The concept of well-being is central in ethics and important in any plausible moral theory. But how is it to be understood? In the history of ethics both perfectionist and hedonist theories of welfare have had a prominent place. Perfectionists, ever since Aristotle, focus on the ideal human life as a function of human nature and claim that there is a prudential value in such things as accomplishments, understanding, deep personal relations and so on, irrespective of whether these things are objects of subjective valuation. So my well-being, in this theory, is objectively affected by the extent to which these things (and other things on the perfectionist list) have a place in my life.