Science of Discworld III

by Terry Pratchett

  2 Michael Brooks, ‘Time Twister’, New Scientist, 19 May 2001, 27–9.

  3 Jason Breckenridge, Rob Myers, Amanda Peet, and Cumrun Vafa.

  4 It’s OK for electrons and probably nonsense for cats. See Greebo’s cameo appearance in The Science of Discworld.

  5 See Ian Stewart, Jack Cohen, Figments of Reality: the origins of the curious mind (Cambridge University Press, 1997).

  NINE

  AVOIDING MADEIRA

  THE JOINER WAS AMAZED, AS he told his mates in the pub after work

  ‘– so I was just finishing, and this feller comes down the ladder and says beggin’ your pardon, sir, but I’d just like to check that bulkhead, please. Nothing wrong with it, says I, it’s as sound as a bell. Then he says, right, right, of course, but I’ve just got to check something. He pulls this piece of paper out of his pocket and reads it careful, and says he’s got to check that the new timber hasn’t got a rare tropical worm that’ll leave it looking like good wood but weaken it so much that the ship will take in too much water and will have to put in to Madeira for repairs, or something, possibly. I’ll soon see about that, says I and whacks it with my hammer and, blow me, it cracks in half. I’d have sworn it was prime timber, too. Little worms everywhere!’

  ‘Funny you should say that,’ said the man opposite. ‘One of ’em came up when I was working and asked if he could look at the copper nails I was usin’. Well, he takes out a knife, scrapes away at one, it’s a bit of rubbish iron under a skin ’o copper! Had to do half a day’s work again! Beats me how he knew. Tom said the chandler swore they were all copper when he supplied ’em.’

  ‘Hah,’ said a third man, ‘one came up to me and said what would I do if a giant squid pulled the ship under. I told him I’d do nothing, being as I live in Portsmouth.’ He drained his mug. ‘Damned thorough, these inspectors.’

  ‘Yeah,’ said the first man, reflectively. ‘They think of everything …’

  ‘A goose is an inconvenient bird, I’ve always thought,’ said Mustrum Ridcully, carving it. ‘Just a bit too much for one but not quite enough for two.’ He extended a fork. ‘Anyone else want some? Rincewind, just get the man to send up some more oysters, will you? What do you say, gentlemen? Another six dozen? Let’s push the boat out, eh? Hahah …’

  The wizards had taken rooms at an inn, and the owner, watching the bustling staff down in his kitchen, was already thinking happily of an early retirement.

  Money had not been a problem. Hex had merely teleported some from a distant bank. The wizards had debated the moral implications of this for some time, with their mouths full, but had come down in favour of the idea. They were, after all, Doing The Right Thing.

  Only Ponder wasn’t eating much. He nibbled a biscuit and updated his notes, before announcing: ‘We have covered everything, Archchancellor. The nails, the leaking water barrels, the defective compass, the bad meat … there were nine reasons why the Beagle would have called in at the island of Madeira. Hex believes the giant squid may be a red herring. As for the nine … yes, I think we have assured that they will no longer occur.’

  ‘Remind me why that’s important, will you?’ said the Dean. ‘And pass the wine, Mustrum.’

  ‘Without this intervention it’s more than likely that Darwin will leave the ship at Madeira, should the Beagle call there,’ said Ponder. ‘He will be terribly seasick on the voyage.’

  ‘Madeira being –?’ said the Dean.

  ‘One of a group of islands on the way, Dean. After that it’s a long haul down to the South Atlantic, round the bottom of South America with a few stops, and straight up to the Galapagos Islands.’

  ‘Down, bottom, up,’ muttered the Dean. ‘How can anyone get the hang of globular navigation?’

  ‘The phenomenon we call The Love Of Iron, sir,’ said Ponder, smoothly. ‘We only find it in rare metals that drop from the sky, but it’s very common here. Iron here tries to point north.’

  Silence fell around the table.

  ‘North? Is that the bit at the top?’ said Ridcully.

  ‘Conventionally, sir, yes,’ said Ponder, and rather foolishly added, ‘but on a globe it doesn’t really matter, of course.’

  ‘Ye gods,’ muttered the Dean, putting his hand over his eyes.

  ‘How does the iron know which way to point?’ Ridcully persisted. ‘Metal can’t think.’

  ‘It’s a bit like … like peas turning to follow the Sun, sir,’ hazarded Ponder, not sure if they actually did; perhaps it was pea farmers.

