Fire: The Surplus That Started Everything

Fire was the first element humanity learned to control, and the results reshaped what our species could become. It gave us time, calories, and eventually the brainpower to ask what other surpluses might be found.

Key Milestones

• Control of fire, roughly 1.5 to 2 million years ago. Fire provided warmth, protection, and cooking: the first use of an external energy source to extend human capability.
• The Bronze Age, with the smelting of bronze and then iron, roughly 4000 to 1200 BC. Sustained heat was used to extract metal from raw ore, turning rock into a usable resource.
• Forging and blacksmithing, from roughly 1200 BC onward. Fire was used to shape metal into tools and weapons, and applied to farming, hunting, and war.

The Energy, Social, and Economic Impact of Fire

Fire started it all, and it started as a biological economy: caloric return on energy invested. A raw food diet required roughly 42% of the day spent chewing, leaving little time for anything else. Cooking freed both that time and the calories dedicated to chewing, and, as the cooking hypothesis suggests, the surplus calories were taken up by the brain, which consumes roughly 25% of the body's total energy budget. Brain volume nearly tripled, and our civilization thrived.

View chart in the full report

View chart in the full report

Later, smelting and forging turned fire into a direct economic multiplier. Raw ore became a tradeable resource, and better tools and weapons compounded productivity in both farming and warfare: an early example of a technology that expanded the economic surplus it created even as it threatened it.