Chapter Seven of Life, Liberty and the Pursuit of Utility asks "do people know if they are happy?":
If the most important elements in happiness are welfare and dignity, then individuals are not necessarily the best authorities on their own condition. We may be mistaken about the state of our bodily health,and our acquiescence in our social status may be the result of ignorance and lack of imagination. But surely each person is in the best position to say whether he or she is contented or not?
It is wrong to suppose that each of us has access to a private realm of consciousness, from which we have to think our way out to a public world. Even in our most secret thoughts we are using a language that only makes sense in the context of social activities shared with other beings like ourselves. This applies to emotions, too --the intelligibility of their expression depends upon their behavioural and environmental context. This must be particularly borne in mind when we are considering the role of mental states in the good life, and the value to be placed on self-ascriptions of them.
Contentment is not so much a feeling as a belief or judgement; a judgement that one’s life, considered overall, as a whole, is going well, and that one’s major desires are either satisfied or on the way to satisfaction. It is a judgement on these issues that the pollster wishes to elicit when he asks ‘taking your life as a whole, would you consider yourself very happy, somewhat happy, or not happy at all?’ The first person is certainly in a position of greater authority on the topic of contentment than she is on either the topics of welfare or of dignity. On the other hand, because an expression of contentment is a judgement about a long-term state, a person uttering it does not have the overriding authority that she would have if she were reporting a pain or narrating a dream. It is possible for a claim to contentment to be mistaken, and a person may well come to revise her own past estimates of her contentment. ‘In those days I thought I was happy. Now I know better.’ Or ‘I wish I had realised how happy I was’. Again, if someone gives a positive answer to an inquiry about his contentment, but is regularly irritable, frequently quarrels with family and friends, is constantly trying to change his job, and often exhibits symptoms of psychosomatic illness, it may not be unreasonable to discount his evidence even if given in good faith.
Of course, not all evidence is given in good faith. Furthermore, a positive or negative response to a standard subjective wellbeing question will depend on imagination, ambition, and character. The problem is compounded when respondents are asked not just whether they are happy or not, but where they would place themselves upon a scale of happiness from one to five, or give themselves marks out of ten for well-being. Accuracy in answering here depends not just on unbiased introspection, but some estimate of an overall standard.
Questions regarding the accuracy of subjective wellbeing polls as a measure of contentment aside, surely the secret of contentment lies somewhere between the frenzied pursuit of every passing want and the total renunciation of desire.