• Another difficulty with problem solving:
– The goal test is another black‐box function, states are
domain‐specific data structures, and heuristics must
be supplied for each new problem
– Suppose that the goal is
HAVE(MILK) ∧ HAVE(BOOK)
– Without an explicit representation of the goal, the
problem solver cannot know that a state where
HAVE(MILK) is already achieved is more promising
than a state where neither HAVE(MILK) nor
HAVE(BOOK) is achieved