It's another nonsensically busy day at the Serious Crimes Division. Whether the same is true in your reality or not, here it is the part of the police which handles such diverse and exciting tasks as large-scale arson, pre-meditated murder, illegal chemical dumping, drug trafficking and madmen roaming the countryside with sniper rifles. The sheer quantity of paper and telephone calls it takes to merely keep a department like this running to stand still would make mortal men's minds freeze solid with shock; when stuff is actually in live progress (rather than simply being under intensive investigation after the fact, with serious public pressure to get results or sack the head man if no results are got), the office is chaos. Some students did actually do a study on the events during a recent murder investigation and found serious and not entirely unjustified comparisons with real mathematical chaos and turbulence, particularly in the way information circulates around the place.

In a way that's a source of pride.

Were you deaf and blind, you could still detect incoming, brewing trouble just from the increasing quantity of hurrying feet making the floorboards bounce. Detective Chuck McDonnell senses it while standing in the next room at the coffee machine waiting for thirty-five-penny sludge to finish drooling into his paper cup. Regardless of the phone calls, he feels the slight tremble. He hears his superior bounding up the adjoining stairs-- no other man in the world climbs to this floor like he does, three stairs at a time.

Chuck turns away from the stairs and aims down the corridor, hoping to be out of sight by the time the stairwell door is flung open, but he doesn't make it. There are six phones ringing on the office floor, and this is pretty much a truism, but even though they all have the same ringer he can tell that one of them is his. At his waist, his pager starts buzzing.

"Chuck," bellows his superior, whose name is Gary and who is, while three inches shorter, substantially more intimidating, "we've got a pretty serious problem down at County Hall. There's a man is holding the world to ransom with an iPhone."

"I..." and Chuck is exceptionally proud to have come up with this one so quickly, because in reality quippery isn't really as quippy as it is in, say, Spider-Hyphen-Man comics, "...I didn't think there was an app for that."

"Effing hilarious. He also has a gun. And eight or nine office workers."

"A gun?" replies Chuck, in the same tones that he might have remarked "A hyena?" or "A Sputnik?" "What is this, ten years from now? Don't look at me that way."

"Don't talk to me that way. It's computational and there's severe hypothetical stuff going on here. Like, he's talking about computers. In ways that nobody currently down there understands."

"I can fix a jammed photocopier and I read the first quarter of Snow Crash, does that qualify me for this? Are you sure you don't want me to bring down Adam from I.T. Services?"

"Yes. That's a great idea."

"Oh for Pete's sake."

Ten minutes later he has Adam in tow. For the purposes of this operation, Adam is operating in the same capacity as an interpreter would operate, if the crazy man in question were speaking, for example, Urdu, or Gaelic. Luckily, it is English, or there'd be two people in Chuck's car.

"An iPhone?" is all Adam can ask. He seems game. It's chilling. Chuck has déjà vu of his first day. Adam is smiling as he climbs into the passenger seat. Chuck gets enthusiastic tingles by proxy and this riles him up slightly. Chuck is not a smoker. This was a conscious decision he made long ago, because it would add too much depth to his character. If he was, there are various occasions when he would become irritable and smoke, or fiddle with a cigarette lighter. There aren't, because he doesn't. When he does fiddle, it's usually with transparent Bic biros which he chews until they shatter into plastic shreds in his teeth, or a small pointless magnetic executive toy that his mum got him for his birthday about ten years ago.

Kids.

*

"This is the real world!" cries the madman into the (conventional, desk-based, curly-wired) telephone handset. He's old and a little wobbly, but that much isn't visible yet because there are still people trying to get into position to see inside the building and he's keeping away from the windows. "And I've had it! I've had it! It doesn't matter what I do! I'll get what I want."

"And what is it that you want?" Chuck asks patiently, having heard all this from the speakerphone outside behind the police barricade. Adam and several others are also listening in there on the site, and it's going on the permanent record too. Chuck's in Negotiation mode, which replaces his cynical persona with something so sympathetic and understanding as to be physically disconcerting to people who know him personally.

"I don't really want... well, I can't explain it that well. To you. You won't get it."

"That's okay. I'll do my best to understand. We'll get some communication going. That's the solution to all problems-- clearer communication and understanding. What's your name, sir?"

"Max."

"Okay, Max, and why is it that you've taken these hostages?"

"Because-- well. Well. I work up at, at, at Juku Systems." Hearing this, Chuck points at one nearby officer, looks at him meaningfully, and receives a nod in reply, and the officer hurries off to get information. "In their hypercomputation department."

"You get that too?" asks Chuck to the retreating cop, on mute.

"Yup."

Max continues: "And we, uh, we were trying an experiment to break reality. W-well, more like, force reality to stop working properly by giving it something too complicated to actually h-handle. You know?"

"Not entirely, Max, I'm sorry. Why don't you explain that to me?"

"We figured out how to instantiate virtual universes with data read out of reality. Directly. Like a magnetic head reading bits off an HDD. And we've done it and it worked."

"Uh oh," says Adam.

"So here's what I'm saying. I've duplicated reality a million times. Give me one million dollars. Pounds. Pounds is better. Or I shut down this universe and kill everybody in it."

