Terry Pratchett - The Science of Discworld I

'The Luggage may consist of a subset of at least n dimensions which may co-exist with any other set of >n dimensions,' said the Bursar.

'Don't pay any attention, Stibbons,' said Ridcully wearily. 'He's been spouting this stuff ever since he tried to understand HEX's write-out. It's completely gibberish. What's 'V, then, old chap?'

'Umpt,' said the Bursar.

'Ah, imaginary numbers again,' said the Dean. 'That's the one he says should come between three and four.'

'There isn't a number between three and four,' said Ridcully.

'He imagines there is,' said the Dean.

'Could we get inside the Luggage in order to physically go into the project universe?' said Ponder.

'You could try,' said Rincewind. 'I personally would rather saw my own nose off.'

'Ah. Really?'

'But the thought occurs,' said Ridcully, 'that we can use it to bring things back. Eh?'

Down under the warm water, the strange creature's stone struc­ture collapsed for the umpteenth time.

A week went past. On Tuesday a left-over snowball collided with the planet, causing considerable vexation to the wizards and destroying an entire species of net-weaving jellyfish of which the Senior Wrangler had professed great hopes. But at least the Luggage could be used to bring back any specimens stupid enough to swim into something sitting underwater with its lid open, and this included practically everything in the sea at the moment.

Life in the round world seemed to possess a quality so prevalent that the wizards even discussed the idea that it was some conceptual element, which was perhaps trying to fill the gap left by the non­existent deitygen.

'However,' Ridcully announced, 'Bloodimindium is not a good name.'

'Perhaps if we change the accent slightly,' said the Lecturer in Recent Runes. 'Blod-di- min -dium, do you think?'

'They've certainly got a lot of it, whatever we call it,' said the Dean. 'It's not a world to let a complete catastrophe get it down.'

Things turned up. Shellfish suddenly seemed very popular, A theory gaining ground was that the world itself was generating them in some sort of automatic way.

'Obviously, if you have too many rabbits, you need to invent foxes,' said the Dean, at one of the regular meetings. 'If you've got fish, and you want phosphates, you need seabirds.'

'That only works if you have narrativium,' said Ponder 'We've got no evidence, sir, that anything on the planet has any concept of causality. Things just live and die.'

And then, on Thursday, the Senior Wrangler spotted a fish. A real, swimming fish.

'There you are,' he said triumphantly. 'The seas are the natural home of life. Look at the land. It's just rubbish, quite frankly.'

'But the sea's not getting anywhere,' said Ridcully. 'Look at those tentacled shellfish you were trying to educate yesterday. Even if you so much as made a sudden movement they just squirted ink at you and swam away.'

'No, no, they were trying to communicate,' the Senior Wrangler insisted. 'Ink is a natural medium, after all. Don't you get the impression that everything is striving? Look at them. You can see them thinking, can't you?'

There were a couple of the things in a tank behind him, peering out of their big spiral shells. The Senior Wrangler had the idea that they could be taught simple tasks, which they would then pass on to the other ammonites. They were turning out to be rather a dis­appointment. They might be good at thinking, ran the general view, but they were pants at actually doing anything about it.

'That's because here's no point in being able to think if you haven't got much to think about,' said the Dean. 'Damn all to think about in the sea. Tide comes in, tide goes out, everything's damp, end of philosophical discourse.'

'Now these are the chaps,' he went on, strolling along to another tank. The Luggage had been quite good as a collector, provided the specimens didn't appear to be threatening Rincewind.

'Hmph,' sniffed the Senior Wrangler. 'Underwater woodlice.'

'But there's a lot of them,' said the Dean. 'And they have legs. I've seen them on the seashore.'

'By accident. And they haven't got anything to use as hands.'

'Ah, well, I'm glad you've pointed that out ...' said the Dean, walking along to the next aquarium.

It contained crabs.

The Senior Wrangler had to admit that crabs looked a good con­tender for Highest Lifeform status. HEX had located some on the other side of the world that were moving along very well indeed, with small underwater cities guarded by carefully transplanted sea-anemones and what appeared to be shellfish farms. They had even invented a primitive form of warfare and had built statues, of sand and spit, apparently to famous crabs who had fallen in the struggle.

The wizards went and had another look fifty thousand years later, after coffee. To the Dean's glee, population pressure had forced the crabs on to the land as well. The architecture hadn't improved, but there were now seaweed farms in the lagoons, and some apparently more stupid crabs had been enslaved for transport purposes and use in inter-clan campaigns. Several large rafts with crudely woven sails were moored in one lagoon, and swarming with crabs. It seemed that crabkind was planning a Great Leap Sideways..

'Not quite there yet,' said Ridcully. 'But definitely very promis­ing, Dean.'

'You see, water's too easy ,'said the Dean. 'Your food floats by, there's not much in the way of weather, there's nothing to kick against... mark my words, the land is the place for building a bit of backbone ...'

There was a clatter from HEX, and the field of vision of the omniscope was pulled back rapidly until the world was just a mar­ble floating in space.

'Oh dear,' said the Archchancellor, pointing to a trail of gas, 'Incoming.'

The wizards watched gloomily as a large part of one hemisphere became a cauldron of steam and fire.

'Is this going to happen every time?' said the Dean, as the smoke died away and spread out across the seas.

'I blame the over-large sun and all those planets,' said Ridcully.

'And you fellows should have cleared out the snowballs. Sooner or later, they fall in.'

'It'd just be nice for a species to make a go of things for five min­utes without being frozen solid or broiled,' said the Senior Wrangler.

'That's life,' said Ridcully.

'But not for long,' said the Senior Wrangler.

There was a whimper from behind them.

Rincewind hung in the air, the outline of the virtually-there suit shimmering around him.

'What's up with him?' said Ridcully.

'Er ... I asked him to investigate the crab civilization, sir.'

"The one the comet just landed on?'

'Yes, sir. A billion tons of rock have just evaporated around him, sir.'

'It couldn't have hurt him, though, could it?' 'Probably made him jump, sir.'

CHANCE MAY HAVE PLAYED A GREATER ROLE than we imagine in ensuring our presence on the Earth. Not only aren't we the pinnacle of evolution: it's conceivable that we very nearly didn't appear at all. On the other hand, if life had wandered off the particular evolutionary track that led to us, it might well have blun­dered into something similar instead. Intelligent crabs, for example. Or very brainy net-weaving jellyfish.

We have no idea how many promising species got wiped out by a sudden drought, a collapse of some vital resource, a meteorite strike, or a collision with a comet. All we have is a record of those species that happen to have left fossils. When we look at the fossil record, we start to see a vague pattern, a tendency towards increas­ing complexity. And many of the most important evolutionary innovations seem to have been associated with major catastrophes…