On the Importance of Subject Matter in Mathematics Education: A Conversation with Erich Christian Wittmann

Erich Christian Wittmann is one of the primary founders of mathematics education research as an autonomous field of work and research in Germany. The interview presented here reflects on his role in promoting mathematics education as a design science. The interview addresses the following topics: (1) The importance of subject matter in international traditions in mathematics education; (2) Mathematics education as design science; (3) The importance of the subject matter for research in mathematics education; and (4) The importance of the subject matter for teaching of mathematics.