What is the fine-grained topic of the following text: A teacher may get good, even astounding, results from his pupils while he is teaching them and yet not be a good teacher; because it may be that, while his pupils are directly under his influence, he raises them to a height which is not natural to them, without fostering their own capacities for work at this level, so that they immediately decline again as soon as the teacher leaves the classroom. Only return the topic.
The effectiveness of a teacher in fostering students' independent capacities