Karl Heinrich Marx was a German philosopher and critic of political economy. Marxist theory focuses on the struggle between capitalists and the working class. Marxist theory posits that power relationships between capitalists and the working class are naturally exploitative. Renée discusses Marx briefly with a tenant at the beginning of the book and suspects she may have exposed her true nature in doing so.

Edmund Husserl was a German philosopher and founder of the school of phenomenology. Husserl’s theory believes that consciousness cannot be measured the way nature is and should be explored through induction. His science of consciousness centers on intentionality. Renée compares Husserl’s and Kant’s approaches to consciousness early on in the novel and finds Husserl’s ideas depressing.

Immanuel Kant was a German philosopher whose central contribution to philosophy was his philosophy of human freedom. Kant proposed that without freedom, human beings cannot act morally. While Renée prefers Kant over Husserl, she still comes to the conclusion that her understanding of Kant does not really help her understand or appreciate Husserl.