Outputs reflect a sum of inputs, the system is closed, and if big change comes it comes as an external shock. The system's default state is equilibrium. The prevailing metaphor is a machine.

The traditional approach, in short, completely misunderstands human behavior and natural economic forces. The problem is that the traditional model is not an academic curiosity; it is the basis for an ideological story about the economy and government's role--and hat story has fueled policy making and has morphed into a selfishness-justifying conventional wisdom.

Even today, the debate between free marketeers and Keynesians unfolds on the terms of the market fundamentalists: government stimulus efforts are usually justifies as a way to restore equilibrium, an defend as regrettable deviations from government's naturally minimalist role.