  ‘Yes, but peas are living things,’ said Ridcully. ‘They … know about the Sun, right?’

  ‘Peas aren’t exactly renowned for their brains, Archchancellor,’ said the Chair of Indefinite Studies, ‘hence the term pea-brained.’

  ‘But a pea must be a bloody genius compared to a lump of iron, yes?’ said Ridcully.

  Ponder knew he had to put a stop to this. The wizards were still determined to apply common sense to Roundworld, and that would get them nowhere.

  ‘It’s a force that can occur on globe-shaped worlds,’ he said. ‘It’s caused by the molten iron core spinning, and helps prevent life on the surface being fried by the Sun.’

  ‘Sounds like Deitium in disguise, doesn’t it,’ said Ridcully. ‘Planet gets this big magical umbrella so that life can survive? Shows forethought’

  ‘It doesn’t work quite like that, Archchancellor,’ said Ponder. ‘Life evolved because conditions allowed it to do so.’

  ‘Ah, but if conditions hadn’t been right, there wouldn’t have been any life,’ said Ridcully. ‘Therefore the whole exercise would have been pointless.’

  ‘Not really, sir. There wouldn’t have been anyone to point out the pointlessness of it,’ said Ponder. ‘I was about to add that some birds, like pigeons, use The Love Of Iron to help them navigate long distances. They have tiny things called “magnets” in their head, says Hex. They’re … little bits of iron that know where the North Pole is …’

  ‘Ah, I know that bit,’ said the Lecturer in Recent Runes. ‘The North and South Poles are those bits on a globe where the spindle comes out. But they’re invisible, of course,’ he added.

  ‘Um,’ said Ponder.

  ‘Just a minute, can we get back to these birds?’ said Ridcully. ‘Birds with magnet heads?’

  ‘Yes?’ said Ponder, knowing that this was going to be loaded.

  ‘How?’ said Ridcully, flourishing a goose leg. ‘On this globe, birds grew out of great big monstrous lizard beasts, isn’t that so?’

  ‘Er … small great monstrous beasts, sir,’ said Ponder, wishing not for the first time that his Archchancellor did not have a knack for remembering inconvenient details.

  ‘Did they have to fly long distances through fog and bad weather?’ said the Archchancellor.

  ‘I doubt it, sir,’ said Ponder.

  ‘So did they already have these magnets in their heads from day one, or did they turn up by some godly hand? What does Mr Darwin of The Origin say about that?’

  ‘Not very much, sir,’ said Ponder. It had been a long day.

  ‘But it suggests, does it not, that The Ology haha, is right and The Origin is wrong. Perhaps the magnets were added when needed?’

  ‘Could be, sir,’ said Ponder. Just don’t let him start on the eyeball, he thought.

  ‘I’ve got a question,’ said Rincewind, from the end of the table.

  ‘Yes?’ said Ponder, quickly.

  ‘There’s going to be monster creatures on these island we’re heading for, yes?’

  ‘How did you know that?’ said Ponder.

  ‘It just came to me,’ said Rincewind gloomily. ‘So there are monsters?’

  ‘Oh, yes. Giants of their kind.’

  ‘With big teeth?’

  ‘No, not really. They’re tortoises.’

  ‘How big?’

  ‘About the size of an easy chair, I think.’

  Rincewind looked suspicious.

  ‘How fast?’

 
‘I don’t know. Not very fast.’

  ‘And that’s it?’

  ‘From a Darwinian perspective, the islands are famous for their many species of finches.’

  ‘Any of them carnivorous?’

  ‘They eat seeds.’

  ‘So … there’s nothing dangerous where we’re going?’

  ‘No. Anyway, we don’t have to go there. All we have to do now is find the point where he decides to write The Ology instead of The Origin.’

  Rincewind pulled the dish of potatoes towards him.

  ‘Sez you,’ he said.

  +++ I need to communicate grave news +++

  The words came out of the air. In Roundworld, Hex had a voice.

  ‘We’re having a bit of a celebration here,’ said Ridcully. ‘I’m sure your news can wait, Mr Hex!’

  +++ Yes. It can +++

  ‘Good. In that case, Dean would you pass me—’

  +++ I would not wish to spoil your appetite +++ Hex went on.

  ‘Glad to hear it.’

  +++ The destruction of the human race can wait until after the pudding +++.

  Ridcully’s fork hovered between his plate and his mouth. Then he said: ‘Would you care to explain this, please, Mr Stibbons?’

