Dunbar's Number suggests humans can maintain approximately 150 stable social relationships — the size of a tribal community for most of human evolutionary history. Within that 150: ~5 intimate relationships (the support group), ~15 close friends, ~50 friends, and ~150 meaningful acquaintances.

Modern life provides the population but not the belonging. You may interact with hundreds of people weekly — none of whom know your name. Community is not proximity — it's the experience of being known, belonging to something larger than yourself, and having reciprocal obligations.

The collapse of community institutions (churches, lodges, unions, civic organizations) removed the infrastructure that provided belonging. Robert Putnam documented this in "Bowling Alone" (2000): Americans dramatically reduced participation in every form of civic and social group measured. The decline continued and accelerated after social media created the illusion of connection without the substance.

Building community intentionally requires: shared purpose (a group united around something beyond social interaction), repeated gathering (the friendship formula applied at group scale), mutual accountability (obligations to each other, not just shared entertainment), and rituals (regular practices that mark belonging — shared meals, traditions, celebrations).