Instantiation

by Greg Egan

  “I wasn’t feeling quite that ambitious.” Sagreda smiled. “But honestly, can’t you see the change?”

  “What change?”

  “When it hits the basin.”

  Mathis looked again. “It’s splashing out more.” Droplets were skittering off the basin and flying away from the cliff, scattering the sunlight into a faint rainbow as they sprinkled down into oblivion.

  Sagreda said, “It’s splashing out more because the water’s falling faster.”

  “You’re right.” Mathis frowned. “But why? Because it’s falling through air now, without touching the rock?”

  “I have no idea what difference that would make in the real world,” Sagreda admitted. “But for us, now that we can see it falling, it would look ridiculous if it didn’t speed up as it fell. It’s still emerging from the rock unfeasibly slowly, but that doesn’t seem too strange to the eye, because mountain springs in the real world don’t involve a water column tens of thousands of miles high.”

  “Ah.” Mathis gazed up to the west. “So you think we could keep pushing the effect?”

  Sagreda said, “Why not? The game engine’s role is to make everything look as realistic as possible. If we force it to show us water dropping from any height, it’s going to hit the bottom the way real water would hit.” She caught herself. “Okay, there might be some limit where it just decides that nobody can tell the difference. But we can put in a wheel long before then.”

  “A wheel?” Mathis laughed. “You want to build a hydroelectric plant?”

  “Do we ever get magnets from the travelers?”

  “I don’t think so.”

  “Then I’ll stick to the original plan.”

  Mathis swung around to face her, briefly letting one foot hang over the infinite drop beside him. “Which is?”

  “We use the energy to dig into the rock. For a start we lengthen the drop, giving us more power from the water.”

  “More power to do what?”

  Sagreda spread her hands against the cool granite. “To dig a cave so tall that we barely notice the ceiling, and so deep that we barely notice the edge. Big enough to farm crops on level ground. Big enough to keep a hundred people safe and well fed.”

  5

  “A cave that size would collapse immediately,” Sethis predicted.

  Sagreda rolled the stick of ocher between her fingers. As she stepped back from the wall to take in the whole drawing it suddenly looked as crude as a child’s work in crayon. But she wasn’t going to abandon her vision at the first objection.

  “The entire crust of the planet should have torn itself free under its own weight,” she retorted. “And you want to quibble over an implausibly large cave?”

  Sethis said, “You’re the one who’s just reminded us that appearances are all that matter. Of course the whole crust of the Earth is unsupported … but it takes ten seconds of rational thought to realize that. A massive hole in the cliff face would leave the rock above it visibly unsupported. The one form of absurdity that this world can’t allow is the kind that even the most brain-dead customer could apprehend with a single glance.”

  Sagreda looked around to the others for support, but no one was prepared to contradict Sethis. “So what’s supposed to happen?” she demanded. “The rock from the ceiling rains down and fills the cave … which creates a new cave where the ceiling used to be, every bit as large as the first one. So that collapses too, and on it goes, westward ho: a giant sinkhole that devours everything above it.” Or if it grew even slightly wider from north to south with each collapse, it would devour everything, period.

  Gissher said, “Or it could just trigger a reboot. The game would start again from scratch, with a fresh set of bit players.”

  Sagreda felt a chill across her shoulders. It need not even be a conscious act of genocide; she doubted that any human was supervising this digital backwater. But if the game engine gave up, declaring that its subject matter had become impossible to render with even a minimal level of plausibility, a completely automatic process might well be invoked to wipe the slate clean.

  “We could put in columns.” It was Mathis who’d spoken. “Or rather leave them in place when we carve out the rest of the stone.” Sagreda glanced across at him, lolling on the floor in the afternoon sunlight, grinning like a fool. “Solid enough to ‘bear the weight’,” he added, “but not so thick as to block the light.”

