Terry Pratchett - The Science of Discworld

by Terry Pratchett

  Humans add narrativium to their world. They insist in inter­preting the universe as if it’s telling a story. This leads them to focus on facts that fit the story, while ignoring those that don’t. But we mustn’t let the coincidence, the clump, choose the sample space -when we do that, we’re ignoring the surrounding space of near-coincidences.

  Jack and Ian managed to test this theory on a trip to Sweden. On the plane, Jack predicted that a coincidence would happen at Stockholm airport - for reasons of selective reporting. If they looked hard enough, they’d find one. They got to the bus stop out­side the terminal, and no coincidences had occurred. But they couldn’t find the right bus, so Jack went back to the enquiries desk. As he waited, someone came up next to him ­Stefano, a mathe­matician who normally occupied the office next door to Jack’s. Prediction confirmed. But what was really needed was evidence of a near-coincidence - one that hadn’t happened, but could have been selectively reported if it had. For instance, if some other acquain­tance had shown up at exactly the same time, but on the wrong day, or at the wrong airport, they’d never have noticed. Near coinci­dences, by definition, are hard to observe ... but not impossible. Ianhappened to mention all of the above to his friend Ted, who was vis­iting soon after. ’Stockholm?’ said Ted: ’When?’ Iantold him. ’Which hotel?’ Iantold him ’Funny, I was staying there one day later than your Had the trip been one day later, the ’coincidental’ encounter with Stefano wouldn’t have happened - but the one with Ted would.

  What we must not do, then, is to look back at past events and find significance in the inevitable few that look odd. That is the way of the pyramidologists and the tea-leaf readers. Every pattern of raindrops on the pavement is unique. We’re not saying that if one such patterns happens to spell your name, this is not to be won­dered at - but if your name had been written on the pavement in Beijing during the Ming dynasty, at midnight, nobody would have noticed. We should not look at past history when assessing signifi­cance: we should look at all the other things that might have happened instead.

  Every event is unique. Until we place that event in a category, we can’t work out which background to view it against. Until we choose a background, we can’t estimate the event’s probability. If we consider the sample space of all possible DNA codes, for instance, then we can calculate the probability of a human being having exactly your DNA code - which is vanishingly small. But it would be silly to conclude that it is impossible for you to exist.

  THIRTY-THREE

  STILL BLOODY LIZARDS

  ’THE FUTURE IS LIZARD,’ said Ridcully. ’Obviously.’ It was a few days later. The omniscope was focused on a mound of leaves and rotting vegeta­tion a little way from the banks of the river. There was a large depression hanging over the Senior Wrangler, and the Dean had a black eye. The war between land and sea had just entered a terminal stage.

  ’Little portable seas,’ said Ponder. ’You know, I never thought of them like that.’

  ’An egg is an egg, however you look at it,’ said Ridcully. ’Look, you two, I don’t want to see a scuffle like that again, d’you hear?’ The Senior Wrangler dabbed at his bleeding nose. ’He goaded be,’ he said. ’Id’s still osuns, howeber you look at id.’ ’A private ocean full of food,’ said Ponder, still entranced. ’Hidden in a heap of... well, compost. Which heats up. That’s like having private sunshine.’

  The little lizard-like creatures that had hatched from the eggs in the mound slithered and slid down the bank into the water, bright-eyed and hopeful. The first few were instantly snapped up by a large male lying in wait among the weeds.

  ’However, the mothers still have something to learn about post­natal care,’ said Ridcully. ’I wonder if they’ll have time to learn? And how did they know how to do this? Who’s telling them?’

  The wizards were depressed again. Most days started that way now. Creatures seemed to turn up in the world randomly, and certainly not according to any pictures in a book. If things were changing into other things, and no one had seen that happen yet, why were the original things still the original things? If the land was so great, why were any fish left in the sea?

  The air-breathing fishes that Rincewind had seen still seemed to be around, lurking in swamps and muddy beaches. Things changed, but still stayed the same.

