Poe opens his story "The Murders in the Rue Morgue" with the following paragraph.
The mental features discoursed of as the analytical, are, in themselves, but little susceptible of analysis. We appreciate them only in their effects. We know of them, among other things, that they are always to their possessor, when inordinately possessed, a source of the liveliest enjoyment. As the strong man exults in his physical ability, delighting in such exercises as call his muscles into action, so glories the analyst in that moral activity which disentangles. He derives pleasure from even the most trivial occupations bringing his talents into play. He is fond of enigmas, of conundrums, of hieroglyphics; exhibiting in his solutions of each a degree of acumen which appears to the ordinary apprehension preternatural. His results, brought about by the very soul and essence of method, have, in truth, the whole air of intuition.
Then, after a long and interesting discussion of what he calls the analytical power, he proceeds to tell a story featuring C. Auguste Dupin.
The narrative which follows will appear to the reader somewhat in the light of a commentary upon the propositions just advanced.
Dupin differs from ordinary people in having exceptionally high analytical powers which he enjoys using. "He derives pleasure from even the most trivial occupations bringing his talents into play." In this respect, Dupin is very much like the famous Sherlock Holmes, who was inspired by Poe's creation. Dupin is also very much like Edgar Allan Poe himself.
In Poe's time, before the Civil War, there was no such thing as I.Q. measurement. Otherwise, Poe might have said that Dupin differed from ordinary people because he had a genius I.Q., measuring somewhere around 180. Poe himself must have had a genius I.Q.
Dupin's other characteristics are explained by his exceptional intelligence. He spends much of his life in solitude. He only becomes friendly with the narrator of the story because they are both introverts whose main interests are reading, meditation, and "that infinity of mental excitement which quiet observation can afford." Dupin, like Sherlock Holmes, is a bachelor. It is hard to imagine either one of them getting involved in all the pains and pleasures of family life. A high I.Q. can be a handicap as well as an asset. It makes it hard for the exceptionally intelligent person to relate to ordinary people, i.e., people whose I.Q.s range between 90 and 110--the top of the bell-shaped curve.
Auguste Dupin is Edgar Allan Poe's fictional character who is the precursor to the modern detective. He first appears in Poe's The Murders in The Rue Morgue where he astounds others with his ability to apparently read their thoughts. It is his extraordinary analytical and observational skills that lead him to his conclusions. Dupin is able to put things into context and his extraordinary ability helps him solve mysteries which others believe to be unsolvable. Another unique characteristic of Dupin is his motivation for helping to solve these crimes. In The Murders in The Rue Morgue, he does not get paid and gets involved for his own personal reasons. He is content to beat the police at their own game.
Dupin's method of actually solving the crime is also considered bizarre. "Ratiocination" allows Dupin to combine the scientific with the imaginative and, seemingly, he is able to identify so strongly with the criminal that he must therefore know whatever the criminal knows. His system of finding, following and deciphering the most unlikely of clues sets him apart from others.