The Science of Discworld III - Darwin's Watch tsod-3 Read online

  By the Victorian age, the epitome of reliable gadgetry had become the pocket-watch. Darwin's ideas are intimately bound up with a watch, which again plays the metaphorical role of intricate mechanical perfection. The watch in question was introduced by the clergyman William Paley, who died three years after Darwin was born. It features in the opening paragraph of Paley's great work Natural Theology, first published in 1802[7]. The best way to gain a feeling for his line of thinking is to use his own words: In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there; I might possibly answer, that for anything I knew to the contrary, it had lain there forever: nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place; I should hardly think of the answer which I had before given, that, for anything I knew, the watch might have always been there. Yet why should not this answer serve for the watch as well as for the stone? Why is it not as admissible in the second case, as in the first? For this reason, and for no other, viz. that, when we come to inspect the watch, we perceive (what we could not discover in the stone) that its several parts are framed and put together for a purpose, e.g. that they are so formed and adjusted as to produce motion, and that motion so regulated as to point to the hour of the day; that if the different parts had been differently shaped from what they are, of a different size from what they are, or placed after any other manner, or in any other order, than that in which they are placed, either no motion at all could have been carried on in the machine, or none which would have answered the use that is now served by it.

  Paley goes on to elaborate the components of a watch, leading to the crux of his argument: This mechanism being observed ... the inference, we think, is inevitable; that the watch must have had a maker; that there must have existed, at sometime, and at some place or other, an artificer or artificers, who formed it for the purpose which we find it actually to answer; who comprehended its construction, and designed its use.

  There then follows a long series of numbered paragraphs, in which Paley qualifies his argument more carefully, extends it to cases where, for instance, some parts of the watch are missing, and dismisses several objections to his reasoning. The second chapter takes up the story by describing a hypothetical `watch' that can produce copies of itself - a remarkable anticipation of the twentieth-century concept of a Von Neumann machine. There would still be good reason, Paley states, to infer the existence of a 'contriver'; in fact, if anything, the effect would be to enhance one's admiration for the contriver's skill. Moreover, the intelligent observer would reflect, that though the watch before him were, in some sense, the maker of the watch which was fabricated in the course of its movements, yet it was in a very different sense from that in which a carpenter, for instance, is the maker of a chair.

  He continues to develop this thought, and disposes of one possible suggestion: that, just as a stone might always have existed, for all he knew, so a watch might have always existed. That is, there might have been a chain of watches, each made by its predecessor, going back infinitely far into the past, so that there never was any first watch. However, he tells us, a watch is very different from a stone: it is contrived. Perhaps stones could always have existed: who knows? But not watches. Otherwise we would have `contrivance, but no contriver; proofs of design, but no designer'. Rejecting this suggestion on various metaphysical grounds, Paley states: The conclusion which the first examination of the watch, of its works, construction, and movement, suggested, was, that it must have had, for the cause and author of that construction, an artificer, who understood its mechanism, and designed its use. This conclusion is invincible. A second examination presents us with a new discovery. The watch is found, in the course of its movement, to produce another watch, similar to itself: and not only so, but we perceive in it a system or organisation, separately calculated for that purpose. What effect would this discovery have, or ought it to have, upon our former inference? What, as hath already been said, but to increase, beyond measure, our admiration of the skill which had been employed in the formation of such a machine!

  Well, we can all see where the good reverend is leading, and he homes in on his target in his third chapter. Instead of a watch, consider an eye. Not lying on a heath, but in an animal, which perhaps does lie on a heath. What he does say is: compare the eye to a telescope. There are so many similarities that we are forced to deduce that the eye was `made for vision', just as the telescope was. Some thirty pages of anatomical description reinforce the contention that the eye must have been designed for the purpose of seeing. And the eye is just one example: consider a bird, a fish, a silkworm, or a spider. Now, finally, Paley states explicitly what all his readers knew was coming from page one: Were there no example in the world of contrivance except that of the eye, it would be alone sufficient to support the conclusion which we draw from it, as to the necessity of an intelligent Creator.

  There we have it, in a nutshell. Living creatures are so intricate, and function so effectively, and fit together so perfectly, that they can have arisen only by design. But design implies a designer. Ergo: God exists, and it was He who created Earth's magnificent panoply of life. What more is there to say? The proof is complete.

  3. THEOLOGY OF SPECIES

  IT WAS THREE HOURS LATER ...

  The senior wizards trod carefully in the High Energy Magic Building, partly because it wasn't their natural habitat, but also because most of the students who frequented it used the floor as a filing cabinet and, distressingly, as a larder. Pizza is quite hard to remove from a sole, especially the cheese.

