The Science of Discworld II

by Terry Pratchett

  This nirvanic view of heaven is not for those who enjoy the material ride too much to want to get off the bus. And the paradoxical nature of the prophetic predictions – of all prophetic predictions – is disturbing. There is no way at all that a deterministic Earth can be accommodated by today’s view of what planets are like, and most of today’s more sophisticated religions have no room for an immanent God, tinkering with each life, and its context, to achieve its destiny. Those that do have room for immanence encounter real problems with modern technology, whose basis lies in ways-of-the-universe modelled by science, not by djinns or the whim of a deity or deities. And although we may, with Fredric Brown, be amused that when the djinni that worked the electric light and the radio came out on strike, the steam-power genies came out in sympathy, we enjoy this animistic fantasy as fuel for Murphy’s Law and nice Disneyesque animations. We don’t buy any of it for real causality.

  Joseph Needham brought light to this kind of confusion. He pointed out, in the introduction to his truly gigantic History of Science in China, that the reason why China never developed science as the West knows it is that they never espoused monotheism. In polytheistic philosophies, it isn’t very sensible to search for the cause of something, like a thunderstorm, say: you’re liable to get a very contingent answer involving several incidents in the love lives of the gods, and an explanation of the provenance of thunderbolts that verges on the ridiculous.4

  Monotheists, however, by which we mean someone like Abraham, to whom we shall return later, reckon that God had a consistent set of ideas and causalities in mind when he set the universe up. One set of ideas. If you expect your one God to be consistent, then it’s worth asking how those causalities relate to each other: for example, ‘black clouds and rain will be associated with thunderstorms when …’ whatever. The monotheist can predict the weather, even if rather badly. But the polytheist needs a theopsychologist and a precise account of what the gods are up to at the moment. She needs to know whether a tiff between two gods will result in a thunderstorm. So scientific causality is compatible with God-causality, but not with gods-causality.

  Monotheists, moreover, have a built-in intolerance. The position that there is only one truth, only one avenue to the one God, sets each monotheistic religion in opposition to all others. There is no room for manoeuvre, no way to tolerate the manifest errors of people who believe in some other god. So monotheism laid the foundation for the Inquisition, and for intemperate Christianity through the ages from the crusades through to African and Polynesian missionaries. ‘I have the story, and it is the only one’ is characteristic of many cults, all of them intolerant.

  Faiths, of course, do get along. But they get along because of the hammering they have taken at the hands of science, material development and better education. They get along because of wise people within them who recognise the commonality of humanity. Where there are too few wise people, you get Northern Ireland. If you are lucky.

  If the future is not fixed, but malleable, and we can predict the effects of our present behaviour, however badly, then predicting the future can be self-defeating. And that can even be the reason for predicting it.

  Most of the Biblical prophets seem, like many science-fiction authors today, to be warning against what might happen if we go on as we are doing. So they succeed when their prophecy is not correct, because people heed it and change their actions. We can understand that; even though the prophecy didn’t come true, we can all see that it might have done: it has given us a better idea of the phase space that the future of our culture lives in.

  What about the gypsy who prophesies that a tall dark man will come into your life, thus making you receptive to all those future tall dark men? (if tall dark men interest you, of course; it’s up to you.) This could be a self-fulfilling prophecy, the opposite of the stories told by Biblical prophets. It’s a story that the recipient is sympathetic to, wants to happen.

  There are said to be only seven basic story plots, so perhaps our minds are much less varied than we think, so that the newspaper astrologer and the fortune-teller are navigating a much smaller phase space of human experience than we thought. This would account for so many people feeling that the predictions show deep insight.

  But when astronomers predict the future, and get it right, people are, paradoxically, much less impressed. When they predict eclipses correctly, every time, this seems less meaningful than the astrologers nearly getting many people right, sometimes. Remember Y2K, the prophecy that planes would fall out of the sky soon after the year 2000 dawned and your toaster wouldn’t work? That prophecy cost the world several billion dollars in work to avert the problem – and it didn’t happen. A waste of time, then? Not at all. It didn’t happen because people took precautions. If they hadn’t done, the cost would have been much higher. It was a Biblical prophecy: ‘If this goes on …’ And, lo, the multitude heeded.

