Shu was telling me about the Sagan Principle, which is also called the Mediocre Principle.. In reading about it, I looked up mediocre, and was intrigued that it can either mean “ordinary,” which is how I’d define it, or “inferior/low quality.” How do you use it? In the Sagan Principle it clearly means “ordinary.” In fact, if you consider a bell curve with "ordinary" being in the middle and "good" and "poor" being on both sides, as bell curves go, the Sagan Principle would, by definition, not be called the "Medicrity Principle." It depends on the fact that evolution selects from the most numerous categories, or, in this case, the center of the bell curve.

Maybe it depends on the context?