The following points should help you understand where your philosophy professor is coming from:
 
Philosophers care more about your reasons than about whether you "get the right answer."

You're not expected to solve all the difficult questions in philosophy in your first philosophy course, any more than a physics professor would expect you to be able to solve all the perplexing problems of contemporary physics during your first physics class. One thing which makes philosophy seem so strange at first is that most people believe they have already solved the perplexing problems of philosophy before they've ever taken the course. For example, most people have an opinion about an issue like abortion or the existence of God, and they believe they are right. By contrast, few people believe they have already discovered the correct answer to the most perplexing problems of physics. However, many philosophical issues are really no easier or less complex than the most difficult problems in physics. Knowing this, philosophy professors tend to begin with the assumption that the answers to philosophical questions such as the existence of God or the morality of abortion are as yet unknown. Moreover, they do not expect you to be able to solve them while taking your first philosophy course.

As a result, philosophy professors tend to be more concerned about teaching you how to philosophize, that is, how to reason well about philosophical issues, than they are about what answer you arrive at.
This is not to say that which answer you arrive at is unimportant. After all, the whole point of doing philosophy is to discover interesting and useful truths. But we do not expect you to be able to defend your answers to philosophical questions the way someone who has thought hard about them for 20 years can.

Nothing is sacred.

A good philosopher is willing to question anything and everything, even the methods of philosophy itself.

There often seem to be persuasive reasons which support both sides of an issue.

If you approach philosophical arguments with an open mind, you'll quickly come to see this. If you've discussed several controversial philosophical issues in class and you don't see this, odds are that you're not giving the opposing side the credit its due. As a result, you may not see the point of discussing the views of the opposing side. If this is the case, try being more open to opposing views. One way to do this is to imagine that something important to you, such as winning a court case or getting a great job, depends on your convincing someone of the opposing point of view. What would you say to prove to them that the view you personally disagree with is actually true? How effective could you make your arguments for your view?

That there seem to be persuasive arguments for opposing sides of a view does not prove that there is no correct view. After all, if nothing plausible could be said for the opposing side of an issue, it wouldn't be an issue to begin with! What makes an issue an issue is that there is something to be said for both sides.
Where it seems that equally plausible reasons conflict, we have an indication that someone's reasoning has gone astray in some subtle way. The goal will be to figure out where the mistake is.

Proper Classroom Deportment Never Hurts

Good:


Not So Good:

Additional Resources

Douglas J. Soccio, How To Get The Most Out Of Philosophy, (Belmont, CA: Wadsworth Publishing, 2006).
"What Is Philosophy?" by Keith Korcz.