  This recursive dependence of prophecy upon people’s responses to it, unlike most of the other kinds of thing that we say, relates back to our facility with our own made-up little futures, the stories that we tell ourselves. They confirm us in our identities. It is no wonder that when someone – an astrologer or Nostradamus, say – pokes his finger into this mental place where we live, and inserts some of his own stories, we want to believe him. His stories are more exciting than ours. We wouldn’t have thought, going down the stairs to get a train to work, ‘I wonder if I’m going to meet a tall dark guy today?’ But once it’s been put into our minds, we smile at all the dark men, even some quite short ones. And so our lives are changed (perhaps in quite major ways, if you are a man doing the smiling) as are the stories that we ourselves proposed for our futures.

  This way that we react, fairly predictably, to what the world throws at us, casts doubt on our otherwise unshakeable belief that we get to choose what we do. Do we truly possess free will? Or are we like the amoeba, drifting this way and that, propelled by the dynamic of a phase space that cannot be perceived from outside?

  In Figments of Reality we included a chapter with the title ‘We wanted to have a chapter on free will but we decided not to, so here it is’. There we examined such issues as whether, in a world without genuine free will, it would be fair to blame a person for their actions. We conclude that in a world without genuine free will, there might not be any choice: they would get blamed anyway because the possibility of them not being blamed did not exist.

  We won’t go over that ground in detail, but we do want to summarise the main thrust of the argument. We start by observing that there is no effective scientific test for free will. You can’t run the universe again, with everything exactly as it was, and see if a different choice can be made second time round. Moreover, there seems to be no room in the laws of physics for genuine free will. Quantum indeterminacy, seized on so readily by many philosophers and scientists as a catch-all explanation of ‘consciousness’, is the wrong kind of thing altogether: random unpredictability is not the same as choosing between clear alternatives.

  There are many ways in which the known laws of physics could offer an illusion of free will, for example by exploiting chaos or emergence, but there is no way to set up a system that could make different choices even though every particle in the universe, including those making up the system, is in the same state on both occasions.

  Add to this one rather interesting aspect of human social behaviour: although we feel as if we have free will, we don’t act as if we believe that anybody else has. When somebody does something uncharacteristic, ‘not like them’, we don’t say ‘Oh, Fred is exercising his free will. He’s been a lot happier since he smiled at the tall, dark stranger.’ We say ‘What the devil has got into Fred?’ Only when we find a reason for his actions, an explanation not involving the exercise of free will (like drunkenness, or ‘doing it for a bet’) do we feel satisfied.

  All of this suggests that our minds do not actually make choices: they make judgements. Those judgements reveal not what we
have chosen, but what kind of mind we possess. ‘Well, I never would have guessed,’ we say, and feel we’ve learned something that we can use in future dealings with that person.

  So what about that strong feeling that we get, of making a choice? That’s not what we’re doing, it’s what it feels like to us when we’re doing it, just as that vivid grey quale of the visual system is not actually out there on the elephant, but an added decoration that exists in our heads. ‘Choosing’ is what our minds feel like from inside when they’re judging between alternatives. Free will is not a real attribute of human beings at all: it is merely the quale of judgement.

  1 Admittedly, many African tribes think no such thing: you can hide things from the fairly simple local god. But then it’s not much of a god. Probably the tribal mores have been corrupted with the passage of time.

  2 Why birth, the sheerest accident during our development’ Why not fertilisation? Or hatching from the zona pellucida, the egg membrane? Or the first heartbeat’ Or the first dream (while still in the uterus)? Or the first word, or the first carnal experience? There are aspects of our future that are determined by, at least, the date of our birth (we may end up the youngest or the oldest child in the school intake that year, and that can make a big difference) but we’re not talking about these human-created things here.

  3 The gravitational attraction exerted by a single doctor at a distance of 6 inches is roughly twice that of Jupiter at its closest point to the Earth.

