This dissertation is an interdisciplinary study of scientific change. The undulatory theory of light replaces the emission theory of light in the early nineteenth century, triggering an "optical revolution" and vigorous debates among physicists in British from the 1830s to the 1850s. In this study I give the first full account of this extended episode of scientific change, drawing on methods and concepts from history, sociology and philosophy of science. The interdisciplinary account of the episode provides a basis for criticizing the existing models of scientific change in the philosophy of science. Previous historical studies of the “optical revolution" pay little attention to the period after the 1830s. Because the cognitive superiority of the undulatory theory had become obvious in the early 1830s, some historians have implicitly assumed that any controversy would soon come to a natural end. I, however, document that intensive debates continued from the 1830s until the end of the 1850s, and that emissionists even enjoyed temporary victories in their fights with undulationists. The narrative reveals the historical complexities of this episode: the debates extended long after the cognitive superiority of the undulatory theory should have become apparent by modern standard, the results of the debates did not necessarily coincide with modern cognitive judgements, and individual agents played decisive roles in determining how long a debate lasted and how it would end. On the basis of the historical narrative, I provide a philosophical analysis of the practices of theory appraisal and experiment appraisal that constituted the main theme of the controversy. Instead of merely identifying the criteria of evaluation employed in this episode, I pay special attention to how individual agents actually applied these criteria in concrete situations, what kinds of strategies or tactics they employed for the applications of these criteria, and how they created favorable conditions, both cognitive and social, for successfully applying these criteria. Individual agents’ efforts in selecting application strategies and in creating favorable conditions made the practices of appraisal complicated, exhibiting various features that are incomprehensible if we limit ourselves merely to studying the criteria of evaluation. I finally discuss a different approach to scientific change. The existing philosophical models of scientific change merely analyze the final product of science -- scientific theories, and ignore the impact of social factors and the role of individual agents. I suggest we concentrate on the process of knowledge production, and pay attention to individual agents’s practices in this process, as well as to the relevant cognitive and social factors that influence individual agents. Following this new approach, scientific change is understood as an evolution that involves interactions among three elements: theory, experiment, and human agent. / Ph. D.