Mathematics and Physics of First and Last Instants: Walter Burley and William of Ockham

Abstract

In his De primo et ultimo instanti, Walter Burley paid careful attention to continuity, assuming that continua included and were limited by indivisibles such as instants, points, ubi (or places), degrees of quality, or mutata esse (indivisibles of motion). In his Tractatus primus, Burley applied the logic of first and last instants to reach novel conclusions about qualities and qualitative change. At the end of his Quaestiones in libros Physicorum Aristotelis, William of Ockham used long passages from Burley’s Tractatus primus, sometimes agreeing with Burley and sometimes disagreeing. How may this interaction between Burley and Ockham be understood within its historical context?