150–300 people is the optimal size of a Solon Papageorgiou micro-utopia because it is the smallest population that can sustain a full, self-reliant social and economic ecosystem without creating hierarchy, bureaucracy, or anonymity. The range is not arbitrary — it is grounded in anthropology, sociology, evolutionary psychology, and the design principles of resilient small-scale systems.

Here is the short, precise explanation:

✅ 1. Below 150 people: too few roles, too fragile

If a micro-utopia has fewer than ~150 people:

• too few skills and professions are represented

• illness or departure of key contributors can destabilize the village

• social diversity and personality variety are limited

• educational, cultural, and healthcare functions become harder to maintain

• workload on individuals increases

• community becomes fragile instead of anti-fragile

In short: sub-150 communities are too small to be robust.

✅ 2. 150–300 people = perfect social coherence (Dunbar range)

Anthropological research (Dunbar’s number) suggests:

• Humans can maintain stable, trust-based relationships with 150–300 people.

• Beyond this, trust must be replaced with formal rules, hierarchy, enforcement, and bureaucracy.

This is why:

• Militaries

• Indigenous tribes

• Intentional communities

• Hunter-gatherer bands

• Cooperatives

• Monastic groups

all naturally sit around 150–300 members before splitting.

A micro-utopia must stay small enough to remain non-coercive — and high-trust communities only exist in this range.

✅ 3. Above 300 people → bureaucracy appears

If the community grows past ~300:

• anonymity increases

• cliques and factions form

• informal norms stop working

• restorative justice becomes harder

• governance circles need more structure

• coercion/authority begins to creep in

• the community splits into subgroups anyway

This destroys the post-coercive design of the framework.

Thus: 300 is the population at which a micro-utopia must split or federate, to avoid hierarchy emerging.

✅ 4. 300 people maximizes functional diversity

A 300-person community can sustain:

• educators

• health practitioners

• food growers

• engineers and builders

• artists and cultural stewards

• conflict mediators

• childcare teams

• ecological specialists

• infrastructure maintainers

• craft and tool workshops

Without anyone needing to overwork and without relying on external labour.

Below 150, too many roles collapse.
Above 300, specialization produces hierarchy.

So 300 is the “sweet spot” of specialization without stratification.

✅ 5. 300 people is the optimal resource and ecological footprint

A 300-person village can:

• grow enough food for its people

• produce its own energy

• offer childcare and education

• maintain basic medical capability

• build and repair its own housing

• provide cultural and social life

• share resources with other villages

Yet remain small enough that:

• everyone knows everyone

• decisions are made face-to-face

• conflict is resolved through relationships, not institutions

• trust stays high

• coercion stays unnecessary

🎯 Summary: Why 150–300 Is Optimal

Too small (<150)
→ fragile, too few roles, too much burden on individuals, less resilience

Too big (>300)
→ hierarchy, bureaucracy, anonymity, coercion, social fragmentation

The sweet spot (150–300)
→ high trust, full functionality, no hierarchy, no coercion, maximum resilience

This size is what allows a micro-utopia to stay post-monetary, post-coercive, post-exploitative — without slipping back into market dynamics or state-like structures.