Vain is the word of a philosopher which does not heal any suffering of man. For just as there is no profit in medicine if it does not expel the diseases of the body, so there is no profit in philosophy either, if it does not expel the suffering of the mind.
EpicurusWe begin every act of choice and avoidance from pleasure, and it is to pleasure that we return using our experience of pleasure as the criterion of every good thing.
Epicurus