This chapter talks about the pervasive conflict on what should count as the terms of social cooperation, such as the need for authoritative, enforceable rules that constitute the elementary facts of political life. It discusses the disagreement about the nature of right and good, specific moral questions, and features of the good or just society as the most enduring and polarizing sources of social discord. It also characterizes one of the roles of a conception of justice that shows how to adjudicate conflicts among the members of society. The chapter also explains disagreements that often consist of one person merely holding different views. It illustrates a common experience in some parts of the world in which people enjoy freedom of thought and expression and reasoning about ethical matters that goes beyond platitudes.