The Science of Discworld II Read online

  We can’t build one either, but it might take no more than a couple of hundred years before the things are sprouting all along the equator. All you need is a material with enough tensile strength, perhaps some composite involving carbon nanotubes. Then you dangle cables from geostationary satellites, hang elevator compartments from them, equip them with suitable space elevator music … after which, leaving the planet becomes entirely straightforward. The energy cost, hence the marginal financial cost, is near enough zero, because for everything that needs to go up, something else needs to come down. It could be moon rock, or platinum mined in the asteroid belt, or the astronaut that the person going up is due to replace on duty. The capital cost of such a project is enormous, though, which is why we’re not in any great hurry right now.

  The big scientific problem in this connection is: how can evolution get so quickly from an ape that can’t compete mentally with a chimpanzee to a godlike being that can write poetry as good as Shakespeare’s, and has advanced so rapidly from that point that it will surely soon erect (drop) a space elevator? 100,000 Grandfathers hardly seems long enough, given that it took about 50 million Grandfathers3 to get from a bacterium to the first chimpanzee.

  Something that dramatic needed a new trick. That trick was the invention of culture. Culture allowed any individual ape to make use of the ideas and discoveries of thousands of other apes. It let the ape collective acquire knowledge cumulatively, so that it didn’t all get lost when its owner died. In Figments of Reality we coined the term ‘extelligence’ for this suite of tricks, and the word is beginning to become common currency. Extelligence is like our own personal intelligence, but it lives outside us. Intelligence has limits; extelligence is infinitely expandable. Extelligence lets us pull ourselves upwards, as a group, by our own mental bootstraps.

  The contradiction between Shakespeare’s noble sentiments and the heads-on-spikes culture in which he lived is a consequence of his position as a very intelligent intelligence in a not-very-extelligent extelligence. Many individuals possessed the nobility to qualify for Shakespeare’s praise, but their as yet rudimentary extelligence had not yet transmitted that nobility into the general culture. The culture was, or claimed to be, noble in principle – kings taking their authority from God Himself – but it was a barbarian style of nobility. And it was welded to a barbarian cruelty, the kings’ means of self-preservation.

  There may be many ways to make intelligent creatures, and many more ways to knit them together into an extelligent culture. The crab civilisation in The Science of Discworld was doing fine until its Great Leap Sideways was clobbered by an inbound comet. We made that one up, but who knows what might have happened a hundred million years ago? All we know for sure – or for a given value of ‘sure’, since even now a lot of our knowledge is guesswork – is that some things like apes turned into us. It takes a special kind of arrogance and blindness to extrapolate that story to the rest of the universe without wondering about alternatives.

  An important ingredient in our story was brains. Weight for weight, humans have far bigger brains than any other animal on the planet. The average human brain has a volume of about 1,350 cubic centimetres, which is roughly three times as great as the brain of apes with the same size body as ours. Whale brains are bigger than ours, but whales are even bigger, so the amount of whale per brain cell is greater than the amount of human per brain cell. When it comes to brains, quantity is less important than quality, of course. But a brain capable of really complicated things like carbon nanotube engineering and fixing dishwashers has to be fairly large, because the abilities of small brains are limited by lack of room to do anything interesting.

  We’ll see shortly that brains alone are not enough. Nonetheless, without brains, or adequate substitutes, you don’t get very far.

  There are two main theories of human origins. One is rather dull and probably correct; the other is exciting and most likely wrong. Nevertheless, the second one has quite a lot going for it and is a better story, so let’s take a look at them both.

  The dull, conventional theory is that we evolved on the savannahs. Roving groups of early apes trailed through the long grass, picking up whatever food – seeds, lizards, insects – they could find, much like today’s baboons.4 And as they did so, lions and leopards prowled through the long grass looking for monkeys. Those monkeys or apes that were better at spotting the telltale flicker of a big cat’s tail, and finding a tree rather quickly, survived to have babies; those that performed poorly at such tasks did not. The babies inherited those survival skills, and passed them on to their babies.

  What these tasks need is computational power. Spotting a tail and finding a tree are pattern-recognition problems. Your brain needs to pick out the tail-shape from a background of similarly buff-coloured rocks and mud; it has to choose a tree that is tall enough, and climbable enough, without being too climbable, and it has to be able to do it fast. A capacious brain with a big memory (of past occasions when something hairy poked out from behind a rock, and of locations for climbable trees) can pick up the visual traces of a lion much more effectively than a small brain can. A brain whose nerve cells transmit signals to each other more quickly can analyse incoming sensory data and conclude ‘lion’ a lot faster than a slower brain can. So there was evolutionary pressure on the early apes and monkeys to develop bigger and faster brains. There was also evolutionary pressure on the lions to conceal themselves more effectively, so that those bigger and faster ape and monkey brains still didn’t notice anything suspicious. So a predator-prey ‘arms race’ developed, a positive feedback loop that made both lions and apes far more effective in their ecological roles.

  That is the conventional story of human evolution. But there is another story, less orthodox, with two main sources.

