No. I think we mean different things by "teaching." Teaching someone doesn't ensure success. Teaching is providing a roadmap, a foundation. I can teach portraiture by talking about the differences, for example, between Karsh's portraits and Avedon's portraits, by alerting people to what a difference various kinds of backgrounds make, by suggesting that gestures as well as expressions can add to a portrait. By talking about how to relax a subject or even by verbally questioning whether a subject's being relaxed is necessary or whether tension and uptightness can be used to get a good portrait. That's not going to make the student an excellent portrait photographer. What it's going to do is teach him or her about making portraits.