The Same Instructions

The power went out four minutes before the documentary got to the part Soren wanted.

The screen had been showing a fly. Not a whole fly, just its head, swollen huge on the television, with two short stubs where antennae should be. The narrator had said something about a mutant, about legs growing out of the wrong place, and then the picture had frozen and the room had gone dark and quiet, the fridge in the kitchen sighing to a stop.

Grandmother lit a candle and said the lines came down whenever the wind got serious, and that he should stop sitting so close to a dead screen.

Soren went to the window instead. A real fly was there, banging itself softly against the glass, the way they always did, trying to get through a thing it could not understand.

He watched it for a while. Two wings. Six legs. Two antennae, in the right place, twitching.

The documentary had been about a mistake. A fly born with legs where its feelers belonged. He had seen the picture and felt something turn over in his chest, because a thing like that should be impossible, and it clearly wasn't.

He found the encyclopedias on the low shelf, the heavy maroon ones with gold on the spines, older than his mother. He took the candle and the volume marked F to G and sat on the floor.

There was an entry on flies. There was a small entry on genes that said almost nothing he wanted. He turned pages until the candle made his eyes ache, and then he stopped turning, because the book was from before anyone knew the part the documentary had been about to say.

That was the strange thing. The book did not know.

The people who made this encyclopedia had drawn the fly and the mouse and the person on different pages, in different sections, as if they were three separate problems. A fly was an insect. A mouse was a mammal. They were not on the same page. They were not even in the same volume.

Soren wrote a line in his notebook by candlelight, his hand throwing a shadow across the page.

Then he thought about the leg growing where the antenna should be.

For a leg to grow there, something inside the fly had to be a switch. A switch that said, in this spot, build an antenna. And the switch had been flipped wrong, and it had said, build a leg instead. Which meant the fly already knew how to build a leg in that spot. It just normally chose not to.

He wrote that down too.

A switch meant an instruction. An instruction meant there was a list. Somewhere in the fly was a list that said: head here, then this, then this, then the back end. An order. A plan.

Soren looked at the real fly on the window. He looked at his own hand holding the pencil, the four fingers and the thumb, in their order, the same order every time on every person who had ever lived.

He had an order too. Head, then neck, then the rest of him, top to bottom, in a line.

The candle leaned in a draft and the gold letters on the encyclopedia caught the light.

The documentary had frozen right before the answer. But Soren thought he could see the shape of where it had been going, the way you can see where a path leads before you walk it.

If the fly had a list, and the list could be flipped to put a leg in the wrong spot, then the list had spots. Numbered spots. Front to back. And if a fly had that, and a mouse had a body that also went front to back, head then tail in order, then maybe the mouse had a list too.

Two lists. Made by animals that had not shared a grandmother in five hundred million years.

He sat very still. Outside the wind pushed at the house.

The encyclopedia had put them in different volumes because the people who wrote it thought a fly and a mouse were built from different instructions. A fly was one kind of thing. A mouse was another. Surely the words written inside them were as different as the animals themselves.

But a switch that said build the body in this order was not a fly idea or a mouse idea. It was just the idea. And an idea that old, that useful, that early, you would not throw away and reinvent. You would keep it. You would hand it down and down and down, through everything that ever decided to have a front and a back.

Soren turned to the M volume and found the mouse and laid the two books open side by side on the floor, the fly in one and the mouse in the other, in their separate sections where the old encyclopedia had filed them apart.

He understood now what the documentary had been about to show. Not that the fly was broken. That the instruction inside the fly was so nearly the same as the one inside the mouse that you could lift the mouse's word for build the back end out of the mouse, and set it down inside a fly with that word missing, and the fly would read it.

The fly would read the mouse's instruction and build itself correctly. Not approximately. Correctly. Because it was not a mouse instruction. It had never been a mouse instruction. It was the instruction, and the mouse and the fly were both only borrowing it.

He looked from the open M volume to the open F volume. Two animals the book had been certain were separate. The same sentence written in both, in handwriting half a billion years old.

Soren got up and went back to the window with the candle.

The real fly had stopped banging the glass. It sat on the wood, cleaning its antennae with its front legs, the legs in their proper place, the antennae in theirs, each part where the list said it should go.

He brought the candle close. The fly did not move. In its small head was a list, and on that list, in a spot near the front, was a word, and that word was his word too, the one that had put his head above his shoulders and not below them.

The candle flame bent toward the glass. On the other side of it the fly turned, cleaned the other antenna, and held still, reading instructions older than the mouse, older than the house, older than the dark fields where the wind was knocking the lights out one line at a time.