There are three main categories that can define a piece of literature as a classic. Those three are: If the work can promote deep insight into human behavior, presents a universal theme, or uses language in an exceptional way. I believe the most reoccurring idea is a universal theme, its something everybody and almost all living things naturally have in common. It's the only example out of the three that's a definite; just if it's used in a literary work is up to the author. From the story "To Build A Fire" by Jack London, is where I believe a sense of a universal theme is created.
The theme I believe to be one in the story is Survival. Survival is a natural instinct that can be found anywhere by any living thing. The main setting of this story is a man who is journeying the freezing cold weather, trying to get to a certain goal. Along his journey he is faced with the brutal cold and danger of freezing to death along with his companion, a winter dog, and throughout the story, both him and his dog show signs of the need to survive. "He would kill the dog and bury his hands in the warm body until the numbness went out of them." That is a clear example of a human doing what's necessary in a dangerous situation just to survive. Normally killing a living animal is not acceptable and is considered very beastly. In the situation where the dog would be killed and used as a heater just for survival it's acceptable. Not only in this story does the human show signs of survival, but the dog also shows natural signs of the need to survive. "The dog had learned fire, and it wanted fire, or else to burrow under the snow and cuddle its warmth away from the air." The dog, without having the knowledge really of what a fire was, desired one and needed the warmth of one, just to survive. When the body is in danger or needs something, it will find its ways of letting you know, and making it your main goal to have happen.