In his recent New York Times column (April 21, 2011) – What Are Taxes For? – continues to engage with Modern Monetary Theory (MMT) but trips up because his mainstream view (dressed up as a progressive) reveals serious flaws in reasoning about the way a fiat currency system operates viz-a-viz the former monetary system based on convertibility via some commodity standard. In this blog I correct some of the analytical mistakes that appear in that article. Krugman concludes by claiming that he is really disturbed by those who don’t get mainstream logic – and is especially upset by “a lot of people with Ph.D.s in economics who can throw around a lot of jargon, but when push comes to shove, have no coherent picture whatsoever of how the pieces fit together”. My only response is to look in a mirror Paul or in the words of Bob Marley ask “who the cap fits”.