A quality of the commonsense world is that objects tend to stay in the same state unless they are affected by events. A book sitting on a table remains on the table unless it is picked up, a light stays on until it is turned off, and a falling object continues to fall until it hits something. This is known as the commonsense law of inertia. We discuss the representation of the commonsense law of inertia in the event calculus. We retrace the development of the discrete event calculus axioms, and we discuss the enforcement of the commonsense law of inertia and the release of fluents from inertia.