De Motu (Berkeley's Essay) - Communication of Motion

Communication of Motion

Physical science is concerned only with mechanics. Therefore, it can be said that, in a collision, action and reaction are always opposite and equal. Such actions and forces, though, are only mathematical hypotheses. We only really know that the striking body loses motion and the struck body gains motion. We do not know if the motion is communicated from one body to another or if the motion is destroyed in the striker and is created in the struck. In the true nature of things, all bodies are passive. The truly active cause of motion is metaphysical and not the concern of physical science.