: I argue that knowledge is a particular kind of concept known as a thick concept. Examples of thick concepts include courage, generosity, loyalty, brutality, and so forth. These concepts are commonly said to combine both evaluation and description, and one of the main goals of this dissertation is to provide a new account of how a thick concept combines these elements. It is argued that thick concepts are semantically evaluative, and that they combine evaluation and description in a way similar to that of concepts like good qua dancer and bad qua violinist. In the final chapter, this basic idea is applied to the concept of knowledge. There, the concept of knowledge is analyzed in terms of good qua belief. The upshot is that two central epistemological problems-the Gettier Problem and the Value Problem-can be resolved.