When we think about the future, I suspect many of us are limited by our previous experiences. In other words, we don’t consider the possibilities available to us because we can’t imagine them. Roughly speaking, this is what I would call “potential”. It’s the ability to achieve something that you haven’t already. It’s what people refer to when they see someone with a lot of talent that hasn’t been focused in one direction. We can see that the person could become a master at what they do, but they aren’t quite there yet.
The naïve person thinks that being good at teaching means you know the material. While this is technically true, I think it hides the fact that knowledge of the material isn’t sufficient to be a good teacher. For the most part, having a good command of the material helps a lot in getting the information to the students. However, I think we too often make the mistake that knowing the material is good enough. It isn’t.