The counter-feit of debate will replace it, with its metaphor of victory and its exaltation of the smooth talker. The discussion appears to safeguard openness in inquiry and free expression. But it often leads to domination by the eloquent, a classroom demagoguery that is terminated not by knowledge but by the need to move on to the next class. Dialogue demands a greater degree of conviction and of commitment, at least to the possibility that truth may come to be known. Mere discussion leaves this question open, hence its easy compatibility with the lecture.
Lecturers know things.
Discussants have mere opinions, and talk about them. First of all the issue must be of genuine importance to the students. They must set the agenda, and not the teacher. This requires huge efforts on the part of the typical instructor. She must consciously take a back seat and be willing to learn from her students.