This symposium publishes for the first time three key contributions to the debate on the nature and importance of the distinction between egalitarianism (the view that it is in itself bad, when and because it is unfair, for some to be worse off than others) and prioritarianism (the view that each person's welfare has diminishing marginal moral value and that the moral value of a person's welfare depends only on that person's level of welfare, and not on how anyone else fares). These papers were commissioned by the World Health Organization (WHO) in 2000. They were intended for publication in a WHO volume which has not yet materialized, and this has hindered access to these important papers. Permission was therefore secured from the WHO to publish them here.

This paper questions the distinction between egalitarianism and prioritarianism, arguing that it is important to separate the reasons for particular social preferences from the contents of these preferences, that it is possible to like equality and separability simultaneously, and that some egalitarians and prioritarians may therefore share the same social preferences (though for different reasons). The case of risky prospects, for which Broome has proposed an interesting example meant to show that egalitarians and prioritarians cannot share the same preferences, is scrutinized. The levelling down objection is also examined.

Both egalitarianism and prioritarianism give value to equality. Prioritarianism has an additively separable value function whereas egalitarianism does not. I show that in some cases prioritarianism and egalitarianism necessarily have different implications: I describe two alternatives G and H such that egalitarianism necessarily implies G is better than H whereas prioritarianism necessarily implies G and H are equally good. I also raise a doubt about the intelligibility of prioritarianism.

The question for those who are concerned with inequalities is not whether to be an egalitarian or a prioritarian. That choice is mislabelled and misconceived. The relevant question is why distributive inequalities are of more than merely instrumental importance with respect to unrelated goals, such as maximizing well-being. The answer is that lessening inequalities in well-being serves a fundamental commitment to equality of moral status. Depending on the circumstances and what is to be distributed, the underlying concern with equality of moral status (coupled with non-distributional concerns about deprivation) might make one resemble a prioritarian, a non-prioritarian egalitarian, or neither.

I address an overlooked question about the structure of the cognitive/conative model of the mind that underlies much of the work in economics, psychology and philosophy: namely, whether conative states are fundamentally monistic (desire-like) or comparative (preference-like). I argue that two seemingly promising sets of theoretical considerations – namely, the structure of Rational Choice Theory, and considerations of computational efficiency – are unable to resolve this debate. Given this, I suggest that a consideration that speaks in favour of the preference-based view is the fact that it makes it easier to explain certain empirically observed patterns in decision making.

We propose to strengthen Popper’s notion of falsifiability by adding the requirement that when an observation is inconsistent with a theory, there must be a ‘short proof’ of this inconsistency. We model the concept of a short proof using tools from computational complexity, and provide some examples of economic theories that are falsifiable in the usual sense but not with this additional requirement. We consider several variants of the definition of ‘short proof’ and several assumptions about the difficulty of computation, and study their different implications on the falsifiability of theories.

Robert Sugden has suggested a normative standard of freedom as ‘opportunity’ that is supposed to help realign normative economics – with its traditional rational choice orientation – with behavioural economics. While allowing preferences to be incoherent, he wants to maintain the anti-paternalist stance of orthodox welfare economics. His standard, though, presupposes that people respond to uncertainty about their own future preferences by dismissing any kind of self-constraint. We argue that the approach lacks psychological substance: Sugden's normative benchmark – the ‘responsible person’ – can hardly serve as a convincing role model in a contractarian setting. An alternative concept is introduced, and some implications are briefly discussed.

This paper replies to Christian Schubert's critical review of my work on opportunity as a normative criterion. Schubert argues that the criterion I have proposed would not command general assent because it does not recognize the legitimacy of individuals’ preferences for achieving self-development by constraining their future opportunities. I argue that my account of the ‘responsible agent’ is compatible with self-development, and that preferences for self-constraint are less common than Schubert suggests. For the purposes of normative economics, my opportunity criterion is much more generally applicable than Schubert's criterion of ‘opportunity to learn’.