Professional development needs to be understood as a spontaneous process of learning at work before moving on toward the 'desired' professional development. Learning as a result of working is often implicit, stems from social interaction and direct experience, involves the (thoughtless, implicit) reproduction of habits as well as the building of expertise, does not depend on any educational intervention to go on, and is very powerful in directing behaviour in work situations. A critical social-cultural constructivist view recognises learning as socialization, sharing meaning in more implicit and explicit ways, but also emphasizes learning as critical reflection on premises and joint action to change practice. In short, professional learning implies participating in the social construction and reconstruction of reality. Depending on the organizational culture, professional learning may primarily serve the sharing of dominant discourse (socialization), or support individuals and groups in critical reflection on the shared premises, values, behaviour, (hierarchic) relations in school and community, and possibilities to change these.