"As food makes babies perhaps the critical development was agriculture but then without fossil fuels, we could never have produced as much food as we do now, and deliver it across the world. But then, if we hadn’t started cooking food, we might not have been clever enough to figure out how to use fossil fuels to produce food. And without language, we could never have communicated complex ideas about agriculture, tool making and the use of fossil fuels. So we go round and round."