consists of four linked claims. The first claim is uncontroversial: we can often recognize the effects of design in nature. For example, unintelligent physical forces like plate tectonics and erosion seem quite sufficient to account for the origin of the Rocky Mountains. Yet they are not enough to explain Mount Rushmore. …As Behe acknowledges, many people, including me, dispute the middle claim. The final claim seems not be a claim at all but an assertion. I'm not sure what to make of it.
The next claim in the argument for design is that we have no good explanation for the foundation of life that doesn't involve intelligence. … Darwinists assert that their theory can explain the appearance of design in life as the result of random mutation and natural selection acting over immense stretches of time. Some scientists, however, think the Darwinists' confidence is unjustified.
The fourth claim in the design argument is [that] in the absence of any convincing non-design explanation, we are justified in thinking that real intelligent design was involved in life.
[It wasn't clear to me what the other claim was.]
I think the first claim is most interesting, and it is this claim that is the basis of Behe's argument. He claims that it is uncontroversial that we can often recognize the effects of design in nature.
First of all, the word often is too imprecise. I assume Behe means that we can at least sometimes tell when something is designed, i.e., that there are cases of objects "in nature" that we would all agree are "designed." I don't think that is true. Behe's example is the carving on Mount Rushmore. But that isn't "in nature."
To be generous, let's weaken Behe's primary claim even further to: there are at least some objects about which we can be sure that they have been designed. I suspect that Behe would not argue with this assertion. But I would.
What should we decide, for example, about a beaver dam? Is that "designed?" Does it reflect "intelligent design?" Behe would probably argue that a beaver dam, like Mount Rushmore, is enough unlike "nature" that we must conclude that it was "designed." Beaver dams are not just animal by-products, they have a "purpose," i.e., to dam up a river. And they achieve their purpose because of how they are constructed. Did beavers design them to accomplish that purpose? Behe must think so — although for me that seems to be quite a stretch. So for Behe, beaver dams must be evidence of "intelligent design," which means that beavers must be intelligent designers.
If that's his argument, where does it lead? As far as I can tell, it leads to evolution, which as Dennett in his 1995 book Darwin's Dangerous Idea has pointed out is a powerful enough mechanism to explain just about any creative result.
Beaver dams almost certainly came about as a result of trail and error evolution — beaver ancestors doing better by dropping sticks into narrow parts of streams — until that activity was bred into them. Similar histories apply to birds nests and most other animal artifacts.
Even human-designed objects are the result of trial and error. No one gets a design right the first time. Most objects have evolved over a longer or shorter period to their current design as we learn more about how best to design them. That's exactly evolution in action. The most sophisticated objects are the result of many evolutionary steps. The more sophisticated the more steps.
Since even the most complex human-designed objects are the result of (1) human activity (and humans themselves are evolved beings and like beavers are part of nature) and (2) evolutionary processes, it isn't clear what to make of Behe's claim that designed objects are somehow different from non-designed objects.
It seems to me that what this means is that the more designed an object, the more evolution it has in its pedegree.