Permutation City

lattice as they had; the software they’d used could only function on a level right outside his universe. There was no simple way he could discover the state of any given automaton cell; instead, a system of construction and sensor wires (all joined to specialized processors) had been built around a small region in the center of the lattice. Durham had christened this apparatus “the Chamber.” What went on deep inside the Chamber could be deduced, indirectly, from the data which ended up flowing down the sensor wires. It wasn’t as complicated as working out what had happened in a particle accelerator collision, based on the information registered by surrounding detectors—but the principle was the same, and so was the purpose. The Copy had to conduct experiments to test his own fundamental “laws of physics”—the TVC automaton’s rules. And the (simulated) modern computers running his VR environment had a (simulated) link to the Chamber, like the real-world computers linked to any real-world accelerator.

The Copy said, “Setting up the first experiment.” He deftly typed a sequence of code letters on his keyboard. Durham had rehearsed the whole thing before his scan, until he could perform each of fifty experiments in ten seconds flat, but Maria was still astonished that the Copy—who had woken abruptly to find himself seated in the control room, without any preliminaries, any chance to grow accustomed to his identity, and his fate—had had the presence of mind to leap straight into the task. She’d entertained visions of this first version of Durham to wake inside a computer finally realizing that “the other twenty-three times” were nothing at all like the real experience— and telling his original about it in no uncertain terms. But there didn’t seem to be much chance of that; the Copy just sat there typing as if his life depended on it.

The experimental setups could have been automated. The checking of the results could have been automated, too. The Copy could have spent two minutes sitting and watching a flashing green sign which said everything is just what you would have expected, don’t worry about the messy details. There was no such thing as a set of perceptions for the Copy which could prove that he inhabited a cellular automaton which obeyed all the rules which he hoped were being obeyed. It was all down to Occam’s razor in the end—and hoping that the simplest explanation for perceiving a diplay showing the correct results was that the correct results were actually occurring.

Maria stared into the screen, over the Copy’s shoulder, at the interface window within. When he typed the last code letter, the assembly of cells he’d constructed in the Chamber became unstable and started creating new cells in the surrounding “vacuum,” setting off a cascade which eventually impinged on the sensor wires. Disconcertingly, the Copy watched both a simulation—on his own terms—of what ought to be happening in the Chamber, and then a moment later a reconstruction of the “actual” events, based on the sensor data.

Both evidently matched the results of the simulations which the original Durham had committed to memory. The Copy clapped his hands together loudly in obvious jubilation, bellowed something incoherent, then said, “Setting up the sec—”

Maria was becoming giddy with all the levels of reality they were transecting—but she was determined to appear as blase as ever. She said, “What did you do, wake him up with a brain full of amphetamines?”

Durham replied in the same spirit. “No, he’s high on life. If you’ve only got two minutes of it, you might as well enjoy it.”

They waited, passing the time checking software more or less at random, displaying everything from firing patterns in the Copy’s model brain to statistics on the performance of the TVC computers. Intuitively, the elaborate hierarchy of simulations within simulations seemed vulnerable, unstable—every level multiplying the potential for disaster. But if the setup resembled a house of cards, it was a simulated house of cards: perfectly balanced in a universe free of vibrations and breezes. Maria was satisfied that the architecture at every level was flawless—so long as the level beneath held up. It would take a glitch in the real-world hardware to bring the whole thing tumbling down. That was rare, though not impossible.

They viewed the second installment of the Copy at work, then took a coffee break. Einstein on the Beach was still playing, repetitive and hypnotic. Maria couldn’t relax; she was too wired on caffeine and nervous energy. She was relieved that everything was running smoothly—no software problems, no Operation Butterfly, no sign of either version of Durham going weird on her. At the same time, there was something deeply unsettling about the prospect of the whole thing unwinding, exactly as predicted, for the next six hours—and then simply coming to an end. She’d have the money for Francesca, then, and that justified everything… but the absolute futility of what they were doing still kept striking her anew—in between bouts of worrying over such absurdities as whether or not she could have made a better job of A. hydrophila’s response to dehydration. Durham would let her publish all the Autoverse work, so that hadn’t been a complete waste of time—and she could keep on refining it for as long as she liked before unleashing it on the skeptics… but she could already imagine the—bizarre—regret she’d feel because the improvements had come too late to be incorporated into the “genuine” Planet Lambert: the one they were currently flushing down a multi-million-dollar drain.

She said, “It’s a pity none of your passengers’ originals have bodies. Having paid for all this, they should be here, watching.”

Durham agreed. “Some of them may be here in spirit; I’ve granted them all the same viewing access to the simulation that we have. And their auditors will receive a verified log of everything—proof that they got what they paid for. But you’re right. This isn’t much of a celebration; you should be clinking glasses and sharing caviar with the others.”

She laughed, offended. “Others? I’m not one of your victims—I’m just the confidence artist’s accomplice, remember? And I’m not here to celebrate; I’m only here to make sure your doppelganger doesn’t hot-wire the software and wake me up.”

Durham was amused. “Why would he try to wake you so soon? Do you think he’s going to become unbearably lonely in the space of two minutes?”

“I have no idea what he might do, or why. That’s the whole problem. He’s just as fucked up as you are.”

Durham said nothing. Maria wished she could take back the words. What was the point of needling him and mocking him, again and again—did she think she could ever bring him down to Earth? It was all a matter of pride; she couldn’t let a second go by without reminding him that she hadn’t been seduced by his ideas. Computer junkie, artificial life freak; she still had her feet planted firmly in the real world. His vision of an Autoverse biosphere had impressed her—when she’d thought he’d understood that it could never be anything but a thought experiment. And all the work he’d done on the TVC universe was ingenious—however ultimately pointless it was. In a way, she even admired his stubborn refusal to give in to common sense and accept his delusions for what they were.

She just couldn’t bear the thought that he harbored the faintest hope that he’d persuaded her to take the “dust hypothesis” seriously.

+ + +

At three minutes past ten, the money ran out—all but enough to pay for the final tidying-up. The TVC automaton was shut down between clock ticks; the processors and memory which had been allocated to the massive simulation were freed for other users—the memory, as always, wiped to uniform zeroes first for the sake of security. The whole elaborate structure was dissolved in a matter of nanoseconds.

Night had turned the windows of the flat to mirrors. No lights showed in the empty office towers; if there’d been cooking fires from the squatters, they’d been extinguished long ago. Maria felt disconnected, adrift in time; the trip north across the harbor bridge in sunlight seemed like a distant memory, a dream.

The individual components of the Garden of Eden were still held in mass storage. Maria deleted her scan file, carefully checking the audit records to be sure that the data hadn’t been read more often than it should have been. The numbers checked out; that was no guarantee, but it was reassuring.

Durham deleted everything else.

The recordings of the spy software remained, and they viewed the last brief scene of the Copy at work—and then replayed the whole two-minute recording.

Maria watched with a growing sense of shame. The individual fragments had barely affected her, but viewed without interruption, the Copy took on the air of a deranged sect leader driving a bus full of frozen billionaires straight toward the edge of a cliff—accelerating euphorically in the sure and certain knowledge that the thing would fly, carrying them all off into a land beyond the sunset. She clung to her