The Science of Discworld Revised Edition

couldn’t have been gods of the sort you got now, who by all accounts were largely incapable of making a cup of coffee.
    The universe inside the Project was hurtling through its high-speed time and there was still nothing in there that was even vaguely homely for humans. It was all too hot or too cold or too empty or too crushed. And, distressingly, there was no sign of narrativium.
    Admittedly, it has never been isolated on Discworld either, but its existence had long ago been inferred, as the philosopher Lye Tin Wheedle had put it: ‘in the same way that milk infers cows’. It might not even have a discrete existence. It might be a particular way in which every other element spun through history, something that they had but did not actually possess, like the gleam on the skin of a polished apple. It was the
glue
of the universe, the frame that held all the others, the thing that told the world what it was going to be, that gave it purpose and direction. You could detect narrativium, in fact, by simply thinking about the world.
    Without it, apparently, everything all was just balls spinning in circles, without meaning.
    He doodled on the pad in front of him:
    There are no turtles anywhere
.
    ‘Eat hot plasma! Oh … sorry, sir.’
    Ponder peered over his defensive screen.
    ‘When worlds collide, young man, someone is doing something wrong!’
    That was the voice of the Senior Wrangler. It sounded more petulant than usual.
    Ponder went to see what was going on.

TWELVE
WHERE DO RULES COME FROM?

    SOMETHING IS MAKING Roundworld do strange things …
    It seems to be obeying rules.
    Or maybe it’s just making them up as it goes along.
    Isaac Newton taught us that
our
universe runs on rules, and they are mathematical. In his day they were called ‘laws of nature’, but ‘law’ is too strong a word, too final, too arrogant. But it does seem that there are more or less deep patterns in how the universe works. Human beings can formulate those patterns as mathematical rules, and use the resulting descriptions to work out some aspects of nature that would otherwise be totally mysterious, and even exploit them to make tools, vehicles, technology.
    Thomas Malthus changed a lot of people’s minds when he found a mathematical rule for social behaviour. He said that food grows arithmetically (1-2-3-4-5), but populations grow geometrically (1-2-4-8-16). Whatever the growth rates, eventually population will outstrip food supply: there are limits to growth. 1 Malthus’s law shows that there are rules Down Here as well as Up There, and it tells us that poverty is not the result of evil or sin. Rules can have deep implications.
    What are rules? Do they tell us how the universe ‘really’ works, or do our pattern-seeking brains invent or select them?
    There are two main viewpoints here. One is fundamentalist at heart, as fundamentalist as the Taliban and Southern Baptists – indeed, as fundamentalist as the exquisitor Vorbis in
Small Gods
who states his position thus: ‘… that which appears to our senses is not the
fundamental
truth. Things that are seen and heard and done by the flesh are mere shadows of a deeper reality.’
    Scientific fundamentalism holds that there is
one
set of rules, the Theory of Everything, which doesn’t just describe nature rather well, but
is
nature. For about three centuries science seems to have been converging on just such a system: the deeper our theories of nature become, the simpler they become too. The philosophy behind this view is known as reductionism, and it proceeds by taking things to bits, seeing what the bits are and how they fit together, and using the bits to explain the whole. It’s a very effective research strategy, and it’s served us well for a long time. We’ve now managed to reduce our deepest theories to just two: quantum mechanics and relativity.
    Quantum mechanics set out to describe the universe on very small scales, subatomic scales, but then became involved in the largest scales of all, the origin of the universe in the Big Bang. Relativity set out to describe the universe on very large scales, supergalactic ones, but then became involved in the smallest scales of all, the quantum effects of gravity. Despite this, the two theories disagree in fundamental ways about the nature of the universe and what rules it obeys. The Theory of Everything, it is hoped, will subtly modify both theories in such a way that they fit seamlessly together into a unified whole,