Adopting a post-Cartesian, intersubjective viewpoint that focuses on the interplay of worlds of experience leads to an opening up of the most severe ranges of psychopathology—the so-called psychoses—to psychoanalytic understanding and treatment. A Cartesian theory, inevitably preoccupied with the individual mind and its contact with a stable external reality, cannot encompass experiences of extreme self-loss and of the disintegration of the world. A sketch is offered of varieties of the experience of personal annihilation within an intersubjective, phenomenological framework of understanding. Features of the intersubjective fields typically associated with delusional states, manic episodes, and extreme trauma are discussed.