C. Auguste Dupin discussing Dupin's method in the light of Charles Sanders Peirce's logic of making good guesses or "abductive reasoning," Nancy Harrowitz first quotes Poe's definition of analysis and then shows how "Poe the semiotician is running the gamut of possibilities here—inferences, reasoning backwards, visual, sensual and aural signs, reading faces. Playing cards with the man would have been an interesting experience." There is considerable controversy about the philosophical nature of Dupin's method. According to biographer Joseph Krutch, Dupin is portrayed as a dehumanized thinking machine, a man whose sole interest is in pure logic. However, Krutch has been accused elsewhere of
C. Auguste Dupin the three stories, Dupin travels through three distinct settings. In "The Murders in the Rue Morgue", he travels through city streets; in "The Mystery of Marie Rogêt", he is in the wide outdoors; in "The Purloined Letter", he is in an enclosed private space. Dupin is not actually a professional detective, and his motivations change through his appearances. In "The Murders in the Rue Morgue", he investigates the murders for his personal amusement, and to prove the innocence of a falsely accused man. He refuses a financial reward. However, in "The Purloined Letter", Dupin purposefully pursues a financial reward. While