  Human beings are very weird apes, indeed very weird animals altogether. They have extremely short fur, mostly just a downy covering. They walk upright on two legs. They have a layer of fat, all the year round. They mate face-to-face (often). They have exceptionally good breath-control; good enough to be able to speak. They weep and they sweat. They adore water, and can swim long distances. A newborn baby, dropped in a pool, can keep itself afloat: the ability to swim is instinctive. All these peculiarities led Elaine Morgan to write The Aquatic Ape in 1982. There she suggested a radical theory: that humans evolved not on the savannahs, surrounded by fierce predators, but on the beach. That explains the swimming, the upright stance (it’s easier to evolve a two-legged gait if you are buoyed up by seawater), and the lack of hair (which causes problems when you swim, providing an evolutionary reason for it to disappear). In fact it can be argued that it explains all of the peculiarities of humans that we’ve just listed. The original scientific underpinnings of this theory were developed by Alister Hardy.

  In their 1991 The Driving Force Michael Crawford and David Marsh took the story one stage further, by added one extra ingredient. Literally. The most important thing that the beach provides is seafood. And the most important thing that seafood provides is ‘essential fatty acids’, which are a crucial ingredient in brains. In fact, nearly two-thirds of the human brain is made from them. Fatty acids are good for making membranes, and brains use electrical signals in membranes to compute. Myelin, in a membrane sheath surrounding nerve cells, speeds up the transmission of signals in the human nervous system by a factor of five or so. It takes a lot of essential fatty acids, then, to make a big, fast human brain, so it must have taken almost as much to make the brain of our distant ape ancestor. Oddly, though, our bodies cannot make those special fatty acids from simpler chemicals, like we make most complicated biochemicals that we need. We have to get the fatty acids, ready-made, from our food; that’s why the word ‘essential’ is used to describe them. Even more oddly, there are few essential fatty acids out on the savannahs. They would exist only in living creatures, of course, but even there, they are fairly rare. The richest source of essential fatty acids is seafood.

  Perhaps a
ll this explains why we want to spend so much time on the beach. But whatever the explanation, the ability to make big brains was one key step in our evolution away from our hairy, quadrupedal, 100,000-fold great grandfather.

  Big brains, however, are not enough. What really matters is what you do with them. And what we managed to do was to play off one brain against another, so that over the millennia they got better and better at competing and communicating.

  Ape brains competing with lion brains leads to an arms race that improves both, but the arms race is fairly slow, because both brains are being used for very limited purposes as far as the competition goes. Ape brains competing with other ape brains gives the whole brain a workout, all the time, so the rate of evolution is likely to be much higher.

  For every species, the main competition comes from other creatures of the same species. This is reasonable; they’re the ones that want exactly the same resources that you do. This opens the door to elvish interference, in our Discworld metaphor. The nasty side of human nature, which in extremes leads to evil, is inescapably bound up with the nice side. One very direct way to compete with your neighbour is to bash him on the head, hard.

  However, there are more subtle ways to gain evolutionary advancement, as we will see later. The elvish approach is crude, and ultimately self-defeating, for a sufficiently extelligent species.

  The possession of brains opens up new non-genetic ways to pass characteristics on to your children. You can give them a good start in life by moulding how their brains react to the outside world. The generic term for this kind of non-genetic transfer between the generations is privilege. There are numerous instances of privilege in the animal kingdom. When a mother blackbird provides yolk in her egg for the baby blackbird to feed from, that’s privilege. When a cow provides milk for her calf, that’s even more privilege. When a mother tarantula wasp provides a paralysed, living spider for her grubs to grow in, that’s privilege.

  Humans have taken privilege to a qualitatively new level. Human parents invest an astonishing amount of time and effort in their children, and spend decades – entire lifetimes, in many ways – looking after them. In conjunction with big brains, slowly getting bigger as each generation passes, privilege leads to two new tricks, learning and teaching. Those tricks feed off each other, and both require the best brain you can acquire.5

  Genes are involved in building brains, and genes can perhaps predispose individuals to be unusually good at learning or teaching. However, both of these educational processes involve far more than mere genes: they take place within a culture. The child does not just learn from its parents. It learns from its grandparents, from its siblings, from its aunts and uncles, from the whole troupe or tribe. It learns, as all parents discover, to their dismay, from undesirable sources as well as authorised ones. Teaching is the attempt to transmit ideas from the adult brain to that of the child; learning is the child’s attempt to insert those ideas into its brain. The system is imperfect, with a lot of garbled messages along the way, but despite its faults it is much faster than genetic evolution. That’s because brains, networks of nerve cells, can adapt much more rapidly than genes can.

  The faults, oddly enough, probably accelerate the process, because they are a source of creativity and innovation. An accidental misunderstanding may sometimes lead to an improvement.6 In this respect, cultural evolution is just like genetic evolution: it is only because the DNA copying system makes mistakes that organisms can change.

  Culture didn’t arise in a vacuum: it had many precursors. One crucial step towards the development of culture was the invention of the nest. Before nests came into being, any experimentation by the young either worked, or led to a quick death. Within the protection of the nest, however, young animals can try things out, make mistakes and profit from them; for example, by learning not to do the same thing again. Outside the nest, they never get a chance to try a second time. In this manner nests led to another development, the role of play in educating the young animal. Mother cats bring half-dead mice for their kittens to practise hunting on. Mother birds of prey do the same for their offspring. Polar bear cubs slide down snow-slopes and look cute. Play is good fun, and the kids enjoy it; at the same time, it equips them for their adult roles.

