What is "teaching the controversy?"
What is "teaching the controversy?"
Critical analysis
The Discovery Institute, a well funded think tank devoted to overturning science, promotes "teaching the controversy" as an approach to teaching evolution in high school biology. In science the concept of evolution is not controversial. So what does the Discovery Institute really advocate? They in fact advocate "teaching the obscurity".

"Teaching the obscurity" focuses on the most obscure and complex parts of evolution which are least intelligible by common sense and least amenable to direct scientific study. These include evolution of complex organs, the Cambrian explosion and abiogenesis. "Teaching the obscurity" also employs the complex, poorly defined concept of "intelligence." Approaching science in this way promotes rationalizing at the expense of analytical thinking.

Reductionism is a key feature of science. It breaks complex phenomena into experimentally testable parts. This is in fact how Darwin acquired his evolutionary insights and how beginning students should acquire theirs. Darwin focused on the outer twigs of the tree of life, reasoning that these had arisen most recently and would be the simplest to understand. He also focused on the simplest features of evolution; variation and selection. This is precisely the way that good pedagogy teaches evolution. Once outer twigs are understood, one can proceed further into the tree asking whether these same processes suffice and using the fossil record, comparative anatomy, biogeography and now DNA phylogenetics as tools.

"Teaching the obscurity" appeals to the common sense notion of biological complexity, and focuses on difficult and experimentally complex phenomena which beginners understand only by rationalizing. Employing the ill-defined tool of "intelligence" further obscures understanding. Reinforcing common sense ideas and habits of rationalizing instills a pseudoscientific approach. Continual reinforcement creates barriers to understanding all but the simplest science.

Summary

"Teaching the controversy" imparts the falsehood that evolution is controversial in the scientific community. Worse than the falsehood, it teaches that science requires only common sense and rationalizing rather than discovery and analysis.
Controversy in the scientific literature
Critical thinking in science
Evolution in the scientific literature
Dissent from Darwin
Is intelligent design creationism?