The importance of care for learners is recognised as fundamental of teaching: it is argued that teaching equally requires a care for "knowledge." Within a realist theory, to care for knowledge, moreover, must involve taking into account its relationship to the real world. The implications of this ontological consideration are worked out with particular reference to Bourdieu's theory that social reproduction is effected in educational contexts where the arbitrary knowledge of the school is experienced, particularly by working-class students, as symbolic violence. The "universal pedagogy" advocated by Bourdieu may need, in fact, to be based on a scientific realism in which the definitive knowledge of the school is regarded not as "arbitrary" but as "necessary." The case for a realist approach, reflecting the different classed, gendered, and cultural origins of students, is made in the context of a secondary school science lesson observed by the New Zealand longitudinal Progress at School project.