Another argument commonly used against aggregationism is also hard to understand (Rawls, A Theory of Justice, p. 27). This is the objection that utilitarianism “does not take seriously the distinction between persons”. To explain this objection: it is said that, if we claim that there is a duty to promote maximal preference satisfaction regardless of its distribution, we are treating a great interest of one as of less weight than the lesser interests of a great many, provided that the latter add up in aggregate to more than the former. For example, if I can save five patients moderate pain at the cost of not saving one patient severe pain, I should do so if the interests of the five in the relief of their pain is greater in aggregate than the interest of the one in the relief of his (or hers).

But to think in the way that utilitarians have to think about this kind of example is not to ignore the difference between persons. Why should anybody want to say this? Utilitarians are perfectly well aware that A, B and C in my example are different persons people. They are not blind. All they are doing is trying to do justice between the interests of these people. It is hard to see how else one could do this except by showing them all equal respect, and that, as we have seen, leads straight to aggregationism.

R. M. Hare, in Helga Kuhse and Peter Singer (eds.), A Companion to Bioethics, Oxford, 1998, p. 83