Murder in Rue Morgue-Jess

Man/animal.
Through out the entire novel you are led to believe that either a man (or a woman) was the unidentifiable voice from the crime scene. In society we are taught to believe that violent crimes are perpetrated by men (or women) however in the end we discover that the killer was an orang-otang. The standing belief is that men are the dominate (idea, being race) however if that were the case in this story then the killer would have been a man and not an animal. Futher more, the animal knew enough to try and hide the first body, a skill we contribute to man alone.

living/dead
We naturally assume that living is the dominate idea, however in this text the main focus is on the dead. It doesn't matter that the people who rushed the building are alive, that the narrator is alive. Without there being two bodies upstairs there would be no murder to investigate and thus no story.

Known/unknown
There are several examples in Murder in Rue Morgue that show that dominance of the unknown. The first is the narrator and his or her companion. The companion is well know, he even has a name C. Aguste Dupin. However the narrator is entirely unknown, in fact we aren't even given a gender for the narrator and there are ambiguous statements that indicate it might be female (when they are strolling down the street arm in arm). The second is the two voices that were heard in the apartment murder scene. One was a Frenchman, no one denies that. However it is the second voice that is focused on. It might be Russian, it might be French, it might be Spanish or English. In the end it is that unknown voice that cracks the case.