Грег Иган. Permutation City. 3

And so Peer had made the conscious decision to let that be enough.

<dd> <dd>12 <dd> <dd>(Rip, tie, cut toy man) <dd> <dd>JUNE 2045

Paul switched on the terminal and made contact with his old organic self. The djinn looked tired and frayed; all the begging and bribery required to set up the latest stage of the experiment must have taken its toll. Paul felt more alive than he"d ever felt, in any incarnation; his stomach was knotted with something like fear, but the electric tingling of his skin felt more like the anticipation of triumph. His body was about to be mutilated, carved up beyond recognition-and yet he knew he would survive, suffer no harm, feel no pain.

Squeak. "Experiment three, trial zero. Baseline data. All computations performed by processor cluster number four six two, Hitachi Supercomputer Facility, Tokyo."

"One. Two. Three." It was nice to be told where he was, at last; Paul had never visited Japan before. "Four. Five. Six." And on his own terms, he still hadn"t. The view out the window was Sydney, not Tokyo; why defer to the external geography, when it made no difference at all? "Seven. Eight. Nine. Ten."

Squeak. "Trial number one. Model partitioned into five hundred sections, run on five hundred processor clusters, distributed globally."

Paul counted. Five hundred clusters. Five only for the crudely modeled external world; all the rest were allocated to his body-and most to the brain. He lifted his hand to his eyes-and the information flow that granted him motor control and sight traversed tens of thousands of kilometers of optical cable. There was no (perceptible) delay; each part of him simply hibernated when necessary, waiting for the requisite feedback from around the world.

It was, of course, pure lunacy, computationally and economically; Paul guessed that he was costing at least a hundred times as much as usual-not quite five hundred, since each cluster"s capacity was only being partly used-and his slow-down factor had probably risen from seventeen to as much as fifty. Once, it had been hoped that devoting hundreds of computers to each Copy might improve the slowdown problem, not worsen it-but the bottlenecks in shifting data between processor clusters kept even the richest Copies from reducing the factor below seventeen. It didn"t matter how many supercomputers you owned, because splitting yourself between them wasted more time on communications than was saved by the additional computing power.

Squeak. "Trial number two. One thousand sections, one thousand clusters."

Brain the size of a planet-and here I am, counting to ten. Paul recalled the perennial-naive and paranoid-fear that all the networked computers of the world might one day spontaneously give birth to a global hypermind; but he was, almost certainly, the first planet-sized intelligence on Earth. He didn"t feel much like a digital Gaia, though. He felt exactly like an ordinary human being sitting in a room a few meters wide.

Squeak. "Trial number three. Model partitioned into fifty sections and twenty time sets, implemented on one thousand clusters."

"One. Two. Three." Paul struggled to imagine the outside world on his own terms, but it was almost impossible. Not only was he scattered across the globe, but widely separated machines were simultaneously computing different moments of his subjective time frame. Was the distance from Tokyo to New York now the length of his corpus callosum? Had the world shrunk to the size of his skull-and vanished from time altogether, except for the fifty computers which contributed at any one time to what he called "the present"?

Maybe not-although in the eyes of some hypothetical space traveler the whole planet was virtually frozen in time, and flat as a pancake. Relativity declared that this point of view was perfectly valid-but Paul"s was not. Relativity permitted continuous deformation, but no cutting and pasting. Why not? Because it had to allow for cause and effect. Influences had to be localized, traveling from point to point at a finite velocity; chop up space-time and rearrange it, and the causal structure would fall apart.

What if you were an observer, though, who had no causal structure? A self-aware pattern appearing by chance in the random twitches of a noise machine, your time coordinate dancing back and forth through causally respectable "real time"? Why should you be declared a second-class being, with no right to see the universe your way? Ultimately, what difference was there between so-called cause and effect, and any other internally consistent pattern?

Squeak. "Trial number four. Model partitioned into fifty sections and twenty time sets; sections and states randomly allocated to one thousand clusters."

"One. Two. Three."

Paul stopped counting, stretched his arms wide, stood up slowly. He wheeled around once, to examine the room, checking that it was still intact, still complete. Then he whispered, "This is dust. All dust. This room, this moment, is scattered across the planet, scattered across five hundred seconds or more-but it still holds itself together. Don"t you see what that means?"

The djinn reappeared, but Paul didn"t give him a chance to speak. The words flowed out of him, unstoppable. He understood.

"Imagine... a universe entirely without structure, without shape, without connections. A cloud of microscopic events, like fragments of space-time... except that there is no space or time. What characterizes one point in space, for one instant? Just the values of the fundamental particle fields, just a handful of numbers. Now, take away all notions of position, arrangement, order, and what"s left? A cloud of random numbers.

"That"s it. That"s all there is. The cosmos has no shape at all-no such thing as time or distance, no physical laws, no cause and effect.

"But... if the pattern that is me could pick itself out from all the other events taking place on this planet... why shouldn"t the pattern we think of as "the universe" assemble itself, find itself, in exactly the same way? If I can piece together my own coherent space and time from data scattered so widely that it might as well be part of some giant cloud of random numbers... then what makes you think that you"re not doing the very same thing?"

The djinn"s expression hovered between alarm and irritation.

Squeak. "Paul... what"s the point of all this? "Space-time is a construct; the universe is really nothing but a sea of disconnected events..." Assertions like that are meaningless. You can believe it if you want to... but what difference would it make?"

"What difference? We perceive-we inhabit-one arrangement of the set of events. But why should that arrangement be unique? There"s no reason to believe that the pattern we"ve found is the only coherent way of ordering the dust. There must be billions of other universes coexisting with us, made of the very same stuff-just differently arranged. If I can perceive events thousands of kilometers and hundreds of seconds apart to be side by side and simultaneous, there could be worlds, and creatures, built up from what we"d think of as points in space-time scattered all over the galaxy, all over the universe. We"re one possible solution to a giant cosmic anagram... but it would be ludicrous to believe that we"re the only one."

Squeak. Durham snorted. "A cosmic anagram? So where are all the leftover letters? If any of this were true-and the primordial alphabet soup really is random-don"t you think it"s highly unlikely that we could structure the whole thing?"

Paul thought about it. "We haven"t structured the whole thing. The universe is random, at the quantum level. Macroscopically, the pattern seems to be perfect; microscopically, it decays into uncertainty. We"ve swept the residue of randomness down to the lowest level."

Squeak, The djinn strived visibly for patience. "Paul... none of this could ever be tested. How would anyone ever observe a planet whose constituent parts were scattered across the universe, let alone communicate with its hypothetical inhabitants? What you"re saying might have a certain-purely mathematical-validity: grind the universe into fine enough dust, and maybe it could be rearranged in other ways that make as much sense as the original. If those rearranged worlds are inaccessible, though, it"s all angels on the heads of pins."

"How can you say that? I"ve been rearranged! I"ve visited another world!"

Squeak. "If you did, it was an artificial world; created, not discovered."

"Found, created... there"s no real difference."

Squeak. "What are you claiming? Some influence from this other world flowed into the computers, changed the way the model ran?"

"Of course not! Your pattern hasn"t been violated; the computers did exactly what was expected of them. That doesn"t invalidate my perspective. Stop thinking of explanations, causes and effects; there are only patterns. The scattered events that formed my experience had an internal consistency every bit as real as the consistency in the actions of the computers. And perhaps the computers didn"t provide all of it."

Squeak. "What do you mean?"

"The gaps, in experiment one. What filled them in? What was I made of, when the processors weren"t describing me? Well... it"s a big universe. Plenty of dust to be me, in between descriptions. Plenty of events-nothing to do with your computers, maybe nothing to do with your planet or your epoch-out of which to construct ten seconds of experience."

Squeak, The djinn looked seriously worried now. "You"re a Copy in a virtual environment under computer control. Nothing more, nothing less. These experiments prove that your internal sense of space and time is invariant. That"s exactly what we always expected-remember? Come down to Earth. Your states are computed, your memories have to be what they would have been without manipulation. You haven"t visited any other worlds, you haven"t built yourself out of fragments of distant galaxies."

Paul laughed. "Your stupidity is... surreal. What did you create me for, if you"re not even going to listen to what I have to say? I"ve had a glimpse of the truth behind... everything: space, time, the laws of physics. You can"t shrug that off by saying that what happened to me was inevitable."

Squeak. "Control and subject are still identical."

"Of course they are! That"s the whole point! Like... gravity and acceleration in General Relativity-it all depends on what you can"t tell apart. This is a new Principle of Equivalence, a new symmetry between observers. Relativity threw out absolute space and time-but it didn"t go far enough. We have to throw out absolute cause and effect!"

Squeak. The djinn muttered, dismayed, "Elizabeth said this would happen. She said it was only a matter of time before you"d lose touch."

Paul stared at him, jolted back to the mundane. "Elizabeth? You said you hadn"t even told her."

Squeak. "Well, I have now. I didn"t tell you, because I didn"t think you"d want to hear her reaction."

"Which was?"

Squeak. "I was up all night arguing with her. She wanted me to shut you down. She said I was... seriously disturbed, to even think about doing this."

Paul was stung. "What would she know? Ignore her."

Squeak. Durham frowned apologetically-an expression Paul recognized at once, and his guts turned to ice. "Maybe I should pause you, while I think things over. Elizabeth raised some... valid ethical questions. I think I should talk it through with her again."

"Fuck that! I"m not here for you to put on ice every time you have a change of heart. And if Elizabeth wants to have a say in my life, she can damn well talk it through with me."

Paul could see exactly what would happen. If he was paused, Durham wouldn"t restart him-he"d go back to the original scan file and start again from scratch, handling his prisoner differently, hoping to end up with a more cooperative subject. Maybe he wouldn"t even perform the first set of experiments at all.

The ones which had given him this insight.

The ones which had made him who he was.

Squeak. "I need time to think. It would only be temporary. I promise."

"No! You have no right!"

Durham hesitated. Paul felt numb, disbelieving. Some part of him refused to acknowledge any danger-refused to accept that it could be this easy to die. Being paused wouldn"t kill him, wouldn"t harm him, wouldn"t have the slightest effect. What would kill him would be not being restarted. He"d be passively annihilated, ignored out of existence. The fate that befell his own shit.

