Krugman and other macroeconomists do not generally dispute those commonly-held microeconomic assumptions. Where they differ, and what the original article is re

Krugman and other macroeconomists do not generally dispute those commonly-held microeconomic assumptions. Where they differ, and what the original article is referring to when he says "Keynes vs. Friedman", are in the macroeconomic models. Macro is tricky because 1) we cannot ethically run controlled experiments on the economy, and 2) there are way too many parameters one could include. Macro is a useful but very approximate science; no serious economist would tell you that these models are without flaws.