This article explores some implications of using a critical realist theoretical framework for the study of education, in particular the core activities of learning and teaching. Many approaches have been made to understanding learning and teaching, but they tend to fall into one of two camps. The first includes approaches known as objectivism, instructivism and behaviourism, and is interpreted here as embodying principles of empiricism (positivism). The second com prises various takes on constructivism, particularly social constructiv ism, and is interpreted here as embodying idealism (poststructuralism/ postmodernism/interpretivism). This paper does not wholly endorse or reject either objectivism or constructivism, but draws elements from each. The key difference for educators is that the starting position is not the transmission of knowledge, as in objectivism, or the construction of knowledge by learners, as in social constructivism. Instead it foregrounds the learning environment, arising from the (critical) realist premise that the possibilities for knowledge are given in the ontology. For educators this means the learning environment is not simply the location of learning, as widely construed, but the set of conditions that enable and constrain learning.