Science of Discworld III

by Terry Pratchett

  There are some things that evolution does not explain – which will gladden the heart of anyone who feels that, Darwin notwithstanding, there are some issues that science cannot address.

  It is perfectly possible to agree with Darwin and his successors that the Earth is 4.5 billion years old, and that life has evolved, by purely physical and chemical processes, from inorganic beginnings – yet still find a place for a deity. Yes, in a rich and complex universe, all these things can happen without divine intervention. But … how did that rich and complex universe come into being?

  Here, today’s cosmology offers descriptions of how (Big Bang, various recent alternatives) and when (about 13 billion years ago), but not why. String theory, a recent innovation at the frontiers of physics, makes an interesting attempt at ‘why?’ However, it leaves an even bigger ‘why?’ unanswered: why string theory? Science develops the consequences of physical rules (‘laws’), but it doesn’t explain why those rules apply, or how such a set-up came to exist.

  These are deep mysteries. At the moment, and probably for ever, they are not accessible to the scientific method. Here religions come into their own, offering answers to riddles about which science chooses to remain mute.

  If you want answers, they are available.

  Rather a lot of different ones, in fact. Choose whichever one makes you feel most comfortable.

  Feeling comfortable, however, is not a criterion recognised by science. It may make us feel warm and fuzzy, but the historical development of scientific understanding shows that, time and again, warm and fuzzy is just a polite way of saying ‘wrong’.

  Belief systems rely on faith, not evidence. They provide answers – but they don’t provide any rational process to assess those answers. So although there are questions beyond the capacity of science to answer, that’s mostly because science sets itself high standards for evidence, and holds its tongue when there isn’t any. The alleged superiority of belief systems compared to science, when it comes to these deep mysteries, stems not from a failure of science, but from the willingness of belief systems to accept authority without question.

  So the religious person can take comfort that his or her beliefs provide answers to deep questions of human existence that are beyond the powers of science, and the atheist can take comfort that there is absolutely no reason to expect those answers to be right. But also no way to prove them wrong, so why don’t we just coexist peacefully, stay off each other’s turf, and each get on with our own thing? Which is easy to say but harder to do, especially when some people refuse to stick to their own turf, and use political means, or violence, to promote their views, when rational debate long ago demolished them.

  Some aspects of some belief systems are testable, of course – the Grand Canyon is not evidence for Noah’s flood, unless God is having a quiet joke at our expense, which admittedly would be a very Discworld thing to do. And if He is, then all bets are off, because His revealed word in [insert your preferred Holy Book] may well be a joke too. Other aspects are not testable: the deeper issues stray into intellectual territory where, in the end, you have to settle for whatever explanation your type of mind finds convincing, or just stop asking that kind of question.

  But remember: what’s most interesting about your beliefs, to anyone who does not share them, is not whether you’re right – it’s that what you believe is a window into the workings of your mind. ‘Ah, so you think like that, do you?’

  This is where the great mystery of human existence leads, and where all explanations are true – for a given value of ‘true’.

  1 That is to say, the Richard Dawkins of our leg of the famous Trousers of Time, who is, in a very definite way, not in holy orders.

  2 For detailed and thoughtful rebuttals of the main contentions of the intelligent designers, plus some responses, see Matt Young and Taner Edis, Why Intelligent Design Fails (Rutgers University Press, 2004), and William Dembski and Michael Ruse, Debating Design (Cambridge University Press, 2004). And it’s only a matter of time before someone writes How Intelligent Is the Designer?

  3 Only the camera obscura, a room with a pinhole in the wall. Paley first wrote about the eye in 1802, whereas genuine photography dates from 1826.

  4 ‘A pessimistic estimate of the time required for an eye to evolve’, Proceedings of the Royal Society of London B, volume 256 (1994), pp. 53–8.

  5 They themselves refer to this programme as the ‘wedge strategy’.

  FIVE

  THE WRONG TROUSERS OF TIME

  THE GLASS GLOBE OF ROUNDWORLD had been installed on a pedestal in front of Hex by the time most of the senior faculty were up and milling around. They were always at a bit of a loose end when Second Breakfast had finished and it wasn’t yet time for Elevenses, and this looked like entertainment.

