Abstract
Scholars increasingly express concern over the presence of conspiracy theories on social media platforms and in political discourse. However, such concerns rarely address conceptual questions, such as how to know which ideas count as conspiracy theories and which do not. This chapter provides a definition of conspiracy theory that contains both substantive characteristics and epistemological standards. Building from this definition, it then addresses what it means to hold conspiracy theory beliefs. The chapter concludes by addressing the implications of the proposed definition for debates between generalists (scholars who discount all conspiracy theories) and particularists (scholars who call for examinations of individual conspiracy theories before castigating them).