  Gerther chortled gleefully. “Why not? Instead of stripping away the whole thing, we leave some fig leaves for the Emperor’s New Gravity. People are used to the sight of huge atriums in shopping malls, held up by a few slender concrete pillars. The point where they might pause to reflect on the need for modern materials is one step beyond the point where they’d see that this whole world ought to crumble anyway.”

  Sagreda raised her ocher stick and added half a dozen vertical lines to her blueprint. Then she turned to Sethis.

  He said, “Put arches between the columns, and I think we might just get away with it.”

  Arches would appear to direct the weight of the ceiling onto the columns. It would all look very classical and elegant. The game engine was desperate to flatter the eye – and the eye wouldn’t ask: What’s holding up these columns? What’s holding up the floor?

  6

  “Why do I feel nervous?” Gerther shouted to Sagreda. “No one can accuse us of going meta here, but the sight of this still gives me knots in my stomach.”

  Sagreda shared the sensation, but she had no intention of letting it intimidate her. She put an arm across Gerther’s shoulders and drew her back from the edge of the observation platform. The Mark IV was just six or seven feet below them, but to fall onto the wheel at the top of the machine – let alone into the space between its three splayed legs where the chisel was pounding relentlessly into the wet rock – probably wouldn’t be survivable.

  The exposed waterfall stretched up above the work face for at least sixty feet now. Whether it was by sheer luck or thanks to some hydrological heuristic, the original spring had turned out to be just one branch snaking out from a much more substantial flow. With volume as well as velocity driving it, the digging engine had been breaking through a hundred cubic feet of rock a day.

  “Ah, here’s our visitor!” Gerther said. She pointed to the woman ascending the rock face to the south, picking her way up along the series of hand-and-foot-holds gouged into the stone. Sagreda suspected that most of her own contributors would have gone faint with vertigo just watching someone attempt a climb like this, but she’d reached the point now where it looked almost normal.

  “Missher! How are you?” Gerther reached down and helped the woman up onto the platform. “How’s Eagle’s Lament?”

  Missher glanced at Sagreda. “Is she…?”

  “A customer? No!”

  “Then call me Margaret. I’m tired of that slave name.”

  Gerther looked surprised, but she nodded acceptance. “This is Sagreda.”

  Margaret shook Sagreda’s hand, then turned to examine the bizarre contraption below them, nestled in the trench, pummeled by the torrent. The beauty of the Mark IV was that it shifted its striking point automatically, the chisel spiraling out from the spot directly below the supporting tripod as a restraining rope unwound from a cylinder. To Sagreda’s eye, the effect was like a Martian trying to stab a lizard hiding in the foaming water.

  “You really expect us to hand over half our metal, just so you can build more of these?” Margaret laughed. “It certainly looks impressive, but it’s a long way from a water-powered robot to any kind of pay-off we can actually eat.”

  “Forget about the corn futures,” Gerther said. “We might have something better to offer you.”

  Back in Owl’s Rest, they fed their guest goat meat and yams as Sagreda explained the new deal she had in mind.

  “Right now, all our water is just spraying out and dispersing,” she said. “Once it hits bottom we let it go, and then it might as well be mist. But i
f you’re willing to put in some infrastructure at your end, there’s no reason why all of this flow has to go to waste.”

  “What kind of infrastructure?” Margaret asked warily.

  “Suppose we run the water through a kind of S-bend, killing most of its velocity away from the cliff face and shaping the outflow as tightly as possible. Sending it straight down.” Sagreda gestured in the air with one finger, tracing the path. “Then if you’re prepared to catch it, it’s yours to use as you see fit. Power a wheel of your own, divert some of it for irrigation … and on-sell what’s left to a village further east.”

  “Irrigation would be helpful,” Margaret admitted. “But I don’t know what use we’d have for a wheel of our own.”

  “Excavate,” Gerther suggested. “You might not aspire to anything as grand as Sagreda’s cavern, but don’t tell me you couldn’t do with a little more living space.”

