Fire enabled humans to cook food, and that gave us, Scott argues, and evolutionary advantage. Chimps put a lot of (unconscious) energy into digestion, since they eat raw, hard-to-digest foods. When we cook, foods are easier to digest, we can get more nutrients from them with less energy expended. The excess energy can be devoted to our big brains, which burn much of the energy our bodies produce.
There’s a chicken-and-egg thing here: Would humans have mastered fire without bigger brains to begin with?
Scott thinks that another use of fire is just as important – fire as a tool of landscape architecture: “Hunter-gatherers would set fires as they moved, to clear terrain and make it ready for fast-growing, prey-attracting new plants. They would also drive animals with fire. They used this technology so much that, Scott thinks, we should date the human-dominated phase of earth, the so-called Anthropocene, from the time our forebears mastered this new tool.”Using fire, we were able to claim the shelter of caves: “The earliest, oldest strata of the caves contain whole skeletons of carnivores and many chewed-up bone fragments of the things they were eating, including us. Then comes the layer from when we discovered fire, and ownership of the caves switches: the human skeletons are whole, and the carnivores are bone fragments.” In short, “Fire is the difference between eating lunch and being lunch.”
I don’t buy Scott’s evolutionary account of human origins, but his stress on the importance of fire is on target. No doubt Adam wanted to learn to play and work with fire as soon as he was replaced by cherubim with flaming swords as the guardian of Paradise.