Abstract
This paper argues that Nicholas of Cusa’s investigation of infinity and incommensurability in De docta ignorantia was shaped by the mathematical innovations and thought experiments of fourteenth-century natural philosophy. Cusanus scholarship has overlooked this influence, in part because Raymond Klibansky’s influential edition of De docta ignorantia situated Cusa within the medieval Platonic tradition. However, Cusa departs from this tradition in a number of ways. His willingness to engage incommensurability and to compare different magnitudes of infinity distinguishes him from his Platonic predecessors, who had appropriated the Pythagorean model of universal harmonies. Cusa’s penchant for representing quantity geometrically suggests not only that he has adopted the fourteenth-century method of latitude measurement, but that he accepts incommensurability as normative. Finally, Cusa’s persistent attention to mathematical inaccuracy and to his own learned ignorance suggests his kinship with the meta-critical, conjectural quality of fourteenth-century thought.