Permutation City

Permutation City

by Greg Egan
Permutation City

Permutation City

by Greg Egan



Available on Compatible NOOK Devices and the free NOOK Apps.
WANT A NOOK?  Explore Now

Related collections and offers

LEND ME® See Details


Paul Durham keeps making Copies of himself: software simulations of his own brain and body which can be run in virtual reality, albeit seventeen times more slowly than real time. He wants them to be his guinea pigs for a set of experiments about the nature of artificial intelligence, time, and causality, but they keep changing their mind and baling out on him, shutting themselves down.

Maria Deluca is an Autoverse addict; she’s unemployed and running out of money, but she can’t stop wasting her time playing around with the cellular automaton known as the Autoverse, a virtual world that follows a simple set of mathematical rules as its “laws of physics”.

Paul makes Maria a very strange offer: he asks her to design a seed for an entire virtual biosphere able to exist inside the Autoverse, modelled right down to the molecular level. The job will pay well, and will allow her to indulge her obsession. There has to be a catch, though, because such a seed would be useless without a simulation of the Autoverse large enough to allow the resulting biosphere to grow and flourish — a feat far beyond the capacity of all the computers in the world.

Product Details

BN ID: 2940154009581
Publisher: Greg Egan
Publication date: 02/08/2017
Sold by: Smashwords
Format: eBook
Sales rank: 755,100
File size: 452 KB

About the Author

I am a science fiction writer and computer programmer.

Read an Excerpt

Chapter One

(Remit not paucity)


Maria Deluca had ridden past the stinking hole in Pyrmont Bridge Road for six days running, certain each time, as she'd approached, that she'd be greeted by the reassuring sight of a work team putting things right. She knew that there was no money for road works or drainage repairs this year, but a burst sewage main was a serious health risk; she couldn't believe it would be neglected for long.

On the seventh day, the stench was so bad from half a kilometer away that she turned into a side street, determined to find a detour.

This end of Pyrmont was a depressing sight; not every warehouse was empty, not every factory abandoned, but they all displayed the same neglected look, the same peeling paint and crumbling brickwork. Half a dozen blocks west, she turned again -- to be confronted by a vista of lavish gardens, marble statues, fountains and olive groves, stretching into the distance beneath a cloudless azure sky.

Maria accelerated without thinking -- for a few seconds, almost believing that she'd chanced upon a park of some kind, an impossibly well-kept secret in this decaying corner of the city. Then, as the illusion collapsed -- punctured by sheer implausibility as much as any visible flaw -- she pedaled on wilfully, as if hoping to blur the imperfections and contradictions out of existence. She braked just in time, mounting the narrow footpath at the end of the cul-de-sac, the front wheel of her cycle coming to a halt centimeters from the warehouse wall.

Close up, the mural was unimpressive, the brushstrokes clearly visible, theperspective obviously false. Maria backed away -- and she didn't have to retreat far to see why she'd been fooled. At a distance of twenty meters or so, the painted sky suddenly seemed to merge with the real thing; with a conscious effort, she could make the border reappear, but it was hard work keeping the slight difference in hue from being smoothed out of existence before her eyes -- as if some subsystem deep in her visual cortex had shrugged off the unlikely notion of a sky-blue wall and was actively collaborating in the deception. Further back, the grass and statues began to lose their two-dimensional, painted look -- and at the corner where she'd turned into the cul-de-sac, every element of the composition fell into place, the mural's central avenue now apparently converging toward the very same vanishing point as the interrupted road.

Having found the perfect viewing position, she stood there awhile, propping up her cycle. Sweat on the back of her neck cooled in the faint breeze, then the morning sun began to bite. The vision was entrancing -- and it was heartening to think that the local artists had gone to so much trouble to relieve the monotony of the neighborhood. At the same time, Maria couldn't help feeling cheated. She didn't mind having been taken in, briefly; what she resented was not being able to be fooled again. She could stand there admiring the artistry of the illusion for as long as she liked, but nothing could bring back the surge of elation she'd felt when she'd been deceived.

She turned away.

Home, Maria unpacked the day's food, then lifted her cycle and hooked it into its frame on the living-room ceiling. The terrace house, one hundred and forty years old, was shaped like a cereal box; two stories high, but scarcely wide enough for a staircase. It had originally been part of a row of eight; four on one side had been gutted and remodeled into offices for a firm of architects; the other three had been demolished at the turn of the century to make way for a road that had never been built. The lone survivor was now untouchable under some bizarre piece of heritage legislation, and Maria had bought it for a quarter of the price of the cheapest modem flats. She liked the odd proportions -- and with more space, she was certain, she would have felt less in control. She had as clear a mental image of the layout and contents of the house as she had of her own body, and she couldn't recall ever misplacing even the smallest object. She couldn't have shared the place with anyone, but having it to herself seemed to strike the right balance between her territorial and organizational needs. Besides, she believed that houses were meant to be thought of as vehicles -- physically fixed, but logically mobile -- and compared to a one-person space capsule or submarine, the size was more than generous.

Upstairs, in the bedroom that doubled as an office, Maria switched on her terminal and glanced at a summary of the twenty-one items of mail which had arrived since she'd last checked. All were classified as "Junk"; there was nothing from anyone she knew -- and nothing remotely like an offer of paid work. Camel's Eye, her screening software, had identified six pleas for donations from charities (all worthy causes, but Maria hardened her heart); five invitations to enter lotteries and competitions; seven retail catalogues (all of which boasted that they'd been tailored to her personality and "current lifestyle requirements" -- but Camel's Eye had assessed their contents and found nothing of interest); and three interactives.

The "dumb" audio-visual mail was all in standard transparent data formats, but interactives were executable programs, machine code with heavily encrypted data, intentionally designed to be easier for a human to talk to than for screening software to examine and summarize. Camel's Eye had run all three interactives (on a doubly quarantined virtual machinea simulation of a computer running a simulation of a computer) and tried to fool them into thinking that they were making their pitch to the real Maria Deluca.

From the B&N Reads Blog

Customer Reviews