© Koninklijke Brill NV, Leiden, 2007 DOI: 10.1163/156853407X217803 Vivarium 45 (2007) 328-342 www.brill.nl/viv viva rium Scepticism, Demonstration and the Infinite Regress Argument (Nicholas of Autrecourt and John Buridan)* Christophe Grellard University of Paris 1 Panthéon-Sorbonne Abstract he aim of this paper is to examine the medieval posterity of the Aristotelian and Pyr- rhonian treatments of the infinite regress argument. We show that there are some possible Pyrrhonian elements in Autrecourt’s epistemology when he argues that the truth of our principles is merely hypothetical. By contrast, Buridan’s criticisms of Autrecourt rely heavily on Aristotelian material. Both exemplify a use of scepticism. Keywords scepticism, truth, evidentness, principles, infinite regress he medieval reception of scepticism presents a most interesting example of how a current or—to use the medieval term—a sect in ancient philosophy was reconstructed. In some ways, the approach to sceptical questions in the Middle Ages is a non-historical one, since it is hard to find what the ancient philosophers called scepticism in this period. here were no sceptics in the Middle Ages, in the sense of someone’s professing scepticism (except for John of Salisbury). here was, however, a sceptical problem, understood as a challenge to the theory of knowledge. his scepticism is a construction that is not based on any historical foundation, and for this reason it should be considered, above all, a breeding-ground of arguments (some of which are ancient in origin, others genuinely medieval), a collection of challenges for the theory of knowledge. he main reason why medieval scepticism lacks a history and is reduced to being a breeding-ground of arguments lies in the way ancient traditions of * ) Article translated by John Marenbon.