Despite the common view of good teaching as something that is mostly learned through experience, our argument rests on a con- ception of teaching as unnatural work (Jackson, 1986; Murray, 1989). Because it is, we argue, not natural, carefully designed learning is necessary. The notion that teaching is unnatural is difficult to grasp because of the ubiquity of teaching activity: In fact, as Cohen (in press) argues, most people teach. Parents teach children, friends and coworkers show one another how to do things, and many kinds of professionals provide information, demonstrations, and advice. Teaching, defined as helping others learn to do particular things, is an everyday activity in which many people engage regularly. Professional classroom teaching, on the other hand, is specialized work that is distinct from infor- mal, commonplace showing, telling, or helping (Cohen, in press).
The problem of delineating the specialized, professional version of otherwise commonplace activities is not unique to teaching. In their analysis of the teaching of practice across professions, Grossman and her colleagues (2009) write,