Whom to Believe? (And Why?).

• Commentary to the contributions of the Special Issue Perspective from research on professional learning. • Focus on the role of "others" and of "changes". • Analysis of complex transitions as a bridge of research on conceptual change and on professional learning. The Special Issue aims to explore how research on learning and instruction could be innovated by a more systematic interaction between the areas of conceptual change and professional learning. In this commentary it is claimed that both views have their specific strengths and blind spots but can mutually profit from each other. The meeting points – and contentious points – can be allocated to the ascribed roles of others and of changes. The analysis of complex transitions could be a field of investigation in which research on conceptual change and on professional learning fertilise each other mutually. It is analysed in-how-far the contributions to this Special Issue address such cross-fertilisation. [ABSTRACT FROM AUTHOR]