Durham reached offscreen.

<dd> <dd>13 <dd> <dd>(Remit not paucity) <dd> <dd>FEBRUARY 2051

Maria said, "Recalculate everything up to epoch five, then show me sunrise on Lambert. Latitude zero, longitude zero, altitude one."

She waited, staring into the blank workspace, fighting the temptation to change her instructions and have the software display every stage of the simulation, which would have slowed things down considerably. After several minutes, a fissured dark plain appeared, raked with silver light. The unnamed sun-dazzling and swollen, and, so low in the sky, too white by far-turned a chain of extinct volcanoes on the horizon into black silhouettes like a row of pointed teeth. In the foreground, the surface looked glassy, inhospitable.

Maria raised her viewpoint to a thousand meters, then sent it skimming east. The terrain repeated itself, the eerily symmetric cones of dead volcanoes the only relief from the fractured igneous plains. This specific, detailed scenery was nothing more than a series of computerized "artist"s impressions," manufactured on demand from purely statistical data about the planet"s topography; the simulation itself hadn"t dealt with anything so finicky as individual volcanoes. Touring the planet was a wasteful means of finding out anything-but it was hard to resist playing explorer, treating this world as if its secrets had to be deduced painstakingly from its appearance... even when the truth was the exact opposite. Reluctantly, Maria froze the image and went straight to the underlying numerical data. The atmosphere was much too thin, again. And this time, there was almost no aqua at all.

She backtracked through the simulation"s history to see when the aqua had been lost, but this version of Lambert had never possessed significant oceans-or ice caps, or atmospheric vapor. She"d made a slight change in the composition of the primordial gas-and-dust cloud, increasing the proportion of blue and yellow atoms, in the hope that this would ultimately lead to a denser atmosphere for Lambert. Instead, she"d caused more than half of the debris in the Kuiper belt to condense into a whole new stable outer planet. As a consequence, far fewer ice-rich comets from the belt had ended up striking Lambert, robbing it of its largest source of aqua by far-and much of its atmosphere. Gas released by volcanic eruptions provided a poor substitute; the pressure was far too low, and the chemistry was all wrong.

Maria was beginning to wish she"d kept her mouth shut. It had taken her almost an hour on the phone to persuade Durham that it was worth trying to give Lambert a proper astronomical context, and a geological history that stretched back to the birth of its sun.

"If we present this world as a fait accompli, and say: "Look, it can exist in the Autoverse"... the obvious response to that will be: "Yes, it can exist-if you put it there by hand-but that doesn"t mean it"s ever likely to have formed." If we can demonstrate a range of starting conditions that lead to planetary systems with suitable worlds, that will be one less element of uncertainty to be used against us."

Durham had eventually agreed, so she"d taken an off-the-shelf planetary-system modeling program-irreverently titled The Laplacian Casino-and adapted it to Autoverse chemistry and physics; not the deep physics of the Autoverse cellular automaton, but the macroscopic consequences of those rules. Mostly, that came down to specifying the properties of various Autoverse molecules: bond energies, melting and boiling points versus pressure, and so on. Aqua was not just water by another name, yellow atoms were not identical to nitrogen-and although some chemical reactions could be translated as if there was a one-to-one correspondence, in the giant fractionating still of a protostellar nebula subtle differences in relative densities and volatilities could have profound effects on the final composition of each of the planets.

There were also some fundamental differences. Since the Autoverse had no nuclear forces, the sun would be heated solely by gravitational energy-the velocity its molecules acquired as the diffuse primordial gas cloud fell in on itself. In the real universe, stars unable to ignite fusion reactions ended up as cold, short-lived brown dwarfs-but under Autoverse physics, gravitational heating could power a large enough star for billions of years. (Units of space and time were not strictly translatable-but everybody but the purists did it. If a red atom"s width was taken to be that of hydrogen, and one grid-spacing per clock-tick was taken as the speed of light, a more or less sensible correspondence emerged.) Similarly, although Planet Lambert would lack internal heating from radioisotope decay, its own gravitational heat of formation would be great enough to drive tectonic activity for almost as long as the sun shone.

Without nuclear fusion to synthesize the elements, their origin remained a mystery, and a convenient gas cloud with traces of all thirty-two-and the right mass and rotational velocity-had to be taken for granted. Maria would have liked to have explored the cloud"s possible origins, but she knew the project would never be finished if she kept lobbying Durham to expand the terms of reference. The point was to explore the potential diversity of Autoverse life, not to invent an entire cosmology.

Gravity in the Autoverse came as close as real-world gravity to the classical, Newtonian inverse-square law for the range of conditions that mattered, so all the usual real-world orbital dynamics applied. At extreme densities, the cellular automaton"s discrete nature would cause it to deviate wildly from Newton-and Einstein, and Chu-but Maria had no intention of peppering her universe with black holes, or other exotica.

In fact, gravity had been seen as an irrelevant side effect of Lambert"s original choice of automaton rules-since running an Autoverse large enough for it to make the slightest difference was blatantly impossible-and several people had tried to remove the redundancy, while leaving everything else intact. Nobody had succeeded, though; their "rationalized" versions had always failed to generate anything remotely like the rich chemistry of the original. A Peruvian mathematician, Ricardo Salazar, had eventually proved that they shouldn"t have bothered: the Autoverse rules were poised on the border between two radically different levels of algorithmic complexity, and any tinkering in the hope of improved efficiency was necessarily self-defeating. The presence or absence of gravity, in itself, had no bearing on Autoverse chemistry-but the roots of both phenomena in the simple automaton rules seemed to be inextricably entwined.

Maria was aiming for a star with four planets. Three small worlds, one giant. The seed-world, Lambert, second from the sun-with a decent-sized moon if possible. Whether or not tidal pools had been a driving force in real-world evolution, life"s bridge from sea to land (and even though the sun itself would cause small tides, regardless), it couldn"t hurt to make Lambert as generally Earth-like as possible, since Earth was still the only example to turn to for inspiration. With so much about terrestrial evolution still in dispute, the safest policy was to cover every factor which might have been significant. The gravitational effects of the other planets would ensure a reasonably complex set of Milankovitch cycles: minor orbital changes and axis wobbles, providing long-term climate variations, ice ages and interglacials. A belt of comets and other debris would complete the picture; not merely supplying an atmosphere, early on, but also offering the chance of occasional mass-extinctions for billions of years to come.

The trick was to ensure that all of these supposedly evolution-enhancing features coincided with a version of Lambert which could support the seed organism in the first place. Maria had half a dozen possible modifications to A. lamberti in mind, to render it self-sufficient, but she was waiting to see what kind of environments were available before making a final decision.

That still left unanswered the question of whether the seed organism-or life of any kind-could have arisen on Lambert, rather than being placed there by human hands. Max Lambert"s original reason for designing the Autoverse had been the hope of observing self-replicating molecular systems-primitive life-arising from simple chemical mixtures. The Autoverse was meant to provide a compromise between real-world chemistry-difficult and expensive to manipulate and monitor in test-tube experiments, and hideously slow to compute in faithful simulations-and the tantalizing abstractions of the earliest "artificial life": computer viruses, genetic algorithms, self-replicating machines embedded in simple cellular automaton worlds; all trivially easy to compute, but unable to throw much light on the genesis of real-world molecular biology.

Lambert had spent a decade trying to find conditions which would lead to the spontaneous appearance of Autoverse life, without success. He"d constructed A. lamberti-a twelve-year project-to reassure himself that his goal wasn"t absurd; to demonstrate that a living organism could at least function in the Autoverse, however it had come to be there. A. lamberti had permanently side-tracked him; he"d never returned to his original research.

Maria had daydreamed about embarking on her own attempt at abiogenesis, but she"d never done anything about it. That kind of work was open-ended; in comparison, any problems with mutation in A. lamberti seemed utterly tractable and well-defined. And although, in a sense, it went to the heart of what Durham was trying to prove, she was glad he"d chosen to compromise; if he"d insisted on starting his "thought experiment" with a totally sterile world, the uncertainties in the transition from inanimate matter to the simplest Autoverse life would have overwhelmed every other aspect of the project.

She scrapped the desert Planet Lambert and returned to the primordial gas cloud. She popped up a gadget full of slider controls and adjusted the cloud"s composition, taking back half the increases she"d made in the proportions of blue and yellow. Planetology by trial and error. The starting conditions for real-world systems with Earth-like planets had been mapped out long ago, but nobody had ever done the equivalent for the Autoverse. Nobody had ever had a reason.

Maria felt a flicker of unease. Each time she stopped to remind herself that these worlds would never exist-not even in the sense that a culture of A. lamberti "existed"-the whole project seemed to shift perspective, to retreat into the distance like a mirage. The work itself was exhilarating, she couldn"t have asked for anything more, but each time she forced herself to put it all into context-not in the Autoverse, but in the real world-she found herself light-headed, disoriented. Durham"s reasons for the project were so much flimsier than the watertight internal logic of the thing itself; stepping back from the work was like stepping off a rock-solid planet and seeing it turn into nothing but a lightly tethered balloon.

She stood and walked over to the window, and parted the curtains. The street below was deserted; the concrete glowed in the hyperreal glare of the midday sun.

Durham was paying her good money-money that would kelp get Francesco scanned. That was reason enough to press on. And if the project was ultimately useless, at least it did no harm; it was better than working on some hedonistic VR resort or some interactive war game for psychotic children. She let the curtain fall back into place and returned to her desk.

The cloud floated in the middle of the workspace, roughly spherical, rendered visible in spite of the fact that its universe was empty of stars. That was a shame; it meant the future citizens of Lambert were destined to be alone. They"d have no prospect of ever encountering alien life-unless they built their own computers, and modeled other planetary systems, other biospheres.

Maria said, "Recalculate. Then show me sunrise again."

She waited.

