In “To Build a Fire,” as in so many of Jack London's stories, the central conflict is between man and nature. And here as elsewhere, that conflict is resolved firmly in favor of nature, as the man ends up freezing to death in an icy wilderness.
On the whole, it's difficult to muster up any real sympathy for the man. It was pretty obvious from the outset that his expedition to the frozen wastes of the Yukon was little more than a suicide mission. Even the man's dog knew that it was a hare-brained scheme. But the man was so arrogant, foolish, and utterly determined to pit himself against the forces of nature that he ventured out into sub-zero temperatures when there was absolutely no need to do so.
The consequences are predictably dire. The man freezes to death after his failed efforts to build a fire and stay warm. Nature has triumphed over man. In truth, it was always a pretty one-sided conflict in which the man never really had a chance. But for a time, it looked as if maybe the man might succeed and pull off the remarkable feat of resisting the raw and unrelenting power of nature.