The Science of Discworld IV

is that Unseen University has infringed our theological property rights to the
concept
of a spherical world. They have committed blasphemy.’
    ‘If they have,’ said Om, ‘I can deal with it myself. I don’t need your help. Personally, I don’t see a problem. The turtle moves. Get used to it.’
    Ignoring his god, Stackpole ploughed on, ‘The Church claims custody of the Round World. The true shape of the Disc is irrelevant to our case.’
    Vetinari moved as if to replace his gavel.
    ‘You misunderstand, Mister Stackpole,’ Om countered. ‘I was not referring to the true
shape
of the Disc; I was referring to the origin of your
belief
that the Disc is round.’ He turned towards Ponder Stibbons. ‘Mister Stibbons, I was present, extra-dimensionally, when you switched on your recent experiment in quantum thau-modynamics – your Great Big Thing. But you neglected One Tiny Little Thing.’
    The Librarian gave Ponder a sharp glance. ‘Ook?’
    ‘Of course,’ cried Ponder. ‘You’re absolutely right! I assumed that when narrativium propagates through L-space, it doesn’t interact with librarium! But if we invoke Crumbworthy’s Perpetually Overlooked Constraint, an otherwise negligible interaction could weaken the fabric of L-space and create a chronoclastic fistula! Then the thaum would spontaneously split, and mythons would leak one way and antimythons the other way. I … er …’
    ‘Mythcalculated,’ said Om. ‘Since L-space links libraries across all of space
and time
, the concept of a flat Disc leaked into the distant past of Roundworld. And the concept of a round world leaked the other way, into the distant past of Discworld – where it became a central feature of the old Omnian religion.’
    ‘Discworld reality became a Roundworld myth, and Roundworld rules became a Discworld belief!’ said Ponder.
    Marjorie jabbed the Archchancellor in the ribs. ‘So, Unseen University
didn’t
get the idea of a round world from the ancient roots of Omnianism!’
    ‘No,’ said Ridcully. ‘They got it from
us
.’
    ‘Game, set and myth,’ said the Dean. ‘Done and dusted.’
    Ridcully looked sceptical and continued, ‘I wouldn’t count on that. In my experience, fanatics don’t change their minds whatever the evidence. Even if their own god were to appear before them and tell them they were wrong, they would still—’
    ‘Om is not mocked! That is to say that our concept of the true being of Om is not mocked!’ yelled Stackpole. ‘The Disc
is
round! The turtle does
not
move! There is
no
tur—’
    ‘Oh, do shut up, you horrible little man,’ said Om. ‘And I don’t want any more of this, or I’ll start again and give ants a try.’ He vanished.
    ‘Well, that’s
one
dissenting opinion …’ Stackpole began, picking himself up from the floor.
    Vetinari picked up his gavel with a hopeful expression. ‘The case is closed. My judgement is that the Church of Latter-Day Omnians’ claim to custody of the Round World has no merit, and it shall remain in the care of Unseen University, in perpetuity.’ He banged the gavel, then glared at Ridcully, raising his eyebrow without twitching a muscle, just to show them. ‘I hope you look after it with more care than you have in the past, Mustrum.’
    ‘O Great God Om!’ All eyes turned on Stackpole as he threw himself prostrate, yelling and frothing at the mouth. ‘Help your true believers in their hour of need! Confound the lies of the infidels!’
    ‘He’s wasting his time,’ said the Dean. ‘His god has already pronounced judgement. Why can’t he just accept—?’
    But Stackpole took no notice. ‘We will not stand for this! We will continue fighting! There is a truth even higher than the truth!’
    Suddenly a small group of hooded figures was in the room at speed, taking the onlookers by surprise and gathering around LordVetinari, who in the circumstances appeared to be unflustered, only thoughtful. One of the hooded men grabbed Roundworld from its tripod and ran with it back towards the entrance, and a voice by Marjorie rang out, ‘If our demands are not met, his Lordship and the precious Round World will both be destroyed! Death to the tyrant!’
    Marjorie was impressed at her own presence of mind, but a librarian must be prepared for any eventuality, including terrorists.
When in doubt strike first
,
making certain no valuable volumes are harmed
, she reminded herself. Then she sank to her knees in front of the hooded man and