'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.'

Elves are wonderful. They provoke wonder.

Elves are marvellous. They cause marvels.

Elves are fantastic. They create fantasies.

Elves are glamorous. They project glamour.

Elves are enchanting. They weave enchantment.

Elves are terrific. They beget terror.

The thing about words is that meanings can twist just like a snake, and if you want to find snakes look for them behind words that have changed their meaning.

No-one ever said elves are nice.

Elves are bad.

For most purposes (though, admittedly, not when dealing with elves) it doesn't greatly matter if the traditional tales make no real sense. Father Christmas and the Tooth Fairy make no immediate sense (on Roundworld, but see Hogfather for their Discworld significance). Mind you, it's clear why children are happy to believe in such generosity. The most important role of the tribal Make-a-Human kit is to provide the tribe with its own collective identity, making it possible for it to act as a unit. Tradition is good for such purposes; sense is optional. All religions are strong on tradition, but many are weak on sense, at least if you take their stories literally.

Nevertheless, religion is absolutely central to most cultures' Make-a-Human kit.

The growth of human civilisation is a story of the assembly of ever-larger units, knitted together by some version of that Make-a-Human kit. At first, children were taught what they must do to be accepted as members of the family group. Then they were taught what they must do to be accepted as members of the tribe. (Believing apparently ridiculous things was a very effective test: the naive outsider would all too readily betray a lack of belief, or would simply have no idea what the appropriate belief was. Is it permitted to pluck a chicken before dark on Wednesday?

The tribe knew, the outsider did not, and sine any reasonable person would guess 'yes' the tribal priesthood could go a long way by making the accepted answer 'no'.) After that, the same kind of thing happened for the local baron's serfs, for the village, the town, the city and the nation. We spread the net of True Human Beings.

Once units of any size have acquired their own identity, they can function as units, and in particular they can combine forces to make a bigger unit. The resulting structure is hierarchical: the chains of command reflect the breakdown into sub-units and sub-sub-units. Individual people, or individual sub-units, can be expelled from the hierarchy, or otherwise punished, if they stray outside accepted (or enforced) cultural norms. This is a very effective way for a small group of people (barbarian) to maintain control over a much larger group (tribal). It works, and because of that we still labour under its restrictions, many of which are undesirable. We have invented technique like democracy to try to mitigate the undesirable effects, but these techniques bring new problems. A dictatorship can generally take action more rapidly than a democracy, for example. It's harder to argue.

The path from ape to human is not just one of evolutionary pressures producing more and more effective brains; not just a tale of the evolution of intelligence. Without intelligence, we could never have got started on that path, but intelligence alone was not enough. We had to find a way to share our intelligence with others, and to store useful ideas and tricks for the benefit of the whole group, or at least, those in a position to make use of it. That's where extelligence comes into play. Extelligence is what really gave those apes the springboard that would launch them into sentience, civilisation, technology, and all the other things that make humans unique on this planet. Extelligence amplifies the individual's ability to do good -or evil. It even creates new forms of good and evil, such as, respectively, cooperation and war.

Extelligence operates by putting ever more sophisticated stories into the Make-a-Human-Being kit. It pulled us up by our own bootstraps: we could climb from tribal to barbarian to civilised.

Shakespeare shows us doing it. His period was not a rebirth of Hellenistic Greece or Imperial Rome. Instead, it was the culmination of the barbarian ideas of conquest, honour and aristocracy, codified in the principles of chivalry, meeting its match in the written principles of a tribal peasantry, and disseminated by printing. This kind of sociological confrontation produced many events in which the two cultures meet head on.

This was exemplified by the Warwickshire enclosure uprisings. In Warwickshire, the aristocracy carved up land into small parcels, and the peasantry got very upset because the aristocracy didn't give any heed to what kind of land was in each parcel. All the aristocrats knew about peasant farming was a simplistic calculation: this much land will suffice for that many peasants. The peasants knew what was actually involved in growing food, so that the only thing you could do with a small piece of woodland, for instance, was to chop down all the trees to make room to grow some food.

Today's bean-counting managerial style in many businesses, and all British public services, is exactly the same. This kind of confrontation between the barbarian attitudes of the nobility and the tribal ones of the peasantry is precisely portrayed in many of Shakespeare's plays, as an illustration of low-life, with its folk wisdom as comic relief and pathos, set against the lofty ideals of the ruling classes - leading so often to tragedy.

But also to high comedy. Think of Theseus, Duke of Athens, on the one hand, and Bottom on the other, in A Midsummer Night's Dream.

In the heat of the night, magic moved on silent feet.

One horizon was red with the setting sun. This world went around a central star. The elves did not know this. If they had done, it would not have bothered them. They never bothered with detail of that kind. The universe had given rise to life in many strange places, but the elves were not interested in that, either.

This world had created lots of life, too. None of it had ever had what the elves considered to be potential. But this time ...

It had iron, too. The elves hated iron. But this time, the rewards were worth the risk. This time ...

One of them signalled. The prey was close at hand. And now they saw it, clustered in the trees around a clearing, dark blobs against the sunset.

The elves assembled. And then, at a pitch so strange that it entered the brain without the need to use the ears, they began to sing.

'Charge!' cried Archchancellor Ridcully.

The wizards, all bar Rincewind, charged. He peered around from behind a tree.

The elf song, a creative dissonance of tones that went straight into the back of the brain, ceased abruptly.

Thin figures spun around. Almond eyes glowed in triangular faces.

People who knew the wizards only as the world's most avid diners would have been quite surprised at their turn of speed. Besides, while it may take a little while for a wizard to reach maximum acceleration, he's then very hard to stop. And he carries such a cargo of aggression; the stratagems of the Uncommon Room at UU are guaranteed to give any wizard a maximum load of virulence just itching for a target.