Permutation City

by Greg Egan

  It was no insect by the terrestrial definition; there were four legs, not six, and the body was clearly divided into five segments: the head; sections bearing the forelegs, wings, and hind legs; and the tail. Durham made hand movements and rotated the view. The head was blunt, not quite flat, with two large eyes – if they were eyes: shiny bluish disks, with no apparent structure. The rest of the head was coated in fine hairs, lined up in a complex, symmetrical pattern which reminded Maria of Maori facial tattoos. Sensors for vibration – or scent?

  She said, “Very pretty, but you forgot the mouth.”

  “They put food into a cavity directly under the wings.” He rotated the body to show her. “It adheres to those bristles, and gets dissolved by the enzymes they secrete. You’d think it would fall out, but it doesn’t – not until they’ve finished digesting it and absorbing nutrients, and then a protein on the bristles changes shape, switching off the adhesion. Their whole stomach is nothing but this sticky droplet hanging there, open to the air.”

  “You might have come up with something more plausible.”

  Durham laughed. “Exactly.”

  The single pair of wings were translucent brown, looking like they were made of a thin layer of the same stuff as the exoskeleton. The four legs each had a single joint, and terminated in feathery structures. The tail segment had brown-and-black markings like a bull’s-eye, but there was nothing at the center; a dark tube emerged from the bottom of the rim, narrowing to a needle-sharp point.

  “The Lambertians have diploid chromosomes, but only one gender. Any two of them can inject DNA, one after the other, into certain kinds of plant cell; their genes take over the cell and turn it into a cross between a cyst and an egg. They usually choose a particular spot on the stems of certain species of shrub. I don’t know if you’d call it parasitism – or just nest-building on a molecular level. The plant nourishes the embryo, and survives the whole process in perfect health – and when the young hatch, they return the favor by scattering seeds. Their ancestors stole some of the control mechanisms from a plant virus, a billion years ago. There are a lot of genetic exchanges like that; the ‘kingdoms’ are a lot more biochemically similar here than they were on Earth.”

  Maria turned away from the screen. The stupidest thing was, she kept wanting to ask questions, press him for details. She said, “What’s next? You zoom right in and show me the fine anatomical structure, the insect’s cells, the proteins, the atoms, the Autoverse cells – and that’s supposed to convince me that the whole planet is embedded in the Autoverse? You unfreeze this thing, let it fly around – and I’m meant to conclude that no real-world computer could ever run an organism so complex, modeled at such a deep level? As if I could personally verify that every flap of its wings corresponded to a valid sequence of a few trillion cellular automaton states. It’s no different than the equation results. It wouldn’t prove a thing.”

  Durham nodded slowly. “All right. What if I showed you some of the other species? Or the evolutionary history? The paleogenetic record? We have every mutation on file since the year zero. You want to sit down with that and see if it looks authentic?”

  “No. I want a terminal that works. I want you to let me call my original. I want to talk to her – and between us, maybe we can decide what I’m going to do when I get out of this fucking madhouse and into my own JSN account.”

  Durham looked rattled – and for a moment she believed she might finally be getting through to him. But he said, “I woke you for a reason. We’re going to be making contact with the Lambertians, soon. It might have been sooner – but there’ve been complications, political delays.”

  He’d lost her completely now. “‘Contact with the Lambertians’? What’s that supposed to mean?”

  He gestured at the motionless insect, backside and genitals still facing them. “This is not some species I picked at random. This is the pinnacle of Autoverse life. They’re conscious, self-aware, highly intelligent. They have almost no technology – but their nervous system is about ten times more complex than a human’s – and they can go far beyond that for some tasks, performing a kind of parallel computing in swarms. They have chemistry, physics, astronomy. They know there are thirty-two atoms – although they haven’t figured out the underlying cellular automaton rules yet. And they’re modeling the primordial cloud. These are sentient creatures, and they want to know where they came from.”

  Maria turned her hand in front of the screen, bringing the Lambertian’s head back into view. She was beginning to suspect that Durham actually believed every word he was saying – in which case, maybe he hadn’t, personally, contrived these aliens. Maybe some other version of him – the flesh-and-blood original? – was deceiving both of them. If that was the case, she was arguing with the wrong person – but what was she supposed to do instead? Start shouting pleas for freedom to the sky?

  She said numbly, “Ten times more complex than a human brain?”

  “Their neurons use conducting polymers to carry the signal, instead of membrane action potentials. The cells themselves are comparable in size to a human’s – but each axon and dendrite carries multiple signals.” Durham moved the viewpoint behind the Lambertian’s eye, and showed her. A neuron in the optic nerve, under close examination, contained thousands of molecules like elaborately knotted ropes, running the whole length of the cell body. At the far end, each polymer was joined to a kind of vesicle, the narrow molecular cable dwarfed by the tiny pouch of cell membrane pinched off from the outside world. “There are almost three thousand distinct neurotransmitters; they’re all proteins, built from three sub-units, with fourteen possibilities for each sub-unit. A bit like human antibodies – the same trick for generating a wide spectrum of shapes. And they bind to their receptors just as selectively as an antibody to an antigen; every synapse is a three-thousand-channel biochemical switchboard, with no cross-talk. That’s the molecular basis of Lambertian thought.” He added wryly, “Which is more than you and I possess: a molecular basis for anything. We still run the old patchwork models of the human body – expanded and modified according to taste, but still based on the same principles as John Vines’ first talking Copy. There’s a long-term project to give people the choice of being implemented on an atomic level … but quite apart from the political complications, even the enthusiasts keep finding more pressing things to do.”

