The Critics of Modern Money Theory (MMT) are Right

Eric Tymoigne and Randall Wray's (2014) defense of MMT leaves the MMT emperor even more naked than before (excuse the Yogi Berra-ism). The criticism of MMT is not that it has produced nothing new. The criticism is that MMT is a mix of old and new, the old is correct and well understood, while the new is substantially wrong. Among many failings, T&W fail to provide an explanation of how MMT generates full employment with price stability; lack a credible theory of inflation; and fail to justify the claim that the natural rate of interest is zero. MMT currently has appeal because it is a policy polemic for depressed times. That makes for good politics but, unfortunately, MMT's policy claims are based on unsubstantiated economics.