I misled some of my students last night. So it goes. They need to discover at some point in time that their instructors are flawed and confused about certain things. I wonder if I discussed the subject of "unlearning" on this blog before. It is more difficult than learning, because accumulation of knowledge is quite easy for humans. But, like cleaning out an attic, it's hard to get rid of false beliefs, or subtly change the perception of a complex idea. Grasping a simple truth that flies against convention is even more challenging. And, that simple truth can in turn be upended when new information is revealed.