“There is a great difference between small and great knowledge，short and long life.If there are things to be regretted，this certainly is one.The fact that people do not regret this is for the reason that in the nature of things there are proper limitations.If we know for things there is a proper limit，beyond which nothing can be desired，in the world there would be nothing to be regretted.The great things usually do not crave for the small，but the small usually do long for the great.Therefore，Chuang Tzu showed the proper limitations of the great and the small，which are not to be excelled by merely craving and longing.If people knew this，they would not be troubled with craving and longing.Regret is born in trouble.If there is no trouble，there would be no regret.If there is no regret，life would certainly be in peace.” —Kuo Hsiang