Dependency stacks show what must be stabilized before a capability can be promoted. They are practical chains, not abstract taxonomies. A stack helps editors ask: what has to exist before this method is usable, teachable, and safe?
This page is especially important for the A1-to-A2 transition. A2 should be a prepared promotion, not a leap. A community should not adopt a powered or industrial method merely because a PDF describes it; it needs the energy, tools, measurements, safety routines, feedstocks, and apprenticeships that keep the method alive.
| Domain | A0 | A1 | A2 | A3 |
|---|---|---|---|---|
| Water and sanitation | Locate, carry, boil, filter, isolate contamination | Wells, hand pumps, storage, latrines, soap, community waste handling | Pump manufacture, controlled chemical dosing, industrial cleaners | Municipal waterworks, sewerage, treatment plants |
| Shelter and thermal control | Emergency cover, fire, weather protection | Adobe, rammed earth, timber, thatch, passive solar, insulation | Engineered materials, powered production, standardized components | Public buildings, bridges, codes, regional construction systems |
| Food and agriculture | Acquisition, safety, emergency cooking | Seed saving, soil, animals, preservation, fermentation | Mechanization, controlled environments, industrial processing | Regional logistics, public health, storage and distribution networks |
| Tools and production | Recover tools, hardware, containers, cordage | Repair, blacksmithing, casting, hand-tool making, manual instruments | Machine tools, powered manufacture, standard parts, quality control | Depots, heavy maintenance, standards and regional supply |
| Energy and electrification | Heat, fire, safe power isolation, battery recovery | Human/animal power, water wheels, windmills, passive solar, electrical salvage | Generators, regulation, motors, powered workshops, industrial fuels | Grids, regional generation, distribution and system protection |
| Knowledge reproduction | Emergency records, symbols, messages | Literacy, hand copying, bookbinding, papermaking, relief/stencil printing | Print shops, powered duplication, radio and technical catalogs | Archives, public information networks, institutional education |
This matrix intentionally stops at A3. It describes the dependency path from immediate survival through regional infrastructure, which is the range in which a general cross-domain stack remains useful. A4 and A5 dependencies are too specialized to summarize honestly in one generic row; use the Rebuild Ladder A0-A5 as the stage reference, then follow the relevant A4 or A5 subject page for its precision facilities, research systems, and frontier prerequisites.
Safe workshop layout -> salvaged prime movers and shaft power -> measurement standards -> parts inventories -> lubrication and bearings -> first electrification -> feedstock quality -> apprenticeships -> A2 readiness review.