By necessity teacher education covers two dimensions. One is defined by the applied work that is carried out by each teacher every day. Another is the knowledge formation that gives the understanding of the nature of teachers’ work. The latter dimension is expected to be founded on scientific principles. In many ways this dualistic nature of teacher education raises problems and difficulties regarding what should be included. In our view, two principles should govern teacher education. One is the idea that teacher education is an academic scientific discipline, in the same sense as is valid for the education of medical doctors. The implications of this approach are that the foundations for the education of student teachers must be scientifically secured and founded on scientific knowledge. It also means that teacher education is a scientifically defined area where knowledge can be accumulated. This contradicts to some extent the idea of apprenticeships, the master and apprentice concept of teacher education. From this perspective, the question of what knowledge is needed in teacher education and how knowledge can be accumulated is of central interest. The second idea influencing teacher education, related to the one presented above, is the importance of scientific preparatory training given to each student teacher, resulting in research that is presented in a master thesis. From this several implications can be drawn. Among these, the major importance must be given to the students’ knowledge formation and his/her ability to fulfil expectations as a teacher in the future. In our presentation the two principles presented above will be further discussed and their implications for the content of teacher education will be pointed out.