Russ Roberts at Café Hayek has a very good analysis of Paul Krugman’s NYT column of July 14 on income inequality (see here). What is puzzling for anyone who has studied economics is the policy solution Krugman derives from Piketty’s and Saez’s analysis: raising the minimum wage. Even if the stats were correctly interpreted (which, as Roberts points out, is not the case), it is hard to see how raising the minimum wage would be the best policy response, considering the unintended consequences it creates (this echoes what Pete Boettke said a few days ago on the coherence of economic discourse - see here).
Thomas Piketty and Emmanuel Saez are good examples of the kind of scientists who come out of French universities. They are both highly skilled mathematicians (they both went to the Ecole Normale Supérieure) and then went abroad for their PhDs (EHESS, which is in France, and LSE for Piketty and MIT for Saez).
France has a long tradition in mathematics (along with Russia and others), which is reflected in the importance of a few schools/universities such as the Ecole Polytechnique and the Ecole Normale Supérieure. F. A. Hayek has a very interesting discussion of this topic in relation to the attitude towards planning in his Counter-Revolution of Science.
Looking at Piketty’s and Saez’s publication record, it is probably fair to say that their favorite subject is income inequality. This, in my view, reflects the obsession that many European economists have with market outcomes rather than trying to understand market processes. However important these questions are, they do not justify the rejection of first principles. That the minimum wage is a policy response (at least in Krugman's eyes) to a perceived income distribution problem shows how technical virtuosity can make one blind to the teachings of economics.