This article is a critical survey of the debate over the value of the social discount rate, with a particular focus on climate change. The ma- jority of the material surveyed is from the economics rather than from the philosophy literature, but the emphasis of the survey itself is on founda- tions in ethical and other normative theory rather than highly technical details. I begin by locating the standard approach to discounting within the overall landscape of ethical theory, and explaining (...) the assumptions and simplifications that are needed in order to arrive at the model that is standard in the discounting literature. The article then covers the general theory of the Ramsey equation and its relationship to observed interest rates, arguments for and against a positive rate of pure time preference, the consumption elasticity of utility, and the effect of various sorts of uncertainty on the discount rate. Finally, it turns specifically to the ap- plication of this debate to the case of climate change, focussing on the recent controversy over the low discount rate used in the Stern Review of the Economics of Climate Change. (shrink)

Can material Egalitarianism (requiring, for example, the significant promotion of fortune) include animals in the domain of the equality requirement? The problem can be illustrated as follows: If equality of wellbeing is what matters, and normal mice are included in this egalitarian requirement, then normal mice have a much stronger claim to resources than almost any human. This is because normal mice have a much stronger claim to resources than almost any human. This is because their wellbeing is much lower (...) than that of normal humans. Thus, equality of wellbeing requires a massive shift of resources away from most humans to mice. This view, however, seems crazy. I explore this problem and propose a solution. (shrink)

We do not live in a just world. This may be the least controversial claim one could make in political theory. But it is much less clear what, if anything, justice on a world scale might mean, or what the hope for justice should lead us to want in the domain of international or global institutions, and in the policies of states that are in a position to affect the world order. By comparison with the perplexing and undeveloped state of (...) this subject, domestic political theory is very well understood, with multiple highly developed theories offering alternative solutions to well-defined problems. By contrast, concepts and theories of global justice are in the early stages of formation, and it is not clear what the main questions are, let alone the main possible answers. I believe that the need for workable ideas about the global or international case presents political theory with its most important current task, and even perhaps with the opportunity to make a practical contribution in the long run, though perhaps only the very long run. (shrink)

While holist views such as ecocentrism have considerable intuitive appeal, arguing for the moral considerability of ecological wholes such as ecosystems has turned out to be a very difficult task. In the environmental ethics literature, individualist biocentrists have persuasively argued that individual organisms—but not ecological wholes—are properly regarded as having a good of their own . In this paper, I revisit those arguments and contend that they are fatally flawed. The paper proceeds in five parts. First, I consider some problems (...) brought about by climate change for environmental conservation strategies and argue that these problems give us good pragmatic reasons to want a better account of the welfare of ecological wholes. Second, I describe the theoretical assumptions from normative ethics that form the background of the arguments against holism. Third, I review the arguments given by individualist biocentrists in favour of individualism over holism. Fourth, I review recent work in the philosophy of biology on the units of selection problem, work in medicine on the human biome, and work in evolutionary biology on epigenetics and endogenous viral elements. I show how these developments undermine both the individualist arguments described above as well as the distinction between individuals and wholes as it has been understood by individualists. Finally, I consider five possible theoretical responses to these problems. (shrink)

: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. 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. (shrink)

: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.

We provide a critical assessment of the ambiguity aversion literature, which we characterize in terms of the view that Ellsberg choices are rational responses to ambiguity, to be explained by relaxing Savage's Sure-Thing principle and adding an ambiguity-aversion postulate. First, admitting Ellsberg choices as rational leads to behaviour, such as sensitivity to irrelevant sunk cost, or aversion to information, which most economists would consider absurd or irrational. Second, we argue that the mathematical objects referred to as “beliefs” in the ambiguity (...) aversion literature have little to do with how an economist or game theorist understands and uses the concept. This is because of the lack of a useful notion of updating. Third, the anomaly of the Ellsberg choices can be explained simply and without tampering with the foundations of choice theory. These choices can arise when decision makers form heuristics that serve them well in real-life situations where odds are manipulable, and misapply them to experimental settings. (shrink)

Integrated assessment models (IAMs) of climate and the economy provide estimates of the social cost of carbon and inform climate policy. With the Nested Inequalities Climate Economy model (NICE) (Dennig et al. PNAS 112:15,827–15,832, 2015), which is based on Nordhaus’s Regional Integrated Model of Climate and the Economy (RICE), but also includes inequalities within regions, we investigate the comparative importance of several factors—namely, time preference, inequality aversion, intraregional inequalities in the distribution of both damage and mitigation cost and the damage (...) function. We do so by computing optimal carbon price trajectories that arise from the wide variety of combinations that are possible given the prevailing range of disagreement over each factor. This provides answers to a number of questions, including Thomas Schelling’s conjecture that properly accounting for inequalities could lead the inequality aversion parameter to have an effect opposite to what is suggested by the Ramsey equation. (shrink)

This book presents an exploration of the idea of the common or social good, extended so that alternatives with different populations can be ranked. The approach is, in the main, welfarist, basing rankings on the well-being, broadly conceived, of those who are alive. The axiomatic method is employed, and topics investigated include: the measurement of individual well-being, social attitudes toward inequality of well-being, the main classes of population principles, principles that provide incomplete rankings, principles that rank uncertain alternatives, best choices (...) from feasible sets, and applications. The chapters are divided, with mathematical arguments confined to the second part. The first part is intended to make the arguments accessible to a more general readership. Although the book can be read as a defense of the critical-level generalized-utilitarian class of principles, comprehensive examinations of other classes are included. (shrink)

