Teaching and teachers have recently become the centre of attention of policy makers and researchers. The general idea here is that teaching matters. Yet the question that is either not asked or is only answered implicitly is why teaching matters. In this article I engage with this question in the context of a wider discussion about the role, status and significance of the question of purpose in education. I suggest that this is the most fundamental question in all educational endeavours. It is a normative question which poses itself as a multi-dimensional question, since education always functions in relation to three domains of purpose: qualification, socialisation and subjectification. Against this background I analyse the specific nature of teacher judgement in education and show how the space for teacher judgement is being threatened by recent developments in educational policy and practice that concern the status of the student, the impact of accountability and the role of evidence. I indicate how, where and why these are problematic and what this implies for regaining a space for teachers' professional judgement.