"for the absence of sensation in his feet left him unrelated to the earth...."See in text(To Build a Fire)
The protagonist is “unrelated to the earth” on two levels. On a literal level, the lack of sensation leaves him unable to feel the ground. On a metaphorical level, this numbness describes the character’s broader relationship to the earth. Throughout the story, the protagonist is at odds with the environment, reading it incorrectly and struggling against it.
"The dead fingers could neither touch nor clutch...."See in text(To Build a Fire)
London’s use of “dead” to describe the fingers is metaphorical but purposeful. The fingers are not literally dead, but the word describes the mortal stakes of the protagonist’s situation.
"This fell on the boughs beneath, capsizing them...."See in text(To Build a Fire)
In the image of the snow “capsizing” the boughs, London’s use of metaphorical language serves two purposes. On one level, the word “capsizing” creates a vivid, kinetic picture of the flipping bough and the splashing snow. On another level, the word has a connotation of mortal danger, which rings true for the protagonist in this situation.
"It did not know this. It merely obeyed the mysterious prompting that arose from the deep crypts of its being...."See in text(To Build a Fire)
London addresses an epistemological—knowledge-oriented—question at the story’s heart. He suggests that instinct and knowledge are mutually exclusive and that humans alone are capable of knowledge. The story implicitly asks us which of the two are more effective. It is intriguing that London uses the metaphor of “crypts” to describe the source of the dog’s instincts, because he once again uses a metaphor with connotations of death.