  Durham moved the viewpoint out through the cell wall and turned it back to face the terminal end of the neuron. He changed the color scheme from atomic to molecular, to highlight the individual neurotransmitters with their own distinctive hues. Then he unfroze the image.

  Several of the gray lipid-membrane vesicles twitched open, disgorging floods of brightly colored specks; tumbling past the viewpoint, they resolved into elaborate, irregular globules with a bewildering variety of forms. Durham swung the angle of view forward again, and headed for the far side of the synapse. Eventually, Maria could make out color-coded receptors embedded in the receiving neuron’s cell wall: long-chain molecules folded together into tight zig-zagged rings, with lumpy depressions on the exposed surface.

  For several minutes, they watched thousands of mismatched neurotransmitters bounce off one receptor, until Durham became bored and pleaded with the software, “Show us a fit.” The image blurred for a second, and then returned to the original speed as a correctly-shaped molecule finally stumbled onto its target. It hit the receptor and locked into place; Durham plunged the viewpoint through the cell membrane in time to show the immersed tail section of the receptor changing its configuration in response. He said, “That will now catalyze the activation of a second messenger, which will feed energy into the appropriate polymer – unless there’s an inhibiting messenger already bound there, blocking access.” He spoke to the software again; it took control of the viewpoint, and showed them each of the events he’d described.

  Maria shook her head, bedazzled. “Tell me the truth – who orchestrated this? Three thousand neurotransmitters,
three thousand receptors, three thousand second messengers? No doubt you can show me the individual structures of all of them – and no doubt they really would behave the way you claim they do. Even writing the software to fake this would have been an enormous job. Who did you commission? There can’t be many people who’d take it on.”

  Durham said gently, “I commissioned you. You can’t have forgotten. A seed for a biosphere? A demonstration that life in the Autoverse could be as diverse and elaborate as life on Earth?”

  “No. From A. hydrophila to this would take—”

  “Billions of years of Autoverse time? Computing power orders of magnitude beyond the resources of twenty-first century Earth? That’s what Planet Lambert needed – and that’s exactly what it’s been given.”

  Maria backed away from the screen until she could go no further, then slid down against the wall beside the red-draped window and sat on the plushly carpeted floor. She put her face in her hands, and tried to breath slowly. She felt like she’d been buried alive.

  Did she believe him? It hardly seemed to matter anymore. Whatever she did, he was going to keep on bombarding her with “evidence” like this, consistent with his claims. Whether he was deliberately lying or not – and whether he was being fooled by another version of himself, or whether the “dust hypothesis” was right after all – he was never going to let her out of here, back into the real world. Psychotic liar, fellow victim, or calm purveyor of the truth, he was incapable of setting her free.

  Her original was still out there – with the money to save Francesca. That was the point of the whole insane gamble, the pay-off for risking her soul. If she could remember that, cling to that, maybe she could keep herself sane.

  Durham pressed on – oblivious to her distress, or intent on delivering the coup de grace. He said, “Who could have engineered this? You know how long it took Max Lambert to translate a real-world bacterium. Do you honestly believe that I found someone who could manufacture a functioning – novel – pseudo-insect out of thin air … let alone an intelligent one?

  “All right: you can’t personally check macroscopic behavior against the Autoverse rules. But you can study all the biochemical pathways, trace them back to the ancestral species. You can watch an embryo grow, cell by cell – following the gradients of control hormones, the differentiating tissue layers, the formation of the organs.

  “The whole planet is an open book to us; you can examine whatever you like, scrutinize it on any scale, from viruses to ecosystems, from the activation of a molecule of retinal pigment, to the geochemical cycles.

  “There are six hundred and ninety million species currently living on Planet Lambert. All obeying the laws of the Autoverse. All demonstrably descended from a single organism which lived three billion years ago – and whose characteristics I expect you know by heart. Do you honestly believe that anyone could have designed all that?”

  Maria looked up at him angrily. “No. Of course it evolved; it must have evolved. You can shut up now – you’ve won; I believe you. But why did you have to wake me? I’m going to lose my mind.”

  Durham squatted down and put a hand on her shoulder. She started sobbing dryly as she attempted to dissect her loss into parts she could begin to comprehend. Francesca was gone. Aden was gone. All her friends. All the people she’d ever met: in the flesh, on the networks. All the people she’d ever heard of: musicians and writers, philosophers and movie stars, politicians and serial killers. They weren’t even dead; their lives didn’t lie in her past, whole and comprehensible. They were scattered around her like dust: meaningless, disconnected.

  Everything she’d ever known had been ground down into random noise.

