Matt at RAB put me on to an article J. Ken wrote on TownHall about evolution and the Republican Prez Debate. Blackwell's strategy is to distinguish between "microevolution" and "macroevolution." You can read the piece to understand what he means by the difference. It's a standard tenet of the Creationism Lite favored by wingnuts who nonetheless want to be taken seriously.
It's also based on a bunch of arguments that aren't true. One statement he makes that is argurably false is that many scientists have doubts about macroevolution. It's true that people exist that do science for a living and question macroevolution. They tend to do their main work in other disciplines and visit the biology lab only to criticize evolutionary theory.
It's not true, though implied in his piece, that macroevolution is controversial among biologists and other scientists who study living things systematically. This does lead down the road to both "what is a real biologist" and the Troothish stories anti-evolutionists tell about discrimination against critics of evolution. Generally you can skip over having that debate and wait for the speaker or writer to say something truly outlandishly false. Usually it has to do with eyes.
Oh, look, in the next paragraph:
- There are scientists who echo the concerns of a vast number of Americans. Models like the doctrine of irreducible complexity explain that certain organs, such as the eye, require dozens of different components, each made of billions of cells, all working together to function as a whole. It argues such organs cannot evolve over time, they only benefit the creature at one hundred percent capacity. A 99% evolved eye is useless. This model suggests organs must be entirely present and perfectly fit together or they do not work. Modern theories of macroevolution have no explanation for how such organs came about.[Emphasis mine.]
For evolutionary biology does have an explanation for the eye. Short form: eyes evolved in stages from light-sensitive cells to the complex eyes of vertebrates. Talk Orgins elaborates:
- All of these steps are known to be viable because all exist in animals living today. The increments between these steps are slight and may be broken down into even smaller increments. Natural selection should, under many circumstances, favor the increments. Since eyes do not fossilize well, we do not know that the development of the eye followed exactly that path, but we certainly cannot claim that no path exists.