First off - there is a book that addresses the Watchmaker argument direclty - called "The Blind Watchmaker" by Richard Dawkins (he can be grouped right there with Gould as one of the eminent evolutionary thinkers in the last 50 years).Nightshade wrote:I asked him his definition of irreducible complexity, and he said that (roughly) that it's two very complex mechanisms that serve no function apart from one another, but when combined have some useful ability.
But, to address your friend's definition of irreducible complexity directly, take a look at the following:
A reducibly complex mousetrap (the mousetrap is often used in the same way the watch is)
http://udel.edu/~mcdonald/mousetrap.html
That site is good - has animations, etc.
Here is an excerpt from the previous link I gave http://www.talkorigins.org/faqs/behe/review.html (which you really need to read if you haven't.) The following bit is great (and although it is about the mousetrap, it is not exactly the same stuff as the above link):
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"Behe starts with the example of a mousetrap; he claims that a standard mousetrap is "irreducibly complex". Such a mousetrap consists of (p.42):
(1) a flat wooden platform to act as a base
(2) a metal hammer, which does the actual job of crushing the little mouse
(3) a spring with extended ends to press against the platform and the hammer when the trap is charged
(4) a sensitive catch that releases when slight pressure is applied
(5) a metal bar that connects to the catch and holds the hammer back when the trap is charged (there are also assorted staples to hold the system together)
Behe then continues with his logic as to why this system is "irreducibly complex":
Which part could be missing and still allow you to catch a mouse? If the wooden base were gone, there would be no platform for attaching the other components. If the hammer were gone, the mouse could dance all night on the platform without becoming pinned to the wooden base. If there were no spring, the hammer and platform would jangle loosely, and again the rodent would be unimpeded. If there were no catch or metal holding bar, then the spring would snap the hammer shut as soon as you let go of it...
Suppose you challenge me to show that a standard mousetrap is not irreducibly complex. You hand me all of the parts listed above. I am to set up a functional mousetrap which at least mostly resembles the standard one, except I hand you back one piece. Can it be done?
Yep. The wooden base can be discarded. Where do you put a mousetrap? On the floor. What if I assemble the mousetrap by pounding the staples into the floor? Would I have a fully functional mousetrap?
Of course I would. Would it be just as useful? Nope -- there is actually a selective advantage to having a typical mousetrap, rather than a kit. Not only do I have to assemble the mousetrap, but I can't put it on a stone or concrete floor, or a very irregular floor or a very soft one (such as soil). It's a nuisance to put behind or under appliances & furniture. I can kiss my security deposit goodbye.
Clearly it is inferior. But just as clearly, it is functional!
This neatly illustrates the problem of "irreducible complexity". It is simply a claim. Only as good as the logic and facts used to generate the claim.
When the above was posted to talk.origins, Behe replied
That's an interesting reply, but you've just substituted another wooden base for the one you were given. The trap still can't function without a base.
Which completely misses the point. The base-free mousetrap still functions; it simply uses a component of its natural environment in its workings.
Behe goes on to say:
Furthermore, you were essentially given a disassembled mousetrap, which you then assembled. All of the parts were preadapted to each other by an intelligent agent. The point that has to be addressed is, how do you start with *no* pieces (at least none specifically designed to be part of a mousetrap), and proceed to a functioning, irreducibly complex trap.
Which exposes a general problem with "irreducible complexity" -- it is a "God of the Gaps" explanation. Each time we show that a supposedly "irreducibly complex" system is not, by removing one part, a supporter can claim that our new system is now "irreducibly complex". Any similarity to Zeno's Paradox is surely accidental. "
