One method Poe uses to demarcate and round out the characters of Dupin and the narrator is his intentional use of active and passive voice for each. Even though Dupin’s dialogue is effusive, it is not labored. Like his mind, it appears to run quickly. Poe creates this effect through his choice of lively verbs written in active voice. Readers first hear Dupin during his brain mapping of the narrator’s mental “chain” from the fruiterer to Chantilly (6). The detective states, “we crossed,” “you stepped […] slipped […] strained […] muttered […] proceeded” followed by “I saw,” “I knew,” “I mentioned,” and “I felt” (6-7). In the scientific realm of cause and effect, Dupin shows himself and others as active agents and views events as a series of actions each dependent upon the last.

By contrast, the narrator speaks mostly in a distancing passive voice. Being of lower intellect and lacking the mental power and self-assuredness of his friend, the narrator receives Dupin’s tutelage, receives the action on the street, and receives the emotional boon from having been amazed at Dupin’s cognitive abilities to connect the seemingly arbitrary.