Joined: Sep. 2004
|I thought that IC refered to something that cannot evolve. In Darwin's Black Box, Behe defines it as this:|
|By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.|
That is why I'm a bit confused here. By his definition, it seems to me that the flagellum is IC. Without all the parts, it ceases to function.
Am I wrong here?
This is a good question.
There are two parts to Behe's argument. The first part is merely a definition, and you quoted it. Being a definition, it is not subject to proof: it is just a name for a condition we commonly find in the world.
The second part of Behe's argument, which you did not quote, is that he claims that things that include a set of essential interacting functioning parts can't evolve.
That is a statement subject to investigation, and it has been shown to be false. There are many ways that something can be built up in pieces so that it includes a part that is essential now but at one time was not essential, or served a different purpose.
Notice that I am not talking about any particular thing (for instance, a flagellum which arose billions of years ago.) I am talking about the general argument: scientists have firm, clear examples in the present of systems evolving so that the final product is irreducibly complex according to Behe's definition.
Even non-living things can be irreducibly complex according to Beh'e definition. For instance, the rain cycle, by which water evaporates, condenses, and then rains again. Is the system IC. Yes. Take out any of the components (the clouds, the heat of the sun, etc.) and the system no longer works. Does that mean the system is designed rather than a product of natural causes? No.
It was one thing to make a definition. It is another to prove something about the real world. Behe has conflated the two by incorporating an investigateable assertion into a definition, making it seemed liked he's proved something when he hasn't.
[Added in Edit: Albatrossity and RB gave much more thorough replies than I did while I was composing my post. Good job, guys.]