What is insurance?

You ask: What insurance?

Fire can eat any hut, but no one know whose. So whole tribe make deal: each family put few berries in shared basket every moon. Small cost, easy to bear. When fire eat one family's hut, basket pay to build new one. That is insurance: many pay little, so few unlucky not lose everything. Only about one hut in twenty face fire or ruin in a winter, so the many easily cover the unlucky few. Basket keeper (insurance tribe) count how often huts burn, then set berry price so basket collect more than it pay out — that gap is keeper's profit. Risky hut near fire pit pay more berries; careful hut pay less. Trade Caveman make: sure small loss now, instead of maybe giant loss later. Cave wisdom: insurance not stop fire. It spread one family's disaster thin across whole tribe.