The natural setting of the brutal arctic conditions of the Klondike, conditions which are indifferent to the presence of a man, express Naturalism, a literary movement among novelists who viewed people as hapless victims of an immutable and indifferent universe. Naturalism writers portray life exactly as it is, with objectivity and detachment.
Naturalism French writer Emile Zola, who described the role of the novelist as that of “a scientist, an analyst, an anatomist” who interprets reality through the application of scientific determinism. (Enotes)
Here are elements of Naturalism in "To Build a Fire":
- The protagonist has no name; he is called "the man" in order to make him representative of all people, the rational being in contrast to the dog, who acts upon natural instinct which often serves him better than man's mental powers. Calling him merely "the man" also mitigates the significance of the protagonist.
- Nature is indifferent to the man's plight as he begins to become crippled by frostbite. Since man has no control over nature, the man's poor decision to venture out into the severe temperatures leaves him a victim to this indifference.
...the mysterious, far-reaching hair-line trail, the absence of sun from the sky, the tremendous cold, and the strangeness and weirdness of it all—made no impression on the man....He was a newcomer in the land..
- Lacking the experience of the old man and the instincts of the dog, the man, also falls victim to the harshness of the Yukon. His causal attitude about his initial frostbite is clearly a mistake. Because he is incapable of shaping his own destiny, he is vulnerable to the elements in a deterministic manner that typifies Naturalism.
- The frigid environment has reduced the man to an animal, but he cannot survive because he is not adapted to this environment as the furry dog is.
- As part of nature, the dog instinctively knows not to step where there is water beneath the snow. When the man nears the water, it runs from the man, realizing the danger. Later, when he catches the scent of death, the dog returns to camp, abandoning the man.
- Literary style. Symbols and details are used in Naturalism. For instance, the snow and ice and severe cold are symbolic of the implacable Arctic. Great attention is given to realistic details in this story; for instance, the man is described quite thoroughly and factually.