The Science of Discworld Revised Edition

by Terry Pratchett

  It’s not surprising that we have sex on the brain: our brains have been moulded by sex. The Dean should let sex take its course, for intelligence will surely follow … You just have to think on the scale of Deep Time. There’s no rush.

  1 To find out how, see The science of Discworld II: The Globe.

  FORTY-THREE

  OOK: A SPACE ODYSSEY

  RINCEWIND SAT IN a corner of the High Energy Magic building. It was deserted at the moment. News had got around that the project was really being ended this time, and wizards had drifted away to lunch.

  The round world spun in its protective globe and also, by means of a physics only a wizard might understand, in a space that was infinite only on the inside.

  ‘Poor old bloody place,’ he said, to the world in general. ‘Never really stood a chance, did you.’

  ‘Ook.’

  It was a small grunt, from the other side of the huge room. Rincewind wandered over, and found the Librarian peering into the omniscope.

  ‘Oh, they’ve got sticks now,’ said Rincewind, looking down at a ragged party of apes. ‘And a lot of good it’ll do them, too.’

  ‘Ook?’

  ‘The lizards had sharp shells on the end of theirs, and are they around today? I don’t think so. And the crabs were doing well. Even the blobs were trying to make a go of things. There were some bear sort of things that looked promising. Doesn’t matter. One winter the snow doesn’t melt, next thing there’s a two-mile wall of ice laminating you to the bedrock. Or there’s a funny light in the sky and then you’re trying to breathe burning water.’ He shook his head wearily. ‘Nice place, though. Nice colours. Particularly good horizons, once you get used to them. Lots of dullness, punctuated by short periods of death.’

  ‘Ook?’ said the Librarian.

  ‘Well, maybe they do look a bit like you,’ said Rincewind. ‘Most of the lizards looked a bit like the Bursar. Maybe it’s just coincidence. Everything has to look like something, after all. As above, so below.’

  In the omniscope, some distance behind the ape clan, something lean and powerful was tracking them in the long grass.

  ‘Eeek!’

  The Librarian thumped on the desk.

  ‘Sorry. It’s not up to me. “Live and let live”, you know that’s always been my motto. Well, “let me live”, really, but that’s almost the same thing.’

  Hands waving wildly over his head, which only happened when he was really in a hurry, the Librarian ran out of the room.

  Rincewind caught him up as he entered the main building, and then trotted along after him as the ape wound his way through the university’s less salubrious regions, the realm of broom cupboards, old storerooms and the studies of the very much lesser members of staff. Even using all the shortcuts, it still took quite a while to reach the office of the Egregious Professor of Cruel and Unusual Geography, with the name ‘Rincewind’ written on it in chalk.

  The orangutan flung the door back and knuckled purposefully towards the big stack of boxes.

  ‘Er … that’s the rock collection,’ said Rincewind. ‘Er … I was filing them … er … they belong to the University, I really don’t think you should be throwing them out like that –’

  ‘Ook!’

  The Librarian straightened up, bearing aloft a couple of large rocks that Rincewind recognized as noduley, sharp, brittle, unfriendly rocks.

  ‘Er … why are you …’ Rincewind began.

  The Librarian walked across to the Luggage and gave it a kick. The lid opened obediently, and the rocks were thrown inside. The ape went back for more flints.

  ‘Er …’ said Rincewind, but left it at that. This did not seem to be a time to raise objections.

  He had to run after the Librarian and the Luggage all the way back to the High Energy Magic Building. By the time he got there, the ape was pounding heavily on one of HEX’s keyboards.

  Rincewind tried again.

  ‘Er … should you be …’

  He was interrupted by the rattle of the machine’s writing device.