  And if there was any truth at all in Ponder’s tentative theory that things did change into other things, it led to the depressing thought that, well, the world was filling up with quitters, creatures which -instead of staying where they were, and really making a go of life in the ocean or the swamp or wherever - were running away to lurk in some niche and grow legs. The kind offish that’d come out of water was, frankly, a disgrace to the species. It kept coughing all the time, like someone who’d just given up smoking.

  And there was no purpose, Ridcully kept saying. Life was on land. According to the book, there should be some big lizards. But nothing seemed to be making much of an effort. The moment any­thing felt safe, it stopped bothering.

  Rincewind, currently relaxing on a rock, rather liked it. There were large animals snuffling around in the greenery near the rock he was sitting on; in general shape and appearance, they looked like a small skinny hippopotamus designed in the dark by a complete amateur. They were hairy. They coughed, too.

  Things that were doing sufficiently beetle-like things for him to think of them as beetles ambled across the ground.

  Ponder had told him the continents were moving again, so he kept a firm grip on his rock just in case.

  Best of all, nothing seemed to be thinking. Rincewind was con­vinced that no good came of that sort of thing.

  The last few weeks of Discworld time had been instructive. The wizards had tentatively identified several dozen embryo civiliza­tions, or at least creatures that seemed to be concerned about more than simply where their next meal was coming from. And where were they now? There was a squid one, HEX said, out in the really deep cold water. Apart from that, ice or fire or both at once came to the thinkers and the stupid alike. There was probably some kind of moral involved.

  The air shimmered, and half a dozen ghostly figures appeared in front of him.

  There were, in pale shadowy colours, the wizards. Silvery lines flickered across their bodies and, periodically, they flickered.

  ’Now, remember,’ said Ponder Stibbons, and his voice sounded muffled, ’You are in fact still in the High Energy Magic building. If you walk slowly HEX will try to adjust your feet to local ground level. You’ll have a limited ability to move things, although HEX will do the actual work -’

  ’Can we eat?’ said the Senior Wrangler.

  ’No, sir. Your mouth isn’t here.’

  ’Well, then, what am I talking out of?’

  ’Could be anyone’s guess, sir,’ said Ponder diplomatically. ’We can hear you because our ears are in the HEM, and you can hear the sounds made here because HEX is presenting you with an analogue of them. Don’t worry about it. It’ll seem quite natural after a while.’

  The ghost of the Dean kicked at the soil. A fraction of a second later, a little heap of earth splashed up.

  ’Amazing!’ he said, happily.

  ’Excuse me?’ said Rincewind,

  They turned.

  ’Oh, Rincewind,’ said Ridcully, as one might say ’oh dear, it’s raining’. ’It’s you.’

  ’Yes, sir.’

  ’Mister Stibbons here’s found a way of getting HEX to operate more than one virtually-there suit, d’you see? So we thought we’d come down and smell the roses.’

  ’Not for several hundred million years, sir,’ said Ponder.

  ’Dull, isn’t it,’ said the Lecturer in Recent Runes, looking around. ’Not a lot going on. Lots of life, but it’s just hanging around.’

  Ridcully rubbed his hands together.

  ’Well, we’re going to liven it up,’ he said. ’We’re going to move things forward fast while we’re here. A few prods in the right place, that’s what these creat
ures need.’

  ’The time travelling is not much fun,’ said Rincewind. ’You tend to end up under a volcano or at the bottom of the sea.’

  ’We shall see,’ said Ridcully firmly. ’I’ve had enough of this.

  Look at those damn sloppy things over there. ’He cupped his hands and shouted, ’Life in the sea not good enough for you, eh? Skiving off, eh? Got a note from your mother, have you?’ He lowered his hands. ’All right, Mister Stibbons ... tell HEX to take us forward, oh, fifty million years - hang on, what was that?’

  Thunder rolled around the horizon.

  ’Probably just another snowball landing,’ said Rincewind morosely. ’There’s generally one around just when things are set­tled. It was in the sea, I expect. Stand by for the tidal wave.’ He nodded at the browsing creatures, who had glanced up briefly.

  ’The Dean thinks all this hammering from rocks is making the life on this world very resilient,’ said Ridcully.

