Last week, RhinoTimes writer Orson Scott Card gave his take on the Evolution vs. Intelligent Design debate. Though he sounds reasonable in a few places, he seems to have some misconceptions. In writing about the ID concept of Irreducible Complexity, Card says:
Basically, Behe’s approach was this: Complex systems in advanced organisms depend on many biochemical steps, all of which must be in place for the system to work at all.
So how, Behe asked, could such a complex system have evolved, if the only method available was random variation plus natural selection?
It would be impossible to believe that the entire series of steps in the complex system could randomly appear all at once. But any one step along the way, since it does nothing by itself, could not give the organism that had it any competitive advantage. So why would each of those traits persist and prevail long enough for the complex system to fall into place?
Behe’s conclusion is that since complex biochemical systems in advanced organisms could not have evolved through strict Darwinian evolution, the only possible explanation is that the system was designed and put into place deliberately.
In other words, though he shuns the word, complex systems had to have a creator – they have to be intelligently designed.
He goes on to sum up the “Darwinist response” with a strawman which I will ignore, as I’ve never seen an Evolutionist respond as he claims. There are in fact, perfectly valid responses to claims of irreducible complexity:
1. Some of the examples often given of irreducibly complex (IC) systems are demonstrably not irreducibly complex. For instance, whales are “missing” parts of their blood clotting system, yet their blood still clots with no problem. The eye has been cited as an IC system, however there are many sorts of eyes of varying complexity in the animal kingdom, from light-sensitive spots, to the human eye, and everywhere in between. Each one of them is functional in some way and conveys a competitive advantage.
2. There are several known ways in which IC systems may evolve:
How might an IC system evolve? One possibility is that in the past, the function may have been done with more parts than are strictly necessary. Then an ‘extra’ part may be lost, leaving an IC system. Or the parts may become co-adapted to perform even better, but become unable to perform the specified function at all without each other. This brings up another point: the parts themselves evolve. Behe’s parts are usually whole proteins or even larger. A protein is made up of hundreds of smaller parts called amino acids, of which twenty different kinds may be used. Evolution usually changes these one by one. Another important fact is that DNA evolves. What difference does this make, compared to saying that proteins evolve? If you think about it, each protein that your body makes is made at just the right time, in just the right place and in just the right amount. These details are also coded in your DNA (with timing and quantity susceptible to outside influences) and so are subject to mutation and evolution. For our purposes we can refer to this as deployment of parts. When a protein is deployed out of its usual context, it may be co-opted for a different function. A fourth noteworthy possibility is that brand new parts are created. This typically comes from gene duplication, which is well known in biology. At first the duplicate genes make the same protein, but these genes may evolve to make slightly different proteins that depend on each other.
3. Computer simulations have actually demonstrated IC systems evolving:
What gets IDCs edgy about the Lenski, et al., paper is that the assembly language programs – the genomes of the digital critters – that evolved to perform those complicated logic functions are “irreducibly complex�? in exactly the definition of Michael Behe …
Behe (and Dembski, following him) contends that “irreducibly complex” structures and processes are not accessible to evolutionary processes: they cannot have evolved by “Darwinian” mechanisms … But Lenski, et al., showed that the assembly language programs evolved in avida satisfy Behe’s operational (knockout) definition. If replacing an instruction with a null instruction (a knockout procedure) in a digital critter’s program results in the loss of a logic function, the program is “irreducibly complex” by Behe’s definition (or is part of the “irreducible core” of the critter’s program, to use Dembski’s term). So the Lenski, et al., analysis shows that “irreducibly complex” structures can evolve by plain old “Darwinian” mechanisms.
As you can see, there are arguments against irreducible complexity if one takes the time to look for them. I would have rather seen Card address these rather than the strawman he presented, but maybe he was just unaware of the rebuttals.
Another point to consider is that even though there are indeed gaps in our knowledge about evolution, this doesn’t warrant an attempt to replace the theory of evolution with something else. All scientific theories have gaps. That’s the point of research, to try to fill in those gaps. Claiming to know the answer – that a given system was designed – based on a lack of knowledge is not the way to go. The honest and logical course is to say “we don’t know that yet” and to keep looking for answers.
Further Reading:
http://www.talkorigins.org/faqs/behe.html