Academic freedom is a bedrock principle of higher education—part of the point of having classes taught by working scholars is that, at the university level, students should be exposed to the interplay of ideas at the cutting edge of each field of study, and so professors should have latitude to explore controversial topics and defend their own perspectives.
But there are limits to that principle. Common sense, and the need to organize prerequisites across a multi-year curriculum, dictates that even a tenured professor would get into trouble if she devoted her entire introductory chemistry course to a critical reading of The Lord of the Rings. In a (maybe) less extreme example, a professor who spent an astronomy class arguing that there is a scientific basis to the Zodiac would, at the very least, get a talking-to from his department chair. In order to meaningfully teach a given class, there are topics that need to be covered—and there is material that has no legitimate place in the syllabus.
This is why I was so surprised to learn, a few weeks ago, that the University of Idaho—the institution where I earned my Ph.D., where Noah earned his Master’s degree and Sarah earned both her B.S. and Master’s—has hired someone who believes that the Earth was created over the course of six days about six thousand years ago, to teach an introductory microbiology course.