Concept
Complex adaptive system
Also: CAS
A system of many agents that interact and adapt to each other, so that the system as a whole keeps changing in ways no single agent controls.
Markets, organisations, cities and ecosystems are complex adaptive systems. Their agents follow local rules and respond to each other; the overall behaviour emerges from those interactions. Human systems add something more: people have intentions, identities and stories, and they can change the rules — the starting point of anthro-complexity.