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up a hand. ‘I know, I know! This is Roundworld, I know. But where there’s something as complicated as a watch, you know there must be a watchmaker.’
    ‘That’s what the Darwin who wrote the Theology book said, sir, except that he stated that the watchmaker remained part of the watch,’ said Ponder.
    ‘Oilin’ it, and so forth?’ said Ridcully, cheerfully.
    ‘Sort of, sir. Metaphorically.’
    ‘Hah!’ said Ridcully. ‘No wonder there was a row. Priests don’t like that sort of thing. They always squirm when things get mystical.’
    ‘Oh, the priests? They loved it,’ said Ponder.
    ‘What? I thought you said vested interests were against it!’
    ‘Yes, sir. I meant the philosophers and scientists,’ said Ponder Stibbons. ‘The technomancers. But they lost .’

FOUR
PALEY ONTOLOGY
    P ALEY’S METAPHOR OF THE WATCH , alluded to by Ridcully, still remains powerful; powerful enough for Richard Dawkins to title his neo-Darwinian riposte of 1986 The Blind Watchmaker . Dawkins 1 made it clear that in his view, and those of most evolutionary biologists over the past fifty years, there was no watchmaker for living organisms, in Paley’s sense: ‘Paley’s argument is made with passionate sincerity and is informed by the best biological scholarship of his day, but it is wrong, gloriously and utterly wrong.’ But, says Dawkins, if we must give the watchmaker a role, then that role must be the process of natural selection that Darwin expounded. If so, the watchmaker has no sense of purpose: it is blind. It’s a neat title but easily misunderstood, and it opens the way to replies, such as the recent book by William Dembski, How Blind Is the Watchmaker ? Dembski is an advocate of ‘intelligent design’, a modern reincarnation of Paley with updated biology which repeats the old mistakes in new contexts. 2
    If you did find a watch on a heath, your first thought would probably not be that there must have been a watchmaker, but a watch- owner . You would either wish to get the owner’s property back to them, or look guiltily around to make sure they weren’t anywhere nearby before you snaffled it. Paley tells us that if we find, say, a spider on the path, then we are compelled to infer the existence of a spider-maker. But he finds no such compulsion to infer the existence of a spider-owner. Why is one human social role emphasised, but the other suppressed?
    Moreover, we know what a watch is for, and this colours our thinking. Suppose, instead, that our nineteenth-century heath-walker chanced upon a mobile phone, left there by some careless time traveller from the future. He would probably still infer ‘design’ from its intricate form … but purpose? What conceivable purpose would a mobile phone have in the nineteenth century, with no supporting network of transmission towers? There is no way to look at a mobile phone and infer some evident purpose. If its battery has run down, it doesn’t do anything . And if what was found on the path was a computer chip – say, the engine manager of a car – then even the element of design would be undetectable, and the chip might well be dismissed as some obscure crystalline rock. Chemical analysis would confirm the diagnosis by showing that it was mostly silicon. Of course, we know that these things do have a designer; but in the absence of any clear purpose, Paley’s heath-walker would not be entitled to make any such inference.
    In short, Paley’s logic is heavily biased by what a human being would know about a watch and its maker. And his analogy breaks down when we consider other features of watches. If it doesn’t even work for watches, which we do understand, there’s no reason for it to apply to organisms, which we don’t.
    He is also rather unfair to stones.
    Some of the oldest rocks in the world are found in Greenland, in a 25-mile-long band known as the Isua supracrustal belt. They are the oldest known rocks among those that have been laid down on the