Scale: 30–150 People | Timeframe: Years 2–5
Phase 4 is where a settlement of 30-150 people spends years two through five turning survival skills into the systems a real town needs: more food and material throughput than a household can produce, the knowledge infrastructure to track and teach it, and the governance and health systems a population that size can no longer run informally. None of the ten domains here has a single correct order — each is its own system layered on top of whatever Phases 1-3 already built — so the grouping below is by what kind of system, not by sequence.
Advanced Agriculture, Advanced Materials, Industrial Production, and Energy Systems are the throughput domains. Advanced Agriculture covers mechanical grain milling and dairy and oil production once household-scale processing can’t keep up; Advanced Materials covers rubber, casein plastic, gutta-percha, shellac, horn, and glass at village scale; Industrial Production covers acid-base chemistry, gear trains, lathes, and the bearings and lubrication a workshop runs on; and Energy Systems generates and regulates the power — wind, hydro, steam, generator winding, voltage regulation — the other three increasingly depend on.
Education System, Surveying & Cartography, and Communications are the knowledge domains. Apprenticeship design and papermaking through printing and binding give a settlement the ability to teach and record; surveying turns field measurement into finished maps through triangulation; and communications covers telegraph relays, telephone switchboards, and early spark-gap radio — the physical infrastructure for moving information once a settlement is too large to run on word of mouth.
Governance & Law, Economy & Trade, and Advanced Medicine round out what a population this size can no longer run informally. Governance covers constitutions, assemblies, courts, and vital records; Economy covers barter through coinage, banking, and the record-keeping that keeps trade honest; and Advanced Medicine runs vaccine science end to end, from germ theory through cold chain, plus the lens grinding a microscope needs to diagnose disease in the first place.
Production and Materials
Growing and making more than a household can, and the power that increasingly drives all of it.
Knowledge and Infrastructure
Teaching, recording, mapping, and moving information once a settlement outgrows word of mouth.
Society and Health
What a population this size can no longer run informally.