A very important theme in this book is the way that McCandless seeks to be self-reliant and he does everything he can to escape intimacy or dependence on others. This is shown in the way he leaves his family and the other people in his life as well that threaten to become too important for him, and thus would impede his goal of being only reliant on himself. Note how this is reflected in the following quote:
McCandless was thrilled to be on his way north, and he was relieved as well—relieved that he had again evaded the impending threat of human intimacy, of friendship, and all the messy emotional baggage that comes with it. He had fled the claustrophobic confines of his family. He’d successfully kept Jan Burres and Wayne Westerberg at arm’s length, flitting out of their lives before anything was expected of him. And now he’d slipped painlessly out of Ron Franz’s life as well.
The last person mentioned, Ron Franz, even offered to adopt Chris as his son, but even though this was a touching gesture, and it was clear that Chris felt a great deal for Ron, he saw this as an entanglement that would prevent him from living his Emersonian dream of being self-reliant. Chris's life is one long catalogue of seeking to avoid any kind of relationship that would hamper or hinder his efforts to be independent.
An excellent quote to support the theme of communicating with nature can be found when the author describes how he felt when he scaled the Devil's Thumb by himself in Alaska:
A trancelike state settles over your efforts; the climb becomes a clear-eyed dream. Hours slide by like minutes. The accumulated clutter of day-to-day existence—the lapses of conscience, the unpaid bills, the bungled opportunities, the dust under the couch, the inescapable prison of your genes—all of it is temporarily forgotten, crowded from your thoughts by an overpowering clarity of purpose and by the seriousness of the task at hand.
Note the way in which the author describes how he relates to nature first hand because of the proximity to nature and the way that every move has to be thought through very carefully in order to focus and concentrate his efforts on what he is doing in order to survive. What is particularly attractive is the "trancelike state" that Krakauer describes, and the way that the worries of everyday existence are completely lost when you are communicating and experiencing nature in such a vital and visceral way.