Science of Discworld III

misseltoe [sic], and that these had been produced perfect as we now see them; but this assumption seems to me to be no explanation, for it leaves the case of the coadaptations of organic beings to each other and to their physical conditions of life, untouched and unexplained.
    More heavyweights follow, interspersed with lesser figures. The first heavyweight is Richard Owen, who was convinced that species couldchange, adding that to a zoologist the word ‘creation’ means ‘a process he knows not what’. The next is Wallace. Darwin reviews his interactions with both, at some length. He also mentions Herbert Spencer, who considered the breeding of domesticated varieties of animals as evidence that species could change in the wild, without human intervention. Spencer later became a major populariser of Darwin’s theories. He introduced the memorable phrase ‘survival of the fittest’, which unfortunately has caused more harm than good to the Darwinian cause, by promoting a rather simple-minded version of the theory.
    An unexpected name is that of the Reverend Baden Powell, whose 1855 ‘Essays on the Unity of Worlds’ states that the introduction of new species is a natural process, not a miracle. Credit for mutability of species is also given to Karl Ernst von Baer, Huxley, and Hooker.
    Darwin was determined not to miss out anyone with a legitimate claim, and in all he lists more than twenty people who in various ways anticipated parts of this theory. He is absolutely explicit that he is not claiming credit for the idea that species can change, which was common currency in scientific circles – and, as Baden Powell shows, beyond. What Darwin is laying claim to is not the idea of evolution, but that of natural selection as an evolutionary mechanism.
    So … we come full circle. Does an innovative idea change the world, or does a changing world generate the idea?
    Yes.
    It’s complicity. Both of these things happen – not once, but over and over again, each progressively altering the other. Innovations redirect the course of human civilisation. New social directions encourage further innovation. The world of human ideas, and the world of things, recursively modify each other.
    That is what happens to a planet when a species evolves that isnot merely intelligent, but what we like to call extelligent . One that can store its cultural capital outside individual minds. Which lets that capital grow virtually without limit, and be accessible to almost anybody in any succeeding generation.
    Extelligent species take new ideas and run with them. Before the ink was dry on Origin , biologists and laymen were already trying to test its ideas, shoot them down, push them further. If Darwin had written Ology , and if nobody else had written something like Origin , then Victorian extelligence would have been enfeebled, and perhaps the modern world would have taken longer to arrive.
    But it was evolution time. Somebody would have written such a book, and soon. And in that alternat(iv)e world of if, he or she would have got the credit instead.
    So it’s only fair to give Darwin the credit in this world. Steam engine time notwithstanding.
    1 Dry grass and drops of water are not commonly associated, but perhaps a damp elephant had just emerged from a river crossing on to dry savannah … Oh, invent your own explanation.
    2 See The Science of Discworld .
    3 What would have happened if Darwin had gone back in time and killed his own grandfather?

NINETEEN
LIES TO DARWIN
    A RCHCHANCELLOR R IDCULLY’S MOUTH DROPPED OPEN .
    ‘You mean killed?’ he said.
    +++ No +++, Hex wrote, +++ I mean vanished. Darwin disappears from Roundworld in 1850. This is a new development. That is to say, it has always happened, but has always happened only for the last two minutes +++
    ‘I really hate time travel,’ sighed the Dean.
    ‘Kidnapped?’ said Ponder, hurrying across the hall.
    +++ Unknown. Phase space currently contains proto-histories in which he reappears after a fraction of one second and others where he never reappears at all. Clarity must be restored to this new node +++
    ‘And you only tell us this now?’ said the Dean.
    +++ It has only just happened +++
    ‘But,’ the Dean attempted, ‘when you looked at this … history before, this wasn’t happening!’
    +++ Correct. But that was then then, this is then now. Something has been changed. I surmise that this is as a result of our activities. And, having happened, it has always