Over 50 years after the publication of The Structure of Scientific Revolutions, many of Thomas Kuhn’s (1970a) conceptions of normal science continue to influence thinking about how science progresses. Research in a field is often assumed to be driven by a predominant paradigm. The paradigm is thought to guide the problems that are addressed by studies and the solutions that are generated. Science is often likened to a process of puzzle solving. However, we argue that Kuhn greatly overestimated the role of the paradigm in research and greatly underestimated the theoretical developments that take place in normal science. In our view, his position appeared reasonable only because he changed the definition of “paradigm” from the innovations to the entire constellation of beliefs and practices in a field. He also exaggerated scientists’ commitment to a paradigm and the degree to which they are biased toward confirmation. Kuhn’s misconceptions stem, in part, from psychological misassumptions about the thinking and motivations of scientists. We close by suggesting that the simple numbers indicate that most important discoveries are made during normal science and that the revolutions conceived by Kuhn are not central to the advancement of science.