If your leader and two hefty articles three weeks ago indeed caricatured modern economic theory, as Robert Lucas claims, so does his defense of the embattled social science, as well (“In Defense of the Dismal Science,” August 8, 2009). If you were too critical of its failure to warn of the impending financial crisis, he surely is too uncritical, if not outright apologetic, of this failure. “One thing we are not going to have, now or ever,” he goes as far as arguing, “is a set of models that forecast sudden falls in the value of financial assets, like the declines that followed the failure of Lehman Brothers in September 2008.” This would be like an astronomer proudly arguing that his science can easily predict meteorites impacting earth, especially if tiny, but that catastrophic asteroid impacts are forever out of its reach. Some science, we would all agree. If models cannot forecast sudden falls in the value of financial assets, what should we turn to instead? That is the question that modern economic theory will eschew at its peril.