  4 At least on Discworld you can see the gods acting disgracefully.

  SEVENTEEN

  FREEDOM OF INFORMATION

  PEOPLE BELIEVED THAT ELVES could look like anything they wanted to, but this was, strictly speaking, wrong. Elves looked the same all the time (rather dull and grey, with large eyes, rather similar to bushbabies without the charm) but they could, without effort, cause others to see them differently.

  Currently the Queen looked like a fashionable lady of the time, in black lace, sparkling here and there with diamonds. Only with a hand over one eye and extreme concentration could even a trained wizard dimly see the true nature of the elf, and even then his eye would water alarmingly.

  Nevertheless, the wizards stood up when she entered. There’s such a thing as courtesy, after all.

  ‘Welcome to my world, gentlemen,’ said the Queen, sitting down. Behind her, a couple of guards took up station either side of the door.

  ‘Ours!’ snarled the Dean. ‘It’s our world!’

  ‘Let us continue to disagree, shall we?’ said the Queen brightly. ‘You may have constructed it, but it’s our world now.’

  ‘We have iron, you know,’ said Ridcully. ‘Would you like some tea, by the way? Foul stuff made without actual tea.’

  ‘Much good may it do you. No, thank you,’ said the Queen. ‘Please note that my guards are human. So is your host. The Dean looks angry. You intend to fight here? When you have no magic? Be serious, gentlemen. You should be grateful, after all. This is a world without narrativium. Your strange humans were monkeys without stories. They did not know how the world was supposed to go. We gave them stories, and made them people.’

  ‘You gave them gods and monsters,’ said Ridcully. ‘Stuff that stops people thinking straight. Superstitions. Demons. Unicorns. Bogeymen.’

  ‘You have bogeymen on your world, don’t you?’ said the Queen.

  ‘Yes, we do. But outside, where we can get at ’em. They ain’t stories. When you can see ’em, they don’t have any power.’

  ‘Like unicorns,’ said the Lecturer in Recent Runes. ‘When you meet one, you find out it’s just a big sweaty horse. Looks nice, smells horsey.’

  ‘And it’s magical,’ said the Queen, her eyes gleaming.

  ‘Yes, but that’s just another thing about it,’ said Ridcully. ‘Big, sweaty, magical. There’s nothing mysterious about it. You just learn the rules.’

  ‘But surely you should be pleased!’ said the Queen, her eyes saying that she knew they weren’t and was glad of it. ‘Everyone here thinks this world is just like yours! Many people even believe that it is flat!’

  ‘Yes, but back home they’d be right,’ said Ridcully. ‘Here they’re just ignorant.’

  ‘Well, there is not a single thing you can do about it,’ said the Queen. ‘This is our world, Mister Wizard. It’s all stories. The religions here … amazing! And the beliefs … wonderful! The crop is bountiful, the harvest is rewarding. Do you know that more people believe in magic here than they do on your world?’

  ‘We don’t have to believe in it. It works!’ snapped Ridcully.

  ‘They believe in it here, and it doesn’t,’ said the Queen. ‘And thus they believe in it even more, while ceasing to believe in themselves. Isn’t it astonishing?’

  She stood up. Most of the wizards went to stand up, too, and one or two of them got all the way. Misogynists to a man, the wizards were therefore always punctiliously polite to ladies.

  ‘Here, you are just rather fussy old men,’ she said. ‘But we understand this world and we have had time to cultivate it. We like it. You can’t take us away. Your humans need us. We are part of their world now.’

  ‘This world, madam, has about another thousand years before all life is wiped out,’ said Ridcully.

  ‘Then there are other worlds,’ said the Queen, lightly.

  ‘That’s all you have to say?’

  ‘What else is there? Worlds begin and end,’ said the Queen. ‘That is how the universe works. That is the great circle of existence.’

  ‘The great circle of existence, madam, can eat my underwear!’ said Ridcully.