  ‘One asks oneself whether it really is worth saving,’ said the Chair of Indefinite Studies. ‘It’s had huge ice ages before, hasn’t it? If the humans are too stupid to leave in time, then there’s bound to be another interesting species around in half a million years or so.’

  ‘But extinction is so … sort of … final,’ said the Lecturer in Recent Runes.

  ‘Yes, and we created their world and helped them become intelligent,’ said the Dean. ‘We can’t just let them freeze to death. It’d be like going on holiday and not feeding the hamster.’

  A watchmaker as part of the watch, thought Ponder, adjusting the university’s biggest omniscope; not just making the world, but tweaking it all the time …

  Wizards did not believe in gods. They didn’t deny their existence, of course. They just didn’t believe. It was nothing personal; they weren’t actually rude about it. Gods were a visible part of the narrativium that made things work, that gave the world its purpose. It was just that they were best avoided close up.

  Roundworld had no gods that the wizards had been able to find. But one that was built in … that was a new idea. A god inside every flower and stone … not just a god who was everywhere, but a god who was everywhere.

  The last chapter of Theology of Species had been very impressive …

  He stood back. Hex had been busy all morning. So had the Librarian. Right now he was carefully dusting books and feeding them into Hex’s hopper. Hex had mastered the secret of osmotic reading, normally only ever attempted by students.

  And the Librarian had located a copy of the right Origin of Species, the book Darwin ought to have written. It had a picture of Darwin as a frontispiece. With a pointy hat he would have passed for a wizard anywhere. If it came to that, he could have passed for the Archchancellor.

  Ponder waited until the wizards had settled down and opened their popcorn.

  ‘Gentlemen,’ he said, ‘I do hope you’ve all read my analysis …?’

  The wizards stared at him.

  ‘I worked very hard on it all morning,’ said Ponder. ‘And it was delivered to all your offices … .’

  There was more staring.

  ‘It had a green cover … .’ Ponder prompted.

  The staring was quite intense now. Ponder gave in.

  ‘Perhaps I should remind you of the important points?’ he said.

  The faces lit up.

  ‘Just jog our memories,’ said the Dean, cheerfully.

  ‘I discussed alternate timelines in phase space,’1 said Ponder. That was a mistake, he could see. His fellow wizards weren’t stupid, but you had to be careful to shape ideas to fit the holes in their heads.

  ‘Two different legs in the Trousers of Time,’ said Ponder. ‘In the year 1859, by the counting system commonly in use in that part of Roundworld, a book changed the way a lot of people thought about the world. It just happened to be the wrong book—’

  ‘Prove it,’ said the Chair of Indefinite Studies.

  ‘Pardon, sir?’

  ‘Well, correct me if I’m wrong, but supposing Theology of Species was the right book?’ said the Chair.

  ‘It muted scientific – that is, technomantic – progre
ss for almost a hundred years, sir,’ said Ponder, wearily. ‘It slowed down humanity’s understanding of its place in the universe.’

  ‘You mean that it was built by wizards and left on a shelf in a corridor?’ said the Chair.

  ‘That’s only true on the outside, sir,’ said Ponder. ‘My point is, something happened to Mr Darwin at some time in his life that caused him to write the wrong book. And it was wrong. Yes, it would have been the right book here on Discworld, sir. We know there is a God of Evolution.’

  ‘That’s right. Skinny old chap, lives on an island,’ said Ridcully. ‘Decent sort, in his way. Remember? He was redesigning the elephant when we were there. With wheels, very clever. Very keen on beetles, too, as I recall.’

  ‘So why’d Darwin write this theology book instead?’ the Chair of Indefinite Studies persisted.

  ‘I don’t know, sir, but as I wrote on page 4, I’m sure you recall, it was the wrong book at exactly the right time. Nevertheless, it made sense. There was something in it for everyone. All the technomancers had to do was leave a place in their science for the local god, and all the priests had to give up were a few beliefs that none of the sensible ones believed anyway—’

  ‘Such as what?’ said the Dean.