And this time--false colors, by definition-the disk of the sun was bright cherry red, beneath a thick bank of clouds streaked orange and violet, spread across the sky-and the whole scene was repeated, stretched out before her, shimmering, inverted. Mirrored in the face of the waters. + + +

By a quarter to eight, Maria was thinking about logging off and grabbing some food. She was still on a high, but she could feel how close she was coming to the point where she"d be useless for the next thirty-six hours if she pushed herself any further.

She"d found a range of starting conditions for the cloud which consistently gave rise to hospitable versions of Lambert, along with all the astronomical criteria she"d been aiming for-except for the large satellite, which would have been a nice touch but wasn"t critical. Tomorrow, she could begin the task of providing A. lamberti with the means of surviving alone on this world, manufacturing its own nutrose from thin air, with the help of sunlight. Other workers had already designed a variety of energy-trapping pigment molecules; the "literal translation" of chlorophyll lacked the right photochemical properties, but a number of useful analogues had been found, and it was a matter of determining which could be integrated into the bacteria"s biochemistry with the fewest complications. Bringing photosynthesis to the Autoverse would be the hardest part of the project, but Maria felt confident; she"d studied Lambert"s notes, and she"d familiarized herself with the full range of techniques he"d developed for adapting biochemical processes to the quirks of Autoverse chemistry. And even if the pigment she chose, for the sake of expediency, wasn"t the most efficient molecule for the task, as long as the seed organism could survive and reproduce it would have the potential to stumble on a better solution itself, eventually.

The potential, if not the opportunity.

She was about to shut down The Laplacian Casino when a message appeared in the foreground of the workspace:

Juno: Statistical analysis of response times and error rates suggests that your link to the JSN is being monitored. Would you like to switch to a more heavily encrypted protocol?

Maria shook her head, amused. It had to be a bug in the software, not a bug on the line. Juno was a public-domain program (free, but all donations welcome) which she"d downloaded purely as a gesture of solidarity with the US privacy lobby. Federal laws there still made bug-detection software, and any half-decent encryption algorithms, illegal for personal use-lest the FBI be inconvenienced-so Maria had sent Juno"s authors a donation to help them fight the good fight. Actually installing the program had been a joke; the idea of anyone going to the trouble of listening in to her conversations with her mother, her tedious VR contract work, or her self-indulgent excursions into the Autoverse, was ludicrous.

Still, the joke had to be carried through. She popped up a word processor on the JSN-the terminal"s local one wouldn"t have shown up to an eavesdropper tapping the fiber-and typed:

Whoever you are, be warned: I"m about to display the Longford Mind-Erasing Fractal Basilisk, so

The doorbell rang. Maria checked the peephole camera"s view. There was a woman on the front step, nobody she knew. Early forties, conservatively dressed. The not-so-subtle give-away was clearly visible behind her: one compact two-seater Mitsubishi "Avalon" electric car. The New South Wales Police Department were probably the only people in the world who"d bought that model, before the Bankstown factory closed down in forty-six. Maria had often wondered why they didn"t give in and fit blue flashing lights to all their supposedly unmarked cars; acknowledging the situation would have been more dignified than carrying on as if nobody knew.

Dredging her memory for recent misdemeanors-but finding none-she hurried downstairs.

"Maria Deluca?"

"Yes."

"I"m Detective-Sergeant Hayden. Computer Fraud Squad. I"d like to ask you a few questions, if that"s convenient."

Maria rescanned for guilty secrets; still no trace-but she would have preferred a visitor from Homicide or Armed Robbery, someone who"d clearly come to the wrong house. She said, "Yes, of course. Come in." Then, as she backed away from the door, "Ah-I nearly forgot, I suppose I should verify... ?"

Hayden, with a thin smile of blatantly insincere approval, let Maria plug her notepad into the socket of her Police Department badge. The notepad beeped cheerfully; the badge knew the private code which matched the current public key being broadcast by the Department.

Seated in the living room, Hayden got straight to the point. She displayed a picture on her notepad.

"Do you know this man?"

Maria cleared her throat. "Yes. His name"s Paul Durham. I"m... working for him. He"s given me some contract programming." She felt no surprise; just the jolt of being brought down to earth. Of course the Fraud Squad were interested in Durham. Of course the whole fantasy of the last three months was about to unravel before her eyes. Aden had warned her. She"d known it herself. It was a dream contract, too good to be true.

An instant later, though, she backed away from that reaction, furious with herself. Durham had paid the money into the trust fund, hadn"t he? He"d met the costs of her new JSN account. He hadn"t cheated her. Too good to be true was idiot fatalism. Two consenting adults had kept all their promises to each other; the fact that no outsider would understand the transaction didn"t make it a crime. And after all he"d done for her, at the very least she owed him the benefit of the doubt.

Hayden said, "What kind of "contract programming"?"

Maria did her best to explain without taking all night. Hayden was-not surprisingly-reasonably computer literate, and even knew what a cellular automaton was, but either she hadn"t heard of the Autoverse, or she wanted to hear it all again from Maria.

"So you believe this man"s paying you thirty thousand dollars... to help him state his position on a purely theoretical question about artificial life?"

Maria tried not to sound defensive. "I"ve spent tens of thousands of dollars on the Autoverse, myself. It"s like a lot of other hobbies; it"s a world unto itself. People can get obsessive, extravagant. It"s no stranger than... building model airplanes. Or reenacting battles from the American Civil War."

Hayden didn"t argue the point, but she seemed unmoved by the comparisons. "Did you know that Paul Durham sold insurance to Copies?"

"I knew he was an insurance salesman. He told me that himself. Just because he"s not a professional programmer doesn"t mean he can"t-"

"Did you know he was also trying to sell his clients shares in some kind of sanctuary? A place to go-or to send a clone-in case the political climate turned against them?"

Maria blinked. "No. What do you mean-a sanctuary? A privately owned supercomputer? He"s been trying to raise money, form a consortium... ?"

Hayden said flatly, "He"s certainly raising money-but I doubt he"ll ever raise enough to purchase the kind of hardware he"d need for the kind of service he"s offering."

"So, what are you accusing him of doing? Embarking on a business venture which you don"t happen to believe will be successful?" Hayden said nothing. "Have you spoken to him about this? There might be a simple explanation for whatever you"ve been told. Some senile Copy might have taken his sales pitch for a perpetuity fund the wrong way." Senile Copy? Well... some postdementia scan file might have proved resistant to the cognitive repair algorithms.

Hayden said, "Of course we"ve spoken to him. He"s refused to cooperate, he won"t discuss the matter. That"s why we"re hoping you"ll be able to assist us."

Maria"s defiant optimism wavered. If Durham had nothing to hide, why would he refuse to defend himself?

She said, "I don"t see how I can help you. If you think he"s been misleading his clients, go talk to his clients. It"s their testimony you need, not mine."

There was an awkward pause, then Hayden said, "The testimony of a Copy has no standing; legally, they"re just another kind of computer software."

Maria opened her mouth, then realized that any excuse she offered would only make her sound more foolish. She salvaged some pride with the silent observation that the legal position of Copies was so farcical that any sane person could have trouble keeping it in mind.

Hayden continued. "Durham could be charged with defrauding the executors of the estates, by means of supplying misleading data to the software they use to advise them. There are precedents for that; it"s like publishing false prospectus information that causes automated share-buying programs to buy your stock. But there"s still the question of evidence. We can interview Copies as an informal source of information, to guide an investigation, but nothing they say will stand up in court."

Maria recalled an episode of The Unclear Family where a similar problem had arisen. Babette and Larry Unclear had witnessed bank accounts being pilfered, when the relevant data trail had-inexplicably-taken solid form as an accusing tableau of ice-sculptures in their cyber-suburban backyard. She couldn"t recall exactly how the plot had turned out; ten-year-old Leroy had probably done something marginally illegal, but morally unimpeachable, to trick the thieves into giving themselves away to the authorities...

She said, "I don"t know what you expect me to tell you. Durham hasn"t defrauded me. And I don"t know anything about this scheme."

"But you"re working on it with him."

"I certainly am not!"

Hayden said drily, "You"re designing a planet for him. What do you think that"s for?"

Maria stared at her blankly for a second, then almost laughed. "I"m sorry, I can"t have explained things very well. I"m designing a planet that "could" exist in the Autoverse, in the broadest sense of the word. It"s a mathematical possibility. But it"s too large to be run on a real computer. It"s not some VR-"

Hayden cut her off. "I understand that perfectly. That doesn"t mean Durham"s clients would have grasped the distinction. Technical details about the Autoverse aren"t exactly general knowledge."

True. Maria hesitated. But-

"It still makes no sense. For a start, these people would have advisers, researchers, who"d tell them that anyone promising them an Autoverse planet was full of shit. And why would Durham offer them an Autoverse planet-covered in primordial slime-when he could offer them a standard set of VR environments which would be a thousand times more attractive and a thousand times more plausible?"

"I believe he"s offering them both. He"s hired an architect in the US to work on the VR part."

"But why both? Why not just VR? You couldn"t fit a single Copy into the Autoverse-and if you did, it would die on the spot. It would take fifty or sixty years of research to translate human biochemistry into Autoverse terms."

"They wouldn"t know that."

"They could find out in ten seconds flat. Forget about advisers; it would take one call to a knowledge miner, total cost five dollars. So why tell a lie that could be so easily uncovered? What"s the advantage-from a Copy"s point of view-of an Autoverse planet over patchwork VR?"

Hayden was unfazed. "You"re the Autoverse expert. So you tell me."

"I don"t know." Maria stood up. She was beginning to feel claustrophobic; she hated having strangers in the house. "Can I get you something to drink? Tea? Coffee?"

"No. But you go ahead-"

Maria shook her head and sat down again; she had a feeling that if she went into the kitchen, she wouldn"t want to return.

She couldn"t see why Durham would refuse to talk to the police, unless he was involved in something dubious enough to have him thrown out of his job, at the very least. Fuck him. He might not have intended to cheat her, but he"d screwed her nonetheless. She wouldn"t get a cent for the work she"d completed; other creditors would have no call on the trust fund if Durham merely went bankrupt-but if the money was the pro-ceeds of crime...

Lorenzo the Magnificent. Yeah.

The worst of it was, for all she knew, Hayden believed she was a willing accomplice. And if Durham intended to remain silent, she"d have to clear her own name.

