Abstract

The anonymous treatise De sex inconvenientibus is a good example of the calculatores’ approach when dealing with motion. It is organized around four main questions relating to the determination of rapidity in four kinds of changes, i.e. in the generation of substantial forms, in alteration, in increase, and in local motion. In some arguments the author points out the paradoxes to which the two ways of determining the rapidity of a motion can lead: rapidity is determined by the effect produced (the degree of quality generated, the space covered, etc.) or it results from the ratio between the moving power and the resistance of the mobile or patient. While this twofold approach to determining rapidity appears in the majority of calculator texts, the two points of view – the analysis according to its effects and the analysis according to its causes – have rarely been confronted.