Northrop Frye compares the cultural envelope to the windows of a lit-up railway car at night. The lights inside cause the windows to act as mirrors reflecting the interior of the railway car. But every so often the lights flicker and fail, leaving the interior of the car in darkness and revealing, through the windows, an alien nature in which it is impossible to survive without equipment, preparation, and skill. Our experience of the world is for the most part the experience in the railway car at night when the lights are on. If we try to look into nature, beyond our cultural envelope, what we see is mostly a reflection of ourselves. But at unexpected moments this hallucination fails and we glimpse the imponderable otherness of the wilderness in which we actually live.