And that is when a person stops being a student. He or she has just raised himself or herself to become an equal to the teacher.
I am not saying the teacher is always right. But in a learning situation, there is always a teacher and a student. And yes, those roles are not mutually exclusive; in fact, in a learning situation, both parties are teachers and students at the same time. When I teach taiji to someone, I am the teacher, but at the same time, my student is teaching me something: how to teach. In that, I am the student.
But that does not make us equal. There is always a "power" difference in the relationship, although that difference flows in different directions depending on what we are talking about. That is how knowledge is passed.
Because when we start out by questioning the teacher, we have stopped being the student, we have stopped learning. From my years of taiji, I think the trick is this: do not question (challenge the teacher's knowledge) right from the start. Do not let your previous learning cloud your current learning journey. Take time to absorb what is being taught first. Have faith, and stay faithful to the new knowledge being taught. Spend time to practise it, to understand it through practice and pondering. Because I have found that, what originally looks to be counter-intuitive at first, will over time become assimilated into our knowledge to broaden our knowledge base. And when we broaden our knowledge base, we will have a bigger foundation on which to build a higher pillar of knowledge.
Do not be too quick to judge. Give your teacher a chance to show that he is not wrong, and yourself a chance to learn something new.