Particularism is one of the most interesting and controversial doctrines in moral philosophy today. Yet despite the considerable attention it has received in recent years, there is still extensive disagreement about its precise content, and whether it is a viable alternative to traditional moral theories. In this dissertation I develop, motivate, and defend a novel formulation of particularism. In Chapter One, I present my formulation of particularism. I claim that particularism is not a single thesis but a research program. Research programs are collections of theories and methodological rules that can be characterized by their hard core —the set of commitments that cannot be abandoned without abandoning the research program altogether. T...