  However, the philosophical problem is not exhausted by this computational issue. The outstanding philosophical question is how the robot could ever determine that it had successfully revised all its beliefs to match the consequences of its actions.  Only then would it be in a position safely to apply the “common sense law of inertia” and assume the rest of the world is untouched.  Fodor suggestively likens this to “Hamlet's problem: when to stop thinking” (Fodor 1987, 140). The frame problem, he claims, is “Hamlet's problem viewed from an engineer's perspective”. So construed, the obvious way to try to avoid the frame problem is by appealing to the notion of relevance. Only certain properties of a situation are relevant in the context of any given action, so the counter-argument goes, and consideration of the action's consequences can be conveniently confined to those.