One of the peculiarities of my recent debate with Jerry Bergman was that he announced his definition of irreducible complexity, which he claimed to be the same as Michael Behe’s…and under which carbon atoms were IC. It was utterly absurd. A reader wrote to Behe to get his opinion.

I recently attended a debate between Dr. P. Z. Myers and Dr. Jerry Bergman on the topic of “Should Intelligent Design be Taught in the Schools?” The topic of irreducible complexity came up, and Dr. Bergman had an interesting definition. His definition of irreducible complexity was “two or more parts are required for something to function” and that if you “remove one part, it will not work properly.” The example he gave was that a carbon atom is irreducibly complex. He said that “you will not have a carbon 12 atom unless you have 6 protons, 6 neutrons and 6 electrons, therefore it is irreducibly complex.” Dr. Bergman went on to say that, the only things that aren’t irreducibly complex were elementary particles, such as a lepton, because they could not be broken down into smaller parts. Much of the audience was confused about this, because as Dr. Myers pointed out, your definition of irreducible complexity dealt with biochemical systems. Dr. Myers also pointed out that carbon is formed naturally in stars, and if Dr. Bergman’s definition of irreducible complexity were correct, it would show that irreducible complexity occurs naturally, therefore negating it as an argument for intelligent design. Dr. Bergman claimed that he was using your definition of irreducible complexity in the example of the carbon atom. That is why I wanted to ask you for a concise definition of irreducible complexity and if you believe Dr. Bergman’s example and definition fits with yours.

Thanks for you time,
David

Behe wrote back.

Hi, David, nice to meet you. Dr. Myers is right; my definition deals with biochemical systems. I take the underlying laws and elements of nature as given. I do not know where Prof. Bergman got the idea that the concept applies to atoms, but he didn’t get it from me. In Darwin’s Black Box, I defined IC as:

“By irreducibly complex I mean a single system which is composed of several well-matched, interacting parts that contribute to the basic function, and where the removal of any one of the parts causes the system to effectively cease functioning.”

Best wishes.

mjb

I got the answer right. I feel so dirty now.

However, I will go on (as I did in the debate) to explain that while it is definitely true that many biochemical systems actually do exhibit the property of irreducible complexity, the fact that an existing pathway can suffer a loss of function when modified says absolutely nothing about whether it evolved or not. Antecedent versions of the current pathway may have 1) had different functions (the exaptation explanation), 2) had less stringent requirements for function because other physiological functions had less specific demands (the coevolution explanation), or 3) had redundant or alternative paths to the final output of the pathway (the scaffolding explanation). IC, even as defined by the author of the concept, is no obstacle to evolution.