In The Road to Character he writes,

"All human beings seek to lead lives not just of pleasure, but of purpose, righteousness, and virtue. As John Stuart Mill put it, people have a responsibility to become more moral over time. The best life is oriented around the increasing excellence of the soul and is nourished by moral joy, the quiet sense of gratitude and tranquillity that comes as a byproduct of successful moral struggle. The meaningful life is the same eternal thing, the combination of some set of ideals and some man or woman’s struggle for those ideals. Life is essentially a moral drama, not a hedonistic one."