Why the former does not require the latter
Happiness and meaning are often mentioned in one breath in discussions about quality of life. Yet these are different things both conceptually and empirically.
Happiness is defined as subjective appreciation of one’s life as a whole. Meaningfulness is sometimes conceived as a subjective appreciation as well, and represents in that case as aspect appraisal of life. Meaningfulness is also conceived as objective significance of a life beyond that life, which does not necessarily reflect in subjective appreciation. This keynote focuses on the relationship between happiness and perceived meaning of life.
Empirical studies have shown strong correlations between happiness and perceived meaning of life. These correlations are typically interpreted as an effect of meaning on happiness. Yet causality can work the other way as well. This paper explores the probability of both causal paths.
It is commonly assumed that humans have an innate need for meaning, and that gratification of that need causes happiness. However, that assumption should not be taken for sure. An alternative theory holds that we have no hardwired 'need' for meaning but rather a universal ‘interest' in meaning as a consequence of the fact that we can think. This theory fits the fact that we can live fairly well without convincing answers about the objective meaning of life.
An alternative account for the observed correlation between happiness and perceived meaning of life is that happy people are more likely to see their lives as meaningful, partly because of their more positive view and possibly also because they do more good. In this line one can also imagine that unhappy people will more inclined to worry about the meaningfulness of their life.