"Motion," or "movement," in its modern meaning, is change—or more precisely, change of the relative positions of bodies. The concept of motion thus involves the ideas of space and time. Kinematics, in the nineteenth century usually called "kinetics" or "phoronomics," is the science that deals exclusively with the geometrical and chronometrical aspects of motion, in contrast to dynamics, which considers force and mass in relation to motion. In medieval terminology, following Aristotelian tradition, "motion" (motus or kinesis) had a much wider significance, denoting any continuous change in quality, quantity, or place.

Early Concepts of Motion

Ever since the beginning of philosophical speculation and scientific analysis, the concept of motion has played a predominant role in Western thought. Anaximander of Miletus (sixth century BCE) saw in motion an eternal agent of the cosmos. For Heraclitus motion was a cosmological principle underlying all...