According to Li Xing and Timothy Shaw, the central feature of analyzing China as a civilization state is the view that the Chinese state derives its legitimacy from the continuation of a sociopolitical order which posits that the state maintains natural authority over its subjects, and that it is the "guardian" of both its citizens and their society, a view of the state that is completely distinct from the Westphalian nation-state model.[1] Other scholars make the case that the key features of a civilization-state are the maintenance of an ethos of cultural unity despite displaying significant cultural diversity, across centuries of history and a large geographic space.[8] Some specifically draw attention to the longevity of the Chinese writing system,[9] or describe China's existence as being uniquely and inexorably tied to the past.[10][11]