To be a good teacher, you need many skills. For today
let's focus on two of them:
-- fundamentals of instruction (FoI), and
-- mastery of the subject (MoS).
Neither is a substitute for the other, except possibly
to a very limited degree. Credentials in FoI should
not be accepted in lieu of credentials in MoS or vice
versa.
The previous threads asked whether a PhD was necessary
for college-level teaching. I wish to address a narrower
question relating to the MoS part of the issue. My
opinion is that the PhD is
-- not necessary, and
-- usually but not strictly sufficient.
It is not strictly sufficient, because some PhD programs
are not rigorous enough to do what needs to be done.
It is certainly not necessary, for the following reasons:
I have seen industrial research jobs where people did
work that was equivalent to doing PhD-level research and
writing a new PhD thesis every year, year after year,
on a succession of topics not all the same. Most of
these folks had PhDs, and some had fancy prizes ... but
there were also some verrry successful folks who didn't
even have a college degree. In a hiring situation, I'd
be happy to give these folks credit for a virtual PhD,
or maybe ten PhDs.
==============
The reason I bring this up is because I sometimes see an
alarming shortage of MoS. For example, I see people teaching
thermodynamics without having any clue about what entropy is.
Here's another way of saying what bothers me: I see people who
learned the material out of a book, and now they are teaching
it out of a book. That's a recipe for problems in the short
run and disaster in the long run, because the books have many
shortcomings, including outright errors.
So I think the hiring committees are well within their rights
to ask for MoS beyond book-learning.
Usually research experience (in grad school or industry) is
a tough school of hard knocks, usually sufficient to knock
quite a few misconceptions out of your head. Also it gives
some perspective as to what's important and what's not.
I'm not saying everyone with practical experience has mastered
the field. Conversely I wouldn't go so far as to say that
book-learning is never sufficient, but it very very commonly
is not.
They say some people have their head in the clouds, while some
people have their feet on the ground, and it takes a giant to
do both. Most of us are not giants, but we ought to as least
try, or perhaps take turns in one place then the other.
I want to hire a teacher who (in addition to FoI skills)
has both an understanding of theory and a feel for the real
world, perhaps from his days as Chief Research Chemist at
the Metaplast Corporation. http://www.google.com/search?q=metaplast+research-chemist