In this paper, we examine the problems facing a policy maker who observes inconsistent choices made by agents who are boundedly rational. We contrast a model-less and a model-based approach to welfare economics. We make the case for the model-based approach and examine its advantages as well as some problematic issues associated with it.

We study preferences over lotteries which do not necessarily satisfy completeness. We provide a characterization which generalizes Expected Utility theory. We show in particular that various sure-thing axioms are needed to guaranteee the representability in terms of utility intervals rather than numbers, and to provide a linear interval order representation which is very much in the spirit of Expected Utility theory.

We propose a new principle of 'non-interference' applied to social welfare orderings. The principle, together with two other standard requirements, implies a strong egalitarian conclusion: the ordering must lexicographically maximize the welfare of the worst off.

We study a principle of ‘Non-Interference’ in social welfare judgements. Non-Interference captures aspects of liberal approaches (particularly a Millian approach) to social decision making. In its full generality, Non-Interference produces an impossibility result: together with Weak Pareto Optimality, it implies that a social welfare ordering must be dictatorial. However, interesting restricted versions of Non-Interference are compatible with standard social welfare orderings.

We model opportunities in society as ‘chances of success’, that is as they are commonly described by practitioners. We show that a classical liberal principle of justice together with a limited principle of social rationality imply that the social objective should be to maximise the chance that everybody in society succeeds. Technically, this means using a ‘Nash’ welfare criterion. A particular consequence is that the failure of even only one individual must be considered maximally detrimental. We also study a refinement (...) of this criterion and its extension to problems of intergenerational justice. (shrink)

We analyse the liberal ethics of noninterference in social choice. A liberal principle, capturing noninterfering views of society and inspired by John Stuart Mill's conception of liberty, is examined. The principle expresses the idea that society should not penalise individuals after changes in their situation that do not affect others. An impossibility for liberal approaches is highlighted: every social decision rule that satisfies unanimity and a general principle of noninterference must be dictatorial. This raises some important issues for liberal approaches (...) in social choice and political philosophy. (shrink)

Sufficientarianism is a prominent approach to distributive justice in political philosophy and in policy analyses. However, it is virtually absent from the formal normative economics literature. We analyze sufficientarianism axiomatically in the context of the allocation of 0–1 normalized well-being in society. We present three characterizations of the core sufficientarian criterion, which counts the number of agents who attain a “good enough” level of well-being. The main characterization captures the “hybrid” nature of the criterion, which embodies at the same time (...) a threshold around which the worst off in society is prioritized, and an indifference to equality in other regions. The other two characterizations relate sufficientarianism, respectively, to a liberal principle of noninterference and to a classic neutrality property. (shrink)

In this paper we deal with the extension of Nash bargaining theory to nonconvex problems. By focussing on the Social Welfare Ordering associated with a bargaining solution, we characterize the symmetric Nash Bargaining Solution (NBS). Moreover, we obtain a unified method of proof of recent characterization results for the asymmetric single-valued NBS and the symmetric multivalued NBS, as well as their extensions to different domains.

This paper provides an ethical intepretation of the Nash choice rule. In a setting in which (cardinal) utilities are interpersonally comparable, this procedure is characterised by an impartiality requirement and by the assumption that choices are not responsive to the agents' relative ability to convert resources into utility.

We formulate and investigate experimentally a model of how individuals choose between time sequences of monetary outcomes. The model assumes that a decision maker uses, sequentially, two criteria to screen options. Each criterion only permits a decision between some pairs of options, while the other options are incomparable according to that criterion. When the first criterion is not decisive, the decision maker resorts to the second criterion to select an alternative. We find that: (1) traditional economic models based on discounting (...) alone cannot explain a significant (almost 30%) proportion of the data no matter how much variability in the discount functions is allowed; (2) our model, despite considering only a specific (exponential) form of discounting, can explain the data much better solely thanks to the use of the secondary criterion; (3) our model explains certain specific patterns in the choices of the “irrational” people. We reject the hypothesis that anomalous behavior is due simply to random “mistakes” around the basic predictions of discounting theories: deviations are not random and there are clear systematic patterns of association between “irrational” choices. (shrink)