6 ideas
In a non-zero-sum interaction, both parties can win or both can lose together, so each side's fortunes are tied to the other's. Wright argues that biological and cultural evolution keep producing more of these interactions, and at larger scales. The reason is that systems which capture the gains from cooperation outcompete those that don't.
Each breakthrough in information processing lowers the cost of coordinating and trusting across distance. Examples include writing, money, the printing press and the telegraph. That lets non-zero-sum games spread to larger groups, which in turn pushes social organization toward bigger, more complex units.
Human history moves through rising levels of organization: hunter-gatherer bands, big-man villages, chiefdoms, states, empires and a globalizing world. Each step arises when new technologies make bigger non-zero-sum payoffs available. It stabilizes when political structures can capture those payoffs and enforce cooperation.
Conflict between groups is zero-sum on the outside but forces cooperation on the inside. Societies that organize more effectively absorb or displace their rivals. Violence has therefore acted as an engine of the same trend toward larger cooperative units that trade drives.
Agriculture, writing, cities and states emerged separately in Mesopotamia, China and Mesoamerica with no contact between them. Wright treats this parallel development as evidence that social complexity is a likely, near-inevitable result of the underlying dynamics rather than historical accident.
Look for where people's fortunes are becoming linked, and you'll see where moral concern is about to spread. People extend empathy and tolerance to outsiders once their own welfare depends on those outsiders' success, so the moral circle tracks the reach of non-zero-sum ties. Global interdependence, such as trade, shared environmental threats and weapons, therefore creates structural pressure toward a wider sense of who counts.