Nations are defined by cultural unity
Originating with Herder is the idea that mankind is divided into a variety of distinct incommensurable cultural communities. The idea has proved very influential and to this day many assume nations are, and should be, based on cultural unity.
Nations are long-existing communities of people whose unity has been sustained by a shared cultural heritage. This heritage might include language, religion, myths and legends, cultural artefacts, value systems, generalities, etc... Modern ethno-symbolist theory sees cultural unity as being based on a common set of inherited myths and symbols. These form the basis of a common set of beliefs and values about the world and shared reference point for all members of the cultural community. Nations are merely a modern expression of this ancient sense of cultural community.
Many modern nations contain a variety of different cultural groups and are nonetheless called nations. Those nations which are culturally homogeneous only became so thanks to sustained political and governmental action to promote a particular national culture. Evidence of pre-modern cultural homogeneity is very thin.
[P1] There exist long standing coherent and distinctive cultural communities. [P2] These cultural communities are the natural basis from which people organise themselves socially.
[P1] Many modern nations are not culturally homogeneous. [P2] National homogeneity is rarely natural and is instead the result of sustained efforts to promote a particular culture.
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