The Science of Discworld


I've just finished reading "The Science of Discworld" by Terry Pratchett, Ian Stewart and Jack Cohen. The book alternates chapters based in Discworld, where Ponder Stibbons has created a miniature cosmos called "Roundworld", and chapters in which the science of our own world (from the Big Bang to the present day) is explained. I have a confession to make. I'm a biologist, but I don't really like reading popular science books for fun, or indeed any non-fiction. Call me mad, but after a long day at work doing science^1^, the last thing I want to do of an evening is read more about it: give me fiction, and the more escapist, the better. So I approached this book with the secret, guilty intention of quietly skipping over the science chapters.

Happily, it turns out that I underestimated the powers of the authors. The science chapters were as interesting and engaging as the ones based in Discworld. I should explain that "The Science of Discworld" doesn't debate whether the events in the books could have a scientific explanation. On the contrary, they use Discworld as a thought experiment: if you came from a perpendicularly different universe, how would you explain the science of our world? The science is very well explained, with a lot of dry little Pratchett style jokes, which are sharp and true and get the message across. For example, while discussing that old evolutionary chestnut of how anything as complicated as an eye could evolve:

The question is often asked in the form ‘What use is half an eye?', to which you are expected to conclude ‘nothing', followed by a rapid conversion to some religion or other. ‘Nothing' is a reasonable answer — but to the wrong question.

And again, talking about the advances made by triploblasts:

Their excreta became a major resource for other creatures; to get an interestingly complicated world, it is vitally important that shit happens.

They make some interesting points. One of their themes is that of "lies-to-children": many of the ideas communicated about science (and not just to children) are almost entirely untrue, but make a compelling story. Another is the distinction between making an accurate model which describes the way the world is, or making a model which tells how the world works - the rules which govern it. This is very important, and difficult even for scientists to keep in mind. Their opinion (which I think I share), is that the latter kind of model is probably impossible, especially for biological systems. You can see what happened after it happened, but you couldn't ever predict that it would happen that way observing it at the start. If you see what I mean…

Anyway, I thoroughly recommend it to anyone. In one of the Discworld chapters, there's a priceless accidental meeting between The Librarian (who regular Pratchett readers will know is an orang utan) and Darwin, when the Librarian travels through L-space (Library Space):

A hand reached out, tremulously. Feeling that something was expected of him, the Librarian reached out as well, and the tips of the fingers touched.

The author blinked.

‘Tell me, then,' he said, ‘is Man an ape, or is he an angel?' The Librarian knew this one.

‘Ook,' he said, which meant: ape is best, because you don't have to fly and you're allowed sex, unless you work at Unseen University, worst luck.

^1^ Those of you in academia know that I mean "long days trying to do science, while facing constant, infuriating interruptions from students and piles of administration".