Purity and Danger
Mary Douglas's classic work of cultural anthropology Purity and Danger points out the relativism inherent in our concept of dirt: Soil on the forest floor has a kind of purity, but move it to the kitchen floor and it's filth. It's not about dirt, she argues, but order, and whether something is out of its natural place.
 Explore the meaning and effects of disorder on your characters. It could be a messy kitchen or a world that's profoundly out of balance. Who determined what the standard of order is? Who or what disturbed it? What ensues?