The Science of Discworld II

differently and therefore represents the universe in its own special way. But we’ve evolved to be pretty good at guessing.
    This ability to get inside other people’s heads has many beneficial consequences. One is that we recognise other people as people, not just automata. We recognise that they have a mind, that to them the universe seems just as real and vivid as it does to us, but that the vivid things they perceive may not be the same as those that we perceive. If intelligent beings are going to get along together without too much friction, it’s important to realise that other members of your species have an internal mental universe, which controls their actions in the same way that your own mind controls yours.
    When you can put yourself inside another person’s mind, stories gain a new dimension. You can identify with a central character, and vicariously experience a different world. This is the appeal of fiction: you can captain a submarine, or spy on the enemy, from the safety and comfort of an armchair.
    Drama has the same appeal, too, but now there are real people to identify with; people who play a fictional role. Actors, actresses. Andthey rely even more on getting inside other people’ss minds, especially the minds of fictional characters. Macbeth. The Second Witch. Oberon. Titania. Bottom.
    How did this ability arise? As usual, it seems to have come about because of a complicity between the internal signal-processing abilities of the brain and the external pressures of culture. It arose through an evolutionary arms race, and the main weapon in that race was the lie.
    The story starts with the development of language. As the brains of proto-humans evolved, getting larger, there was room in them for more kinds of processing tasks to be carried out. Primitive grunts and gestures began to be organised into a relatively systematic code, able to represent aspects of the outside world that were important to the creatures concerned. A complicated concept like ‘dog’ became associated with a particular sound. Thanks to an agreed cultural convention, anyone who heard that sound responded to it with the mental image of a dog; it wasn’t just a funny noise. If you try to listen to someone speaking a language that you know, focusing just on the noises that they are making and trying not to pick up the meaning of their words, you’ll find that it’s almost impossible. If they speak a language far removed from any that you know, however, their speech comes over as a meaningless gabble. It conveys less to you than a cat’s miaow.
    In the brain are circuits of nerve cells that have learned to decode gabble into meaning. We’ve seen that as a child grows, it begins by babbling a random assortment of phonemes, the ‘units’ of sound that a human mouth and larynx can produce. Gradually the child’s brain prunes the list down to those sounds that it hears from its parents and other adults. While it is doing that, the brain is destroying connections between nerve cells that seem to be obsolete. Quite a lot of the early mental development of an infant consists of chopping down a randomly connected, all-purpose brain, and pruning it into a brain that can detect the things that are considered important in the child’s culture. If the child is not exposed to much linguistic stimulus in early childhood – such as a ‘feral’ child brought up by animals – then they can’t learn a language properly in later life. After about the age of ten, the brain’s ability to learn language fades away.
    Much the same happens with other senses, in particular the sense of smell. Different people smell the same thing differently. To some, a particular odour may be offensive, to others innocuous, and to yet others, nonexistent. As with language, there are cultural biases to certain smells.
    The primary function of language – by which we mean ‘the main evolutionary trick that made it advantageous, leading to its preservation and enhancement by natural selection’ – is to convey meaningful messages to other members of the same species. We do this in several ways: ‘body language’ and even bodily odours convey vivid messages, largely without our being conscious of them. But spoken language is far more versatile and adaptable than the other kinds, and we are very conscious of what others are saying. Especially when it is about us