Yet even a story can hide wisdom in allegory. Knowledge is not limited to certain (or currently accepted) answers to the question "how." Take aesthetics, for example. Since you can't exactly test what the "right" way of doing something is (i.e. derive an "ought" from an "is"), you have to throw around random ideas and refine them through debate, checking for internal consistency, etc. into something that intuitively "feels right." Knowledge of the purely physical should be testable, but you'd have a hard time doing the same for abstract concepts.