  It spelled out: +++ New Suit Parameters Accepted +++

  On the far side of the room, where the skeletal virtually-there suits flicked on the verge of non-existence, one changed shape. The shoulders widened. The arms grew longer. The legs shortened –

  +++ Adjustment Complete. On You It Looks Good +++

  Rincewind backed away as the Librarian, cradling a large flint nodule in each arm, stepped in the magic circle and began to shimmer as the suit enclosed him. The new parameters definitely made it look more solid …

  ‘You’re not going to interfere, are you?’ said Rincewind.

  ‘Ook?’

  ‘No, no, that’s fine, fine, no problem at all,’ said Rincewind. It is never wise to argue with an ape holding a rock. ‘It’s about time someone did.’

  The Librarian flickered, and became a ghost in the air.

  Rincewind stood alone in the empty room, whistling nervously. In its alcove, HEX began to sparkle, as it always did when it was trying to allow a wizard to interact with the project.

  ‘Blast!’ said Rincewind at last, striding over to the suits. ‘He’s bound to muck it up …’

  Lightning fried the evening sky, turning it purple and pink.

  Above the little hollow in the cliff, where the tribe clustered and flinched, a sleek black shadow moved like an extension of the night. It wasn’t hurrying. Dinner wasn’t going anywhere. When the lightning faded its eyes gleamed for a while.

  Something grabbed its tail. It spun around, snarling, and a fist extended on the end of a very long arm hit it right between the eyes, lifting it off the ledge.

  It landed heavily on the ground, jerked for a moment, and lay still.

  The ape horde scattered around the rocks, screaming, and then stopped to look back.

  The big cat didn’t move.

  Another bolt of lighting hit the ground nearby, and a dead tree exploded into flame. Against the violet corona of the storm, red in the light of the burning tree, a huge figure stood holding a large stone in the crook of each arm.

  As Rincewind said, it was a vision you were unlikely to forget.

  Rincewind couldn’t eat here. Well, not in the usual, definitive way. He thought he could probably manipulate lumps of food into his mouth, but since the food would technically remain in a different universe to his, he was afraid it might drop straight through him, to general embarrassment and the puzzlement of spectators.

  Besides, he didn’t feel like flame-grilled leopard.

  The Librarian had been working furiously. He’d turned the area into a boot camp for people who were barely upright and wouldn’t know what to do with a boot anyway. The apemen had taken to fire quite quickly, after a few misdirected attempts to eat it or have sex with it, and several of them had progressed to setting fire to themselves.

  They’d learned cookery, too, initially on one another.

  Rincewind sighed. He’d seen species come, and he’d seen them go, and this one could only have been put on the world for entertainment value. They had the same approach to life as clowns, with the same touch of cheerful viciousness.

  The Librarian had progressed to lessons in flint-knapping, using the flints brought in via the Luggage. They’d certainly picked up the idea of hitting rocks against other rocks, or anything else in range. Sharp edges intrigued them.

  Finally Rincewind wandered over to the Librarian and tapped him on the shoulder.

  ‘We’ve been here all day,’ he said. ‘We’d better get back.’

  The orangutan nodded, and stood up. ‘Ook.’

  ‘You think it’ll work?’

  ‘Ook!’

  Rincewind looked back at the apemen. One of them was industriously hacking at the corpse of the cat again.

  ‘Really? But they’re just like … hairy parrots.’

  ‘Eek ook.’

  ‘Well … yes. That’s true.’ Rincewind took a final look at the horde. Two of them were squabbling over t
he meat. Monkey see, monkey do …

  ‘I’m glad it was you who said that,’ he said.

  Less than a Discworld second had passed by the time they returned. By the time they looked in the omniscope, several fires were already visible on the night side of the world.

  The Librarian looked pleased. ‘Oook,’ he said.

  Progress means smoke. But Rincewind was not entirely convinced. Most of the fires were forests.

  FORTY-FOUR

  EXTEL OUTSIDE

  PROGRESS MEANS SMOKE … The human race has certainly made a lot of progress over the years, then. How did we do that? Because we’re intelligent, we’ve got brains. Minds, even. But other creatures are intelligent – dolphins, especially. And all they seem to do is enjoy themselves in the sea. What have we got that they haven’t?

