The Science of Discworld IV

them. Spaceships and witches are in its future.
    As life first starts, it’s not remarkable. It proceeds more or less according to the rules of physics and chemistry, according to the laws. Then it begins to compete, perhaps for space, or for particular chemicals, or for membranes that are fatty layers on clay. Those systems that work better lift themselves out of the laws, into a tiny simple narrative that says ‘A does a little bit better than B or C, so there’s more of it in the future …’ Come back in a million years, and the oceans are full of A, while there’s no C to be found. And by then, A has diversified into A1 and A2 and A3. Now, lurking – a good narrative word – in the depths is Q, which loves to include A3 in its system. So later we have QA3XYZ, and the system is well started.
    It’s all gone according to the laws, for sure; but there’s a mite of competition, selection of this over that. Come back in a million years, or perhaps six weeks, and there will be a bacterial cell that has lifted itself into a story …
    The laws facilitate such changes, but they don’t direct them. They are merely history, with all the living stuff transcending them in every direction. Come back in 3000 million years, you’ll find a mess of Burgess Shale organisms. Come back 580 million years later still, and you’ll find a physicist denying that any of this is important. But the action transcends the laws: it’s the spaceships and witches that drive the narrative.
    Life originally emerged from non-living systems, with laws, but it has gone on to complicate itself out of all recognition. Biology isn’t just physics and chemistry with knobs on. It’s a whole new world.
    Within that world, one of its beasts has acquired language, imagination, and a penchant for stories: a special, wholly new thing in the cosmos. Narrativium has escaped from Discworld into Roundworld; now some things
do
happen because there is a creature that wants them to.
    Perhaps there are many such creatures, all over the place; perhaps as many as one species per hundred million stars. But we should be very careful indeed, just in case we’re the only one.
    Just one
story
in the whole cosmos.
    Everywhere else, only laws.
    fn1 A little too promptly for some scientists, who complained that the results were announced before being peer-reviewed for journal publication.
    fn2 Although often thought to be a myth, this story has some basis. Newton often said that he had been inspired by the fall of an apple.
Wikipedia
states: ‘Acquaintances … such as William Stukeley, whose manuscript … has been made available by the Royal Society, confirm the incident, though not the cartoon version that the apple actually hit Newton’s head.’
    fn3 For a dominant frequency ω, the combination sin(ω
t
) + 0.75 sin(3ω
t
) + 0.5 sin(5ω
t
) + 0.14 sin(7ω
t
) + 0.5 sin(9ω
t
) + 0.12 sin(11ω
t
) + 0.17 sin(13ω
t
), going as far as the 13th harmonic, is pretty convincing to the human ear.
    fn4 In the science fiction novel
Light
by M. John Harrison, aliens living around the Galactic Core have invented six different space drives, each based on a different theory of fundamental physics, several of which are known to be wrong. All of the drives work fine. In Roundworld, our theories of aerodynamics are approximations that ignore atomic-scale structure, yet aircraft fly perfectly well. Lies-to-children often
work
.

THIRTEEN
----
RINCEWIND’S ADVENTURES IN ROUNDWORLD

    The arrival into Roundworld was always a hit-or-miss business these days, Rincewind knew. The people in the Inadvisably Applied Magic group had a word for it – or, more accurately, a number of equations, which you would see on the walls, being drawn and then subsequently redrawn by the next researcher, or survivor. But the Dean said that he knew what he was doing, and landed them in the middle of London; regrettably during a race, which Rincewind inadvertently won; and he had to submit to multiple slaps on the back, admiration for his wizard’s outfit, and many thanks from the organisers for helping the Orangutan Foundation to raise so much money.
    He was surprised, as well, when someone he had thought was the Librarian turned out to be a young woman in an outfit, which led to hilarious misunderstanding as a result of which both he and the Dean had to run a little further.
    They found a pleasant park with trees, and ducks in the pond, and considered their circumstances. After a while