The Science of Discworld II

because of the overall activity of your entire brain, plus the nerve fibres that are connected to it, bringing it sensations of the outside world and allowing it to control the movement of your arms, legs and fingers. You feel like you, in fact, because you are busily being You.
    Mind is a process carried out within a brain made of perfectly ordinary matter, in accordance with the rules of physics. It is, however, a very strange process. There is a kind of duality, but it is a duality of interpretation rather than of physical material. When you think a thought – about, let us say, the Fifth Elephant that slipped off the back of Great A’Tuin, orbited in an arc of a circle and crashed on to the surface of the Discworld – the same physical act of thinking that thought has two distinct meanings.
    One of them is straightforward physics. In your brain, various electrons are surging to and fro in various nerve fibres. Chemical moleculesare combining together, or breaking up, to make new ones. Modern sensing apparatus, such as the PET scanner, 1 can reconstruct a three-dimensional image of your brain, showing which regions are active when you are thinking about that elephant. Materially, your brain is buzzing in some complicated way. Science can see how it is buzzing, but it can’t (yet) extract the elephant.
    That’s the second interpretation. From inside, so to speak, you have no sensation of those buzzing electrons and reacting chemicals. Instead, you have a very vivid impression of a large grey creature with flappy ears and a trunk, sailing improbably through space and crashing disastrously to the ground. Mind is what it feels like to be a brain. The same physical events acquire a totally different meaning when viewed from the inside. One task of science is to try to bridge the gap between those two interpretations. The first step is to figure out which bits of the brain do what when you think a particular thought. To reconstruct, in fact, the elephant from the electrons. That’s not yet possible, but every day brings it a step closer. Even when science gets there, it will probably not be able to explain why your impression of that elephant is so vivid, or why it takes exactly the form that it does.
    In the study of consciousness there is a technical term for what a perception ‘feels like’. It is called a quale (pronounced ‘kwah-lay’, not ‘quail’), a figment that our minds paint on to their model of the universe in the way that an artist adds pigment to a portrait. Such qualia (plural) paint the world in vivid colours so that we can respond more quickly to it, and, in particular, respond to signs of danger, food, possible sexual partners … Science has no explanation of why qualia feel like they do, and it’s not likely to get one. So science can explain how a mind works, but not what it is like to be one. No shame in that: after all, physicists can explain how an electron works, but not what it is like to be one. Some questions are beyond science. And, we suspect, beyond anything else: it is easy enough to claim an explanation of these metaphysical problems, but just as impossible to prove you’reright. Science admits it can’t handle these things, so at least it’s honest.
    At any rate, the science of the mind (small ‘M’ now because we’re not talking metaphysics) addresses how the mind works, and how it evolved, but not what it’s like to be one. Even with this limitation, the science of the brain is not the whole story. There is another important dimension to the question of Mind. Not how the brain works and what it does, but how it came to be like that.
    How, on Roundworld, did Mind evolve from mindless creatures?
    Much of the answer lies not inside the brain, but in its interactions with the rest of the universe. Especially other brains. Human beings are social animals, and they communicate with each other. The trick of communication made a huge, qualitative change to the evolution of the brain and its ability to house a mind. It accelerated the evolutionary process, because the transfer of ideas happens much faster than the transfer of genes.
    How do we communicate? We tell stories. And that, we shall argue, is the real secret of Mind. Which brings us back to Discworld, because on Discworld things really do work the way human minds think they do on Roundworld. Especially when it comes to stories.
    Discworld runs on