As Susan Wolf observes, meaningful lives may “frequently involve stress, danger, exertion, or sorrow” (“Happiness and meaning: two aspects of the good life”, Social Philosophy and Policy, 14, p.209), all of which are incompatible with pleasure. Wolf understands meaningful lives as “lives of active engagement in projects of worth” (ibid.); it is not difficult to see why such engagement does not always give us pleasure --- is not necessarily happy in the hedonistic sense.
As long as happiness is understood phenomenologically, that is, in terms of some of the subject’s positive feelings, states of mind, or experiences, it seems that we can always imagine that a person whose life is meaningful does not have any such feelings, states of mind, or experiences. It is, I think, true that a meaningful life is usually accompanied by a sense of fulfillment. Although fulfillment is not the same as happiness, it, as Wolf rightly maintains, “deserves an important place in an adequate theory of happiness” and should be considered “a major component of happiness” (ibid., p.220). Nevertheless, there is still no guarantee that living a meaningful life will give one a sense of fulfillment. Even for Wolf, who thinks that “the links between meaningfulness and fulfillment are tight” (ibid.), there is no such guarantee, for she can only say that “[n]ine times out of ten, perhaps ninety-nine times out of a hundred, a meaningful life will be happier [through having a sense of fulfillment] than a meaningless one” (ibid., p.222). Ninety or ninety-nine percent is still not one-hundred percent, though it may well be good enough.
It is even clearer that a meaningful life does not imply happiness when happiness is understood as objective well-being rather than in terms of subjective positive experiences. A meaning life is not necessarily a life that prospers or goes well, or a life in which most of one’s important desires are satisfied, or a life in which one enjoys a high quality of life (materialistically construed), or a life full of great achievements. I cannot agree more with the following remarks by Harry Frankfurt:
A life may be full of meaning, then, and yet so gravely deficient in other ways that no reasonable person would choose to live it. It cannot even be assumed that a meaningful life must always be preferable to one that lacks meaning. What fills a certain life with meaning may be some intricate and demanding conflict, or a terribly frustrating but compelling struggle, which involves a great deal of anxiety or pain and which is extremely destructive. Thus the very circumstances that make the life meaningful may be deeply objectionable. It might be better to live an empty life than to generate or to endure so much suffering and disorder. (Necessity, Volition, and Love, CUP, p.85)
Viktor Frankl may be right when he says that “[t]here is nothing in the world […] that would so effectively help one to survive even the worst conditions as the knowledge that there is a meaning in one’s life” (Man's Search for Meaning, Simon & Schuster, p.109), but for a more balanced understanding of the importance of meaningfulness we have to keep in mind that there could be conditions so bad that nothing could help one survive them, not even the knowledge that there is a meaning in one’s life. To think otherwise is to romanticize human nature.
Some may insist that a meaningful life is necessarily better than a meaningless life. Although we do not have to object to this, we should notice that meaningfulness is only one dimension of the evaluation of life. As far as this dimension of evaluation is concerned, it is true that a meaningful life is always better than a meaningless life. Indeed, it is true trivially, for this dimension of evaluation is understood by us in such a way that ‘meaningful’ is on the positive side of it and ‘meaningless’ on the negative side (and a gray area in between). In any case, there are other dimensions of the evaluation of life, such as happiness, with ‘happy’ on the positive side and ‘unhappy’ on the negative side (and a gray area in between). It is possible for the very same life to be placed on the positive side of one dimension of evaluation while being placed on the negative side of another dimension. This is what happens when a life is meaningful but unhappy. It is not always clear which dimension of evaluation should trump which: in some cases it might be better to live a happy life that is not meaningful than live a meaningful life that is unhappy, but vice versa in other cases.