Utopias are expressions of political philosophy and theory, to be sure, but they are descriptions of fictional states in which the philosophy and theory are already implemented in the institutions and procedures of the social structure. The Quest for Utopia (1952)
In the first place, utopia literally means "no place", and the use of the fiction of an imagined or mythical state is indeed a characteristic mark of utopian writing. This primary and necessary discrimination eliminates from utopian literature all speculation the form of which indicates that it should properly be designated political philosophy or political theory. The Quest for Utopia (1952)