This is the kind of thing that happens when a big, powerful priesthood latches on to what started as one person's awe at the universe. It is what happens when people construct elaborate verbal traps for themselves, trip over the logic, and fall headlong into them. It is where Holy Wars come from, where neighbour can inflict atrocity on neighbour merely because this otherwise reasonable person goes to a church with a round tower instead of a square one. It is the attitude that Jonathan Swift caricatured in Gulliver's Travels, with the conflict between the big-endians and the little-endians, over which end of an egg to slice into when eating it. It is, perhaps, why so many people today are turning to unorthodox cults in an effort to find a home for their own spirituality. But cults run the same risk as the Inquisition. The only safe home for one's personal spirituality is oneself.

THE NEW SCIENTIST

These was something called, as far as Ponder could work out, psyence. All his expertise as a reader of invisible writings was needed to get a grip on this idea -L-space was very hazy about the future of this world. 'As far as I can tell,' he reported, 'it's a way of making up stories that work. It's a way of finding things out and thinking about them ... psy-ence, you see? "Psy" means

"mind" and "ence" means, er, esness. It works on Roundworld in the way magic does at home.'

'Useful stuff, then,' said Ridcully. Anyone doing it?' 'Hex is going to try to take us to what appear to be practical examples of it,' said Ponder.

'Time travel again?' said the Dean. The white circle appeared on the floor ... ... and on the sand, and vanished. The wizards looked around.

'All right, then,' said Ponder. 'So ... dry climate, evidence of agriculture, fields of crops, irrigation ditches, naked man turning a handle, man staring at us, man screaming and running away ...'

Rincewind stepped down into the ditch and inspected the pipe-like device the man had been turning.

'It's just a water-lifting screw,' he announced. 'I've seen a lot of them. You turn the handle, water is screwed out of the ditch, goes up the thread inside and spills out of the top. The screw makes a sort of line of travelling buckets inside the tube. There's nothing special about it. It's just basic ...

stuff.'

'Not psyence, then?' said Ridcully.

'You tell me, sir,' said Rincewind.

'Psyence is quite a difficult concept,' said Ponder. 'But I think perhaps tinkering with this thing to make it more efficient might be psyence?'

'Sounds like engineering,' said the Lecturer in Recent Runes. 'That's where you try and make it in different ways to see if any of them are better.'

'The Librarian did turn up one book, very grudgingly,' said Ponder, pulling it out of his pocket.

It was called Basic Science for Schools, pub.1920.

'They've spelt it wrong,' said Ridcully.

'And it's not very helpful,' said Ponder. 'There's quite a lot of what looks like alchemy. You know, mixing stuff up to see what happens.'

'Is that all it is, then?' said the Archchancellor, leafing through the book. 'Hold on, hold on.

Alchemy is, at bottom, all about the alchemist. His books tell him all the stuff he's got to do in order make things work - what to wear, when to wear it, that sort of thing. It's very personal.'

'And?' said the Lecturer in Recent Runes.

'Hark at this,' said Ridcully. 'There's no invocations, nothing to tell you what to wear or what phase of the moon it should be. Nothing important. It just says here "A clean beaker was taken.

To this was added 20 grammes" - whatever they are - "of copper sulphate" ...' He stopped.

'Well?' said the Lecturer in Recent Runes.

'Well, who did the taking? Who added the stuff? What's going on here?'

'Perhaps it's trying to say that it doesn't matter who does it?' said Ponder. He'd already glanced at the book, and felt that the perfectly ordinary ignorance he'd had just before opening it had been multiplied several times by page ten.

'Anyone can do it?' shouted Ridcully. 'Science is incredibly important but anyone can do it? And what's this?'

He held the book open for all to see, his finger pointing at an illustration. It showed a drawing of an eye, side on, to one side of the apparatus.

'Perhaps it's a God of Science?' Rincewind suggested. 'Watching to see who keeps taking things?'

'So ... science is done by anyone,' said Ridcully, 'and most of the equipment is stolen and it's all watched by a giant eyeball?'

As one wizard, they looked around, guiltily.

'There's just us,' said Ponder.

'Then this isn't science,' said Ridcully. 'No giant eyeball visible. Anyway, we can see it isn't science. It's just engineering. Any bright lad could have built it. It's obvious how it works.'

'How does it work?' said Rincewind.

'Very simply,' said Ridcully. The screw goes round and round and the water comes out here.'

'Hex?' said Ponder, and held out his hand. A large volume appeared in it. It was slim, full of colourful pictures, and entitled Great Moments in Science. It hadn't escaped his notice that when Hex or the Librarian wanted to explain something to the wizards they used a children's book.

He flicked through the passages. Big pictures, big writing.

'Ah,' he said. 'Archimedes invented this. He was a philosopher. He's also famous because one day, when he got into his bath, it overflowed. It says here this gave him an idea—'

'Buy a bigger bath?' said the Dean.

'Philosophers are always having ideas in the bath,' said Ridcully. 'All right, if we've got nothing else to go on ...'

'Gentlemen, please?' pleaded Ponder. 'Hex, take us to Archimedes. Oh, and give me a towel.'

'Nice place,' said the Dean, as the wizards sat on the sea wall, staring out at the wine-dark sea. 'I can feel the sea air doing me good. Anyone got more wine?'

It had been quite an interesting day. But, Ponder asked, had it been science? There was a pile of books beside him. Hex had been busy.

'Must have been science,' said Ridcully. 'King gave your man a problem. How to tell if the crown was all gold. He was thinking about it. Water sloshed out of bath. He leaped out, we handed him a towel, and then he worked out that ... what was it?'

'The apparent loss of weight of a body totally or partially immersed in a liquid is equal to the weight of the liquid it displaces,' said Ponder.

'Right. And he sees it doesn't just work with bodies, it works with crowns, too. A few tests, and bingo, science,' said Ridcully. 'Science is just working things out. And paying attention. And hoping there's someone around to dry you off.'

'I'm not ... exactly sure that's all there is to it,' said Ponder. 'I've been doing some reading and even people who do science don't seem clear about what it is. Look at Archimedes, for example.

Is a bright idea enough? Is it science if you just solve problems? Is that science, or what you get before you have science?'

'Your book of Great Moments calls him a scienter,' Ridcully pointed.

'Scientist,' Ponder corrected him. 'But I'm not sure about that, either. I mean, that sort of thing happens a lot. People always like to believe that what they're doing has been hallowed by history. Supposing men found out how to fly. They'd probably say "Early experimenters with man-powered flight included Gudrun the Idiot, who leaped off the clock tower in Pseudopolis after soaking his trousers in dew and gluing swan feathers to his shirt" when in fact he wasn't an early aviator—'

'—he was a late idiot?' said Rincewind.

'Exactly. It's like with wizards, Archchancellor. You can't just call yourself a wizard. Other wizards have to agree that you're a wizard.'

'So you can't have just one scientist, but you can have two?'