Interpreting Epigraphs in 'Into The Wild'

The author of Into the Wild, Jon Krakauer, using an epigraph, sometimes two, at the beginning of each chapter in the book. Sometimes, the epigraphs including notes that Chris McCandless had written in regards to something he read and felt connected to. Other times the epigraphs were passages that were found highlighted in Chris’ books, The rest of the epigraphs that Jon Krakauer pulled from books because, he thought the connected to Chris’ story. The author, Jon Krakauer, does a great job at choosing epigraphs that connect to the chapter.
In White Fang, Jack London says “There was a hint in it of laughter, but of a laughter more terrible than any sadness-a laughter cold as the frost and partaking of the grimness of infallibility. It was the

masterful and incommunicable wisdom of eternity laughing at the futility of life and the effort of life. It was the Wild, the savage, frozen-hearted Northland.” (Krakauer).
Jon Krakauer uses this passage at the beginning of chapter 2 and he also included something that Chris McCandless carved into a piece of wood. “Jack London is King Alexander Supertramp May 1992” (Krakauer). London’s passage refers to how cruel, merciless, and unforgiving the Alaskan wilderness can be. I believe the reason the author paired McCandless’ carving with London’s passage to convey a sense of irony. Chris McCandless had a very obvious love of Alaska. Jack London, one of his favorite authors, writes about how Alaska can be ominous. A favorite author states in his passage probably the exact opposite of how McCandless thought of Alaska. Krakauer never mentions that Chris ever read this passage from London and that’s what leads me to believe that he used it for irony.