  ‘Well, that the world was created in a week and isn’t very old,’ said Ponder.

  ‘But that’s true!’

  ‘Once again, only on the outside, Dean,’ said Ponder smoothly. ‘As far as we can tell, Theology of Species polarised intellectual opinion in a curious way. In fact, haha, it equatorialised it, you might say.’

  ‘I don’t think we would,’ said Ridcully. ‘What does the word mean?’

  ‘Ah … er, on a globe, the equator is an imaginary line around the middle,’ said Ponder. ‘What happened was that the bulk of the technomancers and the priests got behind the ideas expressed in Darwin’s book, because they gave everyone pretty much what they wanted. Quite of few of the technomancers had a strong belief in the god, and most of the brighter priests could see big flaws in the dogma. Together, they were a very large and influential force. The hard-line religionists and the unbending technomancers were marginalised. Out in the cold. Polarised, in fact.’ This rather neat pun, although he said it himself, failed to get even a groan of acknowledgement, so he went on: ‘They didn’t agree with the united group and they certainly didn’t agree with one another. And, thus, happy compromise ruled. For well over sixty years.’

  ‘That’s nice,’ said the Lecturer in Recent Runes.

  ‘Er … yes, sir, and then again, no,’ said Ponder. ‘Technomancy doesn’t work well in those circumstances. It can’t make real progress by consensus. Hah, being led by a bunch of self-satisfied old men who are more interesting in big dinners than asking questions is a recipe for stagnation, anyone can see that.’

  The wizards nodded sagely.

  ‘Very true,’ said Archchancellor Ridcully, narrowing his eyes. ‘That was an important point which needed to be made.’

  ‘Thank you, Archchancellor.’

  ‘And now it needs to be apologised for.’

  ‘Sorry, Archchancellor.’

  ‘Good. So, Mr Stibbons, what do—’

  There was a rattle from Hex’s writing engine. The spidery arms wove across the paper and wrote:

  +++ The Chair of Indefinite Studies is correct +++

  The wizards clustered round.

  ‘Right about what?’ said Ponder.

  +++ Charles Darwin of Theology of Species was for much of his life a Rector in the Church of England, a sub-set of the British nation +++ the computer scrawled. +++ The chief function of the priests of that religion at the time was to further the arts of archaeology, local history, lepidoptery, botany, palaeontology, geology and the making of fireworks +++

  ‘Priests did that?’ said the Dean. ‘What about the praying and so on?’

  +++ Some of them did that too, yes, although it was considered to be showing off. The God of the English did not require much in the way of sacrifice, only that people acted decently and kept the noise down. Being a priest in that church was a natural job for a young man of good breeding and education but no very specific talent. In the rural areas they had much free time. My calculations suggest that Theology of Species was the book that he was destined to write. In all the histories of third-level phase space, there is only one in which he writes The Origin of Species +++

  ‘Why is that?’ said Ponder.

  +++ The explanation is complex +++

  ‘Well, out with it,’ said Ridcully. ‘We’re all sensible men here.’

  Another piece of paper slid off Hex’s tray. It read: +++ Yes. That is the problem. You understand that every possibility of choice gives birth to a new universe in which that choice is manifest? +++

  ‘This is the Trousers of Time again, isn’t if said Ridcully.

  +++ Yes. Except that every leg of the Trousers of Time branches into many other legs, and so do those legs and every following leg, until everywhere is full of legs, which often pass through one another or join up again +++

  ‘I think I’m losin’ track,’ said Ridcully.

  +++ Yes. Language is not good at this. Even mathematics gets lost. But a little story might work. I will tell you the story. It will be not completely inaccurate +++

  ‘Go ahead,’ said Ridcully.

  +++ Imagine an unimaginably large number +++

  ‘Right. No problem there,’ said Ridcully, after the wizards had consulted among themselves.