  Durham hesitated, then put his arms around her clumsily. She wanted to hurt him, but instead she clung to him and wept, teeth clenched, fists tight, shuddering with rage and grief.

  He said, “You’re not going to lose your mind. You can live any life you want to, here. Seven thousand years means nothing; we haven’t lost the old culture – we still have all the libraries, the archives, the databases. And there are thousands of people who’ll want to meet you; people who respect you for what you’ve done. You’re a myth; you’re a hero of Elysium; you’re the sleeping eighteenth founder. We’ll hold a festival in honor of your awakening.”

  Maria pushed him away. “I don’t want that. I don’t want any of that.”

  “All right. It’s up to you.”

  She closed her eyes and huddled against the wall. She knew she must have looked like a petulant child, but she didn’t care. She said fiercely, “You’ve had the last word. The last laugh. You’ve brought me to life just to rub my nose in the proof of your precious beliefs. And now I want to go back to sleep. Forever. I want all of this to vanish.”

  Durham was silent for a while. Then he said, “You can do that, if you really want to. Once I’ve shown you what you’ve inherited, once I’ve shown you how to control it, you’ll have the power to seal yourself off from the rest of Elysium. If you choose sleep, then nobody will ever be able to wake you.

  “But don’t you want to be there, on Planet Lambert, when we make first contact with the civilization that owes its existence to you?”

  Chapter 24

  (Rut City)

  Peer was in his workshop, making a table leg on his lathe, when Kate’s latest message caught his eye: You have to see this. Please! Meet me in the City.

  He looked away.

  He was working with his favorite timber, sugar pine. He’d constructed his own plantation from a gene library and plant cell maps – modeling individual examples of each cell type down to an atomic level, then encapsulating their essential behavior in rules which he could afford to run billions of times over, for tens of thousands of trees. In theory, he could have built the whole plantation from individual atoms – and that would have been the most elegant way to do it, by far – but slowing himself down to a time frame in which the trees grew fast enough to meet his needs would have meant leaving Kate far behind.

  He stopped the lathe and re-read the message, which was written on a poster tacked to the workshop’s noticeboard (the only part of his environment he allowed her to access, while he was working). The poster looked quite ordinary, except for an eye-catching tendency for the letters to jump up and down when they crossed his peripheral vision.

  He muttered, “I’m happy here. I don’t care what they’re doing in the City.” The workshop abutted a warehouse full of table legs – one hundred and sixty-two thousand, three hundred and twenty-nine, so far. Peer could imagine nothing more satisfying than reaching the two hundred thousand mark – although he knew it was likely that he’d change his mind and abandon the workshop before that happened; new vocations were imposed by his exoself at random intervals, but statistically, the next one was overdue. Immediately before taking up woodwork, he’d passionately devoured all the higher mathematics texts in the central library, ran all the tutorial software, and then personally contributed several important new results to group theory – untroubled by the fact that none of the Elysian mathematicians would ever be aware of his work. Before that, he’d written over three hundred comic operas, with librettos in Italian, French and English – and staged most of them, with puppet performers and audience. Before that, he’d patiently studied the structure and biochemistry of the human brain for sixty-seven years; toward the end he had fully grasped, to his own satisfaction, the nature of the process of consciousness. Every one of these pursuits had been utterly engrossing, and satisfying, at the time. He’d even been interested in the Elysians, once.

  No longer. He preferred to think about table legs.

  He was still interested in Kate, though. He’d chosen that as one of his few invariants. And he’d been neglecting her lately; they hadn’t met in almost a decade.

  He looked around the workshop wistfully, his gaze falling on the pile of fresh timber in the corner, but then he strengthened his resolve. The pleasures of the lathe beckoned – but lo
ve meant making sacrifices.

  Peer took off his dustcoat, stretched out his arms, and fell backward into the sky above the City.

  Kate met him while he was still airborne, swooping down from nowhere and grabbing his hand, nearly wrenching his arm from its socket. She yelled above the wind, “So, you’re still alive after all. I was beginning to think you’d shut yourself down. Gone looking for the next life without me.” Her tone was sarcastic, but there was an edge of genuine relief. Ten years could still be a long time, if you let it.

  Peer said gently, but audibly, “You know how busy I am. And when I’m working—”

  She laughed derisively. “Working? Is that what you call it? Taking pleasure from something that would bore the stupidest factory robot to death?” Her hair was long and jet black, whipping up around her face as if caught by the wind at random – but always concealing just enough to mask her expression.

  “You’re still —” The wind drowned out his words; Kate had disabled his aphysical intelligibility. He shouted, “You’re still a sculptor, aren’t you? You ought to understand. The wood, the grain, the texture—”

  “I understand that you need prosthetic interests to help pass the time – but you could try setting the parameters more carefully.”

  “Why should I?” Being forced to raise his voice made him feel argumentative; he willed his exoself to circumvent the effect, and screamed calmly: “Every few decades, at random, I take on new goals, at random. It’s perfect. How could I improve on a scheme like that? I’m not stuck on any one thing forever; however much you think I’m wasting my time, it’s only for fifty or a hundred years. What difference does that make, in the long run?”