What are "irreducibly complex systems on the cellular level?"?

Question

I find this concept to be hilarious: just because human beings cannot yet explain how chemical reactions at the molecular level work together to form complex systems on the cellular level does not mean that these systems are irreducibly complex.

Answer 1

There are none.  Michael Behe suggested that there were several systems that are complex and have no function unless complete, most notably the flagellar motor.  That notion was killed while he was on the stand at Kitzmiller v. Dover, when all his bases were shot down.  His flagellar motor, in incomplete form, is a potent cellular weapon in plague bacteria.  His classic analogy, the mousetrap -- supposedly useless if any part was removed -- was similarly discredited when testifying scientists took off pieces and used it as a tie clip.

Answer 2

They're fiction.  Some years ago, somebody whose name I've forgotten declared several things to be "irreducibly complex".  Therefore, the theory of evolution must be smelly and can't be entirely true.  Nasty people took advantage of knowing more than this heroic goodling, and naughtily explained why the things cited weren't "irreducibly complex", and could well have evolved incrementally.

Rising to this challenge, whatever his name is has been repeating much the same waffle for some years.  It's known as 'intelligent design'.  It's central tenet appears to be: "I don't understand.  Therefore, there must be an intelligent designer.  As I didn't mention the word god, this must be science."

Answer 3

An irreducibly complex system is one in which the individual components are useless on their own.  Since the individual components don't provide any benefit, then there would have been no selective pressure acting on them, and therefore could not have arisen through evolutionary processes.  

Despite very loud claims to the contrary (by creationists), we have not yet found any irreducibly complex structures.  Your response to it is absolutely right.  The argument is two logical fallacies, the "argument from ignorance," combined with a false dichotomy, stating that since we don't know how these structures came about, then there can be no answer, therefore they must have been designed.

It also relies on a flawed understanding of biochemistry, physiology, and evolution itself.  The argument I hear most often is "what use is half of an eye?"  In the arguer's mind, they picture an eyeball, literally cut in half.  This is *not* the way that evolution works!  The eye arose from photosensitive neurons (they couldn't form an image, but they could help navigate and avoid the shadows of predators - very useful).  They made the jump to more sensitive eyespots (also useful) and then evolved a protective cup of tissue around them (very useful).  The protective cup allowed more dense and complex eyespots, eventually resulting in retinas (useful).  Eventually, the eye cup closed off nearly entirely, forming a pinhole lens much like in the modern Nautilus, and resulting in actual image formation (even more useful).  Eventually the cornea and lens arose allowing further protection and image clarity (incredibly useful).  Alongside all of these developments, the brain, being a very adaptable organ, could have easily kept up with the small increases in vision.  Granted, this example is on a systemic (rather than cellular) level, but the same logic applies.

That really gets me is the fact that irreducible complexity is still used as an argument.  It relies on ignorance, but since the concept was first thought up, we've *filled* the gaps in our knowledge.  Yet, the argument is still made, citing old and outdated research.  In the end, it's willful ignorance, akin to pretending that disease is caused by imbalances in the four humours, and that maggots spontaneously arise from rotting meat.

Answer 4

Yep, it's an internally inconsistent hypothesis from creationist Behe, and Ken Miller did a great job at debunking it.  In fact, I was just recently reading a great article on this on Miller's site:

http://www.millerandlevine.com/km/evol/d...

You can also find a good summary in this video clip from a lecture of his:

http://www.youtube.com/watch?v=RQQ7ubVIq...

Answer 5

You've hit the nail on the head of why the "irreducible complexity" argument is not just bogus, but is easy to fool people with.

The classic example, on which Intelligent Design advocate Michael Behe has pretty much based his career ... is the bacterial flagellum "motor".  

(BTW, the word "motor" is often used to describe this structure, which is like calling the brain a "computer" or the eye a "camera" ... it is a useful metaphor for explaining how something works.  But the word "motor" is often taken literally and *emphasized* in Creationist or ID literature for two reasons:  First, because "motors", "computers" and "cameras" all have "Designers" ... so it leads to the argument: "the flagellum is a motor ... motors have designers ... therefore the flagellum has a designer."  But second, a "motor" is a familiar structure to non-scientists who have no idea what a "flagellum" is ... so it gives the structure a nice simple name so that the Creationist readers who read this stuff can feel they understand what it does.)

What is cynical about the "irreducible complexity" argument, and which you have hit on the head, is the tactic of asking a deceptively "simple" question that requires a complex answer.   There is no way to explain the flagellum, or its evolution, without breaking it down to its component parts and explaining how they could have evolved serving *different* functions, (ion transport across the cell membrane), before the current function (movement) emerged as a side-effect which had such advantages that it itself underwent further natural selection.  I.e. a simple question (using words like "motor") that involves complex answers (an understanding of molecular dynamics in biochemistry).

This is why this argument is so effective with Creationists.   A "simple" question (at the cellular level) that requires a complex answer (at the molecular level).