  Social animals, ones that gather in groups and operate as groups, are a fertile breeding-ground for privilege and for education. And with appropriate communication, groups of animals can achieve things that no individual can manage. A good example is dogs, which evolved the ability to hunt in packs. When such tricks are being played, it is important to have some recognition signal that lets the pack distinguish its own members from outsiders, otherwise the pack can do all the work and then an outsider can steal the food. Each dog pack has its own call-sign, a special howl that only insiders know. The more elaborate your brain, the more elaborate the communication from brain to brain can be, and the more effectively education works.

  Communication helps with the organisation of group behaviour, and it opens up survival techniques that are more subtle than bashing others on the head. Within the group, cooperation becomes a far more viable option. Today’s great apes generally work as small groups, and it seems likely that their ancestors did the same. When humans split off from the chimpanzee lineage, those groups became what we now call tribes.

  Competition between tribes was intense, and even today some jungle tribes in South America and New Guinea think nothing of killing anyone they meet who comes from a different tribe. This is a reversion to the ‘bash on the head’ option, but now one group cooperates to bash the other group’s members on the head. Or, usually, one such member at a time. Less than a century ago, most such tribes did the same (one of the stories we’ve told ourselves throughout our tribal history is that we are The People, The True Human Beings – which means that everyone else isn’t).

  Chimpanzees have been observed killing other chimpanzees, and they regularly hunt smaller monkeys for meat. That isn’t cannibalism. The food is a different species. Most humans cheerfully consume other mammals, even quite intelligent ones like pigs.7

  Just as dog-packs need an agreed recognition signal to identify their members, so each tribe needs to establish a distinct identity. The possession of big brains makes it possible to do this by means of elaborate, shared rituals.

  Ritual is by no means confined to humans: many species of birds, for instance, have special mating dances, or engage in strange devices to attract the female’s attention, like the decorative collections of berries and pebbles assembled by the male bower-bird. But humans, with their highly developed brains, have turned ritual into a way of life. Every tribe, and nowadays every culture, has developed a Make-a-Human kit whose object is to bring up the next generation to adopt the tribal or cultural norms and pass them on to their own children.

  It doesn’t always work, especially nowadays when the world has shrunk and cultures clash across non-geographical boundaries – Iranian teenagers accessing the Internet, for example – but it still works surprisingly well. Corporations have taken up the same idea, with ‘corporate bonding’ sessions. This is what the wizards were up to with their paintballs. Studies have shown that sessions of this kind have no useful effect, but businesses still waste billions on them every year. The second most probable reason is that such sessions are fun anyway. The first most probable is that everyone likes an opportunity to shoot Mr Davis in Human Resources. And one important reason is that it sounds as though it ought to work; our culture is full of stories where such things do.

  An important part of the Make-a-Human kit is the Story. We tell our children stories, and through those stories they learn what it is like to be a member of our tribe or our culture. They learn from the story of Winnie the Pooh getting stuck in Rabbit’s hole that greed can lead to constraints on food. From the Three Little Pigs (a civilising story, not a tribal one) they learn that if you watch your enemy for repetitive patterns, you can outwit him. We use stories to build our brains, and the
n we use the brains to tell ourselves, and each other, stories.

  As time passes, those tribal stories acquire their own status, and people cease to question them because they are traditional tribal stories. They acquire a veneer of – well, the elves would call it ‘glamour’. They seem wonderful, despite numerous obvious faults, and most people do not question them. On Discworld, precisely this process occurred with stories and folk-memories about elves, as we can illustrate with three quotations from Lords and Ladies. In the first, the god of all small furry prey, Herne the Hunted, has just come to the terrified realisation that ‘They’re all coming back!’. Jason Ogg, who is a blacksmith, the eldest son of the witch Nanny Ogg, and not very bright, asks her who They are:

  ‘The Lords and Ladies,’ she said.

  ‘Who’re they?’

  Nanny looked around. But, after all, this was a forge … It wasn’t just a place of iron, it was a place where iron died and was reborn. If you couldn’t speak the words here, you couldn’t speak ’em anywhere.

  Even so, she’d rather not.

  ‘You know,’ she said. ‘The Fair Folk. The Gentry. The Shining Ones. The Star People. You know.’

  ‘What?’

  Nanny put her hand on the anvil, just in case, and said the word.

  Jason’s frown very gently cleared, at about the same speed as a sunrise.

  ‘Them?’ he said. ‘But aren’t they nice and—’

  ‘See?’ said Nanny. ‘I told you you’d get it wrong!’

  You said: The Shining Ones. You said: The Fair Folk. And you spat, and touched iron. But generations later, you forgot about the spitting and the iron, and you forgot why you used those names for them, and you remembered only that they were beautiful … We’re stupid, and the memory plays tricks, and we remember the elves for their beauty and the way they move, and we forget what they were. We’re like mice saying, ‘Say what you like, cats have got real style.’