Permutation City (42 page)

Maria glanced at Dominic Repetto, but apparently he was resigned to the need to keep his family in the dark. She said, "It makes me feel like a coward. Fleeing to the opposite side of the universe, while we poke the hornet's nest by remote control."

Repetto said drily, "Don't worry; for all we know, the TVC geometry might be irrelevant. The logical connection between us and the Autoverse might put us at more risk than the closet physical neighbors."

Maria still chose to do everything manually, via her "solid" terminal; no interface windows floating in midair, no telepathic links to her exoself. Zemansky showed her how to run the obscure utility program which would transport her right out of her own territory. The less wealthy Copies back on Earth had darted from continent to continent in search of the cheapest QIPS -- but in Elysium there would never have been a reason for anyone to shift this way, before. As she okayed the last query on the terminal, she pictured her model being halted, taken apart and piped through the hub into Durham's pyramid -- no doubt with a billion careful verification steps along the way . . . but it was impossible to know what even the most stringent error-checking procedures were worth, now that the deepest rules upon which they relied had been called into question.

As a final touch, Durham cloned the apartment, and they moved -- imperceptibly -- to the duplicated version. Maria glanced out the window. "Did you copy the whole City as well?"

"No. That's the original you're looking at; I've patched in a genuine view."

Zemansky created a series of interface windows on the livingroom wall; one showed the region running the Autoverse, with the triangular face which bordered Maria's own pyramid seen head-on. On top of the software map -- the midnight-blue of the Autoverse cellular automation program, finely veined with silver spy software -- she overlayed a schematic of the Lambertian planetary system, the orbits weirdly chopped up and rearranged to fit into the five adjacent pyramids. The space being modeled was -- on its own terms -- a relatively thin disk, only a few hundred thousand kilometers thick, but stretching about fifty per cent beyond the orbit of the outermost planet. Most of it was empty -- or filled with nothing but light streaming out from the sun -- but there were no short-cuts taken; every cubic kilometer, however featureless, was being modeled right down to the level of Autoverse cells. The profligacy of it was breathtaking; Maria could barely look at the map without trying to think of techniques to approximate the computations going on in all the near-vacuum. When she forced herself to stop and accept the thing as it was, she realized that she'd never fully grasped the scale of Elysium before. She'd toured the Lambertian biosphere from the planetary level right down to the molecular -- but that was nothing compared to a solar-system's-worth of subatomic calculations.

Durham touched her elbow. "I'm going to need your authorization." She went with him to the terminal he'd created for himself in a corner of the room, and typed out the code number which had been embedded in her scan file back on Earth; the ninety-nine digits flowed from her fingers effortlessly, as if she'd rehearsed the sequence a thousand times. The code which would have granted her access to her deceased estate, on Earth, here unlocked the processors of her pyramid.

She said, "I really am your accomplice, now. Who goes to prison when you commit a crime using my ID?"

"We don't have prisons."

"So what exactly will the other Elysians do to us, when they find out what we've done?"

"Express appropriate gratitude."

Zemansky zoomed in on the map to show the individual TVC processors along the border, and then enlarged the view still further to reveal their elaborate structure. It looked like a false-color schematic of an array of three-dimensional microcircuits -- but it was too rectilinear, too perfect, to be a micrograph of any real object. The map was largely conjecture, now: a simulation guided by limited data flowing in from the grid itself. There were good reasons why it "should have been" correct, but there could be no watertight evidence that anything they were seeing was actually there.

Zemansky manipulated the view until they were peering straight down the middle of the thin layer of transparent "null" cells which separated the Autoverse region from Maria's territory -- bringing her own processors into sight for the first time. An arrow in a small key diagram above showed the orientation; they were looking straight toward the distant hub. All the processors were structurally identical, but those in the Autoverse were alive with the coded streams of activated states marking data flows, while her own were almost idle. Then Durham plugged her territory into the software he was running, and a wave of data swept out from the hub -- looking like something from the stargate sequence in
2001
-- as the processors were reprogrammed. The real wave would have passed in a Standard Time picosecond; the map was smart enough to show the event in slow motion.

The reprogrammed processors flickered with data -- and then began to sprout construction wires. Every processor in the TVC grid was a von Neumann machine as well as a Turing machine -- a universal constructor as well as a universal computer. The only construction task they'd performed in the past had been a one-off act of self-replication, but they still retained the potential to build anything at all, given the appropriate blueprint.

The construction wires reached across the gap and touched the surface of the Autoverse processors. Maria held her breath, almost expecting to see a defensive reaction, a counterattack. Durham had analyzed the possibilities in advance: if the TVC rules continued to hold true, any "war" between these machines would soon reach a perpetual stalemate; they could face each other forever, annihilating each other's "weapons" as fast as they grew, and no strategy could ever break the deadlock.

If the TVC rules failed, though, there was no way of predicting the outcome.

There was no -- detectable -- counterattack. The construction wires withdrew, leaving behind data links bridging the gap between the pyramids. Since the map was showing the links as intact, the software must have received some evidence that they were actually working: the Autoverse processors were at least reacting as they should to simple tests of the integrity of the connections.

Durham said, "Well, that's something. They haven't managed to shut us out completely."

Repetto grimaced. "You make it sound like the Lambertians have taken control of the processors -- that they're deciding what's going on here. They don't even know that this level exists."

Durham kept his eyes on the screen. "Of course they don't. But it still feels like we're sneaking up on some kind of . . . sentient adversary. The Lambertians' guardian angels: aware of all the levels -- but jealously defending their own people's version of reality." He caught Maria's worried glance, and smiled. "Only joking."

Maria looked on as Durham and Zemansky ran a series of tests to verify that they really had plugged in to the Autoverse region. Everything checked out -- but then, all the same tests had worked when run through the authorized link, down at the hub. The suspect processors were merely acting as messengers, passing data around in a giant loop which confirmed that they could still talk to each other -- that the basic structure of the grid hadn't 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.