  ‘I can’t, sir. What is happening, Hex? We completed all those tasks properly, didn’t we?’

  +++ Yes. But, pause for significance, have you heard of a mythical creature called a, pause again, hydra? +++

  ‘The monster with many heads?’ said Ponder. ‘You don’t need to tell us when you pause, by the way.’

  +++ Thank you. Yes. Cut off one head and a dozen grow in its place. This history is a hydra +++

  Rincewind nodded at Ponder. ‘Told you,’ he said, with his mouth full.

  +++ I am unable to explain why this is the case, but there are now 1457 reasons why Darwin did not write The Origin of Species. The book has never been written in this history. The voyage has never taken place +++

  ‘Don’t be silly! We know it did!’ said the Dean.

  +++ Yes. It did. But now, it hasn’t. Charles Darwin the scientist has been removed from this history while you ate. He was, and now he was not. He became a little-remembered priest who caught butterflies. He wrote no book. The human race dies in five hundred years +++

  ‘But yesterday—’ Ridcully began.

  +++ Consider time not as a continuous process but as a succession of discrete events. Darwin’s scientific career has been excised. You remember him, but that is because you are not part of this universe. To deny this is simply to scream at the monkeys in the next tree +++

  ‘Who did it?’ said Rincewind.

  ‘What sort of question is that?’ said Ponder. ‘No one did it. There isn’t anyone to do things. This is some kind of strange phenomenon.’

  +++ No. The act shows intelligence +++ said Hex. +++ Remember, I detected malignity. I surmise that your interference in this history has led to some counter-measure +++

  ‘Elves again?’ said Ridcully.

  +++ No. They are not clever enough. I can detect nothing except natural forces +++

  ‘Natural forces aren’t animate,’ said Ponder. ‘They can’t think!’

  +++ pause for dramatic effect … Perhaps the ones here have learned to +++ said Hex.

  TEN

  WATCH-22

  IN THE STANDARD VERSION OF Roundworld history, Charles Darwin’s presence on the Beagle came about only because of a highly improbable series of coincidences – so improbable that it is tempting to view them as wizardly intervention. What Darwin expected to become was not a globetrotting naturalist who revolutionised humanity’s view of living creatures, but a country vicar.

  And it was all Paley’s fault.

  Natural Theology’s seductive and beautifully argued line of reasoning found considerable favour with the devout people of Georgian (III and IV) England, and after them, the equally devout subjects of William IV and Victoria. By the time Victoria ascended to the throne, in 1837, it was indeed almost compulsory for country vicars to become experts in some local moth, or bird, or flower, and the Church actively encouraged such activities because they were continuing revelations of the glory of God. The Suffolk rector William Kirby was co-author, with the businessman William Spence, of a lavish four-volume treatise An Introduction to Entomology, for example. It was fine for a clergyman to interest himself in beetles. Or geology, a relatively new branch of science that had grabbed the young Charles Darwin’s attention.

  The big breakthrough in geology, which turned it into a fully fledged science, was Charles Lyell’s discovery of Deep Time – the idea that the Earth is enormously older than Ussher’s 6000 years. Lyell argued that the rocks that we find at the Earth’s surface are the product of an ongoing sequence of physical, chemical, and biological processes. By measuring the thickness of the rock layers, and estimating the rate at which those layers can form, he deduced that the Earth must be extraordinarily ancient.

  Darwin had a passion for geology, and absorbed Lyell’s ideas like a sponge. However, Charles was basically rather lazy, and his father knew it. He also knew, to quote Adrian Desmond and James Moore’s biography Darwin, that:

  The Anglican Church, fat, complacent, and corrupt, lived luxuriously on tithes and endowments, as it had for a century. Desirable parishes were routinely auctioned to the highest bidder. A fine rural ‘living’ with a commodious rectory, a few acres to rent or farm, and perhaps a tithe barn to hold the local levy worth hundreds of pounds a year, could easily be bought as an investment by a gentleman of Dr. Darwin’s means and held for his son.

  That, at least, was the plan.

  And at first, the plan seemed to be working. In 1828 Charles was admitted to the University of Cambridge, taking his oath of matriculation one cold January morning, swearing to uphold the university’s ancient statutes and customs, ‘so help me God and his holy Gospels’. He was enrolled at Christ’s College for a degree in theology, alongside his cousin William Darwin Fox who had started the previous year. (Charles had previously attempted medicine in Edinburgh, following in the footsteps of his father and grandfather, but he became disillusioned and left without a degree.) After getting his Batchelor of Arts degree, he might spend a further year reading theology, ready to be ordained in the Anglican Church. He could become a curate, marry, and take up a rural position near Shrewsbury.