How?

First, she had to find out about the scam, and untangle her role in it.

She said, "What exactly is he promising these Copies?"

"A refuge. A place where they"ll be safe from any kind of backlash-because they won"t be connected to the outside world. No telecommunications; nothing to trace. He feeds them a long spiel about the coming dark age, when the unwashed masses will no longer put up with being lorded over by rich immortals-and evil socialist governments will confiscate all the supercomputers for weather control."

Hayden seemed to find the prospect laughable. Maria suspended judgement; what mattered was how Durham"s clients felt, and she could imagine Operation Butterfly making a lot of Copies feel threatened. "So they send their clones in, and slam the door, in case the originals don"t make it through the purges. But then what? How long is this "dark age" supposed to last?"

Hayden shrugged. "Who knows? Hundreds of years? Presumably Durham himself-or some trustworthy successor, several generations later-will decide when it"s safe to come out. The two Copies whose executors filed complaints didn"t wait to hear the whole scenario; they threw him out before he could get down to details like that."

"He must have approached other Copies."

"Of course. No one else has come forward, but we have a tentative list of names. All with estates incorporated overseas, unfortunately; I haven"t been able to interview any of them, yet-we"re still working on the jurisdictional red tape. But a few have made it clear already, through their lawyers, that they won"t be willing to discuss the matter-which presumably means that they"ve swallowed Durham"s line, and now they don"t want to hear a word against him."

Maria struggled to imagine it: No communications. Cut off from reality, indefinitely. A few "Solipsist Nation" Copies might relish the prospect-but most of them had too little money to be the targets of an elaborate scam. And even if Durham"s richest, most paranoid clients seriously believed that the world was on the verge of turning against them... what if things went so badly wrong, outside, that links were never restored? The humans guarding the sanctuary could die out-or just walk away. How could any but the most radically separatist of Copies face the risk of being stranded inside a hidden computer, buried in the middle of a desert somewhere, with no means of discovering for themselves when civilization was worth rejoining-and no means of initiating contact in any case?

Radioisotope power sources could run for thousands of years; multiply redundant hardware of the highest standard could last almost as long, in theory. All these Copies would have, to remember reality by, would be the information they"d brought in with them at the start. If it turned into a one-way trip, they"d be like interstellar colonists, carrying a snapshot of Earth culture off into the void.

Except that interstellar colonists would merely face a growing radio time lag, not absolute silence. And whatever they were leaving behind, at least they"d have something to look forward to: a new world to explore.

A new world-and the possibility of new life.

So what better cure could there be for claustrophobia than the promise of dragging an entire planet into the refuge, seeded with the potential for developing its own exotic life?

Maria didn"t know whether to be outraged or impressed. If she was right, she had to admire Durham"s sheer audacity. When he had asked for a package of results which would persuade "the skeptics" about the prospects for an Autoverse biosphere, he hadn"t been thinking of academics in the artificial life scene. He"d wanted to convince his clients that, even in total isolation, they"d have everything reality could ever offer the human race-including a kind of "space exploration," complete with the chance of alien contact. And these would be genuine aliens; not the stylish designer creatures from VR games, constructs of nothing but the human psyche; not the slick, unconvincing biomorphs of the high-level phenotype-selection models, the Darwinian equivalent of Platonic ideals. Life which had come the whole tortuous way, molecule by molecule, just like the real thing. Or, almost the whole way; with a biogenesis still poorly understood, Durham had had enough sense to start with "hand-made" microbes-otherwise his clients might never have believed that the planet would bear life at all.

Maria explained the idea, tentatively. "He"d have to have convinced these Copies that running the Autoverse is much faster than modeling real biochemistry-which it is-without being too specific about the actual figures. And I still think it"s a crazy risk to take; anyone could easily find out the truth."

Hayden thought it over. "Would it matter if they did? If the point of this world is mainly psychological-a place to "escape to" if the worst happens, and reality becomes permanently inaccessible-then it wouldn"t matter how slowly it ran. Once they"d given up hope of reestablishing contact, slowdown would become irrelevant."

"Yes, but there"s slow-and there"s physically impossible. Sure, they could take in a crude sketch of the planet-which is what Durham"s asked me to provide-but they wouldn"t have a fraction of the memory needed to bring it to life. And even if they found a way around that, it could take a billion years of Autoverse time before the seed organism turned into anything more exciting than blue-green algae. Multiply that by a slow-down of a trillion... I think you get the picture."

"Flat batteries?"

"Flat universe."

Hayden said, "Still... if they don"t want to think too seriously about the prospect of ending up permanently trapped, they might not want to look too closely at any of this. Thanks to you, Durham will have a thick pile of impressive technical details that he can wave in their faces, convincing enough to take the edge off their fear of cabin fever. Maybe that"s all they want. The only part that matters, if everything goes smoothly, is the conventional VR-good enough to keep them amused for a couple of real-time centuries-and that checks out perfectly."

Maria thought this sounded too glib by far, but she let it pass. "What about the hardware? How does that check out?"

"It doesn"t. There"ll never be any hardware. Durham will vanish long before he has to produce it."

"Vanish with what? Money handed over with no questions asked-no safeguards, no guarantees?"

Hayden smiled knowingly. "Money handed over, mostly, for legitimate purposes. He"s commissioned a VR city. He"s commissioned an Autoverse planet. He"s entitled to take a percentage of the fees-there"s no crime in that, so long as it"s disclosed. For the first few months, everything he does will be scrupulously honest. Then at some point, he"ll ask his backers to pay for a consultants" report-say, a study of suitably robust hardware configurations. Tenders will be called for. Some of them will be genuine-but the most attractive ones will be forged. Later, Durham will claim to have received the report, the "consultants" will be paid... and he"ll never be seen again."

Maria said, "You"re guessing. You have no idea what his plans are."

"We don"t know the specifics-but it will be something along those lines."

Maria slumped back in her chair. "So, what now? What do I do? Call Durham and tell him the whole thing"s off?"

"Absolutely not! Keep working as if nothing had happened-but try to make contact with him more often. Find excuses to talk to him. See if you can gain his trust. See if you can get him to talk about his work. His clients. The refuge."

Maria was indignant. "I don"t remember volunteering to be your informant."

Hayden said coolly, "It"s up to you, but if you"re not willing to cooperate, that makes our job very difficult..."

"There"s a difference between cooperation and playing unpaid spy!"

Hayden almost smiled. "If you"re worried about money, you"ll have a far better chance of being paid if you help us to convict Durham."

"Why? What am I meant to do-try suing him after he"s already gone bankrupt repaying the people he"s cheated?"

"You won"t have to sue him. The court is almost certain to award you compensation as one of the victims-especially if you"ve helped bring the case to trial. There"s a fund, revenue from fines. It doesn"t matter whether Durham can pay you himself."

Maria digested that. The truth was, it still stank. What she wanted to do was cut her losses and walk away from the whole mess. Pretend it had never happened.

And then what? Go crawling back to Aden for money? There were still no jobs around; she couldn"t afford to write off three months" work. A few thousand dollars wouldn"t get Francesca scanned-but the lack of it could force her to sell the house sooner than she wanted to.

She said, "What if I make him suspicious? If I suddenly start asking all these questions..."

"Just keep it natural. Anyone in your position would be curious; it"s a strange job he"s given you-he must expect questions. And I know you went along with what he told you at the start, but that doesn"t mean you can"t have given it more thought and decided that there are a few things that still puzzle you."

Maria said, "All right, I"ll do it." Had she ever had a choice? "But don"t expect him to tell me the truth. He"s already lied to me; he"s not going to change his story now."

"Maybe not. But you might be surprised. He might be desperate to have someone to take into his confidence-someone to boast to. Or he might just drop a few oblique hints. Anything"s possible, as long as you keep talking to him."

When Hayden had left, Maria sat in the living room, too agitated to do anything but run through the whole exchange again in her head. An hour before, she"d been exhausted, but triumphant; now she just felt weary and stupid. Keep working as if nothing had happened! The thought of tackling photo-synthesis in A. lamberti-for the sake, now, of ingratiating herself with the Fraud Squad-was so bizarre it made her giddy.

It was a pity Durham hadn"t been honest with her, and invited her in on the scam. If she"d known all along that she was meant to be helping to screw rich Copies out of their petty cash, at least the work would have had the real-world foundation she"d always felt was missing.

She finally went upstairs, without having eaten. Her connection to the JSN had been logged off automatically, but the message from Juno, locally generated, still hovered in the workspace. As she gestured to the terminal to switch itself off, she wondered if she should have asked Hayden: Is it you who"s been tapping my phone line?

<dd> <dd>14 <dd> <dd>(Remit not paucity) <dd> <dd>FEBRUARY 2051

Seated in his library, Thomas viewed the final report in his knowledge miner"s selection from the last real-time week of news. A journalist in a fur-lined coat appeared to address the camera, standing in light snow in front of the US Supreme Court building-although she was more likely to have been seated in a warm studio, watching a software puppet mime to her words.

"Today"s five-to-one majority decision means that the controversial Californian statute will remain in force. Authorities taking possession of computer storage media to check for simulations of the brain, body or personality of a suspected felon, dead or alive, are not violating the Fourth Amendment rights of either the next of kin or the owners of the computer hardware. Chief Justice Andrea Steiner stressed that the ruling does not affect the status of Copies themselves, one way or another. The software, she said, can be confiscated and examined-but it will not stand trial."

The terminal blinked back to a menu. Thomas stretched his arms above his head, acutely conscious for a moment of the disparity between his frail appearance and the easy strength he felt in his limbs. He had become his young self again, after all. Become him in the flesh-whether or not he chose to face him in the mirror. But the thought led nowhere.

Thomas had been following the saga of the Californian legislation from the start. He hoped Sanderson and her colleagues knew what they were doing; if their efforts backfired, it could have unpleasant ramifications for Copies everywhere. Thomas"s own public opinion model had shrugged its stochastic shoulders and declared that the effects of the law could go either way, depending on the steps taken to follow through-and several other factors, most of which would be difficult to anticipate, or manipulate.

