First Studies on the Causes of Resistance

Who was first to develop the themes of the First and Second Days of the Discorsi? According to Fr. Guido Grandi, a monk of Camaldoli, it was Vincenzo Viviani, Galileo’s favorite pupil. As we shall see, the matter is not quite so simple, and Grandi cannot be considered impartial. In fact, Viviani had published nothing before the discussion on the resistance of solids exploded, with considerable eclat, in Italy and France. All the same, Grandi’s reasons for this claim are significant, and they may provide a good introduction to the debate that arose as early as the 1640s about the physical (or even metaphysical) causes of resistance.