One major way this concept is explored is through the character Jaques. Jaques is a fool character, but he has many wise moments. Consider his "All the world's a stage" speech... it contains many truths about life. Jaques is by no means stupid. He is a fool because he dwells on negative aspects of life instead of living and being an optimist to see what life can bring. He is also foolish because he generalizes life as bad instead of focusing on particular aspects of life to improve.
Touchstone, the other fool in the play, can also be seen as a wise fool, but in a different way. Touchstone is not traditionally wise, but he handles life well. He is like a foil for Jaques.