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New historical criticism is a branch of historical criticism that seeks to understand literature through the author's interpretation of historical, cultural, and social events of a work's time period. More specifically, new historical criticism "assumes that every work is a product of the historic moment that created it" and seeks to understand the interpretation of the moment (OWL, "New Historicism, Cultural Studies (1980s-present)"). It should also be noted that new historicists do not believe that history can be understood objectively. Instead, they believe history can only be understood through the subjective eyes of the observer of the historic moment. For that reason, there is a slight difference between simply historical criticism and new historical criticism. Historians and those who interpret literature through historical criticism only ask two simple questions: "What happened?" "What does the event tell us about history?" In contrast, new historicists ask questions concerning interpretation: "How has the event been interpreted?" "What do the interpretations tell us about the interpreters?" ("New Historicism, Cultural Studies"). Since new historical criticism looks for interpretations of historical events, in order to apply new historical criticism to Graham Greene's novel The Comedians, you'll need to first figure out what what historical events are present in the work and then understand Greene's own interpretation, or own reaction to or feelings about, the event. You'll want to ask yourself the question, what is Greene trying to say about the events in this novel?
There are many contextual clues that help us figure out the historical events the novel refers to and the historic time period in which the novel is set. For one thing, we know that the narrator, called Mr. Brown, is recounting his experiences in Haiti. We also learn in the beginning of the book that, while sailing on a cargo ship from New York to Haiti, he meets Major Jones, who may have fought in Burma during World War II; hence, we know the book is set in Haiti after World War II, which we also know was a terrible time period for Haitians. We also learn that Brown is trying to sell his hotel, which suffered financial loss when Francois Duvalier, also called Papa Doc, became President of Haiti. The name Papa Doc is especially critical for telling the readers about the historic events surrounding the novel. If we research things, we learn that Papa Doc was elected into the presidency in 1957 by the Afro-Haitian majority. He was elected to the title President for Life; therefore, though elected, Papa Doc was a dictator. He particularly exercised his dictatorial authority to eliminate the power of the mulatto elite and any opposition to his own regime ("Francois Duvalier"). Mulatto is a racial term used to refer to individuals born of white fathers and black mothers. In Haiti, mulattoes were not made to be slaves even though their mothers were. They were also educated along with the white class, and due to their education and social statuses, were given "positions in office" and other elite positions ("Mulatto: Haiti"). Even though only 15% of Haiti's population is mulatto, the social hierarchy of mulattoes is still a problem today, a problem that Papa Doc tried to put an end to. However, like all dictators before him, Papa Doc used corrupt means to try and shift power from the mulatto minority to the Afro-Haitian majority, leading to the "murder of an estimated 30,000 Haitians and the exile of many more" ("Francois Duvalier"). He was particularly known for enforcing his power through developing his own personality cult based on voodoo, called vodou in Haiti, in which he declared himself to be a "houngan, or vodou priest" and a Loa, which is a vodou spirit that acts as an intermediary between God and man (Loa).
One event the book speaks of that ties directly to the dictatorship of Papa Doc, complete with all of its cruelty, is the moment Brown learns from his bartender that Doctor Philipot, persecuted by Papa Doc, took his own life. Earlier, in Chapter II, the narrator even says himself, "I was returning without much hope to a country of fear and frustration" and one full of secret police "violence, injustice, and torture" (43; 283). After researching the historical background surrounding the story, we can then examine the author's voice and details to better understand how the author is interpreting the surrounding history and the author's thoughts and feelings concerning the history. An author's voice is the author's attitude toward the subject matter. We can glean the author's voice through diction, or word choices, like in the quotes above, and through events told in the story