Clearly, the aim was to shock apathetic US voters into supporting human rights for Copies-lest the alternative be de facto kidnap, mind pillage, and possibly even execution, all without trial. The computer-literate would understand just how useless the law would be in practice-but they"d already been largely won over. The Unclear Family rated highest with the demographics least likely to grasp the technical realities-a storehouse of good will that had yet to be fully exploited. Thomas could see the possibilities. Resurrected blue-collar worker Larry Unclear could turn out to have been under suspicion of murder at the time of his death. Flashback: Misunderstanding in bar leads to heated, highly visible, argument between Larry and guest-star X. Comic escalation to full-scale brawl. Taking advantage of the confusion, guest-star Y smashes a bottle over the skull of guest-star X-while Larry, with his usual endearing ineffectuality, has ended up comatose under a table. The new law could see him dragged from his home and family in the dead of night for a Kafkaesque virtual interrogation, in which his guilty dreams of being responsible are taken to be memories of actually committing the crime... while guest-star Y, still a living human, receives a civilized trial, lies through his teeth, and is acquitted. Son Leroy could save the day somehow, at the last minute, as usual.

Thomas closed his eyes and buried his face in his hands. Most of the room ceased being computed; he pictured himself adrift in Durham"s sea of random numbers, carrying the chair and a fragment of floor with him, the only objects granted solidity by his touch.

He said, "I"m not in any danger." The room flickered half-way back into existence, subtly modified the sound of his words, then dissolved into static again. Who did he believe would accuse him? There was no one left to care about Anna"s death. He"d outlived them all.

But as long as the knowledge of what he"d done continued to exist, inside him, he could never be certain that it wouldn"t be revealed.

For months after the crime, he"d dreamed that Anna had come to his apartment. He"d wake, sweating and shouting, staring into the darkness of his room, waiting for her to show herself. Waiting for her to tear the skin of normality from the world around him, to reveal the proof of his damnation: blood, fire, insanity.

Then he"d started rising from his bed when the nightmare woke him, walking naked into the shadows, daring her to be there. Willing it. He"d enter every room in the apartment, most of them so dark that he had to feel his way with an outstretched hand, waiting for her fingers suddenly to mesh with his.

Night after night, she failed to appear. And gradually, her absence became a horror in itself; vertiginous, icy. The shadows were empty, the darkness was indifferent. Nothing lay beneath the surface of the world. He could have slaughtered a hundred thousand people, and the night would still have failed to conjure up a single apparition to confront him.

He wondered if this understanding would drive him mad.

It didn"t.

After that, his dreams had changed; there were no more walking corpses. Instead, he dreamed of marching into Hamburg police station and making a full confession.

Thomas stroked the scar on the inside of his right forearm, where he"d scraped himself on the brickwork outside the window of Anna"s room, making his clumsy escape. No one, not even Ilse, had ever asked him to account for it; he"d invented a plausible explanation, but the lie had remained untold.

He knew he could have his memories of the crime erased. Edited out of his original scan file, his current brain model, his emergency snapshots. No other evidence remained. It was ludicrous to imagine that anyone would ever have the slightest reason-let alone the legal right, let alone the power-to seize and examine the data which comprised him... but if it eased his paranoid fears, why not? Why not neutralize his unease at the technical possibility of his mind being read like a book-or a ROM chip-by turning the metaphor, or near-literal truth, to his own advantage? Why not rewrite the last incriminating version of his past? Other Copies exploited what they"d become with inane sybaritic excesses. Why not indulge himself in some peace of mind?

Why not? Because it would rob him of his identity. For sixty-five years, the tug on his thoughts of that one night in Hamburg had been as constant as gravity; everything he"d done since had been shaped by its influence. To tear out the entire tangled strand of his psyche-render half of his remaining memories incomprehensible-would be to leave himself a baffled stranger in his own life.

Of course, any sense of loss, or disorientation, could be dealt with, too, subtracted out... but where would the process of amputation end? Who would remain to enjoy the untroubled conscience he"d manufactured? Who"d sleep the sleep of the just in his bed?

Memory editing wasn"t the only option. Algorithms existed which could transport him smoothly and swiftly into a state of enlightened acceptance: rehabilitated, healed, at peace with himself and his entire uncensored past. He wouldn"t need to forget anything; his absurd fear of incrimination by mind-reading would surely vanish, along with his other neuroses-of-guilt.

But he wasn"t prepared to swallow that fate, either-however blessed he might have felt once the transformation was complete. He wasn"t sure that there was any meaningful distinction between redemption and the delusion of redemption... but some part of his personality-though he cursed it as masochistic and sentimental-baulked at the prospect of instant grace.

Anna"s killer was dead! He"d burnt the man"s corpse! What more could he do, to put the crime behind him?

On his "deathbed," as his illness had progressed-as he"d flirted giddily every morning with the prospect of ordering his final scan-he"d felt certain that witnessing the fate of his body would be dramatic enough to purge him of his stale, mechanical, relentless guilt. Anna was dead; nothing could change that. A lifetime of remorse hadn"t brought her back. Thomas had never believed that he"d "earned" the right to be free of her-but he"d come to realize that he had nothing left to offer the little tin metronome in his skull but an extravagant ritual of atonement: the death of the murderer himself.

But the murderer had never really died. The corpse consigned to the furnace had been nothing but shed skin. Two days before being scanned, Thomas had lost his nerve and countermanded his earlier instructions: that his flesh-and-blood self be allowed to regain consciousness after the scan.

So the dying human had never woken, never known that he was facing death. And there had been no separate, mortal Thomas Riemann to carry the burden of guilt into the flames. + + +

Thomas had met Anna in Hamburg in the summer of 1983, in a railway station cafe. He was in town to run errands for his father. She was on her way to West Berlin, for a concert. Nick Cave and the Bad Seeds.

The cafe was crowded, they shared a table. Anna"s appearance wasn"t striking-dark-haired, green-eyed, her face round and flat. Thomas would never have looked twice at her if they"d passed in the street-but she soon made an impression.

She looked him over appraisingly, then said, "I"d kill for a shirt like that. You have expensive tastes. What do you do to support them?"

Thomas lied carefully. "I was a student. Engineering. Up until a few months ago. It was hopeless, though; I was failing everything."

"So what do you do now?"

He looked doleful. "My father owns a merchant bank. I went into engineering to try to get away from the family business, but-"

She wasn"t sympathetic at all. "But you screwed up, and now he"s stuck with you?"

"And vice versa."

"Is he very rich?"

"Yes."

"And you hate him?"

"Of course."

She smiled sweetly. "Why don"t I kidnap him for you? You give me all the inside information, and we"ll split the ransom money, fifty-fifty."

"You kidnap bankers for a living, do you?"

"Not exclusively."

"I think you work in a record store."

"You"re wrong."

"Or a second-hand clothes shop."

"You"re getting colder."

"Who are you meeting in Berlin?"

"Just some friends."

When her train was announced, he asked her for her number. She wrote it on the sleeve of his shirt.

For the next few months whenever he was traveling north, be phoned her. Three times, she made excuses. He almost gave up, but he kept recalling the mocking expression on her face, and he knew he wanted to see her again.

Early in November, she finally said, "Drop round, if you like. I"m not doing anything."

He"d planned to take her to a nightclub, but she had a child with her, a baby just a few months old. "He"s not mine. I"m looking after him for a friend." They watched TV, then had sex on the sofa. Climbing off him, Anna said, "You"re really quite sweet." She kissed him on the cheek, then vanished into the bedroom, locking him out. Thomas fell asleep watching an old John Wayne movie. Two teenage girls with smeared mascara pounded on the door around two in the morning and Anna sold them a plastic sachet of white powder.

Thomas, still on the couch, asked her if the powder was heroin, or cocaine.

"Heroin."

"Do you use that shit?"

"No." She regarded him with mild amusement; she didn"t care if he believed her or not.

He woke again at half past five. Anna had gone. The baby was still in his crib, screaming. Thomas changed him and fed him; Anna had shown him where everything was. He wanted a shower, but there was no hot water. He shaved, and left in time for his meeting, telling himself Anna would be back soon. All morning, and all through lunch, he could smell the sour odor of the child"s skin on his hands, and he wondered if the smiling property developers could smell it too.

He phoned from the hotel, paying for the night he hadn"t spent there, knowing that his father would scrutinize his expenses. Anna was home; he"d woken her. Someone nearby grunted with displeasure. Thomas didn"t mention the child.

The next time, he came on a Saturday afternoon, with no need to be anywhere else in a hurry. They met at the Alsterpavillon, drank their coffee looking down on the buffoons in rowboats on the Binnenalster, then went shopping on Jungfernstieg. Thomas paid for the clothes Anna chose, authentic gothic designer trash that looked far worse than the cheapest imitation; it seemed she didn"t really want to dress like him, after all. They walked arm-in-arm from shop to shop, and in the entrance to the most expensive boutique, they stopped and kissed for several minutes, blocking the way of customers trying to get past, then went in and spent a lot of money.

Later, in a nightclub with a bad live band who dressed like the Beatles and did Sex Pistols covers, they ran into Martin, a tall wiry blond youth who Anna introduced as a friend. Martin was all vicious back-slapping amiability, trying so hard to be intimidating that he was almost comical. They all staggered back to Anna"s flat together, and sat on the floor listening to records. When Anna went to the toilet, Martin drew a knife and told Thomas he intended to kill him. He was very drunk. Thomas stood up, kicked him once in the face, breaking his nose, then took away the knife and dragged him moaning out into the hall. Thomas turned him on his side so he wouldn"t choke on the blood, then locked the door.

Anna came out of the bathroom. Thomas told her what had happened. She went out and checked on Martin, and put a pillow under his head.

While Anna was undressing him, Thomas said, "On TV once, I saw an English soldier who"d just come back from Northern Ireland. And he said, "It was hell there, but at least it was real. At least I"ve lived now."" Thomas laughed sadly. "The poor fool had it all upside down. Slaughtering people is real-and living an ordinary life is some kind of dream, some kind of delusion? Poor fucked-up kid."

