ABSTRACT
At the end of Chapter 7, we considered the possibility of teaching Robbie the Robot to play the Tower of Hanoi, moving real disks from peg to peg with an arm that could grasp and move. If you thought about the questions posed there, you may have realized that Robbie would have to know a great deal about the relations of world objects to each other, and how these relations change when one object is moved. To move one disk, Robbie would have to make sure that he was not holding anything, that the disk to be moved had nothing on its top, and that the destination peg could accept the disk to be moved. If any of these conditions were not met, Robbie would have to create and carry out a plan to satisfy these conditions before moving that one disk.
