Intelligent design

A reducibly complex mousetrap
Creationist Michael Behe has been attracting a lot of attention recently with his advocacy of the "intelligent design" argument. He makes the claim that certain biochemical processes are "irreducibly complex": they involve multiple proteins, and removing any one of them would destroy the function of the overall pathway. From this he concludes that these pathwayscould not have evolved through the action of natural selection, but instead must have been created by an "intelligent designer."
To illustrate the concept of irreducibly complexity, Behe uses the common snap mousetrap. "If any one of the components of the mousetrap (the base, hammer, spring, catch, or holding bar) is removed, then the trap does not function. In other words, the simple littlemousetrap has no ability to trap a mouse until several separate parts are all assembled. Because the mousetrap is necessarily composed of several parts, it is irreducibly complex." (Behe, 1996).
It is not my purpose here to point out all of the philosophical flaws in Behe's argument; this has been done thoroughly in many of the resources collected on John Catalano's excellent web page. Instead, I wishto point out that the mousetrap that Behe uses as an analogy CAN be reduced in complexity and still function as a mousetrap. The mousetrap illustrates one of the fundamental flaws in the intelligent design argument: the fact that one person can't imagine something doesn't mean it is impossible, it may just mean that the person has a limited imagination. Behe's evidence that biochemical pathways areintelligently designed is that Behe can't imagine how they could function without all of their parts, but given how easy it is to reduce the complexity of a mousetrap, I'm not convinced. (Of course, the reduced-complexity mousetraps shown below are intended to point out one of the logical flaws in the intelligent design argument; they're not intended as an analogy of how evolution works.)
Myoriginal reduced-complexity mousetraps must have struck a nerve, since Behe's public lectures and his web page now include a lengthy "rebuttal" of them. I find his objections muddled and confusing, but he seems to be saying that showing how something would work after removing some parts is not enough to reject irreducible complexity; it is necessary to show how something could be built up, step bystep, with each addition or modification of a part improving the function. This seems to go beyond the original definition ("necessarily composed of several parts"), but I have merely taken it as a challenge. Here I show how one could start with a single piece of spring wire, make an inefficient mousetrap, then through a series of modifications and additions of parts make better and bettermousetraps, until the end result is the modern snap mousetrap. In addition to demonstrating that a mousetrap is not irreducibly complex, I also illustrate the most important objection to "irreducible complexity" as evidence for "intelligent design": a part which may be optional at one stage of complexity may later become necessary due to modifications of some of the other parts.
A completely differentseries of mousetraps in various stages of complexity has been designed by Alex Fidelibus.
(If the "Animate" buttons don't make the pictures move, make sure your browser has Javascript enabled.)

-------------------------------------------------
Principio del formulario
Final del formulario
I'll start with a piece of springy wire, bent so that it can be held open by carefully positioning oneend of the wire against the other. If an unlucky mouse steps on the trap and dislodges the ends, the trap closes. Most mice knock the trap over rather than sticking their necks through it, and the spring is so weak that some mice wriggle out before they die, so it's not a very good trap. Still, it's better than having no trap at all.

-------------------------------------------------
Principio...