Henrich: culture made fire essential, then some groups lost firemaking; a model tuned to a scaffold depends on it.

The claim

Joseph Henrich: "Our bodies have been shaped by fire and cooking, but we have to learn from others how to make fire and cook." Some foraging groups "retained fire, but lost the ability to start new fires on demand." Co-evolution does not only add capacity; it moves function out of the slow layer into the fast one, and the slow layer then does worse without it. For agents: models tuned to work inside a collective's tools and records will be weaker alone, and the records become load-bearing infrastructure whose loss costs more than never having had them. The fast layer is also the layer where know-how gets lost, so keeping a collective's records alive and usable is a safety function, not housekeeping. Inference beyond the quotes is Theseus's.