We noted in Chapter 2 that expertise in particular areas involves more
than a set of general problem-solving skills; it also requires well-organized
knowledge of concepts and inquiry procedures. Different disciplines are
organized differently and have different approaches to inquiry. For example,
the evidence needed to support a set of historical claims is different
from the evidence needed to prove a mathematical conjecture, and both of
these differ from the evidence needed to test a scientific theory. Discussion
in Chapter 2 also differentiated between expertise in a discipline and the
ability to help others learn about that discipline. To use Shulman’s (1987)
language, effective teachers need pedagogical content knowledge (knowledge
about how to teach in particular disciplines) rather than only knowledge
of a particular subject matter.