Post-capitalism is a state in which the economic systems of the world can no longer be described as forms of capitalism. Various individuals and political ideologies have speculated on what would define such a world. According to some classical Marxist and some social evolutionary theories, post-capitalist societies may come about as a result of spontaneous evolution as capitalism becomes obsolete. Others propose models to intentionally replace capitalism. The most notable among them are socialism, anarchism, and degrowth.