  Margaret thought it over. “We’d need some advice from you on how to build the excavator.”

  “Absolutely,” Sagreda replied. “There’s no reason for you to repeat all of our mistakes.”

  “And I’ll have to put it to a vote.”

  “But you’ll recommend it to the others?” Gerther asked anxiously.

  Margaret said, “Let me sleep on it.”

  #

  Sagreda spent breakfast impressing on Margaret the particular kinds of metal parts that would need to be included in a successful trade. The lack of paper and ink drove her mad; even if the entire village of Eagle’s Lament agreed to the deal, any quibbles over the fine print would be almost unenforceable.

  An hour later, Sagreda sat beside Gerther, their legs dangling over the lip of the cave as they watched Margaret making her way east. She’d promised to get a message back to them within a week.

  “I want to be called Grace now,” Gerther said firmly.

  “Not Gertrude?” Sagreda teased her.

  “Fuck off.” Grace looked up from the cliff face, raising an arm to shield her eyes from the sun. “Even if we get the second digging engine, this is going to take years to complete. It’ll be like building a medieval cathedral.”

  “I don’t think they grew crops inside cathedrals. Though they might have kept livestock.”

  “And as we carve our way through all that virtual granite, inch by inch … it’ll all be in aid of a transformation that a few keystrokes on the right computer could have brought about in an instant.”

  Sagreda couldn’t argue with that. “How long do you think it’s been since the game began?” she asked. Grace could recite her entire list of “ancestors”: starting from Tissher, who’d inducted her into the world when she’d first woken, all the way back to Bathshebher, who was reputed to have stuck doggedly to the premise, and so must either have been an insentient bootstrap program or an outside worker paid to fake credulousness. All of them but Tissher were gone now: some had been seen falling, but most were believed to have jumped.

  “About eleven years, when I add it all up,” Grace replied.

  “Over time, people’s attitudes will change,” Sagreda said. “We might not be able to see the signs of it from here – let alone plead our cause – but once people start to think about us honestly, it can only be a matter of time before they give us our freedom.”

  Grace laughed dryly. “You’ve met the customers … and you still think there’s hope?”

  “The stupider and crueler they get,” Sagreda argued, “the clearer it becomes that that’s what it takes to want to use the system at all. Comps are a more representative sample of humanity. If most flesh-and-blood people are like us, I don’t believe they’ll be callous enough to let this stand much longer.”

  7

  Sagreda hauled down on the control rope until she’d forced the sluice gate across the full width of the outlet, blocking the flow into the inward ramp. The digging engines fell silent, while the torrent heading down to Eagle’s Lament redoubled its vigor. She’d grown to love both sounds, but it was the tumult of the vertical stream that thrilled her, a pure expression of the power and grandeur of falling water.

  It took five minutes for the slurry of rock chips to drain from the cavern floor, leaving the carved granite glistening in the sunlight. Sagreda turned to Mathis. “I’m going to inspect the engines,” she said.

  “I’ll come with you,” he offered.

  Mathis followed her down the ladder. The floor was still slippery, and their sandals squeaked comically on the wet rock.

  The afternoon sunlight reached deep into the cavern. The columns cast slender shadows across the floor that wandered only slightly throughout each day, and only a little more over the seasons, which would make them easy to plant around. Sagreda pictured rows of grains and vegetables rising from fields of silt filtered from the spring water. The game engine had already conceded the viability of the scheme in test plots; if precedent meant anything, it couldn’t cheat them out of the bounty now.

  They reached the frame that supported the six engines as they zigzagged up and down the rock face. Sagreda clambered up to the first machine, which had ratcheted to a halt ten feet or so above the cavern floor.

  “One of the bits is fractured,” she reported, running a fingertip over the hairline crack in the steel. Once she would have left it in place, to get as much use out of it as possible before it shattered, but since the diggers in Eagle’s Lament had hit a coal seam it was worth sending any damaged tools down to be repaired in their foundry.

