  The epistemological difficulty now discerned by philosophers is this. How could the robot limit the scope of the propositions it must reconsider in the light of its actions?  In a sufficiently simple robot, this doesn't seem like much of a problem. Surely the robot can simply examine its entire database of propositions one-by-one and work out which require modification. But if we imagine that our robot has near human-level intelligence, and is therefore burdened with an enormous database of facts to examine every time it so much as spins a motor, such a strategy starts to look computationally intractable. 