  Many discussions of the mind treat it essentially as a question about the architecture of the brain. The viewpoint is that this determines what brains can do, and then the various things that we associate with minds – the difficult problems of free will, consciousness and intelligence – come out of neurophysiology. That’s one approach. The other common one is to view the problem through the eyes of a social scientist or an anthropologist. From this viewpoint the mind’s capabilities are pretty much taken as ‘given’, and the main questions are how human culture builds on those capabilities to create minds able to think original thoughts, feel emotions, have concepts like love and beauty, and so on. It may seem that between them these two approaches pretty much cover the territory. Link them, and you have a complete answer to the question of mind.

  However, neurophysiology and culture aren’t independent: they are ‘complicit’. By this we mean that they have evolved together, each changing the other repeatedly, and their mutual coevolution built on the unpredictable results of that ongoing interaction. The view of culture building on, and changing, brains is incomplete, because brains also build on, and change, culture. The concept of complicity captures this recursive, mutual influence.

  We call the brain’s internal capabilities ‘intelligence’. It is convenient to give a similar name to all of the external influences, cultural or otherwise, that affect the evolution of the brain – and with it, the mind. We shall call these influences extelligence, a term that HEX has picked up thanks to once-and-future computing. Mind is not just intelligence plus extelligence – its inside and outside, so to speak. Instead, mind is a feedback loop in which intelligence influences extelligence, extelligence influences intelligence, and the combination transcends the capabilities of both.

  Intelligence is the ability of the brain to process information. But intelligence is only part of what is needed to make a mind. And even intelligence is unlikely to evolve in isolation.

  Culture is basically a collection of interacting minds. Without individual minds you can’t have a culture. The converse is perhaps less obvious, but equally true: without a shared culture, the human mind cannot evolve. The reason is that there is nothing in the environment of the evolving mind that can drive it towards self-complication – becoming more sophisticated – unless that brain has something else fairly sophisticated to interact with. And the main sophisticated thing around to interact with is minds of other people. So the evolution of intelligence and that of extelligence are inextricably linked, and complicity between them is inevitable.

  In the world around us are things that we, or other human beings, have created – things which play a similar role to intelligence but sit outside us. They are things like libraries, books, and the Internet – which from the viewpoint of extelligence would be better named the ‘Extranet’. The Discworld concept of ‘L-space’ – library-space – is similar: it’s all one thing. These influences, sources not just of information but of meaning, are ‘cultural capital’. They are things that people put out into the culture, which can then sit there, or even reproduce, or interact in a way that individuals can’t control.

  The old artificial intelligence question: ‘Can we create an intelligent machine?’ viewed the machine as a once-off object in its own right. The problem, people assumed, was to get the machine’s architecture right, and then program intelligent behaviour into it. But that’s probably the wrong approach. Of course, it is certainly conceivable that the collective extelligence of all the human beings interacting with that machine could put a mind into it – and in particular endow it with intelligence. But it seems much more likely that, unless you had a whole community of machines interacting with each other and evolving, providing the requisite extelligence too, then you wouldn’t be actually able to structure the Ant Country of the neural connections of the machine in a way that could generate a mind. So the story of the mind is one of complicity and emergence. Indeed, mind is one of the great examples of complicity.

  The internal story of the development of the mind can be summed up as a series of steps in which the key ‘player’ is the nerve cell. A nerve cell is an extended object that can send signals from one place to another. Once you’ve got nerve cells you can have networks of nerve cells; and once you’ve got networks, then a whole pile of stuff comes along free of charge. For example, there is an area of complexity theory called ‘emergent computation’. It turns out that when you evolve a network – randomly chosen networks, arbitrary networks, not constructed with specific purposes – they do things. They do something, which may or may not seem meaningful; they do whatever it is that that network does. But you can often look at what that network does, and spot emergent features. You discover that even though its architecture was random, it evolved the ability to compute things. It carries out algorithmic processes (or something close to algorithmic processes). The ability to do calculations, computations, algorithms seems to come free of charge once you’ve invented devices that send signals from one place to another and react to those signals to send new signals. If you allow evolution you don’t have to work hard to create the ability to do some kind of processing.

