"Indeed, schooling and reform have been hindered by the view that it is most "professional" if individual teachers decide for themselves how to teach. The result is not merely an inconsistent array of unexamined approaches to instruction (as if medicine were still what any country doctor 200 years ago thought it should be); a more harmful effect is that any critique of teaching inevitably is seen as an attack on teachers."
From "Craft Knowledge: The Road to Transforming Schools" by Deanna Burney (From page 2 of the journal article:)
"Usually, though, craft knowledge is confined to isolated classrooms, where individual teachers keep a tight grip on instruction and student learning. Our education system, quite simply, does not invest in the cultivation and dissemination of craft knowledge. Schools and school systems are not learning communities. But teachers have a right to investments in their professional development as well as a responsibility to reflect on their work, build their knowledge, share it with others, and pay attention to what others are learning. School systems have an obligation to provide the conditions that will foster this learning, because it is the only way we will continuously improve instruction instead of spinning our wheels."