email - January 2004

Two Kinds of Complexity

From: Eddy
Date: Wed, 7 Jan 2004 16:32:27 -0800 (PST)

In your last newsletter, your website of the month was "origins". An article there by Dembski makes me wonder.

Here is an excerpt from the link above.

"Irreducible complexity needs to be contrasted with cumulative complexity. A system is cumulatively complex if the components of the system can be arranged sequentially so that the successive removal of components never leads to the complete loss of function. An example of a cumulatively complex system is a city. It is possible successively to remove people and services from a city until one is down to a tiny village-all without losing the sense of community, the cityís 'function.'

"From this characterization of cumulative complexity, it is clear that the Darwinian mechanism of natural selection and random mutation can readily account for cumulative complexity. Darwinís account of how organisms gradually become more complex as favorable adaptations accumulate is the flip side of the city in our example from which people and services are removed. In both cases, the simpler and more complex versions both work, only less or more effectively."

It seems like there are different conclusions. Some people, like Dembski and Behe, don't see a thermodynamic problem with a system building cumulative complexity (which I take from Dembski's comments above). Am I confused, or do some creationists (or ID) proponents believe that complexity can arise from non-complexity (which I think violates the 2nd Law)??

Again, Thanks Eddy. (happy new year)

We agree that it is confusing, and we are glad that Eddy asked us for clarification.

The issue of complexity really has nothing to do with thermodynamics or chemical evolution, per se. Suppose the second law of thermodynamics did not exist, and suppose that amino acids, sugars, proteins, and DNA, and all sorts of other organic compounds necessary for life, formed naturally at the drop of a hat. Even if that were the case, the life forms we see today could not be the product of Darwinian evolution because of the kind of complexity they posses.

Dembskiís argument is that there are two different kinds of complexity. There is cumulative complexity, which could (theoretically, at least) be the result of something like descent with modification (which is the foundation of Darwinian evolution). There is also irreducible complexity, which could not, under any circumstances, be produced by Darwinian evolution. In both cases it is assumed that there is available raw material and energy to construct the complex object, even though there are other compelling reasons to believe that assumption isnít true. But this line of reasoning is willing to admit the availability of material and energy because even if material and energy are available, the logical conclusion is that evolution could not have happened anyway.

The automobile is an example of something that could (theoretically) be the result of Darwinian evolution because it has cumulative complexity. The concept of the automobile could have originated with a plank placed on several logs. As the plank was pushed forward, the logs rolled. Every so often, the plank rolled off the last log. Someone had to pick up the last log and put it in front of the plank, and then the plank was pushed some more.

Eventually, somebody could have gotten the idea that one could avoid having to move the back log to the front if the logs were attached to the plank. So, the logs could have been replaced by wheels on an axle. Then one could add a harness that could be pulled by horses. The horses could later be replaced by an internal combustion engine. Step by step, cumulative improvements could be made, resulting in an SUV with leather upholstery and a DVD player.

We arenít saying that cars actually evolved this way. Nor are we saying that cars can be produced by time and chance without any intelligent design involved. The point is simply that there exists a plausible path by which a simple cart could evolve step by step into a carriage, which could eventually evolve into a modern automobile, through a process of descent with modification. Each vehicle is very much like the preceding one, but with one or two small improvements. Cars are an example of cumulative complexity.

The evolution of computer hardware and computer software is a better example of cumulative complexity. If you are familiar with computers you know how operating systems have changed gradually over the years, becoming more and more powerful (and much more complex). If you arenít familiar with computers, well, it is too complex to try to explain it to you.

Television, on the other hand, is an example of irreducible complexity. It required independent development of at least three different components that are useless without each other. There must be a signal source (a TV station), a transmission mechanism (antenna or cable), and a signal receiver (a TV set). (Of course, the same thing is true of radio.) All three components have to come together at the same time for the system to work. None of the pieces is useful all by itself, so there is no reason to create one without the others. The system is irreducibly complex because if you reduce it by taking away any one of those three elements, it wonít work at all.

An automobile is reducibly complex because you can take away complex parts and replace them with simpler parts (reducing its complexity). You can take out the engine and replace it with a harness and horse. You can take away the wheels and replace them with logs. Things that are cumulatively complex can be made simpler (at the expense of performance), but things that are irreducibly complex canít.

Irreducibly complex things cannot be created by descent with modification. In our spoof, the Evolution of Television, we showed how silly it would be to think that radios evolved into television sets by random changes. If someone accidentally added a picture tube to a radio, there would be no survival advantage without a TV station broadcasting pictures, or the other circuitry needed to display the picture.

Having recognized the difference between cumulative complexity and irreducible complexity, the intelligent design community noticed that living things have features that are irreducibly complex, which could not have evolved through a process of descent with modification.

Take spiders, for example. What good is silk if a spider doesnít have a way to squirt it out? What good is squirting out silk if the spider doesnít know how to build a web with it, or make an egg sack, or any of the other things that spiders do with silk? What good is poison if the spider doesnít have fangs to inject it into the prey? What good is poison if the spider doesnít have some way to keep the poison out of its own vital organs? A spider is irreducibly complex because all the components of the whole silk-producing system would have to evolve all at once. All the components of the poison injection system would have to have evolved at once. These parts of the spider could not have evolved cumulatively through descent with modification because they arenít cumulatively complex.

So, the intelligent design argument is that even if all the necessary raw materials were available (which certainly werenít), and even if heat does naturally flow from a cold spot to a hot spot in such a way as to put the raw material together properly (which it certainly doesnít), descent with modification filtered by natural selection, could not possibly produce irreducibly complex systems. Therefore Darwinian evolution of new kinds of life is impossible regardless of thermodynamic and chemical considerations.

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