Terry Pratchett - The Science of Discworld

by Terry Pratchett

  According to the details of the Big Bang, the cosmic background radiation should have a ’temperature’ (the analogue of loudness) of about 3° Kelvin (0° Kelvin is the coldest anything can get - equiv­alent to about -273° Celsius). Astronomers can measure the temperature of the cosmic background radiation, and they do indeed get 3° Kelvin. The Big Bang isn’t just a wild speculation. Not so long ago, most scientists didn’t want to believe it, and they only changed their minds because of Hubble’s evidence for the expansion of the universe, and that impressively accurate figure of 3° Kelvin for the temperature of the cosmic background radiation.

  It was, indeed, a very loud, and hot, bang.

  We are ambivalent, then, about beginnings - their ’creation myth’ aspect appeals to our sense of narrative imperative, but we some­times find the ’first it wasn’t, then it was’ lie-to-children unpalatable. We have even more trouble with becomings. Our minds attach labels to things in the surrounding world, and we interpret those labels as discontinuities. If things have different labels, then we expect there to be a clear line of demarcation between them. The universe, however, runs on processes rather than things, and a process starts as one thing and becomes another without ever crossing a clear boundary. Worse, if there is some apparent boundary, we are likely to point to it and shout ’that’s it!’ just because we can’t see anything else worth getting agitated about. How many times have you been in a discussion in which some­body says ’We have to decide where to draw the line’? For instance, most people seem to accept that in general terms women should be permitted abortions during the earliest stages of pregnancy but not during the very late stages. ’Where you draw the line’, though, is hotly debated - and of course some people wish to draw it at one extreme or the other. There are similar debates about exactly when a developing embryo becomes a person, with legal and moral rights. Is it at conception? When the brain first forms? At birth? Or was it always a potential person, even when it ’existed’ as one egg and one sperm?

  The ’draw a line’ philosophy offers a substantial political advan­tage to people with hidden agendas. The method for getting what you want is first to draw the line somewhere that nobody would object to, and then gradually move it to where you really want it, arguing continuity all the way. For example, having agreed that killing a child is murder, the line labelled ’murder’ is then slid back to the instant of conception; having agreed that people should be allowed to read whichever newspaper they like, you end up sup­porting the right to put the recipe for nerve gas on the Internet.

  If we were less obsessed with labels and discontinuity, it would be much easier to recognize that the problem here is not where to draw the line: it is that the image of drawing a line is inappropriate. There is no sharp line, only shades of grey that merge unnoticed into one another - despite which, one end is manifestly white and the other is equally clearly black. An embryo is not a person, but as it develops it gradually becomes one. There is no magic moment at which it switches from non-person to person - instead, it merges continuously from one into the other. Unfortunately our legal sys­tem operates in rigid black-and-white terms - legal or illegal, no shades of grey - and this causes a mismatch, reinforced by our use of words as labels. A kind of triage might be better: this end of the spectrum is legal, that end of the spectrum is illegal, and in between is a grey area which we do our best to avoid if we possibly can. If we can’t avoid it, we can at least adjust the degree of criminality and the appropriate penalty according to whereabouts in the spectrum the activity seems to lie.

  Even such obviously black-and-white distinctions as alive/dead or male/female turn out, on close examination, to be more like a continuous merging than a sharp discontinuity. Pork sausages from the butcher’s contain many live pig cells. With today’s techniques you might even clone an adult pig from one. A person’s brain can have ceased to function but their body, with medical assistance, can keep going. There are at least a dozen different combinations of sex chromosomes in humans, of which only XX represents the tradi­tional female and XY the traditional male.

  Although the Big Bang is a scientific story about a beginning, it also raises important questions about becomings. The Big Bang theory is a beautiful bit of science - very nearly consistent with the picture we now have of the atomic and the subatomic world, with its diverse kinds of atom, their protons and neutrons, their clouds of electrons, and the more exotic particles that we see when cosmic rays hit our atmosphere or when we insult the more familiar parti­cles by slamming them together very hard. Now that physicists have ’found’, or perhaps invented, the allegedly ’ultimate’ constituents of these familiar particles (more exotic things known as quarks, glu-ons ... at least the names are familiar) they’re starting to wonder whether there are more layers further down, more ’ultimate’ still.

  Turtles all the way down?

  Does physics go all the way down, or does it stop at some level? If it stops, is that the Ultimate Secret, or just a point beyond which the physicists’ way of thinking fails?

  The conceptual problem here is difficult because the universe is a becoming - a process - and we want to think of it as a thing. We don’t only find it puzzling that the universe was so different back then, that particles behaved differently, that the universe then became the universe now, and will perhaps eventually cease expand­ing and collapse back to a point in a Big Crunch. We are familiar with babies becoming children becoming adults, but these processes always surprise us

  -we like things to keep the same char­acter, so ’becoming’ is difficult for our minds to handle.

