In Into the Wild, why does Chris McCandless isolate himself from his family?
What causes Chris more than anything else to isolate himself from his family is both the materialism that they live their lives buy and also the fact that his father had a previous wife and had carried out relationships with her and with his new wife, Chris's mother, at the same time, fathering a son by his previous wife at the same time he fathered Chris. For Chris, who put such value on honesty and integrity, his father's double and duplicitous life meant that he had lost respect for him, as the following quote makes clear:
Chris kept careful score. And over time he worked himself into a choler of self-righteous indignation that was impossible to keep bottled up.
Chris therefore chose to distance himself from his parents because of the way that he sees them as being materialistic, but also because of his father's past misdemeanours in his previous marriage whilst also pursuing a relationship with Chris's mother. Chris later said to his sister that this revelation made his "entire childhood seem like a fiction," and it can be understood how his parents came to embody everything that Chris, in his desire for simiplicity, purity and truth, stood against.