  It was all arranged.

  Shortly after starting at Christ’s, Charles was bitten by the beetle bug, as it were. An Introduction to Entomology sparked off an intense interest in beetles, when seemingly half the nation was out searching the woods and hedgerows to find new species. Since there were more species of beetle in the world than anything else, this was a serious prospect. Charles and his cousin scoured the byways of rural Cambridgeshire, pinning their catches in neat rows on large sheets of cardboard. He didn’t find a new species of beetle, but he found a rare German one, seen only twice before in the whole of England.

  Towards the end of his second year at university, exams loomed. Darwin had been too intent on beetles and a young lady named Fanny Owen and had neglected his academic studies. Now he had a mere two months left to do the work of two years. In particular, there would be ten questions on the book Evidences of Christianity, by one William Paley. Darwin had already read the book, but now he read it again with new attention – and loved it. He found the logic fascinating. Moreover, Paley’s political leanings were distinctly left-wing, which appealed to Charles’s innate sense of social justice. Bolstered by his studies of Paley, Darwin scraped through.

  Next in line were the final exams. Another of Paley’s books was on the syllabus: Principles of Moral and Political Philosophy. The book was outdated, and sailed close to the wind of (political) heresy and well into the shallows of unorthodoxy; that was why it was on the syllabus. You had to be able to argue the case against it, where applicable. It said, for example, that an established Church formed no part of Christianity. Darwin, then a very conventional Christi
an, wasn’t sure what to think. He needed to broaden his reading, and in so doing he selected yet another book by his idol Paley: Natural Theology. He knew that many intellectuals derided Paley’s stance on design as naive. He knew that his own grandfather, Erasmus Darwin, had held a radically different view, speculating about spontaneous changes in organisms in his own book Zoonomia. Darwin’s sympathies were with Paley, but he started wondering how scientific laws were established, and what kind of evidence was acceptable, a quest that led him to a book by Sir John Herschel with the mind-numbing tide Preliminary Discourse on the Study of Natural Philosophy. He also picked up a copy of Alexander von Humboldt’s Personal Narrative, a 3754-page blockbuster about the intrepid explorer’s trip to South America.

  Darwin was entranced. Herschel stimulated his interest in science, and Humboldt showed him how exciting scientific discoveries could be. He determined, then and there, to visit the volcanoes of the Canary Islands and see for himself the Great Dragon Tree. His friend Marmaduke Ramsay agreed to accompany him. They would leave for the tropics once Darwin had signed the 39 Articles of the Anglican Church at his degree ceremony. To prepare for the journey, Charles went to Wales to carry out geological fieldwork. He discovered that there was no Old Red Sandstone in the Vale of Clwyd, contrary to the current national geological map. He had won his geologists’ spurs.

  Then a message arrived. Ramsay had died. The Canary scheme shuddered to a halt. The tropics seemed further away than ever. Could Charles go it alone? He was still trying to decide when a bulky package arrived from London. Inside was a letter, offering him the opportunity to join a voyage round the world. The ship would sail in a month.

  The British Navy was planning to explore and map the coast of South America. It was to be a chronometric survey, meaning that all navigation would be done using the relatively new and not fully trusted technique of finding longitude with the aid of a very accurate watch or chronometer. A 26-year-old sea captain, Robert FitzRoy, would head the expedition; his ship would be the Beagle.

  FitzRoy was worried that the solitude of his command might drive him to suicide. The risk was not far-fetched: the Beagle’s former captain Pringle Stokes had shot himself while mapping a particularly convoluted bit of the coast of South America. Further, one of FitzRoy’s uncles had slit his own throat in a fit of depression.1 So he had decided that he needed someone to talk to, to keep him sane. It was this position that was now being offered to Darwin. The job would be especially suitable for someone with an interest in natural history, and the ship had the necessary scientific equipment. Technically, Darwin would not be ‘ship’s naturalist’, as later he sometimes claimed, and that presumption would eventually lead to an almighty row with the Beagle’s surgeon Robert McCormick, because by tradition the surgeon did the job of naturalist in his spare time. Darwin was being hired as a ‘gentleman companion’ for the captain.