As one of the two surviving members of the Usher family in “The Fall of the House of Usher,” Roderick is one of Poe’s character doubles, or doppelgangers. Roderick is intellectual and bookish, and his twin sister, Madeline, is ill and bedridden. Roderick’s inability to distinguish fantasy from reality resembles his sister’s physical weakness. Poe uses these characters to explore the philosophical mystery of the relationship between mind and body. With these twins, Poe imagines what would happen if the connection between mind and body were severed and assigned to separate people. The twin imagery and the incestuous history of the Usher line establish that Roderick is actually inseparable from his sister. Although mind and body are separated, they remain dependent on each other for survival. This interdependence causes a chain reaction when one of the elements suffers a breakdown. Madeline’s physical death coincides with the collapse of both Roderick’s sanity and the Ushers’ mansion.