We are too many and the ecosystem is too badly damaged to allow us to live outside a society. In order to live in a society we need rules to coordinate our activities, for example a common language and economic activity rules for property and currency. These rules must be created and defended by people.
There are only two ways to create and defend these rules:
1. A powerful person or group of people can impose the rules, keeping other people weak, divided and economically dependent. This is the case of a vertically integrated society. In such a society the patron to client relationships are more powerful than the peer to peer relationships. This situation describes a stable social equilibrium because the patron rewards informers and punishes those who associate to defend their rights. This social structure generates a propagandistic public discourse.
2. A voluntary association of equals can impose the rules. In this case the peer to peer relationships are stronger than the patron to client relationships. This is the case of a horizontally integrated society. This situation describes a stable social equilibrium because the association provides security and government to its members and it excludes those who betray its interests. The members of the association meet and communicate regularly, get involved into local administration and politics, initiate business ventures and address public problems of their society. Usually there is a large number of associations which pursue sometimes contradictory ends. This social structure allows and requires a rational public discourse.
These two social structures are stable over thousands of years in spite of powerful exogenous factors. Even though each individual's motivations to support the current social structure are weak, they are ubiquitous.
Bibliography: R. D. Putnam, Robert Leonardi, Raffaella Y. Nanetti, Making Democracy Work, Civic Traditions in Modern Italy, Princeton University Press, Princeton, New Jersey, 1993