There is a phenomenon which often happens in philosophy classrooms. I will call it "the pretend doubt phenomenon".
An example. It is the first day of an introductory ethics class. The professor raises the questions, "What is ethics? Why does it matter?" A moment of reflection has been introduced. The students await the answer. The professor continues, "Ethics is the study of values. Are there any objective values? Or is everything subjective? For instance, we normally believe that lying is wrong. But is it really wrong? How can we know? Is there a fact of the matter about that? Similarly, we think that killing is wrong. But could it be that it is simply a subjective claim? These question are enormously significant because the answers to them matter to our everyday lives. If we can't justify that there are objective values, then we would have to rethink our whole way of living. Ethics is the study of these questions. It concerns the most basic questions of value, and they are essential for every human being to think about." The professor has given the justification for the subject matter of the course. The students are excited.
Now the professor hands out the syllabus. Goes through the readings. She comes to the requirements for the course: "The main work for this course will be writing essays. The university has a strong no plagarism policy. If you plagarize, you will fail the course. Also, doing philosophy involves a lot conversation, and so we will be talking with each other a fair amount in this course. So it is expected that you will be civil with your classmates. Getting angry will not be tolerated. Nor interrupting others. The use of laptops for anything other than taking notes is strictly prohibited. If you miss class more than 5 times, your grade will be docked a third of a grade. These are common sense points, so I expect and hope that no one will have a problem following them." The terms for the semester have been set.
The professor concludes the class by saying, "Ok, for next time we will read Harman's essay on relativism, and we will consider if there are any objective values. See you then."
This is usually the first day in many introductory ethics classes. It can be seen as having two parts. In the first part a pressing doubt is introduced: Are there any objective values? Oh no, what will happen if there are no such values? How will we survive as a society? We need to think about this. You need to think about this. Once the pressing doubt has been introduced, and the justification for the course established, the doubt seems to magically disappear. There is no more doubt. There is only the mechanical procedure of setting the terms for the semester, and of what values will guide the course. In the first part of the class - the content part - the doubt is raised as deep and pressing. In the second part of the class - the procedural part - the doubt is set aside to go over the basic values which are going to be taken for granted in the class.
As the philosopher J.L.Austin said, regarding a similar kind of double move, "There's the bit where you say it and the bit where you take it back."