[W]hile the problem of interpersonal comparability of utility is a tricky one, it is not insoluble in principle. It is conceivable that, perhaps several hundred (or a thousand) years from now, neurology may have advanced to the stage where the level of happiness can be accurately correlated to some cerebral reaction that can be measured by a ‘eudaimonometer’. Hence the definition of social welfare [in terms of the sum total of individual happiness] is an objective definition, although the objects are the subjective feelings of individuals.
Yew-Kwang Ng, Welfare Economics: Towards a More Complete Analysis, Basingstoke, Hampshire, 2004, p. 4
[T]he sums that the Metropolitan Museum of Art and MoMA have spent and are planning to spend on their extensions and renovations would have done more good if they had been used to restore or preserve the sight of people too poor to pay for such treatment themselves. I am not suggesting that these museums should have done that. They were set up for a different purpose, and to use their funds to help the global poor would presumably be a breach of their founding deeds or statutory obligations, and would invite litigation from past donors who could perceive it as a violation of the purposes for which they had donated. (Perhaps, though, the museums could justify, as part of their mission, restoring sight in people who would then be able to visit and appreciate the art they display?)
Peter Singer, The Most Good You Can Do: How Effective Altruism Is Changing Ideas about Living Ethically, New Haven, 2015, chap. 11
A person who is among the poorest 10 percent of the people in the U.S. today may rightly feel unfortunate, even if she is quite well off in absolute terms and better off than 95 percent of the world’s current population and 99.9 percent of the world’s population over the past five millennia. [T]he judgment that she is unfortunate is based on a comparison with other contemporary Americans.
It is important to notice, however, that these comparative judgments presuppose different comparison classes. When we judge that I am not unfortunate for being unable to walk on walls (even though flies can and I would certainly be better off if I could), the relevant comparison class is the entire human species. If a significant enough fraction of the human population were to acquire the ability to walk on walls, then I might feel unfortunate, just as I would now if I were unable to walk at all. In the case of the poor American, the comparison class is narrower. In other cases, it is even narrower still. During his recent tribulations, Michael Jackson elicited a copious flow of pity for his unfortunate condition, the assumption being that anything less than perfect bliss must count as a deprived state for a star entertainer.
Jeff McMahan, ‘Cognitive Disability, Misfortune, and Justice’, Philosophy and Public Affairs, vol. 25, no. 1 (Winter, 1996), pp. 3-35
[T]he Utilitarian cannot confine himself to a single mind; he has to consider what he calls “the total happiness of a collection of minds”. Now this is an extremely odd notion. It is plain that a collection cannot literally be happy or unhappy. The oddity is clearly illustrated if we […] use the analogy of greyness. Suppose that a number of different areas, which are not adjoined to each other, all go through successive phases of greyness. What could we possibly mean by “the total whiteness of this collection of areas”?
C. D. Broad, Five Types of Ethical Theory, London, 1930, pp. 248-249
I am against the insistence on the purely ordinal measurability of happiness only. In fact, I am not only certain that I am happier now than when I was 30-something, I am also absolutely sure that I am now at least 3 times happier than then. It is difficult to be sure that my happiness now is exactly 3.5 or 4.3 times my happiness then. However, I am pretty sure that it is more than 3 times.
Yew-Kwang Ng, ‘Happiness Studies: Ways to Improve Comparability and Some Public Policy Implications’, The Economic Record, vol. 84, no. 265 (June, 2008), p. 256
To make sense of interpersonal compensation it is not necessary to invoke the silly idea of a social entity, thus establishing an analogy with intrapersonal compensation. All one needs is the belief, shared by most people, that it is better for each of 10 people to receive a benefit than for one person to receive it, worse for 10 people to be harmed than for one person to be similarly harmed, better for one person to benefit greatly than for another to benefit slightly, and so forth.
Thomas Nagel, ‘Libertarianism Without Foundations’, in Jeffrey Paul (ed.), Reading Nozick, New Jersey, 1981, p. 197