“Epistemology of the Closet proposes that many of the major nodes of thought and knowledge in twentieth-century Western culture as a whole are structured [...] by a chronic, now endemic crisis of homo/heterosexual definition, indicatively male, dating from the end of the nineteenth century. The book will argue that an understanding of virtually any aspect of modern Western culture must be, not merely incomplete, but damaged in its central substance to the degree that it does not incorporate a critical analysis of modern homo/heterosexual definition.”

In this passage, Sedgwick provides the reader with the general subject matter, aim, and aspirations of the text as a whole. For Sedgwick, any serious understanding of the various social categories and cultural binaries that define contemporary Western society must include the history of how the sexual binary (heterosexual/homosexual) came into existence and codified in everyday language. As is shown throughout the text, various idiomatic expressions such as “coming out” point to the foundational role played by questions concerning the relationship between knowledge and ignorance, publicity and secrecy, public and private, and so on—questions whose origins in the eighteenth century continue to inform how the frameworks we rely upon to know the world inherently involve social and political biases privilege one term within a given binary (heterosexual) over and against the other (homosexual). 

“Insofar as ignorance is ignorance of a knowledge [...] these ignorances, far from being pieces of the originary dark, are produced by and correspond to particular knowledges and circulate as part of particular regimes of truth.”

In this passage Sedgwick notes that the asymmetry at the heart of cultural binaries affects how an individual comes to know the world and who belongs to privileged and disadvantaged positions in a given binary relation. Knowing how individuals correspond to places of privilege and disadvantage within a given cultural binary (straight/gay, white/person of color, able-bodied/disabled, etc.) relies on a form of knowledge that views the underprivileged term from the vantage point of the privileged position.