  There is another element of the first moments of our universe that is even more difficult to think about. Where did the Laws come from? Why are there such things as protons and electrons, quarks and gluons? We usually separate processes into two conceptually distinct causal chunks: the initial conditions, and the rules by which they are transformed as time passes. For the solar system, for instance, the initial conditions are the positions and speeds of the planets at some chosen instant of time; the rules are the laws of gravitation and motion, which tell us how those positions and speeds will change thereafter. But for the beginning of the universe,

  the initial conditions seem not to be there at all. Even there isn’t there! So it seems that it’s all done by rules. Where did the rules come from? Did they have to be invented? Or were they just sitting in some unimaginable timeless pseudo-existence, waiting to be called up? Or did they uncurl in the early moments of the universe, as Something appeared - so that the universe invented its own rules along with space and time?

  During the becoming of its first moments, our universe kept changing its state, changing the rules it accessed. In this respect it was rather like a flame, which changes its composition according to its own dynamics and the things that it is burning. Flames are all more or less the same shape, but they don’t inherit that shape from a ’parent’. When you set light to a piece of paper, the flame builds itself from scratch using the rules of the outside universe.

  In the opening instants of the universe, it wasn’t just substances, temperatures and sizes that changed. The rules by which they changed also changed. We don’t like to think this way: we want immutable laws, the same always. So we look for ’deeper’ laws to govern how the rules changed. Possibly the universe is ’really’ gov­erned by these deeper laws. But perhaps it just makes up its own rules as it goes along.

  SEVEN

  BEYOND THE FIFTH ELEMENT

  IN THE QUIET OF THE NIGHT, HEX COMPUTED. Along its myriad glass tubes, the ants scurried. Crude magic sparkled along cobwebs of fine bronze wire, changing colour as it changed logic states.[15] In the special room next door the beehives, long-term storage, buzzed. The thing that went ’parp’ did so occasionally. Huge wheels turned, stopped, turned back. And still it wasn’t enough.

  The light of the Project fell across HEX’s keyboard. Things were happening in there, and HEX did not understand them. And that was taxing
, because there was something there to understand.

  HEX was largely self-designed, which was why it worked better than most things in the University. It generally tried to develop a responsive way of coming to grips with any new task; the bees had been a particularly good idea, because although the memory retrieval was slow, the total memory increased with time and good apiary practice.

  Now it reasoned thus:

  One day it would find a way of increasing its conceptual capac­ity to understand what was happening in the Project;

  If this could ever happen, then - according to Stryme’s Directionless Law - there was already a shape in happening-space, where time did not exist, caused by the fact of that happening; all that was required was a virtual collapse of the wave form;

  ... and, although this was in a very strict sense garbage, it was not complete garbage. Any answer that would exist somewhere in the future must, inevitably, be available in potentia now.

  The ants went faster. Magic flashed. HEX could be said to be concentrating.

  Then silvery, shimmering lines appeared in the air around it, outlining towers of unimaginable cogitation.

  Ah. That was acceptable.

  Once-and-future computing was now in operation. Of course, it always had been.

  HEX wondered how much he should tell the wizards. He felt it would not be a good idea to burden them with too much input.

  HEX always thought of his reports as Lies-to-People.

  It was the second day ...

  The Project was nudged gently under a glass dome to prevent any more interference. A variety of spells had been installed around it.

  ’So that’s a universe, is it?’ said the Archchancellor.

  ’Yes, sir. HEX says that ...’ Ponder hesitated. You had to think hard before trying to explain things to Mustrum Ridcully.’... HEX seems to suggest that complete and utter nothing is automatically a universe waiting to happen.’

  ’You mean nothing becomes everything?’

  ’Why, yes, sir. Er ... in a way, it has to, sir.’

  ’And the Dean here swirled it all around and that started it off?’

  ’It could have been anything at all, sir. Even a stray thought. Absolute nothing is very unstable. It’s so desperate to be something?

  ’I thought you had to have creators and gods,’ mumbled the Senior Wrangler.

  ’I should jolly well think so,’ said Ridcully, who was examining the Project with a thaumic omniscope. ’It’s been here since last night and there’s nothing to be seen except elements, if you could call them that. Bloody stupid elements, too. Half of them fall to bits as soon as you look at them.’

  ’Well, what do you expect?’ said the Lecturer in Recent Runes. ’They’re made out of nothing, right? Even a really bad creator would at least have started with Earth, Air, Fire, Water and Surprise.’

  ’Proper worlds are out of the question here, too,’ said Ridcully, peering into the omniscope again. ’There’s no sign of chelonium and elephantigen. What kind of worlds can you build without them?’

  Ridcully turned to Ponder.

  ’Not much of a universe, then,’ he said. ’It must have gone wrong, Mister Stibbons. It’s a dud. By now the first human should be looking for his trousers.’

  ’Perhaps we could give him a hand,’ said the Senior Wrangler.

  ’What are you suggesting?’

  ’Well, it’s our universe, isn’t it?’

  Ponder was shocked. ’We can’t own a universe, Senior Wrangler!’

  ’It’s a very small one.’

  ’Only on the outside, sir. HEX says it’s a lot bigger on the inside.’

  ’And the Dean stirred it up,’ the Senior Wrangler went on.

