universally considered to be morally good actions; and a two-step procedure for determining when the violations of a moral rule are strongly justified, weakly justified, and unjustified. The first step of this two-step procedure uses the morally relevant features to provide a morally relevant description of the action. The second step involves estimating whether more harm would be caused by publicly allowing such a violation or by not allowing it. This justified moral system is commonly used, although usually only implicitly, by people when they are making thoughtful moral decisions and judgments. Morality is a public system that is known by all normal adults, and that is not irrational for any of them to use to govern their own behavior and to judge the behavior of others. These analyses and justifications are used to provide an account of virtues and vices and of moral judgments, to answer the question of why one should be moral, and show that the same morality applies to governments as to individuals.

Keywords: rationality, irrationality, reasons, goods, evils, moral rules, moral ideals, impartiality, justification, violations