Dupin is different than ordinary people because of his ability to identify with the criminal mindset and solve crimes. He is able to see patterns and sequences that others cannot see. He is reclusive, reflecting another difference with other people. For example, Dupin has to see the exact location of the crime where he is able ascertain details that others miss or could not see. This represents how he is different from ordinary people. His mind enables him to identify with the criminal behavior, allowing his profiling abilities to differentiate him from others. His analytical perspective puts him in an another realm which is different from others. He is extraordinary and this becomes the basis for his reclusivity, symbolic of how he is different than others.
Dupin prides himself on being different from others. It is this ego that enables him to solve the crimes that baffle others. Due to this, Dupin is fundamentally different from others. He knows this and it enables him to establish himself as apart from the herd. Dupin's gifts and talents as a detective and someone who can identify with the criminal behavior mindset are elements that differentiate him from others. Dupin is created as the source of where crime is solved and where questions become answers. Such attributes are fundamentally different from others, who are simply left confused by the presence of crime and fundamentally baffled by the ability of Dupin to solve it.