From your tone, I gather that you are asking about a practice that you disagree with. Since we're speaking in extremely broad generalities, and general procedure that you could follow is:
- Ask the professor follow-up questions. You are there to learn!
- Absolutely follow the professor's advice during that course. To do otherwise would be disrespectful.
- Try to seek out additional sources of information, and think about how you would approach the issue in order to solve whatever problems the professor's technique solves later, when you are not constrained by the professor's directives.