"Max, you can't do that with just an iPhone."

"No! No!" hisses Adam.

Max continues: "I'm sick of the not knowing! I don't want to be in a computer and I don't care if I am in one! I'll kill myself! And you, a million times! Just do what I say! I have the button right here and a charger and everything! No waiting for the battery to run down. I was ready."

*

"What in God's name is he talking about?" demands Chuck from anybody who'll listen.

"He's a doctor of computer science and his last name is Hastings," says the policeman who went and got that information.

"No relation," Adam hurriedly, guiltily interjects.

Chuck looks blankly at Adam for a moment, chewing his biro, carefully mentally folding up and filing the fact that Adam's surname is also Hastings, something which he, Chuck, did not know until this point. A few seconds elapse.

Adam continues: "This is this virtuality wossname. Juku Systems has basically just broken philosophy and solipsism in half across their knees."

"How so?" Chuck politely prompts.

"Well, if you can simulate the real world in every detail, then you can... well, simulate the real world in every detail. So you don't know (and we don't know) if we're in the simulation or not. We can't know, unless the person overseeing our universe (if there is one) decides to wave hello. Which hasn't happened unless you believe in God. Do you believe in God?"

"I don't think God is Max Hastings if that's your question and I don't think anybody else here does either, least of all Max Hastings."

"Well, he actually might. Anyway the point is that his threat might be real. He probably took a snapshot of the informational ultrastructure of the universe about two hours ago. That's useless for reading unless you have a cosmic simulator to run it in so I guess they have that now. If he's kicked off a million simulations of us at the lab then there's one REAL us where this standoff is actually taking place, and a million VIRTUAL worlds where the standoff is not actually happening and we aren't real. And more below those, probably, although not to infinite depth. But that doesn't matter. If--"

"Stop talking for a moment," says Chuck, holding a hand up. He points at several people in the circle. "Are you getting this? Are you getting this."

"I think so."

Chuck: "So he could have actually made a million and one universes? But we're in the real one. Or we'd know."

"Ah. Uh," confesses Adam. "Probably... probably not. We don't know. And he doesn't know. I don't think he has any way to know. He doesn't know if he created himself or not."

"This is crazy."

"Well, yeah. And so is Max Hastings."

Biro chewing. "Draw me the diagram."

*

"So there's one of us and a million simulated usses and we don't know which one we are. Okay. So let's say we're the real world. We give him what he wants, and he lets the hostages go. We don't give him what he wants, and he turns off a computer remotely using the remote control app on his iPhone or whatever he's got."

"Probably some sort of remote SSH command line--"

"That's great."

"But there's a million simulated usses all having the same conversation. We give him what he wants and it's okay. We don't, and he turns off a computer-- but the thing is that that means that the real us in reality have made the same decision and they turn off their computer which turns off our reality which destroys our world. Hence, the ransom."

"Give me ten minutes to straighten this out in my head," sighs Chuck.

*

"He's crazy because he doesn't know whether he lives inside one of his own simulations or not. He went nuts because he couldn't figure it out and made a million versions of our reality just to make the picture as complicated as possible and it's bloody working for me if nobody else!"

"That seems logical," says Adam.

"Do we have access to this machine?"

The other cop who investigated the whole Juku problem nods.

Adam: "Sure, but that doesn't mean we can turn it off. That's the whole problem. In fact if there's a power failure there's a one million in one million and one chance, which is very high and very bad, that it'll completely take us out too."

"Why would you build a universe in which there are power failures?" asks Chuck, still not getting it.

"Because ripping off something somebody else made using copy and paste is piss-easy compared to actually creating anything worthwhile," says Adam.

"Ah! You're speaking my language."

*

"Max Hastings! Are you there? We've been listening to your terms. You can come out now, with your hands up. It's no problem at all, right?"

Max replies: "I can't take living in a fake world."

"Correction," Detective Chuck McDonnell replies, between chews. "You can't living in a fake world where you don't have a million pounds. And why should you? It's a strain. It's just like reality except you've got no control over your destiny because all that happened for real one layer up. Terrible! You should be compensated. Compensated by God for living in such uncertain times."

"Right?"

"So we went to the computer and we modified the other realities. We gave all the fake simulated yous a million pounds. And keep this on the down low, all right? Your bank manager shouldn't know about this, for example. So you can come out. Either there's a simulated million pounds in simulated-you's simulated house right now (and we haven't checked, swear to God, whether God is or is not you), or there's no money but you're guaranteed that this is real reality, top level and all."

"Right?"

"Right. I mean, pick one. Real reality, or a million quid for your trouble. Sounds good?"

"Sounds good."

And that's how they get him. They take him to prison and counsel the hostages. Job done.

*

"And what about these simulations that we can't ever, ever turn off?"

"Well, it's a hypercomputer," says Adam. "So the obvious answer is to just run them at a million billion trillion times speed until the universe ends and then turn them off, like a light."

"Of course. I'm sure that makes sense," says Chuck. "Right. Someone do that. Coffee?"

With thanks to Paul Almond