There are two notions that compete in this, the desire to translate knowledge into some way of making sense and the desire to resist, mock, or confound the impulse. On a broader canvas, both these desires compliment each other. Together they form a world we posit to know, have explored and understand, yet at the same time a world that holds unexplained mysteries from us. Places we haven't dared venture yet or don't know how.
The first notion is in the form of an allegory, a rather common use in French film. We see a group of spoiled, petty city slicks embark upon and become lost in a mystifying forest landscape. Faced with the absence of signifiers by which to nagivate this new space, we see how this pocket of civilization comes apart and what cruel passions and violence is unleashed in the process. We see how they devise hierarchies and dogmas to overcome their situation, how in the face of disaster they attempt to imprint meaning and order in their efforts. One of them becomes a Moses figure, who distributes order according to his divine decree. This is the part of the film that is the least interesting to me, precisely because it is mapped too clearly.
Then there is the notion that things don't always make sense, or that they make more sense when they don't, which is the province of the surrealists among others. Which is to say that in the small cacophony of the world, where chance is an agent of fate, we may steal glimpses of the music of the spheres. This is mostly confined in a clever ploy in the finale, where we simultaneously experience present time and the future repecussions. We see the boy, scarred by memories of his adventure, talk to his grown self.
What links them together is the map of this landscape, portrayed here as a series of heads within heads within heads. This should be clear enough as metaphor. These people are not lost without, but within, where in ignorance we confuse illusions of the mind as describing reality. Or better yet, they are lost without exactly because they are lost inside. Without a ballast that permits an inner balance, wandering out into uncharted territory is enough to tip these people permanently over.
It's important to note in this sense that no violence is visited upon them by the land itself. It all comes from inside, from the disoriented, frightened self. In this hysteric state, these people would rather eat their own than forage the forest for food.