Iwao Hirose

In this dissertation, I discuss two distributive principles in moral philosophy: Derek Parfit's Prioritarianism and Egalitarianism. I attempt to defend a version of Egalitarianism, which I call Weighted Egalitarianism. Although Parfit claims that Egalitarianism is subject to what he calls the Levelling Down Objection, I show that my proposed Weighted Egalitarianism is not subject to the Objection, and that it gives priority to the worse off people. The real difference between the two principles lies in how the weight of each person's well-being is determined. Prioritarianism assumes that there is a moral scale of the goodness of well-being, independently of distributions of people's well-being. I raise two objections to this claim: firstly, it is hard to believe that the choice of the level of well-being affects our distributive judgement; secondly, it is hard to believe that there is such a moral scale independently of distributions of people's well-being. On the other hand, Weighted Egalitarianism claims that the weight is given by the rank order position of the person in the ranking by well-being level. This means that, in Weighted Egalitarianism, the goodness of a distribution is an increasing, linear function of people's well-being. Weighted Egalitarianism is not affected by the choice of the level of people's well-being. Nor does it require require the moral scale of the goodness of well-being independently of distributions of people's well-being. Leximin, which might be a version of Prioritarianism, avoids my objections. But it is hard to support Leximin, because it rules out the trade off between the better off and the worse off. I conclude that Weighted Egalitarianism is more acceptable than Prioritarianism.