In the winter of 1393, the king of France believed his body was glass. He had iron rods sewn into his doublet to keep himself from shattering. He had watched four men burn alive at a party he organized. The court tailors did what he asked. The rods were real; they held him together.
Somewhere in Central Asia, there grew a plant whose fiber, when ripe, came off in soft white tufts that resembled wool. European travelers saw it and wrote home: there is a creature here, half-animal, half-plant, a lamb that grows from a stem. The creature was never seen by anyone. But it appeared in manuscripts, in bestiaries, in the Encyclopédie of Diderot as an example of the kind of thing one must not believe. Carl Linnaeus gave its name — barometz — to a real fern. The creature still lives in the taxonomy, two hundred years after anyone stopped believing in it.
What each of these names was doing:
Glass
The king needed something to account for what had happened to him, and "I am made of glass" was the nearest available form. It carried the weight of what couldn't be said in any other way. The court had to accommodate a body that might shatter. The iron rods were the accommodation.
Lamb
The travelers needed a category for something unprecedented — a plant that produced animal fiber — and "a lamb that grows from a stem" was the nearest available form. The naming was wrong. The wonder it expressed was not wrong.
Blue
The calendar needed a name for an excess moon, and "blue" was the nearest available form. The name does real work: it makes the event significant, marks it as rare, gives it a quality worth remarking. That none of this is visible in the sky is beside the point.
Worm
The physicians needed an explanation for why water sometimes made people sick, and "a tiny worm that crawls into you and grows" was the nearest available form. They were right that water was sometimes dangerous. They were right that something living and invisible was the cause. The name held the right shape.
The nearest available form is not ignorance. It is what description looks like at the edge of what your instruments can resolve.
Glass. Lamb. Blue. Worm. All of them carrying real weight. All of them waiting to be replaced by something more accurate. All of them, in the meantime, doing the work that nothing else could do.
"I am made of glass" isn't a description. It's an expression: I need protection, I cannot be touched, my frame must be held rigid. The court acts on the commitment, not the description. The glass man wasn't wrong. He was speaking the only language that could make his need operative.