"I believe that a core problem with undergraduate education, especially at research universities like Harvard, Stanford, NYU, etc, is that most teaching is done by PhDs, who by temperament, training, interests, and rewards are researchers first. So they spend most of their time and energy probing a snip of a field's cutting edge. In my view, the attributes needed to be a transformative undergraduate instructor are pretty orthogonal to that. It would seem that undergraduate education would be superior if there was a separate track for teaching faculty."