  ’That’s right!’ said the Dean. ’That means I’m a sort of god.’

  ’Waggling your fingers around and saying "oo, it prickles" is not godliness,’ said Ridcully severely.

  ’Well, I’m the next best thing,’ said the Dean, reluctant to let go of anything that placed him socially higher than the Archchancellor.

  ’My grandmother always said that cleanliness was next to godli­ness,’ mused the Lecturer in Recent Runes.

  ’Ah, that’s more like it,’ said Ridcully cheerfully. ’You’re more like a janitor, Dean.’

  ’I was really just suggesting that we give the thing a few shoves in the right direction,’ said the Senior Wrangler. ’We are, after all, learned men. And we know what a proper universe ought to be like, don’t we?’

  ’I imagine we have a better idea than the average god with a dog’s head and nineteen arms, certainly,’ said Ridcully. ’But this is pretty second-rate material. It just wants to spin all the time. What do you expect us to do, bang on the side and shout "Come on, you lot, stop messing about with stupid gases, they’ll never amount to any­thing"?’

  They compromised, and selected a small area for experimenta­

  tion. They were, after all, wizards. That meant that if they saw something, they prodded it. If it wobbled, they prodded it some more. If you built a guillotine, and then put a sign on it saying ’Do Not Put Your Neck On This Block’, many wizards would never have to buy a hat again.

  Moving the matter was simple. As Ponder said, it almost moved under the pressure of thought.

  And spinning it into a disc was easy. The new matter liked to spin. But it was also far too sociable.

  ’You see?’ said Ridcully, around mid-morning. ’It seems to get the idea, and then you just end up with a ball of rubbish.’

  ’Which gets hot in the middle, have you noticed?’ said Ponder.

  ’Embarrassment, probably,’ said the Archchancellor. ’We’ve lost half the elements since elevenses. There’s no more cohenium, explodium went ten minutes ago, and I’m beginning to suspect that the detonium is falling to bits. Temporarium didn’t last for any time at all.’

  ’Any Runium?’ said the Lecturer in Recent Runes.

  HEX wrote: +++ Runium May Or May Not Still Exist. It Was Down To One Atom Ten Minutes Ago, Which I Do Not Seem to Be Able To Find Any More +++

  ’How’s Wranglium doing?’ said the Senior Wrangler hopefully.

  ’Exploded after breakfast, according to HEX. Sorry,’ said Ridcully. ’You can’t build a world out of smoke and mirrors. Damn ... there goes Bursarium, too. I mean, I know iron rusts, but these elements collapse for a pastime.’

  ’My hypothesis, for what it’s worth,’ said the Lecturer in Recent Runes, ’is that since it was all started off by the Dean, a certain Dean-like tendency may have imparted itself to the ensuing ... er ... developments.’

  ’What? You mean we’ve got a huge windy universe with a ten­dency to sulk?’

  ’Thank you, Archchancellor,’ said the Dean.

  ’I was referring to the predilection of matter to ... er ...

  accrete into ... er ... spherical shapes.’

  ’Like the Dean, you mean,’ said Archchancellor.

  ’I can see I’m among friends here,’ said the Dean.

  There was a soft chime from the apparatus that had

  been accu­mulated around the Project.

  ’That’ll be etherium vanishing,’ said Ridcully gloomily.

  ’I knew that’d be the next to go.’

  ’Actually ... no,’ said Ponder Stibbons, peering into the

  Project. ’Er ... something has caught fire.’

  Points of light were appearing.

  ’I knew something like that would happen,’ said the

  Archchancellor. ’All those discs are heating up, just like

  damn com­post heaps.’

  ’Or suns,’ said Ponder.

  ’Don’t be silly, Stibbons, they’re far too large for that.

  I’d hate to see one of those floating over the clouds,’

  said the Lecturer in Recent Runes.

  ’I said there was far too much gas,’ the Archchancellor

  went on. ’That wraps it up, then.’

  ’I wonder,’ said the Senior Wr
angler.

  ’What?’ said the Dean.

  ’Well, at least we’ve got some heat in there ... and there

  nothing like a good furnace for improving matters.’

  ’Good point,’ said Ridcully. ’Look at bronze - you can

  make that out of just about anything. And we could

  burn off some of the rub­bish. All right, you fellows,

  help me dump more of the stuff in it...’

  Around about teatime, the first of the furnaces

  exploded, just as happened every day down at the

  Alchemists’ Guild.

  ’Ye gods,’ said Ridcully, watching the shapes in the

  omniscope.

  ’Yo?’ said the Dean.

  ’We’ve made new elements!’

  ’Keep it down, keep it down!’ hissed the Senior Wrangler.

  ’There’s iron ... silicon ... we’ve got rocks, even ...’

  ’We’re going to be in serious trouble if the alchemists’ guild finds out,’ said the Lecturer in Recent Runes. ’You know we’re not supposed to do that stuff.’

  ’This is a different universe,’ said Ridcully. He sighed. ’You have to blow things up to get anything useful.’

  ’I see politicium is still there in large quantities, then,’ said the Senior Wrangler.