A recurring motif in “The Murders in the Rue Morgue” is the number two. The most obvious is the dual partnership between Dupin and the narrator. Additionally, there are two women who are murder victims, two doors accessing the victims’ apartment, two windows inside the apartment, and two last words heard by eyewitnesses: “mon Dieu,” or “my God” (28). Two signifies duality, an age-old school of thought where opposite forces achieve synthesis. In the story, Poe contrasts the one who knows from the one who does not, the old from the young, and the front from the back. Yet, rather than keeping them separate, Poe merges them into a single entity according to their function. When observing Dupin’s skillful process in using rationality for detection, the narrator reflects on “the old philosophy of the Bi-Part Soul” and a “double Dupin—the creative and the resolvent” (4). It is worth mentioning that the beginning sound in Dupin, “Du,” is pronounced like the French word for two, “deux,” thus suggesting the detective’s psychological split.

The Ourang-Outang serves as a motif for the absence of reason. Brutish, wild, and instinctual, the mammal embodies superhuman strength and agility which, in turn, generates public fear.