The Science of Discworld Revised Edition

tendency is inevitable; Gregory Benford went further and declared it desirable.
    Technology works because whoever built it in the first place figured out enough of the rules of the universe to make the technology do what was required of it. You don’t need to get the rules
right
to do this, just right
enough
– space rockets work fine even though their orbits are computed using Newton’s stab at the rules of gravity, which aren’t as accurate as Einstein’s. But what you can accomplish is severely constrained by what the universe will permit. With magic, in contrast, things work because people want them to. You still have to find the right spell, but what drives the development is human wishes (and, of course, the knowledge, skill and experience of the practitioner). This is one reason why science often seems inhuman, because it looks at how the universe drives
us
, rather than the other way round.
    Magic, however, is only one aspect of Discworld. There’s a lot of science on Discworld, too – or at least rational engineering. Balls get thrown and caught, the biology of the river Ankh resembles that of a typical terrestrial swamp or sewage farm, and light goes in more or less straight lines. Very slowly, though. As we read in
The Light Fantastic:
‘Another Disc day dawned, but very gradually, and this is why. When light encounters a strong magical field it loses all sense of urgency. It slows right down. And on the Discworld the magic was embarrassingly strong, which meant that the soft yellow light of dawn flowed over the sleeping landscape like the caress of a gentle lover or, as some, would have it, like golden syrup.’ The same quote tells us that as well as rational engineering there’s a lot of magic in Discworld: overt magic which slows light down; magic that allows the sun to orbit the world provided that occasionally one of the elephants lifts its leg to let the sun pass. The sun is small, nearby , and travels faster than its own light. This appears to cause no major problems.
    There is magic in our world, too, but of a different, less obvious kind. It happens around everybody all the time, in all those little causalities which we don’t understand but just accept. When we turn the switch and the light comes on. When we get into the car and start the engine. When we do all those improbable and ridiculous things that, thanks to biological causality, make babies. Certainly many people understand, often to quite a detailed degree, what is going on in particular areas – but sooner or later we all reach our Magical Event Horizon. Clarke’s Law states that any sufficiently advanced technology looks like magic ‘Advanced’ here is usually taken to mean ‘shown to us by advanced aliens or people from the future’, like television shown to Neanderthals. But we should realize that television is magic to nearly everyone that uses it
now
– to those behind the camera as well as to those sitting on the couch in front of the moving picture in the funny box. At some point in the process, in the words of cartoonist S. Harris, ‘a miracle occurs’.
    Science takes on the aura of magic because the design of a civilization proceeds by a type of narrative imperative – it makes a coherent
story
. In about 1970, Jack gave a lecture to a school audience on ‘The Possibility of Life on Other Planets’ 2 . He talked about evolution, what planets were made of – all the things that you’d expect in such a lecture. The first question was from a girl of about 15, who asked ‘You believe in evolution, don’t you, sir?’ The teacher went on about it not being a ‘proper’ question, but Jack answered it anyway, saying – rather pretentiously –‘No, I don’t
believe
in evolution, like people believe in God … Science and technology are not advanced by people who believe, but by people who
don’t know
but are doing their best to find out … steam engine … spinning jenny … television …’ At that, she was on her feet again: ‘No, that ain’t how television was invented!’ The teacher tried to calm the discussion by asking her to explain how she thought television was invented. ‘My father works for Fisher Ludlow making pressed steel for car bodies. He gets paid and he gives some of the money to the government to give him things. So he tells the government he wants to watch television, and they pay someone to invent television, and they do!’
    It’s very easy to make this mistake, because