 Kuhn’s work on scientific revolutions raises difficult questions about whether science progresses and, if so, in what that progress consists. Kuhn asks (p. 60), “Why is progress a perquisite reserved almost exclusively for the activities we call science” and not for art, political theory, or philosophy? Early critics took him to deny scientific progress, because he rejected the traditional correspondence theory of truth and the related idea of cumulative progress toward a representational truth waiting out there for science to find it. For Kuhn the internalist, the technical goals of science are endogenously generated and change over time, rapidly during revolutions. Yet, somewhat paradoxically, Kuhn regarded revolutions as the most progressive components of his model of science. Unfortunately, he was not able to articulate fully in what that progress consists, given the issues of truth, incommensurability and Kuhn loss, a problem that those who reject convergent scientific realism still face. However, problem-solving know-how and success, including predictive precision, are major components of his answer. “[T]he unit of scientific achievement is the solved problem....” (p. 169). In a retreat from his most radical statements, Kuhn responded to critics by saying that we do possess a general set of scientific values that enables us, usually pretty easily, to order scientific works in historical time according to the degree in which they realize these values. A new paradigm, he says, must always treat successfully a serious anomaly left by the old one as well as opening up new questions for fruitful investigation.