When writing his book, Sinclair used a variety of styles and influences to create essentially a new type of novel. Elements of naturalism exist throughout most of the text. Naturalism, as a type of literature, attempts to apply scientific principles and detachment when studying humans. The characters created in naturalistic fiction are "human beasts" who can be studied by examining their surroundings. Emile Zola provided the classical definition and application of naturalism. When Sinclair was taking copious notes about his experiences in Chicago, he was being a naturalist practitioner.
The literary components of character, setting, and theme are three areas where The Jungle exemplifies naturalistic fiction tendencies. Characters in this genre typically are lower-class people who struggle against forces beyond their control. The setting tends to be urban, and the details and examples used to show a slice of life often end up being a chronicle of despair. It is extremely important that harsh realities be portrayed as such, no matter how unsavory they may be. Only when novelists present all the facts do they finally reveal the truth. Finally, two themes dominate naturalistic novels: survival and futile attempts to exercise free will. These themes are apparent throughout The Jungle.
The Jungle, however, is not pure naturalism. Sinclair incorporates just enough of it to suit his rhetorical purpose. Unlike pure Zolaism (another name for naturalism), Sinclair's The Jungle is lacking in objectivity: Sinclair clearly sympathizes with the working class. Sinclair also saves Jurgis, the protagonist, from destruction. This totally undermines the pessimistic naturalistic belief in futility.
