Conscious beings know what it is to be forced. A strong wind or a push can send us in a direction we have not chosen. By analogy we transfer this notion to the physical world. A leaf picked up by a breeze is forced to flutter through the air. Science supports the notion of forces operating in the physical world. The simplest way to account for the regularity of action and reaction is to assume that forces are operating. Often the forces, like that of an impacting billiard ball for example, are directly perceivable by humans. BACK