  The point here is not a logical one. The effect on fridgeons of switching Fodor's fridge on and off can concisely be represented without any difficulty (Shanahan 1997, 25). Rather, the point is metaphysical. The common sense law of inertia is only justified in the context of the right ontology, the right choice of objects and predicates. But what is the right ontology to make the common sense law of inertia work? Clearly, fridgeons and the like are to be excluded. But what metaphysical principle underpins such a decision?