I agree with Brett. Teaching is hard and learning is hard. Also realize that the way you understand something after becoming an expert is vastly different from the way you understood it the first time you encountered it.

Professors are tempted to teach something the way they understand it because it's so much more elegant than the crude understanding they had as a student. Of course their elegant level of understanding comes from years of experience.

Bottomline... good education et. al. comes from repetition and practice. You understand something better everytime you encounter it. Curriculae aren't generally formulated that way but, as we call in engineering, a waterfall approach. Once you've taken a course, you're supposed to know the material. A better approach is an iterative method where material is presented over and over again.. Of course that may take a long time... perhaps about as long as it takes before YOU start teaching the course.

Melvin: I think that's right. Plus, frankly, most people who get Ph.D.s in a given subject probably never had any difficulty learning it. While I got to the point in, say, math, that it became difficult for me to grasp, I never had a poli-sci class that I found intellectually difficult. The work was sometimes hard and meeting paper deadlines was a challenge, but I almost always "got" the material itself on the first go-through. So, when teaching the stuff, it was always a little difficult to understand why others didn't get something so "easy."

I've learned more from teaching than I have from taking courses, to be honest, which might be another reason why Greg's analysis is a little off. He's right about requiring a little empathy from professors, though. Melvin's right about both teaching and learning being tough. Probably students need to hear more about the latter, though. . .

Brett: Yep, that was my experience as well. I "got" the material easily enough while in school, but didn't have it mastered in the sense of being able to recite it and make extensive arguments on it until I started teaching.

Unfortunately, it turns out that my "interesting take" isn't so interesting; I didn't intend such broad statement on learning theory. See my blog for a response to Professor Marston.

Just for information, there is a book called The Idoit's Guide to Dumies (I think I have the mispelling right), it is labeled as a guide to dumbing down to enjoy modern life.