Terran society is a vast experiment in free-market economics. The central concept is the voluntary transaction: an exchange of goods, currency, information or services that is freely made by both parties without any form of coercion. This has lead to a generally beneficial form of anarcho-capitalism. There are no fundamental laws and no fundamental rights.
Earth's social structure is built around two types of entity: local administrations and distributed groupings such as phylai and corporations. This classification of polities is not, of course, absolute: there are many polities that lie somewhere in between. People may be members of several polities, most commonly being citizens of a phyle and employees of a corporation.
Many Terrans belong to phylai, formal groupings of people sharing similar values, beliefs, customs and culture. Each phyle provides security for its members, in a similar manner to the old nation-states. Indeed, many of the nations based around single ethnic groups have become phylai. Unlike nations, the phylai are bound by culture and not geography: claves of a major phyle may be found in cities across the Earth, in Cis-Lunar Space, and, sometimes, beyond.
The 'smeared out' nature of the phylai means that claves are mostly so small that they depend on the regional administration for the support of infrastructure. These small claves are enclaves. The vast majority of phylic citizens live in neighbourhood-sized claves.
Larger claves that are not dependent on regional politiies are exclaves, the true centres of the phyle's power. The exclaves commonly have much tigher border security than enclaves, with a full-spatial defensive perimeter of hunter-killer nanos, sentinel drones and other systems. The border region can sometimes be kilometres thick.
Many phylic citizens do not live within one of their phyle's claves, but in the unaffiliated areas of a regional polity, or a corporate arcology.
As well as the phylai formed from pre-existing ethnic, cultural or religious groups, there are phylai based on historical societies, and synthetic phylai with newly invented or unusually mixed cultures. The weirder synthetics are mostly out in the Belt, but there are certainly a number of bizarre phylai on Earth.
A region may be administered as a nation, quasination, Autonomous Region, Special Economic Area, or in a dozen or more other ways. Many regional entities (especially the larger ones such as Indonesia, California-Cascadia or the United Republic) are the direct descendent of an old nation. Such regions contain enclaves of many phylai. Their chief purpose is to maintain the region's infrastructure: power generation and distribution, transport nets, water and sewerage systems. In addition the region often employs a security force to maintain order, and a judicature to handle disputes between claves. Most regions leave personal legal cover to indiduals.
A phratry is a smaller social unit than a phyle, and a much less frequently used term. Some phratries are sub-divisions of phylai, but others have no phylic affiliation. Phratries are much smaller than phylai, and tend to be extended families or tightly knit groups such as gangs or mercenary companies. The line separating large phratries and small phylai is not absolute. Indeed, many of the synthetic phylai originated as one or more phratries.
The future of Ad Astra