I have read with interest all of the postings on this subject and feel
the fundamental bone of contention is "what constitutes competence?" I
only teach high school and junior college, so my perspective would be
quite different from those who supervise graduate students or even
physics majors. The level that I work at REQUIRES only the rudiments of
physics (of course the more you know the more you can tie in the basics
to some of the big questions in physics). The whole subject area of
"physics" suffers I feel from having too many with a great knowledge of
physics and no great ability to teach. It is a very simple thing to
"present" information, but quite another to develop the subject in such
a way that the average student grasps the conceptual logic and can use
it to interpret his/her world. It is quite hard to make it "easy". I
feel that for this a teacher needs a wide diversity of experience and
expertise to be able to create or import analogies or appplications that
enable this grasping.
In the long run a teacher is best off if (s)he has both deep didactic
knowledge and insightful wisdom, but "competence" has a component
dependent on the audience
"A mind is not a box to be filled, but rather a fire to be ignited"