“The big lesson in economics from Keynes is that we know less than we think we do, and that there is a vast difference between the output of economic models and the actual behaviour of individuals.
"Our basis of knowledge for estimating the yield 10 years hence of a railway, a copper mine, a textile factory, the goodwill of a patent medicine, an Atlantic liner, a building in the City of London amounts to little and sometimes to nothing," Keynes wrote. He was unimpressed by the argument that decisions were "the outcome of a weighted average of quantitative benefits multiplied by quantitative probabilities".
This, though, is where mainstream economics has ended up. It is possible to construct beautifully precise models if you start from the assumption that rational economic agents with perfect information are operating in free markets that always return to equilibrium. But since none of these assumptions holds true in the real world, this is a classic case of "rubbish in, rubbish out".
Even more worryingly, there has been no room in this view of the world for the heterodox. The prestigious economics journals have been cleansed of all but the purveyors of highly technical algebra. Economic history has been removed from the syllabus, because those who yearn for economics to be a hard science believe the past can teach them nothing. Truly, the lunatics have taken over the asylum.”
– From “Rescuing economics from its own crisis” by Larry Elliot in The Guardian