The central goal of all systems of ancient ethics; according to Aristotle, the ‘best, noblest, and most pleasant thing in the world’. Eudaimonia is a place-holder waiting for further specification, and different ethical theories will fill it out differently. Aristotle conceives of it as the active exercise of the powers of the (virtuous) soul in conformity to reason. Eudaimonia is usually translated as happiness or well-being, but it has some of the same connotations as ‘success’, since in addition to living well it includes doing well. For example, it can be diminished by events that happen after the subject’s death, and it is not a state that children can possess. It is complete and self-sufficient, to be attained for no other end than itself, so it includes all other ends that are pursued for themselves. It therefore includes pleasure, but goes beyond it. In Bk. x of the Nicomachean Ethics Aristotle extols the life of study or contemplation as the essential realization of eudaimonia. See also summum bonum.