The psychological condition of being happy is best understood as a matter of a person's emotional condition. I elucidate the notion of an emotional condition by introducing two distinctions concerning affect, and argue that this “emotional state” view is probably superior on intuitive and substantive grounds to theories that identify happiness with pleasure or life satisfaction. Life satisfaction views, for example, appear to have deflationary consequences for happiness’ value. This would make happiness an unpromising candidate for the central element in a theory of well-being, as it is in L. W. Sumner's work. Yet on an emotional state conception, happiness may prove to be a key constituent of well-being. the emotional state view also makes happiness less vulnerable to common doubts about the importance of happiness, and indicates that mood states are more important for well-being than is generally recognized.
Happiness in intelligent people is the rarest thing I know.