He searched Anna for needle marks, but he couldn"t find a single one.

Back in his office in Frankfurt, alone in his apartment, at the dinner table in his parents" home, Thomas thought about Anna, in images and scents. The memories never distracted him; he could carry on a conversation, or keep reading a mortgage schedule, while she played in his head like wallpaper music.

His father cornered him at Easter. "You should think about getting married. It makes no difference to me, but there are social advantages you"re going to need sooner or later. And think how happy it would make your mother."

Thomas said, "I"m twenty-four years old."

"I was engaged when I was twenty-four."

"Maybe I"m gay. Or perhaps I have an incurable venereal disease."

"I don"t see why either should be an obstacle."

Thomas saw Anna every second weekend. He bought her whatever she asked for. Sometimes she had the child with her. The boy was called Erik.

Thomas asked her, "Who"s the mother? Have I met her?"

She said, "You don"t want to."

He worried about her sometimes-afraid she"d get herself arrested, or beaten up by junkies or rivals-but she seemed to be able to take care of herself. He could have hired private detectives to uncover the mysteries of her life, and bodyguards to watch over her, but he knew he had no right. He could have bought her an apartment, set her up with investments-but she never suggested anything of the kind, and he suspected she"d be deeply insulted if he made the offer. His gifts were lavish, but he knew she could have lived without them. They were using each other. She was, he told himself, as independent as he was.

He wouldn"t have said he loved her. He didn"t ache when they were apart; he just felt pleasantly numb, and looked forward to the next time he"d see her. He was jealous, but not obsessive, and she kept her other lovers out of the way; he rarely had to acknowledge their existence. He never saw Martin again.

Anna traveled with him to New York. They fell asleep in the middle of a Broadway show, saw the Pixies play at the Mudd Club, climbed the stairs to the top of Manhattan Chase.

Thomas turned twenty-five. His father promoted him. His mother said, "Look at all your gray hairs."

In the spring, Erik disappeared. Anna said casually, "His mother"s gone, she"s moved away."

Thomas was hurt; he"d liked having the boy around. He said, "You know, I used to think he might be yours."

She was baffled. "Why? I told you he wasn"t. Why would I have lied?"

Thomas had trouble sleeping. He kept trying to picture the future. When his father died, would he still be seeing Anna, once a fortnight in Hamburg, while she dealt heroin and fucked pimps and junkies? The thought made him sick. Not because he didn"t want everything to stay the same, but because he knew that it couldn"t.

The Saturday in June was, almost, the second anniversary of the day they"d met. They went to a flea market in the afternoon, and he bought her cheap jewelery. She said, "Anything nicer would be asking for trouble."

They ate junk food, went dancing. They ended up back at Anna"s flat at half past two. They danced around the tiny living room, propping each other up, more tired than drunk.

Thomas said, "God, you"re beautiful." Marry me.

Anna said, "I"m going to ask you for something I"ve never asked for before. I"ve been trying to work up the courage all day."

"You can ask for anything." Marry me.

"I have a friend, with a lot of cash. Almost two hundred thousand marks. He needs someone who can-"

Thomas stepped back from her, then struck her hard across the face. He was horrified. He"d never hit her before; the thought had never even occurred to him. She started punching him in the chest and face; he stood there and let her do it for a while, then grabbed both her hands by the wrists.

She caught her breath. "Let go of me."

"I"m sorry."

"Then let go of me."

He didn"t. He said, "I"m not a money-laundering facility for your friends."

She looked at him pityingly. "Oh, what have I done? Offended your high moral principles? All I did was ask. You might have made yourself useful. Never mind. I should have known it was too much to expect."

He pushed his face close to hers. "Where are you going to be, in ten years" time? In prison? At the bottom of the Elbe?"

"Fuck off."

"Where? Tell me?"

She said, "I can think of worse fates. I could end up playing happy families with a middle-aged banker."

Thomas threw her toward the wall. Her feet slipped from under her before she hit it; her head struck the bricks as she was going down.

He crouched beside her, disbelieving. There was a wide gash in the back of her head. She was breathing. He patted her cheeks, then tried to open her eyes; they"d rolled up into her skull. She"d ended up almost sitting on the floor, legs sprawled in front of her, head lolling against the wall. Blood pooled around her.

He said, "Think fast. Think fast."

He knelt over her, one knee to either side, took her face in his hands, then closed his eyes. He brought her head forward, then slammed it back against the wall. Five times. Then he held his fingers near her nostrils, without opening his eyes. He felt no exhalation.

He backed away from her, turned away and opened his eyes, then walked around the flat, wiping things he might have touched with his handkerchief. Avoiding looking at her. He was crying and shaking, but he couldn"t think why.

There was blood on his hands, his shirt, his trousers, his shoes. He found a garbage bag, put all his clothes in it, then washed the blood from his skin. There was a black spot in the center of his vision, but he worked around it. He put the garbage bag in his suitcase, and put on fresh clothes: blue jeans and a black T-shirt. He went through the flat, packing away everything that belonged to him. He almost took Anna"s address book, but when he checked he saw that he wasn"t in it. He looked for diaries, but found none.

Dozens of people had seen them together, month after month. Anna"s neighbors, Anna"s friends. Dozens of people had seen them leave the nightclub. He wasn"t sure how many of her friends knew what he did, where he was from. He"d never told any of them more than his first name, he"d always lied about the rest-but Anna might have told them everything she knew.

Having been seen with her alive was bad enough; he couldn"t risk being seen walking out the front door the night she was killed.

The flat was two flights up. The bathroom window opened onto an alley. Thomas threw the suitcase down; it landed with a soft thud. He thought of jumping-almost believing that he could land unhurt, or almost believing that he wouldn"t care-but there was a gray clarity underneath those delusions, and an engine in his skull a billion years old which only wanted to survive.

He climbed up into the window frame, into the gap left by the sliding half-pane, one foot either side of the track. There was no ledge, as such, just the double brickwork of the wall itself. He had to crouch to fit, but he found he could keep his balance by pushing his left hand up against the top of the frame, jamming himself in place.

He turned sideways, then reached across the outside wall, and into the frame of the bathroom window of the neighboring flat. He could hear traffic, and music somewhere, but no lights showed from within the flat, and the alley below was deserted. The two windows were scarcely a meter apart, but the second one was closed, halving its width. With one hand on each edge, he shifted his right foot to the neighbor"s window. Then, gripping the intervening wall tightly between his forearms, he moved his left foot across. Finally, securing himself by pressing up with his right hand, he let go of the first frame completely.

He shuffled across the one-brick"s-width ledge, fighting an impulse to mutter Ave Marias. Pray for us sinners? He realized that he"d stopped weeping. A drain pipe ran close to the far side of the window. He imagined tearing his palms open on jagged rusty metal, but the pipe was smooth; it took all his strength to hold himself in place, gripping it with hands and knees. When he touched the ground with his feet, his legs gave way. But not for long.

He hid in a public toilet for three hours, staring up at one corner of the room. The lights, the tiles, could have belonged to a prison or an asylum. He found himself disconnected, from the world, the past; his time breaking up into moments, shocks of awareness, shimmering droplets of mercury, beads of sweat.

This isn"t me. This is something else that believes it"s me. And it"s wrong, wrong, wrong.

Nobody disturbed him. At six o"clock he walked out into the morning light, and caught a train home.

<dd> <dd>15 <dd> <dd>(Remit not paucity) <dd> <dd>APRIL 2051

Durham"s north Sydney flat was small, and very sparsely furnished; not at all what Maria had expected. The combined living room and kitchen was all she"d seen, but it was clear from the outside that there wasn"t space for much more. Durham was on the sixteenth floor, but the building was hemmed in on all sides by ugly late-twenties office towers, blue and pink ersatz-marble monstrosities; no expensive harbor views here. For someone who was ripping off gullible millionaires-or even someone who merely sold them insurance-Durham didn"t seem to have much to show for it. Maria thought it unlikely that the place had been set up entirely for her benefit, to fit the story he"d told her: to demonstrate the frugal lifestyle which supposedly enabled him to pay her out of his own pocket. He"d invited her out of the blue; she would never have had a reason to insist on seeing where he lived.

She put her notepad down on the scratched dining table, and turned it so that Durham could read the graphs. "These are the latest results for the two most promising species. A. lithophila has the higher mutation rate, per generation, but it reproduces much more slowly, and it"s more vulnerable to climate change. A. hydrophila is more prolific, with a stabler genome. It"s not intrinsically hardier; it"s just better protected by the ocean."

Durham said, "What"s your gut feeling?"

"What"s yours?"

"A. litho evolves into a few promising species-which all get wiped out by one major crisis. A. hydro slowly builds up a huge stock of survival-neutral mutations, some of which turn out to be useful on land. The first few hundred thousand species which blow out of the sea don"t make it-but it doesn"t matter, there are always more. Or am I just being swayed too much by terrestrial preconceptions?"

"The people you"re trying to convince will almost certainly think the same way."

Durham laughed. "It wouldn"t hurt to be right, as well as persuasive. If they"re not mutually exclusive ambitions."

Maria didn"t reply. She stared down at the notepad; she couldn"t look Durham in the eye. Talking to him by phone, with software filters, had been bearable. And the work itself had been an end in itself; immersed in the elaborate game of Autoverse biochemistry, she"d found it all too easy to carry on, as if it made no difference what it was for. But she"d done next to nothing to make Durham more likely to take her into his confidence. That was why she"d agreed to this meeting-and why she had to take advantage of it.

The trouble was, now that she was here, she was so ill at ease that she could barely discuss the most neutral technicalities without her voice faltering. If he started spouting lies about his hopes of debating the skeptics of the artificial life mafia in some future issue of Cellular Automaton World, she"d probably start screaming. Or, more likely, throw up on the bare linoleum floor.

He said, "By the way, I signed the release on your fee this morning-I"ve authorized the trust fund to pay you in full. The work"s been going so well, it seemed only fair."

Maria glanced up at him, startled. He looked perfectly sincere, but she couldn"t help wondering-not for the first time-if he knew that she"d been approached by Hayden, knew exactly what she"d been told. She felt her cheeks flush. She"d spent too many years using phones and filters; she couldn"t keep anything from showing on her face.

