While the main conflict in Jack London's "To Build a Fire" is external with the man pitted against nature at its harshest, and subjected to the laws of nature, there is some conflict involved within the man as he does not tell himself what the dog is able to tell itself because he is too complacent in his own abilities:
Its instinct told it a truer tale than was told to the man by the man's judgment.
For, while the man registers in his mind that it is cold and he knows to avoid the wet spots, he does not direct his thoughts as he should. For instance, he is not observant of the tree under which he starts a fire. London writes,
Such were his thoughts, but he did not sit and think them. He was busy all the time they were passing through his mind.
While he fumbles to get the second fire going, his consciousness registers that his feet are freezing, and he goes into a panic. Still he "fights against it and keeps calm." It is at this point, too, that the man feels envy for the dog who is "warm and secure in its natural covering." His efforts to drive the thoughts of his freezing body from his mind are extremely difficult. And, in the end, he is unable to will himself to movement, realizing that his mental powers are no match for what conflicts with him externally.
So says enotes: "Critics Earle Labor and Jeanne Campbell Reesman observe that it is in fact the man’s pride in his ‘‘own rational faculties’’ that finally results in his demise."