The Science of Discworld IV

showed me a wonderful display of sea creatures in the uttermost depths of the sea.’ He pointed towards an area clearly consisting mostly of sea,a sea moreover that he was implying was now literally teeming with interesting lives. ‘I don’t always see eye to eye with the Dean,’ he said, ‘but I do believe he did surpass himself when he created your planet out of raw firmament. I rather suspect, though, that there could be a template somewhere, and quite possibly even a passing fly might have triggered
Roundworld.’
    ‘A fly … Roundworld?’ Marjorie managed.
    Ridcully chuckled. ‘That’s what we call it. We wizards are pretty good on magic, but somewhat uncreative when it comes to making up names.’ Then he stared at Marjorie and added, ‘I must congratulate you, madam, on your composure in this matter. I am sure many people would, at this point, be telling themselves that it wasn’t happening, and – like your world’s fictional Alice, who you will doubtless know of – will assume they would shortly wake up. Quite possibly at the entrance to a rabbit hole. It seems that you, as a librarian, are excellent at assessing data. Cataloguing and indexing in your mind. All very impressive.’
    ‘Well, I did go to Roedean, and that counts for something … And if
I
were Alice, Mr Archchancellor, Wonderland would most certainly have shaped up, in no short measure.’ Miss Daw’s voice faltered, and she went on, ‘You know
everything
, don’t you?’
    ‘Certainly not. But because what you call Earth lies in a subordinate plane, we can by accident or intent find a way into the place, sometimes in the flesh, but mostly via a variety of devices: crystal balls and so on. It is not intrusive – we may not be good at names, but we are very good at surreptition, and we use such instruments sparingly. Excuse me, come!’
    This was in response to a knocking on the door, the sound level of which had caused bits of plaster and miscellaneous debris to settle gently to the floor; indeed, a scattering of dust tumbled onto the Earth itself, causing Marjorie to giggle.

EIGHT
----
BEMUSING GLOBE

    Roundworld is called Roundworld because, er, it’s round.
    From outside. As the wizards perceive it.
    From inside … well, that’s a good question.
    In the
Science of Discworld
series, the name does double duty for our planet and our universe. The planet is indeed round – ish – though at various times in history and in various cultures this was not appreciated and other shapes were favoured. The universe … well, we don’t really know what shape that is. Round is an obvious possibility, perhaps too obvious. If you not only have a point of view, but
are
one, and you can see equally far in every direction, the entire visible world automatically looks round. With
you
at the centre! Amazing.
    In the absence of narrativium, Roundworld
does not know what shape it ought to be
. Somehow the actual shape, of planet, universe, and everything else for that matter, has to be a consequence of those mysterious rules. But there isn’t a rule that says ‘make planets round’. There isn’t even a rule that says ‘make planets’. The rules as we currently conceive of them say obscure things like
iħ
∂Ψ/∂
t = Ĥ
Ψ. fn1 This perverse lack of human focus in the rules drives thewizards mad. Though they do like the fancy symbols, which are obviously magical.
    Even worse: the rules are not written down. They are not even implicit in narrativium, since there is none, not until human beings invent it for themselves. The rules operate (we think) behind the scenes; an occasional truly sapient human can draw back the veil and glimpse nature’s cogwheels spinning. So the creatures that live in or on Roundworld (that’s us) play a lengthy guessing game in which they make up rules that seem to work, and then argue about whether they really do. This game has gone by many names: religion, philosophy, natural philosophy, science, or just The Truth. We are still playing it.
    In this chapter, we’ll deal with the shape of our planet. The answer is common knowledge, so we’ll focus on the imaginative alternatives that have at times been proposed, the processes that led to the current answer, and the lengths to which some people have gone to deny it. We’ll leave the shape of the universe to chapter 16 . That’s a much harder problem, in part because we can’t stand outside the universe and look at it. However, until the 1960s we had