  Once you’ve got that facility, it’s a relatively short step to the ability to do specific kinds of processing that happen to be useful – that happen to offer survival value. All you need is the standard Darwinian selection procedure. Anything that’s got that ability survives, anything that hasn’t, doesn’t. The ability to process incoming information in ways that extract an interesting feature of the outside world, react to it, and thereby make it easier to evade a predator or to spot food, gets reinforced. The brain’s internal architecture comes from a phase space of possible structures, and evolution selects from that phase space. Put those two together and you can evolve structures in the brain that have specific functions. The brain’s surroundings certainly influence the development of the brain.

  Do animals have minds? They do to some extent, depending on the animal. Even simple animals can have surprisingly sophisticated mental abilities. One of the most surprising is a funny creature called a mantis shrimp.

  It’s like the shrimps you put inside a sandwich and eat, except that it’s about 5 inches (12 cm) long and it’s more complex. You can keep a mantis shrimp in a tank, as part of a miniature marine ecology. If you do, you’ll find that mantis shrimps cause havoc. They tend to destroy things – but they also build things. One thing they love building is tunnels, which they then live in. The mantis shrimp is a bit of an architect, and it decorates the front of its tunnel with bits and pieces of things – especially bits and pieces of what it has just killed. Hunting trophies. It doesn’t like to have just one tunnel – it’s discovered that if you have one tunnel with one entrance, that’s more correctly known as a ‘trap’. So it likes to have a back entrance too – and more. By the time it’s been in the tank for about two months, it’s riddled the entire tank with tunnels, and you find it sticking its head out at one end or the other without seeing it pass between.

  Years ago, Jack used to have a mantis shrimp called Dougal.1 Jack and his students discovered that they could set Dougal puzzles. They would feed it shrimps and it would come out a
nd grab the shrimp. Then they would put the shrimp inside a plastic container with a lid and after a little while Dougal would like to take the lid off the container and eat the shrimp. And then they put an elastic band around the container to hold the lid on, and Dougal would learn to take the band off and open the container and eat the shrimp. And after a while if they stuck a shrimp in on its own, you could almost see the mantis shrimp coming out and looking disappointed: ‘They haven’t set me a puzzle, this is no fun, I don’t want to play this game!’ And it would take a long look at the shrimp and then go back into its tunnel without grabbing it.

  Although we can think of no way to prove this, everyone got the strong impression that the shrimp was developing a little bit of a mind. Its brain had the potential to do so, and humans had provided it with the kind of context that would help it develop that potential. Wild mantis shrimps don’t go out and play with elastic bands, because those aren’t part of their environment, but if you give them that kind of stimulus, you change them. Because we’ve got minds, we also have the capacity to create a little bit of mind in a lot of other creatures.

  Mind is a process, or a network of processes, going on inside the brain. It needs a certain amount of interaction with other minds in order to get anywhere. There isn’t an evolutionary feedback loop that would train an incipient mind and make it develop unless it was getting somewhere. So where does such a loop occur? Human beings are part of a reproductive system – there are a lot of us, and we keep breeding new ones. In consequence, a large part of the environment of any human being is other human beings. In many ways this is the most important part of our environment, the part we respond to most deeply. We have all sorts of cultural systems, such as education, that exploit exactly this feature of our environment to develop the kind of mind that fits into the existing culture and helps to propagate it. So the context for an individual mind, as it evolves, is not that mind – it’s lots of other minds. There is a complicit feedback loop between the entire collection of minds, and that of each individual.