Picture a juice glass sitting on a porch railing in the sunshine. It may look empty, but churning inside that glass are twenty-five thousand microscopic pieces of dust—at least. And these dusts are a little bit of everything on Earth. One minute, they are tiny crumbs chipped off Saharan sand, and invisible shreds of camel hair. Then the wind shifts, and there are spores of forest fungi and fragments of desiccated violets. A bus stops nearby to take on passengers, and invisible flakes of human skin, mixed with miniscule specks of black soot momentarily dominate the mix. Every time you inhale, thousands upon thousands of motes swirl into your body. Some lodge in the maze of your nose. Some stick to your throat. Others find sanctuary deep in your lungs. By the time you have read this far, you may have inhaled one-hundred-fifty thousand of these worldly specks—if you live in one of the cleanest corners of the planet. If you live in a more grubby region, you've probably just inhaled more than a million.
Some of the dust that swirls around us was knocked off distant, colliding asteroids eons ago. Some of it boiled off comets that may have passed our way a few years ago or a few centuries ago. This stuff, still holding its ancient grains of primordial stardust, settles on Earth at a rate of one magical speck per square meter per day. Whenever a dust scholar is able tease out the chemical fingerprint of a grain of space dust, she comes a little bit closer to understanding the origins of our world. That is the secret of our past.
—Hannah Holmes, The Secret Life of Dust
Dust, once recognized, becomes a cultural marker and is used to create social order. If dust seems at first glance to be mere natural detritus, human actors, comfortably and easily give its presence a wide array of interpretations. Dust comes to stand for divisions of gender, class, occupation, and nation. In a world in which the small is becoming increasingly visible, the realm of dust stands for other microscopic worlds: bacteria, radioactivity, nanotechnology, and DNA codes.
—Gary Alan Fine and Tim Hallett, “Dust: A Study in Sociological Miniaturism”
Dirt is essentially disorder. There is no such thing as absolute dirt: it exists in the eye of the beholder. If we shun dirt, it is not because of craven fear, still less dread or holy terror. Nor do our ideas about disease account for the range of our behavior in cleaning or avoiding dirt. Dirt offends against order. In [its] final stage of total disintegration, dirt is utterly undifferentiated. Thus a cycle has been completed. Dirt was created by the differentiating activity of mind, it was a by-product of the creation of order. It started from a state of non-differentiation; all through the process of differentiating its role was to threaten the distinctions made; finally it returns to its true indiscriminable character. Formlessness is therefore an apt symbol of beginning and of growth as it is of decay.
—Mary Douglas, Purity and Danger
—Adrien-Alice Hansel