Krugman responds to fellow columnist David Brooks:

So David Brooks claims that

The economic approach embraced by the most prominent liberals over the past few years is mostly mechanical. The economy is treated like a big machine; the people in it like rational, utility maximizing cogs. The performance of the economic machine can be predicted with quantitative macroeconomic models.

I protest, on several grounds.

First, it’s conservative economists who insist that people are always rational and utility-maximizing; liberal economists are the ones willing to invoke bounded rationality, animal spirits, etc.. The whole salt-water fresh-water split was about which you were going to believe: the assumption of perfect maximization, or your own lying eyes. And the Keynesians were the ones who preferred to believe their eyes.

Second, David would have us believe that the Obama people were misled by their excessive faith in models. But we actually know what happened when the stimulus was being discussed: the modelers, who said that we needed something much bigger, were dismissed in favor of gut feelings about market psychology.

The truth is that we would have been much better off if Obama et al had relied on old-fashioned hydraulic Keynesianism.

David Brooks: Math is Hard, Just Give Money to Rich People by Dean Baker

Brooks is a member of my "rogues gallery."