  In the background - always in the background in the High Energy Magic Building - was Hex, the university's thinking engine.

  Occasionally, bits of it, or possibly `him', moved. Ponder Stibbons had long ago given up trying to understand how Hex worked. Possibly Hex was the only entity in the university who understood how Hex worked.

  Somewhere inside Hex magic happened. Spells were reduced, not to their component candles and wands and chants, but to what they meant. It happened too fast to see, and perhaps too fast to understand. All that Ponder was certain about was that life was intimately involved. When Hex was thinking deeply there was a noticeable hum from the beehives along the back wall, where slots gave them access to the outside world, and everything completely ceased to work if the ant colony was removed from its big glass maze in the heart of the machine.

  Ponder had set up his magic lantern for a presentation. He liked making presentations. For a brief moment in the chaos of the universe, a presentation made everything sound as if it was organised.

  `Hex has run the history of Roundworld against the last copy,' he announced, as the last wizard sat down. 'He has found significant changes beginning in what was known as the nineteenth century. Slide, please, Rincewind.' There was some muffled grumbling behind the magic lantern and a picture of a plump and elderly lady appeared on the screen. `This lady is Queen Victoria, ruler of the Empire of the British.'

  `Why is she upside down?' said the Dean.

  `It could be because with a globe there is technically no right way up,' said Ponder. `But I'm hazarding that it got put in wrong. Next slide, please. With care.' Grumble, click. 'Ah, yes, this is a steam engine. The reign of Victoria was notable for great developments in science and engineering. It was a very exciting time. Except ... next slide, please.' Grumble, click.

  `Wrong slide, that man!' said Ridcully. `It's just blank.'

  'Aha, no, sir,' said Ponder, gleefully. `That is a dynamic way of showing you that the period I just described turns out not, in fact, to have happened. It should have, but it didn't. On this version of the Globe, the Empire of the British did not become as big, and the other developments were all rather muted. The great wave of discovery flattened out. The world settled down to a period of stability and peace.'

  `Sounds good to me,' said Ridcully, and
got a chorus of `hear, hears' from the other wizards.

  `Yes, Archchancellor,' said Ponder. `And, then again, no. Getting off the planet, remember? The big freeze in five hundred years' time? No land life form surviving that was bigger than a cockroach?'

  `No one bothered about that?' said Ridcully.

  `Not until it was too late, sir. In that world as we left it, the first humans walked on the Moon less than seventy years after they flew at all.'

  Ponder looked at their blank faces.

  `Which was quite an achievement,' he said.

  `Why? We've done that,' said the Dean.

  Ponder sighed. `Things are different on a globe, sir. There are no broomsticks, no magic carpets, and going to the Moon is not just a case of pushing off over the edge and trying to avoid the Turtle on the way down.'

  `How did they do it, then?' said the Dean.

  `Using rockets, sir.'

  `The things that go up and explode with lots of coloured lights?'

  `Initially, sir, but fortunately they found out how to stop them doing that. Next slide, please ...' A picture that might have been a pair of old-fashioned pantaloons appeared on the screen. `Ah, this is our old friend, the Trousers of Time. We all know this. It's what you get when history goes two ways. What we have to do now is find out why they split. That means I shall have to-'

  `Are we near the point where you mention quantum?' said Ridcully, quickly.

  `I'm afraid it is looming, sir, yes.'

  Ridcully stood up, gathering his robes about him. `Ah. I think I heard the gong for dinner, gentlemen. Just as well, really.'

  The moon rose. At midnight, Ponder Stibbons read what Hex had written, wandered across the dewy lawn to the Library, woke the Librarian, and asked for a copy of a book called The Origin of Species.

  Two hours later he went back, woke the Librarian again, and asked for Theology of Species. As he left with it, he heard the door being locked behind him.

  Later still, he fell asleep with his face in a cold pizza and both books open on his desk, dripping with bookmarks and stray pieces of anchovy.

  Beside him, Hex's writing table whirred. Twenty quill pens flashed back and forth and gyrated on spring-loaded arms, making the table look like several giant spiders on their backs. And, every minute, a page dropped onto the pile that was forming on the floor ...

  Ponder dreamed fitfully of dinosaurs trying to fly. They always splashed when they reached the bottom of the cliff.

  He woke up at half past eight, read the accumulated papers, and voided a small scream.

  All right, all right, he thought. There is no actual hurry, as such. We can change it back any time we like. That's what time travel means.

