The word "geo-graphy" means "writing the earth". The subject of geography bears responsibility for engaging, constituting and configuring world knowledge, in other words, what the world is. This paper describes an enquiry into the nature of school geographical knowledge at a time of curriculum policy reform. In 2010, the newly appointed Coalition government in Britain introduced the concept of core knowledge for the school curriculum. Some of the problems associated with core knowledge are illustrated by showing two alternative ways of knowing the world that core knowledge overlooks. To understand the nature of the constitution of knowledge, I turn to Heidegger. His idea of Enframing explains the emergence of meaning about the world within the constraints of a technical scheme that conceals as much as it reveals. A second idea of Heidegger's, the event of appropriation, suggests how meaning comes into being through the "belonging together" of humans and the world. This belonging together takes us away from representational thinking into the realm of a more original and authentic sense of what is. Although this appears to provide a very credible argument about world meaning-making, it is superseded by Derrida's critique of Heidegger as someone who claims to deconstruct the history of ontology at the same time as retaining a commitment to it. Derrida's "differance" advances Heidegger's work into a consideration of meaning and justice. The associated deconstructive attitude takes responsibility seriously by disrupting taken-for-granted meanings and conceptual schemes and opening them up to see what other groups of people or ways of knowing might be overlooked. (Contains 4 figures and 4 notes.)