A theoretical essay, based on the results of research projects on teacher education, teachers' work, and justice in education developed by the author, is presented. It reflects on teacher education and the epistemology of teachers' work, and proposes a mediational and a narrative perspective towards a third space in Teacher education. An alternative mediation epistemological approach to justice in education and the epistemology of teachers' work is presented, aiming towards an understanding of the ways in which teachers' education has the possibility of making a difference in the construction of a more just public school.