Oresme, Nicole (c.1325–82)

Nicole Oresme, a French thinker active in the third quarter of the fourteenth century, occupies an important position in late medieval natural philosophy. He was especially notable for his mathematical approach, in which he represented the intensities of qualities and of speeds by geometrical straight lines, which allowed them to be ‘plotted’ in principle against both distance and time. He held that the shapes of the resulting graphs would then have explanatory force in the manner of ancient atomism, but, like the latter, his doctrine had a weak empirical basis. His graphical representations of speed have been compared to those later given by Galileo, but there are no grounds for positing influence. He was prominent in developing a particular mathematical language of ratios, which had earlier been used by Thomas Bradwardine to propose a ‘law’ relating speeds to forces and resistances, and Oresme likewise applied the language to cosmological and physical questions. He was a firm opponent of much of astrology and of magic, and to this end he employed both naturalistic and sceptical arguments. He gave many strong arguments in favour of a daily rotation of the earth, but finally concluded that it was at rest: his gambit had primarily a sceptical and fideistic purpose.