James Tobin on John Maynard Keynes

“Keynes did not challenge the efficacy of price adjustment mechanisms in clearing particular markets in the Marshallian partial equilibrium theory on which he had been reared. He did challenge the mindless application of those mechanisms to economy-wide markets. Founding what came to be known as macroeconomics, he was modeling a whole economy as a closed system. He knew he could not use the Marshallian assumption that the clearing of one market could be safely described on the assumption that the rest of the economy was unaffected.”

“The central message is still that, as Keynes argued, fiscal policy is the answer to liquidity traps, financial or political. The arguments against fiscal policy in Japan, so far as I understand them are intellectually fallacious; they would receive failing grades in an undergraduate macro exam.”