One premise is that there is a teacher, and a student, and they have different roles. Teaching does not describe joint truth seeking; it does not describe friends cooperating to create knowledge. This idea of roles assigned to people is harmful. It assumes that at the start the teacher has the good ideas, and the student does not. Assuming someone is right is a very bad way to figure out what is true.
How do you tell if teaching was a success? Simple: did the student learn the lesson, or not? If the student doesn't like the lesson, thinks it is silly, or has some other criticism or disagreement with it, then teaching has failed. Even thought disagreement and criticism and having your own rival ideas are all good things. Teaching can fail even when a good result is reached. So if you are focussed on teaching you will strive to avoid certain positive results in favor of certain negative results (that student believes what he is told to believe -- it's about obedience, really).
One of the ideas behind teaching is that the teacher chooses what is to be learned, for example by making a lesson plan. Then he teaches the things he believes should be known, and the student learns those. This is a bad attitude. It doesn't leave room for following the student's interests. What if you start and the student finds he is not interested? Or that he wants to continue in a different way than the teacher had planned? Well, the teacher might agree the change is good. Or the teacher might think it is bad. Either way the assumption is that it's the teacher's decision about what should be done next. He's the expert. He's the authority. The assumption is not that a teacher is only there to help the student follow his own interests and learn what he wants to learn and only with as much precision as he chooses.
Teachers give grades. They judge and evaluate students (in terms of how closely the student's ideas after the lesson(s) conform to the teacher's ideas about the subject). What would make more sense is for students to give themselves grades: they should judge if they have learned something to their satisfaction or not.
Grades and tests have another use: they can be used for certification to demonstrate to people (like prospective employers) that you have certain skills. But in that case a third party should do the testing. Having a single person give the lessons and the tests -- help the student and also test the student -- is a conflict of interest. Then a teacher has to decide what is "fair" to tell the students about the test material. The teacher knows what will be on the test and has to keep information secret that the students would want to know. When a third party does the test the teacher has no conflict of interest. He can tell students absolutely everything he knows that would help them. He doesn't have to hold back and make judgments about how much is "fair" to keep secret.
I believe that individuality and freedom are good things.
I also believe that questions have a single true answer, including moral questions.
This belief in single truth does not apply to ambiguous questions. For example, "Is it good to be a banker?" is ambiguous. Any time you can say, "It depends (on something or other the question didn't provide details about)" then the question is ambiguous -- the details could go either way. A proper question which we expect to have a single, true answer must have no ambiguity or it's really a set of different questions (one for each possible interpretation) and that set of many questions certainly might have lots of different answers. A proper question is more like: Is it good for me to choose banking as my career, taking into account my mind, and the entire (relevant) state of the universe? Of course we'd never write out that whole question. But we can still know that is the type of question that has only one answer. The question is still very ambiguous though because the first part isn't clear. What does choosing banking as a career mean? Does it mean taking certain college classes? Committing to it forever? Trying it out in some way, perhaps just by reading some articles? Does it mean avoiding skill at a second type of career? Ultimately the question should either be a factual question, or it should refer specifically to a single choice and ask which option is best (which is actually a type of factual question). We don't know how to write perfect questions. But that's no matter.
It may appear contradictory to believe in single truth, but also in freedom and individuality. What use is individuality if one thing is best? And what use is freedom to do something other than the one truth?
It is not contradictory for two reasons.
First, just because there is a truth does not mean we know what the truth is. Often we have guesses, but we might be mistaken. Having freedom to explore our own guesses at what the truth is, and in general having an open society, contributes to finding a single truth!
Second, what I should do with my life and what you should do with your life are different questions. One truth doesn't mean we should do the same thing with our life. It means for each of us there is a best thing to do.