Two intertwined bodies of work: Conducting research on mathematics teacher development and elaborating theory o f mathematics teaching/learning

In this chapter, I describe how two lines of study, one empirical and one theoretical, can exist in a creative interdependence. Philosophers of science and many practicing scientists have described a dialectical relationship between theory and empirical research (cf., Kuhn, 1962; Cobb, 1995). The common application of this idea would result in considering the relationship between research on teacher development and theory of teacher development. However, my purpose in this chapter is to discuss the less obvious relationship between research on teacher development and theory of mathematics teaching/learning. (Note that I refer to teaching/learning to suggest an integrated theory as opposed to two separate ones.) In an earlier article (Simon, 1997), I argued that for a research team studying mathematics teacher development, an essential part of its conceptual framework is its conception of mathematics teaching/learning, and that a lack of useful, articulated conceptions of mathematics teaching is hampering research on teacher development. I summarize this argument and then go beyond it to describe how the empirical study of teacher development fuels an active program of theoretical work on teaching/learning.