The best way to understand why a truly great college professor appreciates challenges from his or her students is to keep the complete definition of education in mind. Everyone knows education to be a means of imparting knowledge, training towards a particular career, etc. A professor, or any teacher for that matter need to recognize that it is also a process for “developing the powers of reasoning and judgment.”
Overall, a professor’s job is to present the material covered by a particular course in a way that is interesting, if not outright exciting, to the student. Even if a student is genuinely interested in the course material when signing up for the class, that will quickly change if the professor acts as if the material is beneath them and/or does not go to the trouble to actually interact with his or her students. Just like with any career, the professor who is truly passionate about what he does will make sure the job is done thoroughly and completely. This includes ensuring that the student doesn’t just memorize the material well enough to repeat it back to the professor on a test or in a writing assignment, but analyzes it to come up with new angles to consider it from.
Like anyone else who really wishes to excel in and take pride in their chosen career, a great professor will go to the lengths necessary to do the job both completely and in a manner that cause others to take notice. Not everyone will always be pleased with the way a particular professor does his or her job. Sometimes a student will be in a particular class just to get a core requirement out of the way and not be particularly concerned with mastering the course content. Perhaps the student does not have what is required within his or herself to be successful in that class. Those are circumstances out of the professor’s control.
However, it is absolutely essential that the professor be ready to recognize the student that is there to master and build upon the knowledge presented in the classes they teach. Such a student does this through questioning and challenging what the professor presents in class. It is through the initiatives of students such as this that further knowledge is gained and built upon what is already known. Professors who have problems with student challenges or teaching any basic material are thinking more of their own ego than of advancing and increasing knowledge. Sometimes, perhaps even most of the time, the student will come up short when challenging some point in class. That is fine and all part of the actual learning process. Eventually such students will contribute, at least, in some small way to furthering knowledge and/or progress.
The great professor knows and accepts that what he is she is teaching is not about holding themselves up as infallible before their class, but the advancement of their particular field of expertise. Those are the ones who best serve the cause of their chosen profession.