  ‘Fine words,’ said the Queen. ‘You are good at concealing your true thoughts from me, but I can also see them in your face, nevertheless. You think you can still fight us and win. You have forgotten that there is no narrativium in this world. It does not know how stories should go. Here, the third son of a king is probably just a useless weak prince. Here, there are no heroes, only degrees of villainy. An old lady gathering wood in the forest is just an old lady and not, as in your world, almost certainly a witch. Oh, there is a belief in witches. But a witch here is merely a method of ridding society of burdensome old ladies and an inexpensive way of keeping the fire going all night. Here, gentlemen, good does not ultimately triumph at the expense of a few bruises and a non-threatening shoulder wound. Here, evil is generally defeated by a more organised kind of evil. My world, gentlemen. Not yours. Good day to you.’

  And then she was gone.

  The wizards sat down again. Outside, the carriage rattled away.

  ‘Quite well spoken for an elf, I thought,’ said the Lecturer in Recent Runes. ‘Good turn of phrase.’

  ‘And that’s it?’ said Ridcully. ‘We can’t do anything?’

  ‘We don’t have any magic, sir,’ said Ponder.

  ‘But we do know everythin’ is goin’ to turn out all right, though, don’t we?’ said Ridcully. ‘We know that people get off the planet before the next big wallop, right? We saw the evidence. Right?’

  Ponder sighed.

  ‘Yes, sir. But it might not happen. It’s like the Shell Midden people.’

  ‘They didn’t happen?’

  ‘Not … here, sir,’ said Ponder.

  ‘Ah. And you’re goin’ to say “it’s because of quantum” at some point?’

  ‘I hadn’t intended to, sir, but you’re on the right lines.’

  ‘So … when we left them, did they pop out of existence?’

  ‘No, sir. We did.’

  ‘Oh. Well, so long as someone did …’ said Ridcully. ‘Any thoughts, gentlemen?’

  ‘We could go to the pub again?’ said the Lecturer in Recent Runes, hopefully.

  ‘No,’ said Ridcully. ‘This is serious.’

  ‘So am I.’

  ‘I don’t see what we can do,’ said the Dean. ‘The humans here needed the elves to tinker with their heads. When we stopped that, we got the Shell Midden people. When we didn’t stop it, we got people lik
e Dee, head half full of rubbish.’

  ‘I know someone who’d be right at home with this problem,’ said Ridcully, thoughtfully. ‘Mister Stibbons, we would be able to get back home now, wouldn’t we? Just to send a semaphore message?’

  ‘Yes, sir, but there’s no need for that. Hex can do that directly,’ said Ponder, before he could stop himself.

  ‘How?’ said Ridcully.

  ‘I … er … connected him up to the semaphore just after you left, sir. Er … it was just a matter of pulleys and things. Er … I installed a little set of repeater arms on the roof of the High Energy Magic Building. Er … and employed a gargoyle to do the watching, and we needed one anyway, because the pigeons up there have really got too numerous … er …’

  ‘So Hex can send and receive messages?’ said Ridcully.

  ‘Yes, sir. All the time. Er …’

  ‘But that costs a fortune! Is it coming out of your budget, man?’

  ‘Er, no, sir, because it’s actually quite cheap, er … it’s free, actually …’ Ponder went for broke. ‘Hex worked out the codes, you see. The gargoyles up on the big tower don’t bother about where the signals are coming from, they just notice the codes, so, er, Hex started by adding the codes for the Assassins’ Guild or the Fools’ Guilds to the messages and, er, they probably didn’t notice the extra amount on their bills because they’re using the clacks all the time these days—’

  ‘So … we’re stealing?’ said Ridcully.

  ‘Well, er, yes, sir, in a way, but it’s hard to know exactly what. Last month Hex worked out the semaphore company’s own codes so his messages travel as part of their internal signalling, sir. No one gets billed for that.’

  ‘This is very disturbing news, Stibbons,’ said Ridcully sternly.

  ‘Yes, sir,’ said Ponder, looking at his feet.

  ‘I feel I must ask you a rather difficult and worrying question: is it likely that anyone will find out?’