We tend to take the GDP measure for granted as though it has always existed. Most people don’t know that it was invented only recently. It has a history. During the 1930s, the economists Simon Kuznets and John Maynard Keynes set out to design an economic aggregate that would help policymakers figure out how to escape the Great Depression. Kuznets argued for a measure that would help us maximize human well-being and track the progress of human welfare. But when World War II struck, Keynes argued that we should count all money-based activities—even negative ones—so we would know what was available for the war effort.