Friday, April 14, 2006

The Watchmaker Analogy

[The following is excerpted from Michael J. Behe, Darwin's Black Box: The Biochemical Challenge to Evolution, Paperback, New York: Simon & Schuster, 1996, pp. 211-216.]

Over the course of human history, most learned folks (and even more unlearned folks) have thought that design was evident in nature. Up until the time of Darwin, in fact, the argument that the world was designed was commonplace in both philosophy and science. But the intellectual soundness of the argument was poor, probably due to lack of competition from other ideas. The pre-Darwinian strength of the design argument reached its zenith in the writings of the nineteenth-century Anglican clergyman William Paley. An enthusiastic servant of his God, Paley brought a wide scientific scholarship to bear in his writings but, ironically, set himself up for refutation by overreaching.

The famous opening paragraph of Paley's Natural Theology shows the power of the argument and also contains some of the flaws that led to its later rejection:

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 any thing I knew to the contrary it had lain there for ever; 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 any thing I knew the watch might have always been there. Yet why should this answer not 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, namely, 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 out the hour of the day; that if the different parts had been differently shaped 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 would have been carried on in the machine, or none which would have answered the use that is now served by it. To reckon up a few of the plainest of these parts and of their offices, all tending to one result: We see a cylindrical box containing a coiled elastic spring, which, by its endeavor to relax itself, turns round the box. We next observe a flexible chain.... We then find a series of wheels.... We take notice that the wheels are made of brass, in order to keep them from rust;... that over the face of the watch there is placed a glass, a material employed in no other part of the work, but in the room of which, if there had been any other than a transparent substance, the hour could not be seen without opening the case. This mechanism being observed — it requires indeed an examination of the instrument, and perhaps some previous knowledge of the subject, to perceive and understand it; but being once, as we have said, observed and understood, the inference we think is inevitable, that the watch must have had a maker — that there must have existed, at some time 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.[1]

Compared with that of the Greeks, Paley's argument is much improved. Although in Natural Theology he gives many poor examples of design (akin to Diogenes and Socrates), he also frequently hits the nail on the head. Among other things, Paley writes about discrete systems, such as muscles, bones, and mammary glands, that he believes would cease to function if one of several components were missing. This is the essence of the design argument. However, it must be emphasized for the modern reader that, even at his best, Paley was talking about biological black boxes: systems larger than a cell. Paley's example of a watch, in contrast, is excellent because the watch was not a black box; its components and their roles were known.

Paley expresses the design argument so well that he even earns the respect of dedicated evolutionists. Richard Dawkins's The Blind Watchmaker takes its title from Paley's watch analogy but claims that evolution, rather than an intelligent agent, plays the role of the watchmaker:

Paley drives his point home with beautiful and reverent descriptions of the dissected machinery of life, beginning with the human eye.... 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.... If [natural selection] can be said to play the role of the watchmaker in nature, it is the blind watchmaker.... But one thing I shall not do is belittle the wonder of the living "watches" that so inspired Paley. On the contrary, I shall try to illustrate my feeling that here Paley could have gone even further.[2]

Dawkins's feeling toward Paley is that of a conqueror toward a worthy but defeated enemy. Magnanimous in victory, the Oxford scientist can afford to pay tribute to the cleric who shared Dawkins's own concern for complexity in nature. Certainly Dawkins is justified in considering Paley to be defeated; very few philosophers or scientists refer to him anymore. Those that do, like Dawkins, do so only to dismiss rather than engage his argument. Paley has been lumped in with earth-centered astronomy and the phlogiston theory of burning — another loser in science's struggle to explain the world.

But exactly where, we may ask, was Paley refuted? Who has answered his argument? How was the watch produced without an intelligent designer? It is surprising but true that the main argument of the discredited Paley has actually never been refuted. Neither Darwin nor Dawkins, neither science nor philosophy, has explained how an irreducibly complex system such as a watch might be produced without a designer. Instead Paley's argument has been sidetracked by attacks on its injudicious examples and off-the-point theological discussions. Paley, of course, is to blame for not framing his argument more tightly. But many of Paley's detractors are also to blame for refusing to engage his main point, playing dumb in order to reach a more palatable conclusion.

In Natural Theology Paley points to biological examples that, he argues, are systems of interacting components like a watch and therefore indicate a designer. Paley's examples are a mixed bag, ranging from the truly astonishing to the mildly interesting to the rather silly, from mechanical systems to instincts to mere shapes. Almost none of his examples has been specifically refuted by demonstrating that the features could arise without a designer, but because for many examples Paley appeals to no principle that would prevent incremental development, people have assumed since Darwin that such gradual development is possible....

Despite many of his misguided examples, Paley's famous first paragraph concerning the watch is exactly correct — no one would deny that if you found a watch you would immediately, and with certainty, conclude that it had been designed. The reason for the conclusion is just as Paley implied: the ordering of separate components to accomplish a function beyond that of the individual components. The function of the watch is to act as a timekeeping device. Its components are various gears, springs, chains, and the like that Paley lists....

Throughout his book Paley strays from the feature of the watch — a system of interacting components — that caused him to select it as an example in the first place. As is often the case for the rest of us, too, his argument would have been greatly improved if he had said less.

Because of his indiscretion, Paley's argument over the years has been turned into a straw man to knock down. Instead of dealing with the real complexity of a system (such as a retina or a watch), some defenders of Darwinism are satisfied with offering a story to account for peripheral features. As an analogy, a Darwinian "explanation" for a watch with a cover would start by assuming that a factory already was making a watch without a cover! And then the explanation would go on to show what an improvement a cover would be.

Poor Paley. His modern opponents feel justified in assuming enormously complex starting points (such as a watch or a retina) if they think they can then explain a simple improvement (such as a watch cover or curvature of the eye). No further arguments are made; no explanation is given for the real complexity, the irreducible complexity. The refutation of Paley's overreaching is asserted to be a refutation of Paley's main point, even by those who know better.


[1] Paley, W. Natural Theology, American Tract Society, New York, pp. 9-10.

[2] Dawkins, R. (1985) The Blind Watchmaker, W. W. Norton, London, p. 3.

[The above is excerpted from Michael J. Behe, Darwin's Black Box: The Biochemical Challenge to Evolution, Paperback, New York: Simon & Schuster, 1996, pp. 211-216.]


Anonymous Gary said...

Note to readers: The purpose of this post is to establish the relevance of the watchmaker analogy in the current national evolution debate. I'm not really interested in discussing the merits of Behe's book, Paley's analogy, or Dawkins's response to Paley.


4/14/2006 06:14:00 AM  

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