The Science of Discworld II

Above, So Below and all that.’
    â€˜But without magic,’ said Ridcully. ‘And with no narrativium. It doesn’t know where it’s going.’
    â€˜But we do, sir,’ said Ponder, who had been scribbling in his notebook.
    â€˜Do we?’
    â€˜Yes, sir. Remember? In about a thousand years’ time it’s going to be hit by a really big rock. I keep looking at the numbers, sir, and that’s what it means.’
    â€˜But I thought we found there’d been a race that built huge structures to get off the place?’
    â€˜That’s right, sir.’
    â€˜Can a new species turn up in a thousand years?’
    â€˜I don’t think so, sir.’
    â€˜You mean these are the ones that leave?’
    â€˜It seems like it, sir,’ said Ponder.
    The wizards looked at the people in the courtyard. Of course, the presence of beer always greases the rungs of the evolutionary ladder, but even so …
    At a nearby table, one man threw up on another one. There was general applause.
    â€˜I think,’ said Ridcully, summing up the general mood, ‘that we are going to be here for some time.’
    1 An extremely common and versatile substance, unfortunately not available in all universes.
    2 The sad histories of these hitherto unknown civilisations, along with the tale of the two-mile limpet, can be found in The Science of Discworld .

SIX
THE LENS-GRINDER’S PHILOSOPHY
    J OHN D EE, WHO LIVED from 1527 to 1608, was court astrologer to Mary Tudor. At one point he was imprisoned for being a magician, but in 1555 they let him out again, presumably for not being one. Then he became astrologer for Queen Elizabeth I. He devoted much of his life to the occult, both alchemy and astrology. On the other hand, he was also the author of the first English translation of Euclid’s Elements , the renowned treatise on geometry. Actually, if you believe the printed word, the book is attributed to Sir Henry Billingsley, but it was common knowledge that Dee did all the work, and he even wrote a long and erudite preface. Which may be why it was common knowledge that Dee did all the work.
    To the modern mind, Dee’s interests seem contradictory: a mass of superstitious pseudoscience mixed up with some good, solid science and mathematics. But Dee didn’t have a modern mind, and he saw no particular contradiction in the combination. In his day, many mathematicians made their living by casting horoscopes. They could do the sums that foretold in which of the twelve ‘houses’ – the regions of the sky determined by the constellations corresponding to the signs of the zodiac – a planet would be.
    Dee stands at the threshold of modern ways of thinking about causality in the world. We call his time The Renaissance, and the reference is to the rebirth of the philosophy and politics of ancient Athens. But perhaps this view of his times is mistaken, both because Greek society was not then as ‘scientific’ or ‘intellectual’ as we’ve beenled to believe, and because there were other cultural currents that contributed to the culture of his times. Our ideas of narrativium may derive from the melding of these ideas into later philosophies, such as that of Baruch Spinoza.
    Stories encouraged the growth of occultism and mysticism. But they also helped to ease the European world out of medieval superstition into a more rational view of the universe.
    Belief in the occult – magic, astrology, divination, witchcraft, alchemy – is common to most human societies. The European tradition of occultism, to which Dee belonged, is based on an ancient, secret philosophy; it derives from two main sources, ancient Greek alchemy and magic, and Jewish mysticism. Among the Greek sources is the Emerald Tablet , a collection of writings associated with Hermes Trismegistos (‘thrice master’), which was particularly revered by later Arab alchemists; the Jewish source is the Kabbala , a secret, mystical interpretation of a sacred book, the Torah .
    Astrology, of course, is a form of divination based on the stars and the visible planets. It may, perhaps, have contributed to the development of science by supporting people who wanted to observe and understand the heavens. Johannes Kepler, who discovered that planetary orbits are ellipses, made his living as an astrologer. Astrology still survives in watered-down form in the horoscope columns of tabloid