Different and competing conceptions of knowledge have recently been the focus of debate in education, especially art education. The cognitive science conception of knowledge as information processing and storage in long-term memory is especially prominent in educational policy. By contrast, within writing that is directly about art education, discussion of knowledge has often been framed in negative, terms, as reductive, as entailing the imposition of rigid subject content and as antithetical to art. Taking issue with both these contrasting views, and using a non-empirical, philosophical approach, this article puts forward a case for the centrality of knowledge and reasoning within the art and design curriculum. Specifically, the article draws on inferentialism, a theory that has not previously been applied to art education. The argument presented understands art as discursive and rational, as concept using and reason sensitive, as essentially a disjunctive set of historical-social practices. Art education is then best thought of as a rational-critical introduction to knowing those practices, as making explicit their proprieties, entailments and contradictions and the choices that are thereby made possible. This view emphasises learning in art and design as developing increasing levels of responsibility and commitment by integrating concepts in practice and theory.