The turn of the millennium brought an increased interest in issues of multiculturalism, which became a focal point for debates about culture, especially in liberal democracies. The question is particularly important in that most people today live in heterocultural societies. The authors thus do not approach multiculturalism as the simple coexistence in society of members of various ethnic groups but rather as a theoretical basis for the scholarly analysis of the state and of society, which implement policies in regard to internal cultural (ethnic) diversity. Multiculturalism thus defines a social space in which people who adhere to different axiological, normative, religious or moral systems, and who are aware of these differences, live together. At the same time, state policy aims to include all of them in a social order which is being modified under the influence of cultural diversity. Multiculturalism can be presented on the one hand as an idea that is not apprehended directly but is known through concepts, and on the other hand, as an entity identified by the senses. The authors illustrate the transition from an idea to a state policy in regard to a multitude of ethnic cultures by reference to Australia and the Federal Republic of Germany.