 A second strategy forsakes the project of giving a unitary theory of well-being, recognizing instead a family of two or more kinds of prudential value. Happiness could be central to, or even exhaustive of, one of those values. Shelly Kagan, for instance, has suggested that welfare hedonism could be correct as a theory of how well a person is doing, but not of how well a person’s life is going, which should perhaps be regarded as a distinct value (Kagan 1992, 1994). In short, we might distinguish narrow and wide well-being concepts. An experience machine user might be doing well in the narrow sense, but not the wide—she is doing well, though her life is quite sad. Happiness might, then, suffice for well-being, but only in the narrow sense. Others have made similar points, but uptake has been limited, perhaps because distinguishing multiple concepts of prudential value makes the already difficult job of giving a theory of well-being much harder, as Kagan pointedly  observes.[29]  An interesting possibility is that the locution ‘happy life’, and the corresponding well-being sense of happiness, actually refers to a specific variety of well-being—perhaps well-being in the wide sense just suggested, or well-being taken as an ideal state, an ultimate goal of deliberation. This might explain the continued use of ‘happiness’ for the well-being notion in the philosophical literature, rather than the more standard ‘wellbeing.’