Not only this, the system would have to maintain multiple levels of world models and simulate them as well. Consider a sentence: "If he goes there, and then she

Not only this, the system would have to maintain multiple levels of world models and simulate them as well. Consider a sentence: "If he goes there, and then she does not reach in time, he will surely be disappointed." There has to be a hierarchy of world models, and only the bottom-most layer would be the "real" one. Any kind of planning will require simulating hypothetical worlds.