Derek Parfit, answered from the texts and cited to the page.
Benefits to the worse off matter more, but not because equality matters intrinsically. Strict egalitarianism — the view that equality of welfare distribution matters intrinsically, so that an outcome where everyone is at level X is in one respect better than an outcome where some are at X+5 and some at X+10 — generates the Levelling Down Objection: it implies that levelling everyone down to the lowest level would be in one respect a good thing, which is absurd.
Prioritarianism avoids the Levelling Down Objection by saying that benefits matter more the worse off the recipient, where the weighting is on absolute level rather than on equality of distribution.1 A benefit to someone at very low welfare matters more than the same benefit to someone at high welfare, but the difference is not because the gap between them matters intrinsically; it is because the absolute level of the worse-off person is low.2
The Priority View is therefore distinct from utilitarianism (which weights all benefits equally regardless of recipient welfare) and from strict egalitarianism (which values equality intrinsically). The position was developed in the 1995 Lindley Lecture 'Equality and Priority' and defended again in 'Another Defence of the Priority View' (Utilitas 2012) against Otsuka and Voorhoeve's challenge that prioritarianism collapses into either utilitarianism or egalitarianism depending on how the weighting is specified.345
It is irrelevant that these people are worse off than others. Benefits to them would matter just as much even if there were no others who were better off. When Otsuka and Voorhoeve discuss the comparative strength of different people's claims, they may seem to be asserting the Prioritarian PP4.Another Defence of the Priority View, p. 438
In these quoted sentences, however, Otsuka and Voorhoeve were intending to imply that (T) the strength of an individual's claim to receive some benefit depends on whether, and by how much, this person is better off or worse off than other actual people. 41 Quoted in Otsuka and Voorhoeve, 'Why It Matters', pp. 176-7. 42 Otsuka and Voorhoeve, 'Why It Matters', pp. 183-4.Another Defence of the Priority View, p. 439
In some later papers, Michael Otsuka and Alex Voorhoeve defend partly different conclusions. III. COMPETING EXPLANATIONS In Case One, we could either do X, which would benefit Tom, who is very badly off, do Y, which would give a slightly greater benefit to Ted, who is very well off. Utilitarians would believe that we ought to do Y. When Otsuka and Voorhoeve consider cases like One, they reject this view.Another Defence of the Priority View, p. 412
Tom a greater expectable benefit. Otsuka would agree that, in Two, this claim would not answer Tom's complaint, which would be justified. If Tom's complaint would be justified in Two, why would the same complaint not be justified in Four? When Otsuka and Voorhoeve state their objection to the Priority View, they also make some remarks about inequality.Another Defence of the Priority View, p. 416
In such cases, we do not need to know how these people's levels of well-being compare with the levels of other people, in the various ways described by (U). The strength of each person's claim depends only on how well off this person is. One of two people would have a stronger claim if this person is worse off; but this person's claim would not be stronger because there are other people who are better off.Another Defence of the Priority View, pp. 439–440
The Priority View has become a standard position in contemporary distributive-justice literature. Holtug's Persons, Interests, and Justice (2010) is the major systematic engagement. Otsuka and Voorhoeve's 'Why It Matters That Some Are Worse Off Than Others' (2009) is the central recent challenge; the 2012 Utilitas paper is the systematic reply. Temkin's Inequality (1993) and Rethinking the Good (2012) develop a sophisticated egalitarianism that disputes the framing of the Levelling Down Objection. Broome's Weighing Goods and Weighing Lives are the major consequentialist alternatives. The Priority View remains a live position; the debate continues.