 Zhu Xi didn’t feel the need to formulate a theory of motion as such either, because the factors were glossed in his commonsense grasp of the world and he didn’t see any advantage in explicating them. Importantly, he couldn’t conceive of their theoretical ramifications or especially of their practical implications, such as for engineering and technology. At the same time, Zhu did have a grasp of inertia and the relativity of motion, keys to solving the problems of motion, but it was not adequate to the task. The capacity to imagine ideal cases and relationships would have been necessary: for example, Galileo had to conceive of the paradigmatic case of motion in terms of an object moving in a straight line on a frictionless plane at a constant velocity, something that can never occur in nature, for any actual object inevitably will be environed and influenced by a variety of forces, such as gravity and friction. Essential, too, was the mathematical plotting of motions in nature that approximate the paradigmatic motions, such as Kepler’s plotting of planetary motion and Galileo’s plotting of the trajectories of projectiles, to produce precise representations of near-paradigmatic motions. Necessary, too, was an awareness of the possibility of mathematical calculation and precise predictions. Zhu’s philosophy involved viewing all things interactively in relative context. If he had had a notion of paradigmatic (perpetual) motion, it would have been something like wave motions in the sea or the cyclical pumping action of the traditional Chinese waterwheel used for irrigation with rising full troughs of water complemented by the falling empty troughs (receptacles), which he had used to depict the yin-yang operation of taiji. Zhu also lacked the necessary notions of precise mathematicization, measurement, and calculation in terms of which to make the theory of motion bear fruit. Consequently, it is hardly to be expected that Zhu or any one else in his intellectual circle should have had occasion to formulate anything like a scientific theory of motion.