Aesthetic investigations of ugliness have increased in popularity in the last decade, but existing treatments of ugliness either fail to provide a satisfying explanation for ugliness' unique presence and role, or merely provide a compendium of ugly instances. This thesis provides a non-equivocating explanation of ugliness which accounts for its phenomenological variety while retaining the roles of both object and subject, constituting a novel treatment in the field of aesthetics. An account of the concept's popular association as a beauty's negation is reassessed, along with investigation of the proliferation of species, features, and problems associated with ugliness in aesthetic writings. In addition to surveying classic and contemporary notions of ugliness in western aesthetics, this thesis provides a novel survey of ugliness in East Asian aesthetics, with a focus on ugliness in Chinese aesthetics. The project encompasses not only artistic instances of ugliness, but also natural phenomenon as well. The exploration and explanation of the nature of ugliness as a negative aesthetic value is accomplished by locating the conceptual core of ugly experience in a framework of aspectual judgment.