More than anything, White Fang is about nature. London talks about it in the first two paragraphs, shows us what it can do to a pair of hapless mushers, then picks up one of its creatures and demonstrates how he is shaped by, and eventually escapes it. Through White Fang, we also see how humans deal with nature. We try to tame it, rule it, escape it or overthrow it, but in the end, we're still beholden to it in a lot of ways. Scott and his family rise above it, but they're still at the mercy of its laws… especially when Jim Hall comes to visit.
White Fang's story is about escaping the natural world and coming safely to the world of men.
The world of men is an illusion, and White Fang's time in the wild help him survive dangers that men think they have evolved past.