  +++ Very well +++ Hex wrote. +++ From the moment that the Roundworld universe was made, it began to split into almost identical copies of itself, billions of times a second. That unimaginably large number represents all possible Roundworld universes that there are +++

  ‘Do all these universes really exist?’ said the Dean.

  +++ Impossible to prove. Assume that they do. In all those universes there are hardly any in which a man called Charles Darwin exists, takes a momentous ocean voyage, and writes a hugely influential book about the evolution of life on the planet. Nevertheless, that number is still unimaginably large +++

  ‘But imagined by a smaller imagination?’ said Ridcully. ‘I mean, is it half as many as the other unimaginable number?’

  +++ No. It is unimaginably large. But compared to the first number, it is unimaginably small +++

  The wizards debated this in whispers.

  ‘Very well,’ said Ridcully, at last. ‘Keep goin’ and we’ll kind of join in when we can.’

  +++ Even so, it is not so unimaginable as the number of universes in which the book was The Origin of Species. That number is quite strange and can only be imagined at all in very unusual circumstances +++

  ‘It’s unimaginably larger?’ said Ridcully.

  +++ Just unimaginably unique. The number one. Gentlemen. All by itself. One is one and all alone. One. Yes. In third-level phase space there is only one history where he gets on the boat, completes the voyage, considers the findings and writes that book. All the other alternative Darwins either did not exist, did not stay on the boat, did not survive the journey, did not write any book at all or wrote, in a large number of cases, Theology of Species and entered the Church +++

  ‘Boat?’ said Ponder. ‘What boat? What’ve boats got to do with it?’

  +++ I explained, in the successful timeline which led to humanity leaving the planet, Mr Darwin makes a significant voyage. It is one of nineteen pivotal events in the history of the species. It is almost as important as Joshua Goddelson leaving his house by the back door in 1734 +++

  ‘Who was he?’ said Ponder. ‘I don’t recall the name.’

  +++ A shoemaker living in Hamburg, Germany +++ wrote Hex. +++ Had he left his house by the front door that day, commercial nuclear fusion would not have been perfected 283 years later +++

  ‘That was important, was it?’ said Ridcully.

  +++ Vastly. Major technomancy +++

  ‘Did it need much in the way of shoes, then?’ said Ridcully, my
stified.

  +++ No. But the chain of causality, though complex, is clear +++

  ‘How hard is it to get on this boat?’ said the Dean.

  +++ In the case of Charles Darwin, very hard +++

  ‘Where did it go?’

  +++ It sailed from England to England. But there were crucial stops along the way. Even in those histories where he did embark on the boat, he did not complete the voyage and complete The Origin of Species in every case but one +++

  ‘Just one version of history, you say,’ said Ponder Stibbons. ‘Do you know why?’

  +++ Yes. It is the one where you intervene +++

  ‘But we haven’t intervened,’ said Ridcully.

  +++ In a primitive subjective sense this is the case. However, you are going to will have already soon +++ Hex wrote.

  ‘What? And I am not a primitive subject, Mr Hex!’

  +++ I am sorry. It is hard to convey five-dimensional ideas in a language evolved to scream defiance at the monkeys in the next tree +++

  The wizards looked at one another.

  ‘Getting a man on a ship can’t be hard, surely?’ said the Dean.

  ‘Is it dangerous in Darwin’s time?’ said Rincewind.

  +++ Inevitably. The centre of the Globe is an inferno, humanity is protected from being fried alive by nothing more than a skin of air and magnetic forces, and the chance of an asteroid strike is ever present +++

  ‘I think Rincewind was referring to more immediate concerns,’ said Ridcully.

  +++ Understood. The major city you must visit has many squalid areas and open sewers. The river bisecting it is noxious. Your destination could be considered a high-crime drainage ditch in a dangerous and dirty world +++

  ‘Pretty much like here, you mean?’

  +++ The similarity is noticeable, yes +++

  The writing arms stopped moving. Bits of Hex rattled and shook. The ants ceased their purposeful scurrying and began to mill about aimlessly in their glass tubing. Hex appeared to have something on his mind.