 Kuhn states that science does progress, even through revolutions (1962/1970a, 160ff). The phenomenon of Kuhn-loss does, in Kuhn’s view, rule out the traditional cumulative picture of progress. The revolutionary search for a replacement paradigm is driven by the failure of the existing paradigm to solve certain important anomalies. Any replacement paradigm had better solve the majority of those puzzles, or it will not be worth adopting in place of the existing paradigm. At the same time, even if there is some Kuhn-loss, a worthy replacement must also retain much of the problem-solving power of its predecessor (1962/1970a, 169). (Kuhn does clarify the point by asserting that the newer theory must retain pretty well all its predecessor’s power to solve quantitative problems. It may however lose some qualitative, explanatory power [1970b, 20].) Hence we can say that revolutions do bring with them an overall increase in puzzle-solving power, the number and significance of the puzzles and anomalies solved by the revised paradigm exceeding the number and significance of the puzzles-solutions that are no longer available as a result of Kuhn-loss. Kuhn is quick to deny that there is any inference from such increases to improved nearness to the truth ((1962/1970a, 170–1). Indeed he later denies that any sense can be made of the notion of nearness to the truth (1970a, 206).