Since philosophy depends on discussion, class participation is a vital part of your grade. However, it would not promote relaxed discussion if the instructor were assigning grades as students spoke. The relevant portion of your grade is determined informally, at the end of the term, on the basis of flexible guidelines. At a minimum, class participation entails regular attendance and attention to what others have to say. A stellar attendance record may be enough to earn you a B for that portion of your grade in the course, assuming that it doesn't involve distracting behavior such as reading other material in class. However, helpful contributions to discussion and/or playing a valuable role in oral reports is needed to boost this portion of your grade into the A range. On the other hand, Without a good attendance record these other indices of class participation on their own would at best earn you a B. Lower grades depend on how irregular your attendance is and/or whether your oral contributions when you are there tend to support or obstruct the ongoing conversation. Being out-of-touch due to frequent absences is not a help.

As to what makes for helpful contributions to discussion: questions as well as comments and criticisms are welcome. The aim is not to show how much you know but to show that you're thinking intelligently, and sometimes a question that brings up an unclarity can be particularly helpful. So please don't hold back out of fear of revealing ignorance. You're probably not the only one who needs clarification, and pinpointing just what it is that seems confusing takes work and deserves credit. It's an indication that you're thinking seriously, as well as a contribution to the group discussion.