This paper addresses the exclusion of physical and technical media from questions of ontology. It is argued, first, that from Aristotle onwards ontology has dealt with the matter and form of things rather than the relations between things in time and space. Second, it is argued that because the Greeks did not distinguish between speech elements and alphabetic letters there has been a tendency for philosophy to neglect writing as its own technical medium. This paper traces these tendencies through a (...) range of philosophical sources: from Aquinas and Descartes to Fichte and Hegel. It is argued, by way of response, that it is only with Heidegger that a philosophical consciousness for technical media first arose, and that today the connections of mathematics and media, and of media and ontology are to be formulated in more precise terms. (shrink)