Since the days of the New Science, which developed during the 17th Century Enlightenment, the fundamental science was that of physics. Physicists held that all that existed was matter in motion, that matter had geometric form and mass, was essentially passive, reacting only to physical impact, and that the laws of motion were those defined by Newton in terms of mass, momentum, acceleration and force. This last was defined interns of mass and acceleration, where force is a measure of an object mass multiplied by its acceleration, the famous Newtonian equation: f=ma.
Rene Descartes had a profound influence on the philosophical base of the New Science. He held that there existed two categories of substances in the universe: 1. Res Extensia (extended being, that which has geometric properties), and 2. Res Cogitans (ideas or thoughts that resided in the mind, but which had no geometric properties, no shape or figure). Descartes went on to argue that these two substances residing as they do in different realms and having incompatible properties—especially the fundamental properties of locus, shape, and extension, found in res extensa and absent in res cogitans, on the one hand, and the fundamental properties of sentience and ideation found in res cogitans but absent in res extensa—cannot interact with each other. Mind (res cogitans) on the one hand, lacking extension, shape, or form, cannot impact with extended entities which have these properties, i.e., cannot interact with res extensa (‘matter’). Matter on the other hand lacking sentience and ideation cannot causally interact with the mental world or mind stuff (res cogitans). This is the beginning of the mind-body problem that has bedeviled philosophy since Descartes first articulation of his substance dualism, essentially a mind/body dualism.