It's a Lot Like Our Own… But Different
With that said, these differences are key when considering this setting. For example, our world is round—well, mostly round. The Discworld is as flat as its name suggests. And while our world travels through the universe by orbiting the sun—that in turn hitches a ride in the gravity of the Orion arm of the Milky Way galaxy—the Discworld gets through space in a rather unconventional manner.
Said manner of transit is the Great A'Tuin, the cosmic turtle. A'Tuin swims through space for destinations unknown while "think[ing] only of the Weight" (1.Prologue.4). A weight that consists mostly of:
[…] Berilia, Tubul, Great P'Phon and Jerakeen, the four giant elephants upon whose broad and star-tanned shoulders the Disc of the World rests, garlanded by the long waterfall at its vast circumference and domed by the baby-blue vault of Heaven. (1.Prologue. 5)
Of course, once you have a flat world teetering on the backs of four elephants standing on the back of a world-sized turtle, the possibilities become practically limitless.
Where (Almost) Anything Goes
The idea of a flat world teetering on the backs of elephants who are standing on the back of a turtle isn't anything new. It has been used in the mythologies of various cultures throughout history. Perhaps the most famous instance comes from Hindu Mythology, notably the Indian epic Ramayana.
But the inclusion of the Great A'Tuin and his pachyderm herd isn't meant to allude to a particular mythology but rather all of them. Viewed in a certain way, mythology is a story imprinted on reality; it reworks reality and cosmology. In a way, our modern day fantasy novels do the same thing.
The Discworld is very similar to the world of mythology since almost anything can and does happen there. Just check out these set pieces from the novel:
- The Temple of Bel-Shamharoth is composed entirely of octagonal tiles and stonework. Using typical octagons, this should be impossible due to tessellation, but Bel-Shamharoth likes the number eight and could care less about such mathematical truisms (2.8.4).
- The Wyrmberg mountain stands upside-down with its base "a mere score of yards across" and its peak "a plateau fully a quarter of a mile across" (3.1.2). The plate tectonics of our world don't allow this kind of geological tomfoolery, but it seems a different matter on the Disc.
- The Rimfall contains an eighth color exclusive to the Discworld, octarine (4.4.25-26). This means light is a different substance than in our universe.
- Some plants on the Disc belong to a special category called re-annuals that "because of an unusual four-dimensional twist in their genes, could be planted this year to come up last year" (4.5.23).
And that's just a few of our favorite examples. Don't even get us started on the magic, dragons being conjured through sheer imagination, and the fact that Death is a being you can have a chat with before being whisked off to oblivion.
So it seems to us that Discworld is an entire world created as a shrine to the human imagination, much like the mythologies and fantasies it pays homage to.