Planetary Subsidiarity is Blake and Gilman's principle that only what must be planetary should be governed at planetary scale. I offer it as one possible answer to the question of who maintains habitability. It's their idea, and I'm borrowing it with gratitude.
How the word moved
In Oct 2025, in the first PAPE essay, I had "polycentric subsidiarity" as a planetary design principle. In Jul 2026 I named Gilman and Blake's Planetary Subsidiarity directly as a candidate for governance, with a "perhaps" in front of it.
In my words
"Perhaps the solution is Gilman and Blake’s idea of “Planetary Subsidiarity”"
from Habitability: Recasting the Planetarity Syllabus, 27 Jul 2026
Related
- Inherited from Gilman and Blake - it's their concept.
- Related Planetary Steward - stewards work at every scale, which is what subsidiarity needs.
- Related Protocol - coordinate globally only what must be global.