"What is the problem?" If you ever were a student of Joseph Agassi, you remember this question fondly. Agassi expanded and refined Popper's characterization of a "critical tradition," in his philosophical writings, historical studies, and as a teacher. His challenge to his students was both to understand the growth of knowledge in past traditions, and to then take on the task of advancing one—in no matter what field. And "What is the problem?" was always the first question to begin understanding the development of ideas and traditions.