She said, "Thank you. But aren"t you afraid I might take the first plane to the Bahamas? There"s still a lot of work to be done."

"I think I can trust you."

There wasn"t a trace of irony in his voice-but there really didn"t need to be.

He said, "Speaking of trust... I think your phone may be bugged. I"m sorry; I should have told you that sooner."

Maria stared at him. "How did you know?"

"Know? You mean, it is? You"ve had definite signs?"

"I"m not sure. But how... ?"

"Mine is. Bugged. So it makes sense that yours would be, too."

Maria was bewildered. What was he going to do-announce that the Fraud Squad were watching him? If he came right out and said it, she didn"t think she could dissemble any longer. She"d have to confess that she already knew-and then she"d have to tell him everything Hayden had said.

Taking the pressure off completely. Ending the farce for good. She had no talent for these stupid games; the sooner they could both stop lying to each other, the better.

She said, "And who exactly do you think is doing it?"

Durham paused to think it over, as if he hadn"t seriously considered the question before. "Some corporate espionage unit? Some national security organization? There"s really no way of telling. I know very little about the intelligence community; your guess would be as good as mine."

"Then why do you think they"re-?"

Durham said blithely, "If I was developing a computer, say, thirty orders of magnitude more powerful than any processor cluster in existence, don"t you think people like that might take an interest?"

Maria almost choked. "Ah. Yes."

"But of course I"m not, and eventually they"ll convince themselves of that, and leave us both alone. So there"s absolutely nothing to worry about."

"Right."

Durham grinned at her. "Presumably, they think that just because I"ve commissioned an Autoverse planet, there"s a chance that I might possess the means to actually run it. They"ve searched this place a couple of times; I don"t know what they expected to find. A little black box, sitting in a comer of one of the rooms? Hidden under a pot plant, quietly cracking military codes, raking in a fortune on the stock market-and simulating a universe or two on the side, just to keep from getting bored. Any five-year-old could tell them how ludicrous that is. Maybe they think I"ve found a way to shrink individual processors to the size of an atom. That would just about do it."

So much for an end to the lying. He wasn"t going to make this easy for her. All right. Maria forced the words out evenly: "And any five-year-old could tell you that if anyone searched your flat, it was the Fraud Squad."

Durham was still giving nothing away. "Why do you say that?"

"Because I know they"re watching you. They"ve spoken to me. They"ve told me exactly what you"re doing." Maria faced him squarely now. She was tense at the prospect of a confrontation, but she had nothing to be ashamed of; he was the one who"d set out to deceive her from the start.

He said, "Don"t you think the Fraud Squad would need to get a warrant, and search the flat in my presence?"

"Then maybe it hasn"t been searched at all. That"s not the point."

He nodded slightly, as if conceding some minor breach of etiquette. "No, it"s not. You want to know why I lied to you."

Maria said, "I know why. Please don"t treat me like an idiot." Her bitterness surprised her, she"d had to conceal it for so long. "I was hardly going to agree to be your... accomplice-"

Durham raised one hand from the tabletop, a half conciliatory, half impatient gesture. Maria fell silent, more from astonishment at how calmly he seemed to be taking all this than any desire to give him a chance to defend himself.

He said, "I lied because I didn"t know if you"d believe the truth or not. I think you might have, but I couldn"t be sure. And I couldn"t risk it. I"m sorry."

"Of course I would have believed the truth! It would have made a lot more sense than the bullshit you fed me! But, yes, I can see why you couldn"t risk it."

Durham still showed no sign of contrition. "Do you know what it is that I"m offering my backers? The ones who"ve been funding your work?"

"A sanctuary. A privately owned computer somewhere."

"That"s almost true. Depending on what you take those words to mean."

Maria laughed cynically. "Oh, yes? Which words do you have trouble with? "Privately owned"?"

"No. "Computer." And, "somewhere.""

"Now you"re just being childish." She reached out and picked up her notepad, slid her chair back and rose to her feet. Trying to think of a parting shot, it struck her that the most frustrating thing was that the bastard had paid her. He"d lied to her, he"d made her an accomplice-but he hadn"t actually swindled her.

Durham looked up at her calmly. He said, "I"ve committed no crime. My backers know exactly what they"re paying for. The Fraud Squad, like the intelligence agencies, are jumping to absurd conclusions. I"ve told them the whole truth. They"ve chosen not to believe me."

Maria stood by the table, one hand on the back of the chair. "They said you refused to discuss the matter."

"Well, that"s a lie. Although what I had to say certainly wasn"t what they wanted to hear."

"What did you have to say?"

Durham gave her a searching look. "If I try to explain, will you listen? Will you sit down and listen, to the end?"

"I might."

"Because if you don"t want to hear the whole story, you might as well leave right now. Not every Copy took me up on the offer-but the only ones who went to the police were the ones who refused to hear me out."

Maria said, exasperated, "What do you care what I think, now? You"ve extracted all the Autoverse technobabble from me you could possibly need. And I know nothing more about your scam than the police do; they"ll have no reason to ask me to testify against you, if all I can say in court is "Detective Hayden told me this, Detective Hayden told me that." So why don"t you quit while you"re ahead?"

Durham said simply, "Because you don"t understand anything. And I owe you an explanation."

Maria looked toward the door, but she didn"t take her hand off the back of the chair. The work had been an end in itself-but she was still curious to know precisely what Durham had intended to do with the fruits of her labor.

She said, "How was I going to spend the afternoon, anyway? Modeling the survival of Autobacterium hydrophila in sea spray?" She sat. "Go ahead. I"m listening."

Durham said, "Almost six years ago-loosely speaking-a man I know made a Copy of himself. When the Copy woke up, it panicked, and tried to bale out. But the original had sabotaged the software; baling out was impossible."

"That"s illegal."

"I know."

"So who was this man?"

"His name was Paul Durham."

"You? You were the original?"

"Oh, no. I was the Copy."

<dd> <dd>16 <dd> <dd>(Toy man, picture it) <dd> <dd>JUNE 2045

Paul felt a hand gripping his forearm. He tried to shake it off, but his arm barely moved, and a terrible aching started up in his shoulder. He opened his eyes, then closed them again in pain. He tried again. On the fifth or sixth attempt, he managed to see a face through washed-out brightness and tears.

Elizabeth.

She raised a cup to his lips. He took a sip, spluttered and choked, but then managed to force some of the thin sweet liquid down.

She said, "You"re going to be fine. Just take it easy."

"Why are you here?" He coughed, shook his head, wished he hadn"t. He was touched, but confused. Why had his original lied-claiming that she wanted to shut him down-when in fact she was sympathetic enough to go through the arduous process of visiting him?

He was lying on something like a dentist"s couch, in an unfamiliar room. He was in a hospital gown; there was a drip in his right arm, and a catheter in his urethra. He glanced up to see an interface helmet, a bulky hemisphere of magnetic axon current inducers, suspended from a gantry, not far above his head. He thought: fair enough, to construct a simulated meeting place that looked like the room that her real body must be in. Putting him in the couch, though, and giving him all the symptoms of a waking visitor, seemed a little extreme.

He tapped the couch with his left hand. "What"s the message? You want me to know exactly what you"re going through? Okay. I"m grateful. And it"s good to see you." He shuddered with relief, and delayed shock. "Fantastic, to tell the truth." He laughed weakly. "I honestly thought he was going to wipe me out. The man"s a complete lunatic. Believe me, you"re talking to his better half."

Elizabeth was perched on a stool beside him. She said, "Paul. Try to listen carefully to what I"m going to say. You"ll start to reintegrate the memories gradually, on your own, but it"ll help if I talk you through it all first. To start with, you"re not a Copy. You"re flesh and blood."

Paul coughed, tasting acid. Durham had let her do something unspeakable to the model of his digestive system.

"I"m flesh and blood? What kind of sadistic joke is that? Do you have any idea how hard it"s been, coming to terms with the truth?"

She said patiently, "It"s not a joke. I know you don"t remember yet, but... after you made the scan that was going to run as Copy number five, you finally told me what you were doing. And I persuaded you not to run it-until you"d tried another experiment: putting yourself in its place. Finding out, firsthand, what it would be forced to go through.

"And you agreed. You entered the virtual environment which the Copy would have inhabited-with your memories since the day of the scan suppressed, so you had no way of knowing that you were only a visitor."

"I-?"

"You"re not the Copy. Do you understand? All you"ve been doing is visiting the environment you"d prepared for Copy number five. And now you"re out of it. You"re back in the real world."

Her face betrayed no hint of deception-but software could smooth that out. He said, "I don"t believe you. How can I be the original? I spoke to the original. What am I supposed to believe? He was the Copy? Thinking he was the original?"

"Of course not. That would hardly have spared the Copy, would it? The fifth scan was never run. I controlled the puppet that played your "original"-software provided the vocabulary signature and body language, but I pulled the strings. You briefed me, beforehand, on what to have it say and do. You"ll remember that, soon enough."

"But... the experiments?"

"The experiments were a sham. They could hardly have been performed on a visitor, on a physical brain-could they?"

Paul shook his head, and whispered, "Abulafia."

No interface window appeared.

He gripped the couch and closed his eyes, then laughed. "You say I agreed to this? What kind of masochist would do that? I"m going out of my mind. I don"t know what I am."

Elizabeth took hold of his arm again. "You"re disoriented-but that won"t last long. And you know why you agreed. You were sick of Copies baling out on you. You had to come to terms with their experience. Spending a few days believing you were a Copy would make or break the project: you"d either end up psychologically prepared, at last, to give rise to a Copy who"d be able to cope with its fate-or you"d gain enough sympathy for their plight to stop creating them.

"The plan was to tell you everything while you were still inside, after the third experiment. But when you went weird on me in there, I panicked. All I could think of was having the puppet playing your original tell you that it was going to pause you. I wasn"t trying to frighten you. I didn"t think you"d take it so badly."

A technician came into the room and removed the drip and catheter. Paul propped himself up and looked out through the windows of the room"s swing doors; he could see half a dozen people in the corridor. He bellowed wordlessly at the top of his lungs; they all turned to stare in his direction. The technician said mildly, "Your penis might sting for an hour or two."

