Irreducible Complexity (Kenneth R. Miller cross-examines Michael J. Behe)

Michael, I’d like to start out by pouncing upon the notion of irreducible complexity, which is a point that you make again in your book Darwin’s Black Box. On page 43 of this book, you use a mousetrap as an example of irreducible complexity. You point out that a mousetrap has five parts and like a biochemical system, you claim that if you take one of those parts away, it won’t work anymore. The five parts include the base, the spring, the clapper, which does the business and catch, and a little piece to hold the bait, and I have a working mouse trap here. I have here another trap for which I have removed a part, I’ve taken away the trigger. According to Dr Behe’s analogy of the mousetrap as irreducibly complex, I have now removed a part and therefore it must not work. This applies to biochemical systems as well. What I have done is to remove one part and modify another. I want to demonstrate to the audience that the mouse trap works just fine. I want to demonstrate to the audience that the one that Dr. Behe said was irreducibly complex and if we remove a part, it wouldn’t work anymore, looks like it works fine. The argument is that when you see a system made up of multiple parts such as a biochemical system, if you take one of those parts away, it will not work and therefore the separate parts could not have evolved. What I’ve just shown you is that your analogy which you use – the mousetrap – is flawed. Secondly, it doesn’t apply to biochemistry either because biochemical systems can often function missing one of their parts. Isn’t that true?

It is not true. Since my book has come out, a number of people have emailed me and sent me letters about ways that perhaps a mousetrap could function without all of those parts. It turns out that Professor Miller didn’t do away with the catch, he used another part of the mousetrap as a catch. The mousetrap still needs those five parts. In the absence of something functioning as a catch, it just doesn’t work either. Other people have emailed me that perhaps you can do away with a platform by nailing all of the parts like a mousetrap on the floor. You’re using the floor as the platform. You can use a rock as a catch or something. The point is you need all those functions and in my book which Ken alluded to, I explained why many biochemical systems are like that too, you need all those functions to make them work. 

Let’s see if that’s correct. Let’s take a real biological example and in the chart that I have here, what I’ve shown is a very complicated chemical pathway in which a Fucose, a sugar, is metabolized. It turns out that if you carry out an experiment in which you delete the gene which produces the enzyme that metabolizes Fucose, under controlled conditions where you can observe them, what happens in a few generations is that the bacteria evolve a new enzyme that works in the reverse direction. They do it by modification of pre-existing genes and they evolve a new biochemical pathway. This is the exact thing which you are claiming is impossible and yet it can be routinely observed under laboratory conditions.

I disagree with you. That is not irreducibly complex. In my book, in which I explain these concepts, which cannot be explained very well in a few minutes, has been reviewed by a number of scientists. What have they said? James Shapiro, a professor of biochemistry at the University of Chicago wrote in National Review, “There are no detailed Darwinian accounts for the evolution of any fundamental biochemical or cellular system, only a variety of wishful speculations.” So apparently he does not think that this is a relevant example either. Jerry Coyne, an evolutionary biologist at the University of Chicago, wrote in Nature, the world’s leading science journal, “There is no doubt that the pathways described by Dr Behe are complex and their evolution will be hard to unravel. We may forever be unable to envisage the first proto-pathways. Nobody has claimed that these things have been explained.