Most human societies do not actively question whether the relationships of power and authority they are used to are the best way of organizing political arrangements. But some, notably ancient Greece, allowed those questions to be raised and came up, indeed, with very different answers about the strengths and weaknesses of different political constitutions as well as many utopian dreams of the ideal. In modern times political debate has been stalled. Everyone agrees that 'democracy' is a good thing, but what that should mean in practice at national level is disputed. How, on an international level, the relations between nation-states should be regulated, and even whether regulation is desirable, are even more controversial.
One issue that clearly remains with us today can provide a way into the problems. Our investigations of ancient Greek and Chinese views about the world have already brought to light certain connections between the philosophy and science done in those civilizations, and the social and political institutions they developed and that formed the framework for those enquiries. Thus the political world of the classical Greek city-state was an intensely pluralist one. It is true that all classical city-states shared certain institutions, foremost among them slavery, though there are important differences between the enslaved Helot population of Laconia and the individuals and groups, from outside Greece as well as within it, who were enslaved as a consequence of capture or defeat in war. However, the variety of political constitutions imagined in theory and exemplified in practice was very great. They ranged from democracies of more or less moderate or extreme types, through oligarchies, to constitutional monarchies and tyrannies. To those actual constitutions philosophers added others they described in more or less utopian terms, from Plato's republic governed by philosopher-kings, to Stoic adumbrations of the notion of citizens of the world. In practice, the histories of such states as Athens and Corcyra are