Chris rejects many of the things that he is told that he should want out of life Identify the things that he wants instead
Through his rejection of most material possessions and his adventures in the wilderness, Chris seeks to find a kind of "spiritual reality" and freedom that transcends the reality of our material world. Whether or not McCandless ever accomplishes this is open to debate, but I'm inclined to believe he did not.
Just as likely is the idea that Chris is running from his family and from himself in many ways, trying to ignore or repress his own history and role in the social world.
McCandless was reckless and foolhearty in his great Alaskan adventure. As noble and inspiring as the idea of his quest might be, his preparation and lack of knowledge create a situation ripe for disaster. Spiritual reality is a lofty goal, but what is it worth if you have no one to share it with? It reminds me of the old conundrum: If a tree falls in the forest but no one is around to hear it, does it make a sound?
In my mind, Chris is looking to find opportunities to test himself, to prove that he is capable of taking care of himself and finding more and more ways to learn skills that are vital to that effort. His vision of what people are worth, including himself, is completely seperate from possessions and things that people generally use to determine whether someone is "successful" or not.
Chris wants to feel fulfilled and powerful and free, and living on his own in the wild appears to be his method of finding out if he can do that. He values experience over attachment.