The concept of impetus denoted the transmission of a power from the mover to the object moved. Many authors resorted to this concept to explain why a projectile keeps on moving when no longer in contact with its initial mover. But its application went further, as impetus was also appealed to in attempts to explain the acceleration of falling bodies or the motion of the heavens. It was widely applied in Renaissance natural philosophy, but it also raised a number of (...) ontological questions concerning its precise nature. (shrink)