Permutation City

fallen apart.

Durham said, “Now we try to stop the clock.” He hit a few keys, and Maria watched his commands racing across the links. She thought: Maybe there was something wrong down at the hub. Maybe this whole crisis is going to turn out to be nothing but a tiny, localized bug. Perfectly explicable. Easily fixed.

Durham said, “No luck. I’ll try to reduce the rate.”

Again, the commands were ignored.

Next, he increased the Autoverse clock rate by fifty percent—successfully—then slowed it down in small steps, until it was back at the original value.

Maria said numbly, “What kind of sense does that make? We can run it as fast as we like—within our capacity to give it computing resources—but if we try to slow it down, we hit a brick wall. That’s just… perverse.”

Zemansky said, “Think of it from the Autoverse point of view. Slowing down the Autoverse is speeding up Elysium; it’s as if there’s a limit to how fast it can run us—a limit to the computing resources it can spare for us.”

Maria blanched. “What are you suggesting? That Elysium is now a computer program being run somewhere in the Autoverse?”

“No. But there’s a symmetry to it. A principle of relativity. Elysium was envisioned as a fixed frame of reference, a touchstone of reality—against which the Autoverse could be declared a mere simulation. The truth has turned out to be more subtle: there are no fixed points, no immovable objects, no absolute laws.” Zemansky betrayed no fear, smiling beatifically as she spoke, as if the ideas enchanted her. Maria longed to know whether she was merely concealing her emotions, or whether she had actually chosen a state of tranquility in the face of her world’s dethronement.

Durham said flatly, “Symmetries were made to be broken. And we still have the edge: we still know far more about Elysium—and the Autoverse—than the Lambertians. There’s no reason why our version of the truth can’t make as much sense to them as it does to us. All we have to do is give them the proper context for their ideas.”

Repetto had created a puppet team of Lambertians he called Mouthpiece: a swarm of tiny robots resembling Lambertians, capable of functioning in the Autoverse—although ultimately controlled by signals from outside. He’d also created human-shaped “telepresence robots” for the four of them. With Mouthpiece as translator, they could “reveal themselves” to the Lambertians and begin the difficult process of establishing contact.

What remained to be seen was whether or not the Autoverse would let them in.

Zemansky displayed the chosen entry point: a deserted stretch of grassland on one of Planet Lambert’s equatorial islands. Repetto had been observing a team of scientists in a nearby community; the range of ideas they were exploring was wider than that of most other teams, and he believed there was a chance that they’d be receptive to Elysian theories.

Durham said, “Time to dip a toe in the water.” On a second window, he duplicated the grassland scene, then zoomed in at a dizzying rate on a point in midair, until a haze of tumbling molecules appeared, and then individual Autoverse cells. The vacuum between molecules was shown as transparent, but faint lines delineated the lattice.

He said, “One red atom. One tiny miracle. Is that too much to ask for?”

Maria watched the commands stream across the TVC map: instructions to a single processor to rewrite the data which represented this microscopic portion of the Autoverse.

Nothing happened. The vacuum remained vacuum.

Durham swore softly. Maria turned to the window. The City was still standing; Elysium was not decaying like a discredited dream. But she felt herself break out in a sweat, felt her body drag her to the edge of panic. She had never really swallowed Durham’s claim that there was a danger in sharing their knowledge with the other Elysians—but now she wanted to flee the room herself, hide her face from the evidence, lest she add to the weight of disbelief.

Durham tried again, but the Autoverse was holding fast to its laws. Red atoms could not spontaneously appear from nowhere—it would have violated the cellular automaton rules. And if those rules had once been nothing but a few lines of a computer program—a program which could always be halted and rewritten, interrupted and countermanded, subjugated by higher laws—that was no longer true. Zemansky was right: there was no rigid hierarchy of reality and simulation anymore. The chain of cause and effect was a loop now—or a knot of unknown topology.

Durham said evenly, “All right. Plan B.” He turned to Maria. “Do you remember when we discussed closing off the Autoverse? Making it finite, but borderless… the surface of a four-dimensional doughnut?”

“Yes. But it was too small.” She was puzzled by the change of subject, but she welcomed the distraction; talking about the old days calmed her down, slightly. “Sunlight would have circumnavigated the universe and poured back into the system, in a matter of hours; Planet Lambert would have ended up far too hot, for far too long. It tried all kinds of tricks to change the thermal equilibrium—but nothing plausible really worked. So I left in the border. Sunlight and the solar wind disappear across it, right out of the model. And all that comes in is—”

She stopped abruptly. She knew what he was going to try next.

Durham finished for her. “All that comes in is cold thermal radiation, and a small flux of atoms, like a random inflow of interstellar gas. A reasonable boundary condition—better than having the system magically embedded in a perfect vacuum. But there’s no strict logic to it, no Autoverse-level model of exactly what’s supposed to be out there. There could be anything at all.”

He summoned up a view of the edge of the Autoverse; the atoms drifting in were so sparse that he had to send Maxwell’s Demon looking for one. The software which faked the presence of a plausible intestellar medium created atoms in a thin layer of cells, “next to” the border. This layer was not subject to the Autoverse rules—or the atoms could not have been created—but its contents affected the neighboring Autoverse cells in the usual way, allowing the tiny hurricanes which the atoms were to drift across the border.

Durham sent a simple command to the atom-creation sub-process—an instruction designed to merge with the flow of random requests it was already receiving: inject a red atom at a certain point, with a certain velocity.

It worked. The atom conjured up in the boundary layer, and then moved into the Autoverse proper, precisely on cue.

Durham sent a sequence of a thousand similar commands. A thousand more atoms followed, all moving with identical vectors. The “random inflow” was no longer random.

Elysium was affecting the Autoverse; they’d broken through.

Repetto cheered. Zemansky smiled enigmatically. Maria felt sicker than ever. She’d been hoping that the Autoverse would prove to be unbreachable—and then, by symmetry, Elysium might have been equally immune to interference. The two worlds, mutually contradictory or not, might have continued on their separate ways.

She said, “How does this help us? Even if you can make this program inject the puppets into deep space, how would you get them safely down to Planet Lambert? And how could you control their behavior once they were there? We still can’t reach in and manipulate them—that would violate the Autoverse rules.”

Durham had thought it all through. “One, we put them in a spaceship and drop that in. Two, we make them radio-controlled—and beam a signal at them from the edge of the model. If we can persuade the cold thermal radiation software to send in a maser beam.”

“You’re going to sit here and try to design a spaceship which can function in the Autoverse?”

“I don’t have to; it’s already been done. One of the old plans for contact involved masquerading as ‘aliens’ from another part of the Autoverse, to limit the culture shock for the Lambertians. We would have told them that there were billions of other stars, hidden from view by dust clouds shrouding their system. The whole idea was immoral, of course, and it was scrapped thousands of years ago—long before there were sentient Lambertians—but the technical work was completed and filed away. It’s all still there, in the Central Library; it should take us about an hour to assemble the components into a working expedition.”

It sounded bizarre, but Maria could see no flaw in the plan, in principle. She said, “So… we’re crossing space to meet the aliens, after all?”

“It looks that way.”