Problems with GPS
GPS did solve problems in several different domains, but was not as useful
as had been hoped. Problems included:
- Keeping a complete world state at each step takes a lot of storage.
This restricted GPS to small problems.
- The ``difference'' between the current state and the goal may not be an
adequate guide to action. (Consider chess: the goal of checkmating the
opponent doesn't tell how to play the opening.)
- Accomplishing a subgoal might undo a higher-level goal. This could
lead to loops.
- We often want to achieve multiple goals simultaneously.
(``Climb Mt. Everest and live to tell about it.'')