  ’Well, that’s certainly a point of view,’ said Rincewind. ’But in a little while a wave the size of the University is going to wash this beach on to the top of those mountains over there. Then I expect the local volcanoes will all let go ... again ... so stand by for a coun­try-sized sea of lava coming the other way. After that there’ll probably be outbreaks of rain that you could use to etch copper, fol­lowed by a bit of a cold spell for a few years and some fog you could cut up in lumps.’ He sniffed. ’That which does not kill you can give you a really bad headache.’

  He glanced at the sky. Strange lightning was flickering between the clouds, and now there was a glow on the horizon.

  ’Damn,’ he said, in the same tone of voice. ’This is going to be one of the times when the atmosphere catches fire. I hate it when that happens.’

  Ridcully gave him a long blank look, and then said, ’Mister Stibbons?’

  ’Archchancellor?’

  ’Make that seventy thousand years, will you? And, er ... right now, if you would be so good.’

  The wizard vanished.

  All the insects stopped buzzing in the bushes.

  The hairy lizards carried on placidly eating the leaves. Then, something made them look up ­

  The sun jerked across the sky, became very briefly a reddish-yellow band across a twilight hemisphere, and then the world was simply a grey mist. Below Rincewind’s feet it was quite dark, and above him it was almost white. Around him, the greyness flickered.

  ’Is this what it always looks like?’ said the Dean.

  ’Something has to stand still for a couple of thousand years before you see it at all,’ said Rincewind.

  ’I thought it would be more exciting -’

  The light flickered, and sun exploded into the sky, the wizards saw waves around them for a moment, and then there was darkness.

  ’I told you,’ said Rincewind. ’We’re under water.’

  ’The land sank under all the volcanoes?’ said Ridcully.

  ’Probably just moved away,’ said Rincewind. ’There’s a lot of that sort of thing down here.’

  They rose above the surface as HEX adjusted to the new condi­tions. A landmass was smeared on the horizon, under a bank of cloud.

  ’See?’ said Rincewind. ’It’s a pain. Time travel always means you end up walking.’

  ’hex, move us to the nearest land, please. Inland about ten miles,’ said Ponder.

  ’You mean I could have just asked?’ said Rincewind. ’All this time, I needn’t have been walking?’

  ’Oh, yes.’

  The landscape blurred for a second.

  ’You could have said,’ said Rincewind accusingly, as they were rushed past, and sometimes through, a forest of giant ferns.

  The view stabilized. The wizard had been through to the edge of the forest. Low-growing shrubs stretched away towards more ferns.

  ’Not much about,’ said Ridcully, leaning against a trunk. ’Can I smoke my pipe here, Stibbons?’

  ’Since technically you’ll be smoking in the High Energy Building, yes, sir.’

  Rincewind apparently struck a match on the tree trunk. ’Amazing,’ he said.

  ’That’s odd, sir,’ said Ponder. ’I didn’t think there would be any proper trees yet.’

  ’Well, here they are,’ said Ridcully. ’And I can see at least another three more ...’

  Rincewind had already started to run. The fact that nothing can harm you is no reason for not being scared. An expert can always find a reason for being scared.

  The fact that the nearest trunk had toenails was a good one.

  From among the ferns above, a large head appeared on the end of too much neck.

  ’Ah,’ said Ridcully calmly. ’Still bloody lizards, I see.’

  Ponder was working the Rules again. Now they read:

  THE RULES 1 Things fall apart, but centres hold 2 Everything moves in curves 3 You get balls 4 Big balls tell space to bend 5 There are no turtles anywhere (after this one he’d added Except ordinary ones) 6 Life turns up everywhere it can 7 Life turns up everywhere it can’t 8 There is something like narrativium 9 There may be something called bloodimindium (see

  rule 7) 10...

  He stopped to think. Behind him, a very large lizard killed and ate a slightly smaller one. Ponder didn’t bother to turn around. They’d been watching lizards for more than a hundred million years - all day, in fact - and even the Dean was giving up on them.

  ’Too well adapted,’ he said. ’Nopressure on them, you see,’

  ’They’re certainly very dull,’ said Ridcully. ’Interesting colours, though.’

  ’Brain the size of a walnut and some of them think with their backsides,’ said the Senior Wrangler.

  ’Your type of people, Dean,’ said Ridcully.

