These struggles in turn pose serious questions for introductory courses. This is where disciplines like philosophy differ significantly from biology. Relative to philosophy departments, biology departments have a secure identity. There are questions where biologists are the authorities. In this sense, co-operative learning is not a threat to the identity of the biology teacher, whereas in philosophy, allowing students to have a voice in posing the problems threatens the nature of the discipline.
Reality is a philosophical issue only when an authorized philosopher is doing all the talking.
Population and evolution are biological questions whether a biologist is doing all the talking or not. The second constraint I face at this point in my career is my age. At Temple I am the same age as most of my students. When I teach night classes, most students are older than I am. This fact limits my pedagogical repertoire in the sense that I have few mentors who are not significantly older.