This article seeks to examine some of the problems in current policy, pedagogy and practice through the concept of reductionism. It examines various forms which this may take involving inappropriate scientific methodologies, a diminished sense of structure (or, conversely, agency), temporal confusion and teleological/ethical reductionism, drawing on examples from natural and social sciences as well as education. It draws on Critical Realist understandings of causality, stratification and emergence to ground the discussion ontologically and epistemologically. The article then builds on this theoretical foundation for a critical discussion of teaching and learning, poverty-related underachievement, school development, and evidence-based teaching.