  ’I shall choose to ignore that, Archchancellor,’ said the Dean coldly.

  ’You’ve been interfering again, haven’t you,’ Ridcully went on. ’I saw you pushing some of the small lizards out of that tree.’

  ’Well, you’ve got to admit that they look a bit like birds,’ said the Dean.

  ’And did they learn to fly?’

  ’Not in so many words, no. Not horizontally.’

  ’Eat, fight, mate and die,’ said the Lecturer in Recent Runes. ’Even the crabs were better than this. Even the blobs made an effort. When they come to write the history of this world, this is the page everyone will skip. Terribly dull lizards, they’ll be called. You mark my words.’

  ’They have stayed around for a hundred million years, sir,’ said Rincewind, who felt he had to stand up for non-achievers.

  ’And what have they done? Is there a single line of poetry? A building of any sort? A piece of simple artwork?’

  ’They’ve just not died, sir.’

  ’Not dying out is some kind of achievement, is it?’ said the Lecturer in Recent Runes.

  ’Best kind there is, sir.’

  ’Pah!’ said the Dean. ’All they prove is that species go soft when there’s nothing happening! It’s nice and warm, there’s plenty to eat ... it’s just the sea without water. A few periods of vulcanism or a medium-sized comet would soon have them sitting up straight and paying attention.’

  The air shimmered and Ponder Stibbons appeared.

  ’We have intelligence, gentlemen,’ he said.

  ’I know,’ said the Dean.

  ’I mean, the omniscope has found signs of developing intelli­gence. Twice, sir.’

  The herd was big. It was made up of large, almost hemispherical creatures, with faces that had all the incisive cogitation of a cow.

  Much smaller creatures were trotting along at the edges. They were dark, scrawny and warbled to one another almost without cease.

  They also carried pointed sticks.

  ’Well ...’ Ridcully began, dismissively.

  ’They’re herding them, sir!’ said Ponder.

  ’But wolves chase sheep ...’

  ’Not with pointy sticks, sir. And look there ...’

  One of the bea
sts was towing a crude travois, covered with leaves. Several herders were lying on it. They were pale around the muzzles.

  ’Are they sick, d’you think?’ said the Dean.

  ’Just old, sir.’

  ’Why’d they want to slow themselves down with a lot of old peo­ple?’

  Ponder dared a short pause before answering.

  ’They’re the library, sir. I suppose. They can remember things. Places to hunt, good waterholes, that sort of thing. And that means they must have some sort of language.’

  ’It’s a start, I suppose,’ said Ridcully.

  ’Start, sir? They’ve nearly done it all!’ Ponder put his hand to his ear. ’Oh ... and HEX says there’s more, sir. Er ... different.’

  ’How different?’

  ’In the sea again, sir,’

  ’Aha,’ said the Senior Wrangler.

  In fact on the sea was more accurate, he had to admit. The colony they found stretched for miles, linking a chain of small rocky islands and sandbanks as beads on a chain of tethered driftwood and rafts of floating seaweed.

  The creatures inhabiting it were another type of lizard. Still extremely dull, the wizards considered, compared to some of the others. They weren’t even an interesting colour and they had hardly any spikes. But they were ... busy creatures.

  ’That seaweed ... does it look sort of regular to you?’ said the Lecturer in Recent Runes, as they drifted over a crude wall. They’re not farming, are they?’

  ’I think ...’ Ponder looked down. The water washed over the wall of rocks. ’It’s a big cage for fish. The whole lagoon. Er ... I think they’ve built the walls like that so the tide lets the fish come in and then they’re stuck when it goes down.’

  Lizards turned their heads as the semi-transparent men floated past, but seemed to treat them as no more than passing shadows.

  ’They’re harnessing the power of the sea?’ said Ridcully. ’That’s clever.’

  Lizards were diving at the far side of the lagoon. Some were busy around rock pools on one of the lower islands. Small lizards swam in the shallows. Along one stretch of driftwood walkways, strips of seaweed were drying in the breeze. And over everything was a yip-yipping of conversation. And it was conversation, Ponder decided. Animals didn’t wait for other animals to finish. Nor did wizards, of course, but they were a breed apart.