Permutation City

real train again, and walked down a real street -- he didn't want the joy of the experience dulled by years of perfect imitation.

He had no wish to delude himself -- but apart from declining to mimic his corporeal life to the point of parody, it was hard to define exactly what that meant. He baulked at the prospect of the nearest door always opening magically onto his chosen destination, and he had no desire to snap his fingers and teleport. Acknowledging -- and exploiting -- the unlimited plasticity of Virtual Reality might have been the most 'honest' thing to do . . . but Thomas needed a world with a permanent structure, not a dream city which reconfigured itself to his every whim.

Eventually, he'd found a compromise. He'd constructed an auxiliary geography -- or architecture -- for his private version of Frankfurt; an alternative topology for the city, in which all the buildings he moved between were treated as being stacked one on top of the other, allowing a single elevator shaft to link them all. His house 'in the suburbs' began sixteen stories 'above' his city office; in between were board rooms, restaurants, galleries and museums. Having decided upon the arrangement, he now regarded it as immutable -- and if the view from each place, once he arrived, blatantly contradicted the relationship, he could live with that degree of paradox.

Thomas stepped out of the elevator into the ground floor entrance hall of his home. The two-story building, set in a modest ten hectares of garden, was his alone -- as the real-world original had been from the time of his divorce until his terminal illness, when a medical team had moved in. At first, he'd had cleaning robots gliding redundantly through the corridors, and gardening robots at work in the flower beds -- viewing them as part of the architecture, as much as the drain pipes, the air-conditioning grilles, and countless other 'unnecessary' fixtures. He'd banished the robots after the first week. The drain pipes remained.

His dizziness had passed, but he strode into the library and poured himself a drink from two cut-glass decanters, a bracing mixture of Confidence and Optimism. With a word, he could have summoned up a full mood- control panel -- an apparition which always reminded him of a recording studio's mixing desk -- and adjusted the parameters of his state of mind until he reached a point where he no longer wished to change the settings . . . but he'd become disenchanted with that nakedly technological metaphor. Mood-altering 'drugs,' here, could function with a precision, and a lack of side effects, which no real chemical could ever have achieved -- pharmacological accuracy was possible, but hardly mandatory -- and it felt more natural to gulp down a mouthful of 'spirits' for fortification than it did to make adjustments via a hovering bank of sliding potentiometers.

Even if the end result was exactly the same.

Thomas sank into a chair as the drink started to take effect -- as a matter of choice, it worked gradually, a pleasant warmth diffusing out from his stomach before his brain itself was gently manipulated -- and began trying to make sense of his encounter with Paul Durham.

You have to let me show you exactly what you are.

There was a terminal beside the chair. He hit a button, and one of his personal assistants, Hans Lohr, appeared on the screen.

Thomas said casually, 'Find out what you can about my visitor, will you?'

Lohr replied at once, 'Yes, sir.'

Thomas had six assistants, on duty in shifts around the clock. All flesh-and-blood humans -- but so thoroughly wired that they were able to switch their mental processes back and forth between normal speed and slowdown at will. Thomas kept them at a distance, communicating with them only by terminal; the distinction between a visitor 'in the flesh' and a 'mere image' on a screen didn't bear much scrutiny, but in practice it could still be rigorously enforced. He sometimes thought of his staff as working in Munich or Berlin . . . 'far enough away' to 'explain' the fact that he never met them in person, and yet 'near enough' to make a kind of metaphorical sense of their ability to act as go-betweens with the outside world. He'd never bothered to find out where they really were, in case the facts contradicted this convenient mental image.

He sighed, and took another swig of C & O. It was a balancing act, a tightrope walk. A Copy could go insane, either way. Caring too much about the truth could lead to a pathological obsession with the infrastructure -- the algorithms and optical processors, the machinery of 'deception' which lay beneath every surface. Caring too little, you could find yourself gradually surrendering to a complacent fantasy in which life had gone on as normal, and everything which contradicted the illusion of ordinary physical existence was avoided, or explained away.

Was that Durham's real intention? To drive him mad?

Thomas had ordered the usual cursory screening before letting Durham in, revealing only that the man worked as a salesman for Gryphon Financial Products -- a moderately successful Anglo-Australian company -- and that he possessed no criminal record. Elaborate precautions were hardly warranted; visitors could do no harm. Thomas's VR consultants had assured him that nothing short of tampering with the hardware in situ could ever damage or corrupt the system; no mere signal coming down the fiber from the outside world could penetrate the protected layers of the software. Visitors who wreaked havoc, introducing viruses by the fiendishly clever binary-modulated snapping of their fingers, were the stuff of fiction. (Literally; Thomas had seen it happen once on The Unclear Family.)

Durham had said: 'I'm not going to lie to you. I've spent time in a mental institution. Ten years. I suffered delusions. Bizarre, elaborate delusions. And I realize, now, that I was seriously ill. I can look back and understand that.

'But at the very same time, I can look back and remember what it was that I believed was happening when I was insane. And without for one moment ceasing to acknowledge my condition, I still find those memories so convincing . . . '

Thomas's skin crawled. He raised his glass . . . and then put it down. He knew that if he kept on drinking, nothing the man had said would unsettle him in the least -- but he hadn't drunk enough, yet, to be absolutely sure that that was what he wanted.

'If you're not prepared to perform the experiment yourself, at least think about the implications. Imagine that you've modified the way in which you're computed -- and imagine what the consequences would be. A gedanken experiment -- is that too much to ask for? In a sense, that's all I ever performed myself.'

The terminal chimed. Thomas took the call. Lohr said, 'I have a preliminary report on Paul Durham. Would you like me to read it?'

Thomas shook his head. 'I'll view the file.'

He skimmed it, at level one detail. Paul Kingsley Durham. Born in Sydney on June 6, 2000. Parents: Elizabeth Anne Maddox and John Arthur Durham . . . joint owners of a delicatessen in the Sydney suburb of Concord, from 1996 to 2032 . . . retired to Mackay, Queensland . . . now both deceased by natural causes.

Educated at a government high school. 2017: Higher School Certificate aggregate score in third percentile; best subjects physics and mathematics. 2018: completed one year of a science degree at Sydney University, passed all examinations but discontinued studies. 2019 to 2023: traveled in Thailand, Burma, India, Nepal. 2024: on return to Australia, diagnosed with an organic delusional syndrome, probably congenital . . . condition partly controlled by medication. Numerous casual laboring jobs until May, 2029. Condition deteriorating . . . disability pension granted January, 2031. Committed to Psychiatric Ward of Blacktown Hospital on September 4, 2035.

Corrective nanosurgery to the hippocampus and prefrontal cerebral cortex performed on November 11, 2045 . . . declared a complete success.

Thomas switched to level two, to fill in the ten-year gap, but found little more than a long list of the drugs, neural grafts, and gene-therapy vectors which had been injected into Durham's skull during that period, to no apparent benefit. There were frequent notes that the treatments had been tested first on a set of partial brain models, but hadn't worked in practice. Thomas wondered if Durham had been told about this -- and wondered what the man imagined happened when a drug was evaluated on fifteen separate models of different regions of the brain, which, taken together, encompassed the entire organ . . .

2046 to 2048: studying finance and administration at Macquarie University. 2049: graduated with first class honors, and immediately hired by Gryphon as a trainee salesman. As of January 17, 2050, working in the Artificial Intelligence Division.

Which meant selling protection, in various guises, to Copies who were afraid that their assets were going to be pulled out from under them. Durham's job description would certainly cover spending long hours as a visitor --