Recursion

on the front. The demon was standing by a strange machine made out of stainless steel, all blades and needles and with someone strapped inside it… The door suddenly swung closed.

Mary turned to face him, her face pale. “It’s an idle threat, Constantine. It costs too much running the simulation that keeps us all in here. The processing power could be put to better, more profitable uses. You, me, Marion and…the other one. We’re all personalities trapped in this bottle. They’ll just turn us off if we don’t deliver.”

Mary shivered and looked up to the great eye, staring down from the hole where the moon had been. A look of defiance crossed her face.

“I don’t care, Constantine. I’m telling you the truth now. You don’t know what it’s like. You’re more honest than we are. You didn’t volunteer to come in here. The real me, the one out there in the real world, has sentenced a copy of herself to oblivion for the sake of a bonus of a few hundred credits. What does that tell you about human beings, Constantine? Would you do that to yourself? I bet you would.”

She began to shake; she looked as if she was about to start crying.

“I don’t know what to say, Constantine. I don’t know what to tell you. This is the deal: you tell us what we want to know and we keep the simulation going. That way, you have a life; we have a life. You don’t tell us, and I don’t know what will happen. Maybe it will be what you saw through that door. Personally, I think they’ll just turn us off. Why throw good money after bad?”

“How can I trust you?” asked Constantine.

“You can’t. But what other choice do you have?”

“I don’t know. I need to think.”

Mary nodded. “I bet you do. Well, here’s something else to think about. Why are you protecting DIANA? Do you know they’ve already launched three attacks on this computer, the one in which we now reside? The third one almost succeeded. They got a worm into the system that would have wiped the entire simulation if we hadn’t found it in time. For DIANA, the best way to keep secret what you know is to destroy you.”

Constantine opened his mouth to argue, but he couldn’t find the words. What Mary said made sense. He didn’t want it to be so, but it made sense. What would he do if he was outside and not trapped in here?

And that was the point. He was outside. The real Constantine was out there somewhere. And Constantine, now shuddering violently in the warm night air, knew exactly what he would be thinking:

At all costs the project must be protected.

Somehow I must wipe out the copy of my personality.

Herb 5: 2210

The ship reinserted itself into normal space. Herb braced himself for the attack…

Nothing happened.

Gradually he relaxed. Herb felt like an old-fashioned wind-up toy. The tension would slowly build up inside him, hunching his shoulders, bunching his fists, restricting his breathing, until he noticed it was happening. Then it took a conscious effort to relax; release his pent-up breath in one huge sigh; force himself to breathe more slowly. And that would appear to work for a while, but all the time the tension was rebuilding, his body slowly winding itself up again.

It was happening already as Herb scanned the viewing areas.

Where were they? Where was the attack? Nothing. Only empty sky.

Robert coughed. He was about to perform one of his little distractions; Herb just knew it.

“The thing about warp drive, superluminal drive, faster-than-light drive,” said Robert, “is that once you make the jump, you can’t be tracked.”

Herb was not impressed. He had been expecting better than this.

“Well, yes. Everyone knows you can’t track someone making a warp jump,” he said.

Robert grinned. “And they’re right. But what many people don’t realize-and it’s partly because they don’t take the trouble to think about the problem, and partly because the AIs keep quiet about it-is that you can still usually make a pretty good guess at a ship’s position.”

“How?” Herb’s stomach was tightening with uncertainty.

Where were they? Robert scanned the viewing field in the floor again and frowned. “The Enemy Domain saw us insert ourselves into warp at a certain point. There is a certain range of speeds at which we can travel using a warp drive, so that gives the Enemy a minimum and maximum distance that we can have traveled. Think of two concentric bubbles expanding outward from our starting point. As the outer bubble sweeps through a system, they will go on alert. After the inner bubble has trailed through later on, they stand down.

“Once we jump, we’re like the particle in an electron cloud. The Enemy can map a probability of us being at any point within it. Once we materialize, the wave function collapses and a new set of equations comes into play. AIs have been solving these equations for decades. They’re good at them. They need to be; they’re using them to probe-” Robert paused. “Well, that’s another story.”

Herb nodded blankly. He wondered how long this horrible, twisting tension could be held in by the walls of his stomach. He felt as if it would rupture in an acidic explosion at any moment.

Robert reached into his left-hand jacket pocket and pulled out another VNM. This one was smaller than that machine of Herb’s which had been dropped onto the last planet. The new machine was an odd shape; it twisted around on itself like a Mцbius strip. Robert placed it on the white handkerchief that was still spread out neatly on the sofa next to him.

“So now we play a game of cat and mouse,” he grinned at Herb, “if you’ll forgive the clichй. Quantum entanglement provides for instantaneous communication, so the entire Enemy Domain will know of our position the moment we are spotted. Therefore, we must try and outguess them. We must try not to be seen.”

Herb nodded. They seemed to be doing a pretty good job so far; there was still no sign of Enemy activity. He looked around the room, gazing at the viewing fields that covered the ceiling, the walls and the floor, knowing as he did so how unrealistic it was to expect to see anything out there but stars. Nonetheless, he kept looking. The fear that he would see a fleet of ships swooping toward them could not be shaken. Robert remained unfazed. He continued his lecture.

“As long as we remain within the Enemy Domain, more and more of its ships can jump to place themselves within reach of the expanding spheres of our separate jumps. As the wave front passes them by, those ships will jump to follow it. When we jump again, they will repeat the maneuver. I’m afraid, Herb, we can’t keep this up indefinitely. If we wish to stay in here, then sooner or later the Enemy will catch us.”

He smiled again. “I’m planning on later.”

Herb glanced around the screens. He had been expecting explosions, attack ships, anything but this calm nothingness. Where had the Enemy got to? His voice sounded a little high-pitched as he spoke. “There’s nothing happening. Where are we?”

Robert laughed.

“About three hundred AUs from where we started, just floating in empty space. We’ve hardly moved at all. Despite all I’ve just said, they’ll never think of looking for us this close to our jump point.”

Herb got to his feet.

“I need to do something. I’m going to make a cup of fresh coffee. Do you want some?”

“No, thank you,” said Robert. “It would be wasted on me. Robots don’t care for coffee.” He folded his hands on his lap and continued his methodical scanning of the viewing fields. Herb opened a cupboard in the tiny kitchen and pulled out the coffee tin. He pulled off the lid to the rich smell of chilled air and roasted beans.

“Damn. Only half full. I forgot. The rest will be on the other ship. The replicating engine is set not to reproduce luxury goods.”

Robert said nothing.

Herb pulled a glass cup from another cupboard. “I’ve figured out why you dropped my VNM on that planet we