This is the Discworld, which travels through space on the back of four elephants which themselves stand on the shell of Great A'Tuin, the sky turtle.
Once upon a time such a universe was considered unusual and, possibly, impossible.
But then ... it used to be so simple, once upon a time.
Because the universe was full of ignorance all around and the scientist panned through it like a prospector crouched over a mountain stream, looking for the gold of knowledge among the gravel of unreason, the sand of uncertainty and the little whiskery eight-legged swimming things of superstition.
Occasionally he would straighten up and say things like "Hurrah, I've discovered Boyle's Third Law." And everyone knew where they stood. But the trouble was that ignorance became more interesting, especially big fascinating ignorance about huge and important things like matter and creation, and people stopped patiently building their little houses of rational sticks in the chaos of the universe and started getting interested in the chaos itself-partly because it was a lot easier to be an expert on chaos, but mostly because it made really good patterns that you could put on a t-shirt.
And instead of getting on with proper science scientists suddenly went around saying how impossible it was to know anything, and that there wasn't really anything you could call reality to know anything about, and how all this was tremendously exciting, and incidentally did you know there were possibly all these little universes all over the place but no one can see them because they are all curved in on themselves? Incidentally, don't you think this is a rather good t-shirt?
Compared to all this, a large turtle with a world on its back is practically mundane. At least it doesn't pretend it doesn't exist, and no one on the Discworld ever tried to prove it didn't exist in case they turned out to be right and found themselves suddenly floating in empty space. This is because the Discworld exists right on the edge of reality. The least little things can break through to the other side. So, on the Discworld, people take things seriously.
Like stories.
Because stories are important.
People think that stories are shaped by people. In fact, it's the other way around.
Stories exist independently of their players. If you know that, the knowledge is power.
Stories, great flapping ribbons of shaped spacetime, have been blowing and uncoiling around the universe since the beginning of time. And they have evolved. The weakest have died and the strongest have survived and they have grown fat on the retelling . . . stories, twisting and blowing through the darkness.
And their very existence overlays a faint but insistent pattern on the chaos that is history. Stories etch grooves deep enough for people to follow in the same way that water follows certain paths down a mountainside. And every time fresh actors tread the path of the story, the groove runs deeper.
This is called the theory of narrative causality and it means that a story, once started, takes a shape. It picks up all the vibrations of all the other workings of that story that have ever been.
This is why history keeps on repeating all the time.
So a thousand heroes have stolen fire from the gods. A thousand wolves have eaten grandmother, a thousand princesses have been kissed. A million unknowing actors have moved, unknowing, through the pathways of story.
It is now impossible for the third and youngest son of any king, if he should embark on a quest which has so far claimed his older brothers, not to succeed.
Stories don't care who takes part in them. All that matters is that the story gets told, that the...
