I figured the best thing would be to use part of his view on books, and more particularly, his concept of L-space, the mysterious effect that large collections of books can have on the world around them.
The following extract comes shortly after a discussion of the dangers to be found in the magical library at Unseen University, but demonstrates perfectly how Pratchett's Discworld relates to our own round planet.
Even big collections of ordinary books distort space and time, as can readily be proved by anyone who has been around a really old-fashioned second-hand bookshop, one of those that has more staircases than storeys and those rows of shelves that end in little doors that are surely too small for a full sized human to enter.
The relevant equation is Knowledge = Power = Energy = Matter = Mass; a good bookshop is just a genteel Black Hole that knows how to read. Mass distorts space into polyfractal L-space, in which Everywhere is also Everywhere Else.
All libraries are connected in L-space by the bookwormholes created by the strong space-time distortions found in any large collection of books.
First published 1989