On the second affirmation, this is fact and the proper decisions of monetary politics, especially of ' ' world rico' ' (countries that composes the G7), confirm the application of the hypotheses of the rational expectations. On the first affirmation, the surprise is because the belief in the use of monetary politics sidewalk in the approach of the rational expectations, very elaborated well, for example, for the proper Sargent, it has contributed for ' ' world rico' ' to frequently sail for seas of crises each bigger time. In this way, in my opinion, the two affirmations of Sargent professor if complement. Manifesto my surprise also because the prize of this year seems to be unglued of the current world-wide reality, despite the news article of the magazine ' ' The Economist' ' , of 10/10/2011, it has grifado that the hypothesis of the rational expectations defended by Sargent ' ' it cannot badly be interpretada' '. To support my scare with the awarding, they allow to mention some hypotheses me of the boarding of the rational expectations, summarized for Simonsen professor, in 1986 article: ) the economic agents know a model quantitative that, saved occurrence of random disturbances, determines the behavior of the endogenous 0 variable in function of the exgenas; b) all the economic agents make use the same of joint of information, forming therefore the same expectations how much to the behavior of the exgenas 0 variable; c) with these expectations and the model, the economic agents arrive at its forecasts how much to the behavior of the endogenous 0 variable; d) each agent believes that all excessively formulate its forecasts on the basis of the same model and in the same projections of the exgenas 0 variable. This last estimated, conclusive one for Simonsen, says respect to the credibility and, more specifically, to the credibility of the economic policies of the monetary authorities.