  But although the brain can think that, the panic gland never believes it. He snatched up the books and as many notes as he could carry and hurried out. We have heard the chimes of midnight, the saying goes. The wizards had not only heard them but also the ones at one, two and three a.m. They certainly weren't interested in hearing anything at half past eight, however. The only occupant of the tables in the Great Hall was Archchancellor Ridcully, who liked an unhealthy breakfast after his early morning run. He was alone at the trestle tables in the big hall.

  `I've found it!' Ponder announced, with a certain nervous triumph, and dropped the two books in front of the astonished wizard.

  `Found what?' said Ridcully. `And mind where you're putting stuff, man! You nearly had the bacon dish over!

  'I have put my finger,' Ponder declared, `on the precise split in the Trousers of Time!'

  `Good man!' said Ridcully, reaching for the flagon of brown sauce. `Tell me about it after breakfast, will you?'

  `It's a book, sir! Two books in fact! He wrote the wrong one! Look!'

  Ridcully sighed. Against the enthusiasm of wizards there was no defence. He narrowed his eyes and read the title of the book Ponder Stibbons was holding:

  `Theology of Species. And?'

  `Archchancellor, it was written by a Charles Darwin, and caused rather a row when it was published, since it purported to explain the mechanism of evolution in a manner which upset some widely held beliefs. Vested interests railed against it, but it prevailed and had a significant effect on history. Er ... the wrong one.'

  `Why? What is it about?' said Ridcully, carefully taking the top off a boiled egg.

  `I've only glanced at it, Archchancellor, but it appears to describe the process of evolution as one of permanent involvement by an omnipotent deity.'

  `And?' Ridcully selected a piece of toast and began to cut it into soldiers.

  `That's not how it works on Roundworld, sir,' said Ponder, patiently.

  `That's how it does here, more or less. There's a god who sees to it.

  `Yes, sir. But, as I am sure you will remember,' said Ponder, using the words in the sense of `as I know you have forgotten', `we have not found any traces of Deitium on Roundworld.'

  `Well, all right,' the Archchancellor conceded. `But I don't see why the man shouldn't have written it, even so. Good solid book, by the look of it. Took some thinkin' about, I'll be bound.'

  `Yes, sir,' said Ponder. `But the book he should have written ...' he thumped another volume onto the breakfast table, `... was this.'

  Ridcully picked it up. It had a much more colourful cover than `Theology', and the title: Darwin Revisited THE ORIGIN OF SPECIES

  by The Rev. Richard Dawkins

  `Sir, I think I can prove that because Darwin wrote the wrong book the world took a different leg of the Trousers of Time, and humanity didn't leave the planet before the big freeze,' said Ponder, standing back.

  `Why did he do that, then?' said Ridcully, mystified.

  `I don't know, sir. All I know is that, until a few days ago, this Charles Darwin wrote a book that said that evolution all worked naturally, without a god. Now it turns out that he didn't. Instead, he wrote a book that said it worked because a god was involved at every stage.'

  `And this other fella, Dawkins?'

  `He said Darwin had pretty much got it right except the god part. You didn't need one, he said.'

  `Didn't need a god? But it says here he's a priest of some sort!'

  `Er ... sort of, sir. In the ... history where Charles Darwin wrote Theology of Species, it had become more or less compulsory to take holy orders in order to attend university. Dawkins said evolution happened all by itself.'

  He shut his eyes. Ridcully alone was a much better audience than the senior faculty, who'd taken cross-purposes to the status of a fine art, but his Archchancellor was a practical, sensible man and therefore found Roundworld difficult. It wasn't a sensible place.

  `You've foxed me there. How can it just happen?' said Ridcully. `It makes no sense if there isn't someone who knows what's going on. There's got to be a reason.'

  `Quite so, sir. But this is Roundworld,' said Ponder. `Remember? 'But surely this other feller, Dawkins, made it all right again?'

  Ridcully floundered. `You did say it was the right book.'

  `But at the wrong time. It was too late, sir. He didn't write his book until more than a hundred years later. It caused a huge row-'

  `An ungodly one, I suspect?' said Ridcully cheerfully, dipping the toast in the egg.

  'Haha, sir, yes. But it was still too late. Humanity was well on the road to extinction.'

  Ridcully picked up Theology and turned it over in his hands, getting butter on it.

  `Seems innocent enough,' he said. `Gods making it all happen ...

  well, that's common sense.' He held up a hand. `I know, I know!

  This is Roundworld, I know. But where there's something as com plicated 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 t
hat 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.'

  4. PALEY ONTOLOGY

  PALEY'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[8] 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[9].

  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.