This paper explores and challenges a number of the assumptions and claims commonly associated with a constructivist approach to school science education, e.g., that constructivist ideas about learning require a progressive pedagogy or that "active learning' demands engaging students with practical activities. It suggests that constructivist ideas have a particular appeal within primary education because they help to justify classroom practices and activities that primary school teachers, for a variety of other reasons, regard as important. It is suggested that the recent dominant emphasis upon constructivism in science education has narrowed both the professional and the research agenda relating to school science teaching. The paper argues for greater clarity and precision when referring to constructivist ideas in science education and for a better understanding of the role that learning theories should play in influencing the ways in which science is taught in schools.