Paul slumped back onto the couch and turned to Elizabeth. "You wouldn"t pay for reactive crowds. I wouldn"t pay for reactive crowds. It looks like you"re telling the truth." + + +

People, glorious people: thousands of strangers, meeting his eyes with suspicion or puzzlement, stepping out of his way on the street-or, more often, clearly, consciously refusing to. The freedom of the city was so sweet. He walked the streets of Sydney for a full day, rediscovering every ugly shopping arcade, every piss-stinking litter-strewn park and alley, until, with aching feet, he squeezed his way home through the evening rush hour, to watch the real-time news.

There was no room for doubt: he was not in a virtual environment. Nobody in the world could have had reason to spend so much money, simply to deceive him.

When Elizabeth asked if his memories were back, he nodded and said of course. She didn"t grill him on the details. In fact, having gone over her story so many times in his head, he could almost imagine the stages: his qualms after the fifth scan; repeatedly putting off running the model; confessing to Elizabeth about the project; accepting her challenge to experience for himself just what his Copies were suffering.

And if the suppressed memories hadn"t actually reintegrated, well, he"d checked the literature, and there was a two point five percent risk of that happening; electronically censoring access to memories could sometimes permanently weaken the neural connections in which they were encoded.

He even had an account from the database service which showed that he"d consulted the very same articles before.

He reread and replayed the news reports that he"d accessed from inside-and found no discrepancies. He flicked through encyclopedic databases-spot-checking random facts of history, geography, astronomy-and although he was surprised now and then by details which he"d never come across before, there were no startling contradictions. The continents hadn"t moved. Stars and planets hadn"t vanished. The same wars had been lost and won.

Everything was consistent. Everything was explicable.

And yet he couldn"t stop wondering about the fate of a Copy who was shut down and never run again. A normal human death was one thing-woven into a much vaster tapestry, it was a process which made perfect sense. From the internal point of view of a Copy whose model was simply halted, though, there was no explanation whatsoever for its demise-just an edge where the pattern abruptly came to an end.

But if the insight he"d gained from the experiments was true (whether or not they"d ever really happened)-if a Copy could assemble itself from dust scattered across the world, and bridge the gaps in its existence with dust from across the universe... then why should it ever come to an inconsistent end? Why shouldn"t the pattern keep on finding itself?

Or find a larger pattern into which it could merge?

The dust theory implied a countless number of alternative worlds: billions of different possible histories spelled out from the same primordial alphabet soup. One history in which Durham did run Copy number five-and one in which he didn"t, but was persuaded to take its place as a visitor, instead.

But if the visitor had been perfectly deceived, and had experienced everything the Copy did... what set the two of them apart? So long as the flesh-and-blood man had no way of knowing the truth, it was meaningless to talk about "two different people" in "two different worlds." The two patterns of thoughts and perceptions had effectively merged into one.

If the Copy had been allowed to keep on running after the visitor had learned that he was flesh and blood, their two paths would have diverged again. But the Copy had been shut down; it had no future at all in its original world, no separate life to live.

So the two subjective histories remained as one. Paul had been a visitor believing he was a Copy. And he"d also been the Copy itself. The patterns had merged seamlessly; there could be no way of saying that one history was true and the other false. Both explanations were equally valid.

Once, preparing to be scanned, he"d had two futures.

Now he had two pasts. + + +

Paul woke in darkness, confused for a moment, then pulled his cramped left arm out from under the pillow and glanced at his watch. Low power infrared sensors in the watch face detected his gaze, and flashed up the time-followed by a reminder: due at landau 7 a.m. It was barely after five, but it hardly seemed worth going back to sleep.

Memories of the night before came back to him. Elizabeth had finally confronted him, asking what decision he"d reached: to abandon his life"s work, or to forge ahead, now that he knew, firsthand, what was involved.

His answer seemed to have disappointed her. He didn"t expect to see her again.

How could he give up? He knew he could never be sure that he"d discovered the truth-but that didn"t mean that nobody else could.

If he made a Copy, ran it for a few virtual days, then terminated it abruptly... then at least that Copy would know if its own pattern of experience continued.

And if another Paul Durham in one of the countless billions of alternative worlds could provide a future for the terminated Copy-a pattern into which it could merge-then perhaps that flesh-and-blood Durham would repeat the whole process

And so on, again and again.

And although the seams would always be perfect, the "explanation" for the flesh-and-blood human believing that he had a second past as a Copy would necessarily grow ever more "contrived," less convincing... and the dust theory would become ever more compelling.

Paul lay in bed in the darkness, waiting for sunrise, staring into the future down this corridor of mirrors.

One thing nagged at him. He could have sworn he"d had a dream, just before he woke: an elaborate fable, conveying some kind of insight. That"s all he knew-or thought he knew. The details hovered maddeningly on the verge of recollection.

His dreams were evanescent, though, and he didn"t expect to remember anything more.

<dd> <dd>17 <dd> <dd>(Remit not paucity) <dd> <dd>APRIL 2051

Maria shifted in her seat to try to get her circulation flowing, then realized it wasn"t enough. She stood up and limped around the room, bending down to massage her cramped right calf.

She said, "And you claim you"re the twenty-third?" She was almost afraid to sound too skeptical; not because she believed that Durham would take offence, but because the story was so strangely entrancing that she wasn"t sure she wanted to deflate it, yet. One hint of mockery and the floodgates would open. "You"re the twenty-third flesh-and-blood Paul Durham whose past includes all those who came before?"

Durham said, "I may be wrong about the exact number. I may have counted this last version more than once; if I"m capable of believing in twenty-three incarnations, some of them might be false. The whole nature of the delusions I suffered contributes to the uncertainty."

"Contributes. Isn"t that a bit of an understatement?"

Durham was unflappable. "I"m cured now. The nanosurgery worked. The doctors pronounced me sane, and I have no reason to question their judgement. They"ve scanned my brain; it"s functioning impeccably. I"ve seen the data, before and after. Activity in the prefrontal cortex-"

"But don"t you see how absurd that is? You acknowledge that you were deluded. You insist that you"re cured now. But you claim that your delusions weren"t delusions-"

Durham said patiently, "I"ve admitted from the outset: my condition explains everything. I believed-because I was mentally ill-that I was the twenty-third-generation Copy of another Paul Durham, from another world."

"Because you were mentally ill! End of story."

"No. Because I"m certifiably rational now-and the logic of the dust theory makes as much sense to me as ever. And it makes no difference whether my memories are true, false, or both."

Maria groaned. "Logic of the dust theory! It"s not a theory. It can"t be tested."

"Can"t be tested by whom?"

"By anyone! I mean... even assuming that everything you believe is the truth: you"ve "been through" twenty-three separate experiments, and you still don"t know what you"ve proved or disproved! As you say: your condition accounts for everything. Haven"t you heard of Occam"s razor: once you have a perfectly simple explanation for something, you don"t go looking for ever more complicated ways of explaining the very same thing? No dust theory is required." Her words reverberated in the near-empty room. She said, "I need some fresh air."

Durham said firmly, "After twenty-three ambiguous results, I know how to get it right this time. A Copy plus a virtual environment is a patchwork, a mess. A system like that isn"t rich enough, detailed enough, or consistent enough, to be self-sustaining. If it was, when I was shut down, the entire VR world I was in would have persisted. That never happened. Instead-every time-I found a flesh-and-blood human with a reason to believe he shared my past. That explained my pattern of experience far better than VR-even to the point of insanity.

"What I have to do now is construct a consistent pattern which can only have one past."

Maria took a few deep breaths. It was almost too much to bear: Durham"s sad flat, his cosmic visions, his relentless, mechanical logic, grinding away trying to make sense of the legacy of his disease. The doctors had cured him, he was sane. He just didn"t want to disown his delusional past-so he"d invented a flawlessly logical, utterly irrefutable, reason to hang on to it.

If he"d really told the cops all this, why were they still hounding him? They should have seen that he was harmless and left him alone-and left his moronic clients to fend for themselves. The man wasn"t even a danger to himself. And if he could ever harness a fraction of the energy and intelligence he"d put into this "project" and direct it towards something worthwhile-

Durham said, "Do you know what a Garden-of-Eden configuration is?"

Maria was caught blank for a second, then she said, "Yes, of course. In cellular automaton theory, it"s a state of the system that can"t be the result of any previous state. No other pattern of cells can give rise to it. If you want a Garden-of-Eden configuration, you have to start with it-you have to put it in by hand as the system"s first state."

Durham grinned at her as if she"d just conceded the whole argument. She said, "What?"

"Isn"t it obvious? A cellular automaton isn"t like patchwork VR; it"s every bit as consistent as a physical universe. There"s no jumble of ad hoc high-level laws; one set of rules applies to every cell. Right?"

"Yes, but-"

"So if I set up a cellular automaton in a Garden-of-Eden configuration, run it through a few trillion clock ticks, then shut it down... the pattern will continue to find itself in the dust-separate from this version of me, separate from this world, but still flowing unambiguously from that initial state. A state which can"t be explained by the rules of the automaton. A state which must have been constructed in another world-exactly as I remember it.

"The whole problem, so far, has been that my memories are always entirely explicable within the new world. I shut myself down as a Copy-and find myself in a flesh-and-blood body with flesh-and-blood memories which the laws of physics could have produced from earlier states of a flesh-and-blood brain. This world can explain me only as a man whose delusions are unlikely beyond belief-but there"s no denying that I do have a complete extra history, here, that"s not literally, physically impossible. So whatever I prefer to believe, I have to concede that the outcome of the experiment is still ambiguous. I could, still, be wrong.

"But a cellular automaton can"t provide an "extra history" for a Garden-of-Eden configuration! It"s mathematically impossible! If I find myself inside a cellular automaton universe, and I can track my past back to a Garden-of-Eden configuration, that will be conclusive proof that I did seed the whole universe in a previous incarnation. The dust theory will be vindicated. And I"ll finally know-beyond any doubt-that I haven"t merely been insane all along."

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