 Well-being obviously plays a central role in any moral theory. A theory which said that it just does not matter would be given no credence at all. Indeed, it is very tempting to think that well-being, in some ultimate sense, is all that can matter morally. Consider, for example, Joseph Raz’s ‘humanistic principle’: ‘the explanation and justification of the goodness or badness of anything derives ultimately from its contribution, actual or possible, to human life and its quality’ (Raz 1986, p. 194). If we expand this principle to cover non-human well-being, it might be read as claiming that, ultimately speaking, the justificatory force of any moral reason rests on well-being. This view is welfarism.