Three systems that convert philosophy into physical fact. In each, the technical answers are broadly known and the constraint is elsewhere.
Cities
Cities are, per person, the most resource-efficient way humans have found to live — density reduces the energy required for movement, heating and infrastructure. The failure is not urbanism itself but a specific twentieth-century form of it: cities designed around the storage and movement of cars, in which distance is imposed and then solved by fuel.
What works is unexciting and well evidenced: mixed use so daily needs are within walking distance, public transport as a spine rather than a remainder, trees at sufficient canopy cover to reduce summer temperatures measurably, water treated as something to absorb rather than to drain, and enough shared public space that a person’s social life does not depend on their income. None of this requires a new technology. It requires the political will to reallocate space that is currently allocated.
Food
Agriculture is where human intention meets soil biology most directly, and where the ethical vocabulary of this book has the most literal application. Practices that maintain living cover, diversify rotations, integrate trees and reduce disturbance rebuild soil structure and carbon; the evidence base is real and still developing, and the honest position is that outcomes vary substantially by context rather than following a single formula.