The Pareto principle of optimal inequality

inequality aversion, Pareto principle, uncertainty, time consistency

Justifying Social Discounting: The Rank-Discounted Utilitarian Approach

The discounted utilitarian criterion for infinite horizon social choice has been criticized for treating generations unequally. We propose an extended rank-discounted utilitarian (ERDU) criterion instead. The criterion amounts to discounted utilitarianism on non-decreasing streams, but it treats all generations impartially: discounting becomes the mere expression of intergenerational inequality aversion. We show that more inequality averse ERDU societies have higher social discount rates when future generations are better-off. We apply the ERDU approach in two benchmark economic growth models and prove that it promotes sustainable policies that maximize discounted utilitarian welfare.intergenerational equity, social discounting, discounted utilitarianism, sustainability

Social rationality, separability, and equity under uncertainty

Harsanyi (1955) proved that, in the context of uncertainty, social ratio- nality and the Pareto principle impose severe constraints on the degree of priority for the worst-off that can be adopted in the social evaluation. Since then, the literature has hesitated between an ex ante approach that relaxes rationality (Diamond (1967)) and an ex post approach that fails the Pareto principle (Hammond (1983), Broome (1991)). The Hammond-Broome ex post approach conveniently retains the separable form of utilitarianism but does not make it explicit how to give priority to the worst-off, and how much disre- spect of individual preferences this implies. Fleurbaey (2008) studies how to incorporate a priority for the worst-off in an explicit formulation, but leaves aside the issue of ex ante equity in lotteries, retaining a restrictive form of consequentialism. We extend the analysis to a framework allowing for ex ante equity considerations to play a role in the ex post approach, and find a richer configuration of possible criteria. But the general outlook of the Harsanyian dilemma is confirmed in this more general setting.risk, inequality, social welfare, ex ante, ex post, fairness, Harsanyi theorem

The benefits of cooperation under uncertainty: the case of climate change

This article presents an analysis of the behavior of countries defining their climate policies in an uncertain context. The analysis is made using the S-CWS model, a stochastic version of an integrated assessment growth model. The model includes a stochastic definition of the climate sensitivity parameter. We show that the impact of uncertainty on policy design critically depends on the shape of the damage function. We also examine the benefits of cooperation in the context of uncertainty: we highlight the existence of an additional benefit of cooperation, namely risk reduction.cooperation, uncertainty, climate change, integrated assessment model

Probability Adjusted Rank-Discounted Utilitarianism

We propose and axiomatize probability adjusted rank-discounted critical-level generalized utilitarianism (PARDCLU). We thus generalize rank-discounted utilitarianism (RDU) (proposed by Zuber and Asheim, 2012) to variable population and risky situations and thereby take important steps towards preparing RDU for practical use, e.g. for evaluation of climate policies and other policy issues with long-run consequences. We illustrate how PARDCLU yields rank-dependent expected utilitarianism - but with additional structure - in a special case, and show how PARDCLU can handle a situation with positive probability of human extinction

Evaluating intergenerational risks: Probabillity adjusted rank-discounted utilitarianism

Climate policies have stochastic consequences that involve a great number of generations. This calls for evaluating social risk (what kind of societies will future people be born into) rather than individual risk (what will happen to people during their own lifetimes). As a response we propose and axiomatize probability adjusted rank-discounted critical-level generalized utilitarianism (PARDCLU), through a key axiom that requires that the social welfare order both be ethical and satisfy first-order stochastic dominance. PARDCLU is useful for evaluating intergenerational risks, is ethical in contrast to discounted utilitarianism, and avoids objections that have been raised against other ethical criteria. PARDCLU is shown to handle situations with positive probability of human extinction, and is linked to decision theory by yielding rank-dependent expected utilitarianism - but with additional structure - in a special case

Escaping the repugnant conclusion: Rank-discounted utilitarianism with variable population

Evaluation of climate policies and other issues requires a variable population setting where population is endogenously determined. We propose and axiomatize the rank-discounted critical-level utilitarian social welfare order. It is shown to fill out the space between critical-level utilitarianism and (a version of) critical-level leximin. Moreover, it satisfies many conditions and principles used to evaluate variable population criteria. In particular, it avoids the repugnant conclusion even when the critical level is zero

Escaping the repugnant conclusion: Rank-discounted utilitarianism with variable population

Evaluation of climate policies and other issues requires a variable population setting where population is endogenously determined. We propose and axiomatize the rank-discounted critical-level utilitarian social welfare order. It is shown to ll out the space between critical-level utilitarianism and (a version of) critical-level leximin. Moreover, it satis es many conditions and principles used to evaluate variable population criteria. In particular, it avoids the repugnant conclusion even when the critical level is zero

Justifying social discounting: The rank-discounted utilitarian approach

The discounted utilitarian criterion for infinite horizon social choice has been criticized for treating generations unequally. We propose an extended rank-discounted utilitarian (ERDU) criterion instead. The criterion amounts to discounted utilitarianism on non-decreasing streams, but it treats all generations impartially: discounting becomes the mere expression of intergenerational inequality aversion. We show that more inequality averse ERDU societies have higher social discount rates when future generations are better-off. We apply the ERDU approach in two benchmark economic growth models and prove that it promotes sustainable policies that maximize discounted utilitarian welfare

Inequality aversion and separability in social risk evaluation

This paper examines how to satisfy "independence of the utilities of the dead” (Blackorby et al. in Econometrica 63:1303-1320, 1995; Bommier and Zuber in Soc Choice Welf 31:415-434, 2008) in the class of "expected equally distributed equivalent” social orderings (Fleurbaey in J Polit Econ 118:649-680, 2010) and inquires into the possibility to keep some aversion to inequality in this context. It is shown that the social welfare function must either be utilitarian or take a special multiplicative form. The multiplicative form is compatible with any degree of inequality aversion, but only under some constraints on the range of individual utilitie