The Importance of Impetus in Motion

The claim that motions are always caused by qualities is intended to avoid an infinite regress. Prashas Dapada also appeals to qualities to explain why motion continues once it has started. In particular, he refers to a quality called Vega, impetus, or speed. Empitus explains why falling things continue to fall, elasticity, why bodies return to their original shape after being stretched or squeezed. Later Vaisheshika is trying to extend the theory to other sorts of motion such as the motion of an iron needle towards a magnet and the upward flickering of flames. They resort to something they call Adhrstak, literally the unseen, which is postulated to account for movements like these