 Hanks and McDermott, computer scientists at Yale, demonstrated that the existing systems of nonmonotonic logic were unable to give the right solution to a simple problem about predicting the course of events (Hanks and McDermott 1987). The problem became known as the Yale shooting problem. Hanks and McDermott assume that some sort of law of inertia can be assumed: that normally properties of things do not change. In the Yale shooting problem, there are two relevant properties: being loaded (a property of a gun) and being alive (a property of the intended victim of the shooting). Let’s assume that in the initial situation, \(s_0\), the gun is loaded and the victim is alive, Loaded\((s_0)\) and Alive\((s_0)\), and that two actions are performed in sequence: Wait and Shoot. Let’s call the situation that results from a moment of waiting \(s_1\), and the situation that follows both waiting and then shooting \(s_2\). There are then three instances of the law of inertia that are relevant: