  The prioritarian idea is to be sharply distinguished from the idea that across some range, resources secured for a person have declining marginal utility. To illustrate, suppose one person is leading a hellish existence and another is leading a life of sheer bliss. We might think that a single unit of some generally useful resource such as water is likely to do more good, result in a greater aggregate of well-being among all persons, if the unit is provided to the person suffering in hell rather than the person enjoying heavenly bliss. This may be so. The straight utilitarian of well-being will then favor provision of the unit of water to the inhabitant of hell. Now suppose instead that a unit of some resource would provide exactly the same increase in well-being if it is provided either to the person leading the hellish or the person leading the blissful life. (Perhaps the person already in bliss is a very efficient transformer of resources into personal well-being.) The prioritarian gives priority to getting benefits to those whose well-being level is low, so will favor helping the miserable rather than the lucky person even if the well-being aggregate is thereby reduced a bit, compared to what it would have been if the resource had been channeled to the blissful person.