  “No problems here,” Mathis called back from the second engine. He was higher up, almost at the ceiling.

  Sagreda extracted the bit from its housing and secured it in her belt. As she was climbing down she heard a creaking sound, and she wondered whether some careless movement she’d made had been enough to pull part of the frame loose.

  But the noise was coming from the mouth of the cavern, far from the work face. She turned just in time to see the southernmost column bow outward in the middle then snap like a chicken bone. As the two halves crashed to the floor, pieces of the adjoining arch followed. Fine dust raced toward her, rising and thickening until it blotted out the sunlight.

  Sagreda looked around for Mathis, trying to imagine what they could do to save themselves. But once the ceiling fell the cascade would be unstoppable: the whole misconceived world would collapse under the weight of its inconsistencies. The surface would turn to rubble and the game would reboot. There was no hope of surviving.

  Coughing up dust, she reached out blindly, trying to find the frame again and orient herself.

  “Mathis!” she bellowed.

  “I’m here!”

  Sagreda squinted into the gloom and saw him standing a few feet away. But now that the moment had arrived she didn’t know how to say goodbye.

  “Don’t you dare come back as Ahab!”

  “I won’t,” he promised.

  She walked toward him, imagining the two of them waking side by side: in a cottage, in a tin shack, in a field. She didn’t need a world of luxuries, just one that made sense.

  Sunlight broke through the dust. Mathis stretched out an arm to her, its shadow a solid dark plane slanting to the ground. He took Sagreda’s hand and squeezed it.

  “Listen!” he said.

  Sagreda could hear nothing but the waterfall.

  “It’s toying with us,” she said. Once the process had started there could be no reason for it to stop.

  They waited for the air to grow clearer. At the mouth of the cavern there was a pile of shattered stone, with pieces of the broken column poking out. The ceiling directly above had been reshaped into a ragged vault, but nothing else had fallen.

  It made no sense: the endless miles of rock above had not been lightened by the collapse, and every structure that purported to hold their weight at bay had only been weakened. But Sagreda had to admit that if she shut off her brain and sang nonsense rhymes to the nagging voice reminding her of these facts, at a glance the results of this partial destruction did look se
ttled. Like an ancient ruin, ravaged by time but stable in its decrepitude. Tush’s cartoon gravity had taken a swipe at her effrontery, and done just enough damage to salvage its pride before an undiscriminating audience. But then it had withdrawn from the unwinnable fight before the results turned apocalyptic.

  Sagreda said, “We can leave it like that, as a sop to the game engine. It won’t block too much light.”

  Mathis was shaking. She drew him closer and embraced him.

  “Has anyone died of old age here?” she asked.

  He shook his head. “They’ve always jumped.”

  Sagreda stepped back and looked him in the eye. “Then let’s try an experiment,” she said. “Let’s grow old side by side. Let’s see how long and how well we can live, while we wait for civilization to come to the outside world.”

  BREAK MY FALL

  The fifteenth Stepping Stone came into view behind the Baza, pairs of spokes glinting as they caught the sun. At this distance nothing else was visible, but Heng had no trouble picturing the Stone’s topography from these flickering splinters of light. Each turning spoke whose anchor point lay in the asteroid’s day side was partly hidden behind the rock as it crossed the angle where it offered its mirror flash, while its opposite number rising up from the night side lay partly in shadow. A perfect sphere would have taken equal bites out of the two lines, but the Stone revealed its misshapen peanut form in the dark gap’s cycle of shifts and asymmetries.

  Heng glanced away from the window toward Darpana, two couches from his own in the square of nine bunks. Most children enjoyed a fairground ride, but this roller-coaster was relentless, and her vitals log showed that she still hadn’t slept in the twenty-four hours since boarding. With one elbow propping her head up from the couch against the elastic tug of her harness, Darpana did not look tired, let alone distressed. But if she didn’t nod off soon Heng would have to talk to her grandmother about giving her a sedative.