Tony Ballantyne
Recursion
For Barbara
Herb 1: 2210
Herb looked at the viewing field and felt his stomach tighten in horror. He had been expecting to see a neat cityscape: line after line of silver needles linked by lacy bridges, cool silver skyscrapers shot through with pink-tinted crystal windows; artfully designed to resemble the spread of colors on a petal. Instead he saw…bleak nothingness. Cold, featureless, gently undulating wasteland spreading in all directions.
Something had gone badly wrong. Suddenly the cozy white leather and polished yellow wood lounge of his spaceship was not the safe cocoon he had grown used to over the past few months. Now they would be coming to prize him from this warm, cushioned shell to cast him shivering into the real world, all because he had made one tiny mistake.
Somehow he had made a mess of the code that should have told the Von Neumann Machines to stop reproducing and start building.
Herb’s machines had eaten up an entire planet.
But there was nothing to be gained now by crying about it. Herb had known he was on his own when he embarked upon this project. It was up to him to figure out what had gone wrong, and then to extract himself from the situation.
He opened a second viewing field next to the first and called up an image of his prototype Von Neumann Machine. A cylinder, nine centimeters long, with eight silver legs spaced along its body, giving it an insectile appearance. Six months ago Herb had dropped out of warp right over this planet, opened the hatch of his spaceship, and stood in solemn silence for a moment before dropping that same machine onto the desolate, rocky surface below.
What had happened next?
Herb liked to pace when he was thinking, and he had arranged his spaceship lounge to allow him room to do so. Two white sofas facing each other occupied the center of the room. A wide moat of parquet flooring filled the space between the sofas and the surrounding furniture that lined the walls of the room. The smell of beeswax polish and fresh coffee filled the cabin. Herb closed his eyes and ran through the order of events after he had released the Von Neumann Machine.
He imagined that first VNM turning on six of its spindly legs, lifting them in a high stepping motion as it sought to orient itself. The remaining two legs would be extended forward, acting as antennae, vibrating slightly as they read the little machine’s surroundings. It would have walked a few paces, tiny grains of sand sticking to its silver-grey limbs, then maybe changed direction and moved again, executing a random path until it found a patch of rock of just the right composition, then settled itself down, folding its legs around itself to bring its osmotic shell in contact with the surface.
His thoughts on track, Herb began to pace, soft ships’ slippers padding on the wooden floor. He was naked except for a pair of paper shorts.
In his imagination he saw the first machine absorbing matter from the planet, converting it, working it, and sending it around that half-twisted loop that no human mind could comprehend. Soon there would be two identical machines standing on the rock, their legs waving in an explorative fashion. And then four of them, then eight…
The program was perfect, or so the simulations had told him. When they reached the optimum number, the machines should have begun constructing his city out of their own bodies, clamberering on top of each other using the sticky pads on the ends of their feet. Herb was proud of the design of those pads: each seemingly smooth foot ended in a chaotic branching of millions upon millions of tiny strands. Press one foot down and the hairs would spread out, reaching down and around to follow the contours of the surface beneath them so perfectly that they were attracted to it at a molecular level.
Not that any of that mattered now. This was the point where the error lay. The machines hadn’t paused to build his city. They’d just gone on reproducing, continued eating up the planet to make copies of themselves until there was nothing left. He opened his eyes again to look at the viewing field. Maybe he had only imagined it.
Herb groaned as the view zoomed in on the cold grey shifting sea beneath. He could make out the busy motion of millions of VNMs walking over and under each other, struggling to climb upwards to the surface only to be trodden on and forced down by other VNMs, each equally determined about seeking the light. Wasn’t that part of the end program? City spires, growing upwards, seeking the light in the manner of plants? Everywhere he looked, everywhere the ship’s senses could reach-out to the horizon, down to the submerged layers of machines-it was the same: frenzied, pointless activity.
He paused and felt a sudden thrill of horror. That wasn’t quite true. Something was happening directly below. He could see a wave building beneath him: a swelling in the grey, rolling surface. Thousands of pairs of tiny silver antennae were now waving in his direction. They sensed the ship hanging there. They sensed raw materials that could be converted into yet more silver VNMs. Herb felt a peculiar mix of horror and betrayal.
He croaked out a command. “Ship. Up one hundred meters!”
The ship smoothly gained altitude and Herb began to pace again. He needed to think, to isolate the error, but he couldn’t concentrate because one thought kept jumping in front of all the others.
He was in serious trouble.
Herb didn’t exactly fear the EA. Why should he? The EA was like a parent: it cared for and nurtured all its human charges. The EA wanted Herb to become the best that he could be. No, Herb did not fear the EA: he
And it acted to correct the behavior of those who transgressed its boundaries.
The EA would have been upset enough by the thought of a private city being built on an unapproved planet. Never mind the fact that the planet was sterile and uninhabited, they would still point out the fact that a city wasn’t part of this planet’s natural environmental vectors.
The message was as much part of Herb’s childhood as the smell of damp grass, the dull brown tedium of Cultural Appreciation lessons, and the gentle but growing certainty that whatever he wanted was his for the asking. Everything, that is, but this. Everyone knew the EA’s philosophy.
So what would the EA think when they discovered that in failing to build his illegal city he had accidentally destroyed an entire planet instead? Did they know already? Had something in his behavior been picked up by the EA’s monitoring routines? Was someone already on their way here to arrest him?
Herb didn’t remember setting out a bottle of vanilla whisky on the carved glass slab that served as a side table. Nonetheless, he poured a drink and felt himself relax a little. His next moves began to fall into place.
First he had to try and destroy any evidence linking this planet with himself.
Next he had to get away from here undetected.
Then he had to slot back into normal life as if nothing had happened.
Then, and only then, could he pause to think about what had gone wrong with his prototype.
The first objective should be quite straightforward. The original VNM had been designed with anonymity in mind: standard parts, modular pieces of code taken from public libraries. The thought that someone might accidentally stumble across his planet had always been at the back of his mind. He gulped down some more whisky and an idea seemed to crystallize from the alcohol. He prodded it gently.
As far as Herb knew, no one else even knew that this planet existed. He had jumped across space at random and set his ship’s senses wide to find a suitable location. What if this planet were just to disappear? What if he