Recent debates over climate change policy have made it clear that the choice of a social discount rate has enormous consequences for the amount of mitigation that will be recommended. The social discount rate determines how future costs are to be compared to present costs. Philosophers, however, have been almost unanimous in endorsing the view that the only acceptable social rate of time preference is zero, a view that, taken literally, has either absurd or extremely radical implications. The first goal (...) of this paper is to show that the standard arguments against temporal preference are much less persuasive than they are usually taken to be. The second goal is to explore two different avenues of argument that could be adopted, in order to show that temporal discounting of welfare may be permissible. The first involves simply an application of the method of reflective equilibrium, while the second involves consideration of the way that our abstract moral commitments are institutionalized. (shrink)

There are at least two plausible generalisations of subjective expected utility (SEU) theory: cumulative prospect theory (which relaxes the independence axiom) and Levi’s decision theory (which relaxes at least ordering). These theories call for a re-assessment of the minimal requirements of rational choice. Here, I consider how an analysis of sequential decision making contributes to this assessment. I criticise Hammond’s (Economica 44(176):337–350, 1977; Econ Philos 4:292–297, 1988a; Risk, decision and rationality, 1988b; Theory Decis 25:25–78, 1988c) ‘consequentialist’ argument for the SEU (...) preference axioms, but go on to formulate a related diachronic-Dutch-book-style’ argument that better achieves Hammond’s aims. Some deny the importance of Dutch-book sure losses, however, in which case, Seidenfeld’s (Econ Philos 4:267–290, 1988a) argument that distinguishes between theories that relax independence and those that relax ordering is relevant. I unravel Seidenfeld’s argument in light of the various criticisms of it and show that the crux of the argument is somewhat different and much more persuasive than what others have taken it to be; the critical issue is the modelling of future choices between ‘indifferent’ decision-tree branches in the sequential setting. Finally, I consider how Seidenfeld’s conclusions might nonetheless be resisted. (shrink)

The Interpersonal Addition Theorem, due to John Broome, states that, given certain seemingly innocuous assumptions, the overall utility of an uncertain prospect can be represented as the sum of its individual utilities. Given ‘Bernoulli's hypothesis’ according to which individual utility coincides with individual welfare, this result appears to be incompatible with the Priority View. On that view, due to Derek Parfit, the benefits to the worse off should count for more, in the overall evaluation, than the comparable benefits to the (...) better off. Pace Broome, the paper argues that prioritarians should meet this challenge not by denying Bernoulli's hypothesis, but by rejecting one of the basic assumptions behind the addition theorem: that a prospect is better overall if it is better for everyone. This conclusion follows if one interprets the priority weights that are imposed by prioritarians as relevant only to moral, but not to prudential, evaluations of prospects. (shrink)

This paper examines explore the issues of intergenerational equity raised by climate change. A number of different reasons have been suggested as to why current generations may legitimately favor devoting resources to contemporaries rather than to future generations. These - either individually or jointly - challenge the case for combating climate change. In this paper, I distinguish between three different kinds of reason for favoring contemporaries. I argue that none of these arguments is persuasive. My answer in each case appeals (...) to the concept of human rights. It maintains that a human rights-centered perspective to climate change enables us to address each of these reasons. (shrink)

It is often stated that optimal global climate policy requires global harmonization of marginal abatement costs – i.e., a single carbon price throughout the world. Chichilnisky and Heal (1994) have shown quite generally that this is only the case if distributional issues are ignored, or if lump-sum transfers are made between countries. Else, a policy in which different regions face different carbon prices may be superior to one with a single global carbon price from a welfare point of view. Still, (...) most integrated assessment models (IAMs) assume away distributional issues and report a single optimal carbon price. We calculate utilitarian-optimal carbon prices under zero cross-regional lump-sum transfers in the multi-region IAM NICE. The result is optimal global climate policy with different regional carbon prices in which the poorest regions face initially low prices, while the richest regions face very high prices from the outset. This entails significant welfare gains over the standard single price optima commonly reported, which, as we argue briefly in conclusion, can be improved upon still by allowing international trading in the corresponding emissions allocations. (shrink)

In Human Well-Being and the Natural Environment, Partha Dasgupta explores ways to measure the quality of life. In developing quality-of-life indices, he pays particular attention to the natural environment, illustrating how it can be incorporated, more generally, into economic reasoning in a seamless manner. Professor Dasgupta puts the theory that he develops to use in extended commentaries on the economics of population, poverty traps, global warming, structural adjustment programmes, and free trade, particularly in relation to poor countries. The result is (...) a treatise that goes beyond quality-of-life measures and offers a comprehensive account of the newly emergent subject of ecological economics. (shrink)

It is a familiar argument that advocates accommodating the so-called paradoxes of decision theory by abandoning the “independence” postulate. After all, if we grant that choice reveals preference, the anomalous choice patterns of the Allais and Ellsberg problems violate postulate P2 of Savage's system. The strategy of making room for new preference patterns by relaxing independence is adopted in each of the following works: Samuelson, Kahneman and Tversky's “Prospect Theory”, Allais and Hagen, Fishburn, Chew and MacCrimmon, McClennen, and in closely (...) argued essays by Machina. (shrink)

Parfit's requirements for an ideal Theory X cannot be fully met since the Mere Addition Principle and Non-Antiegalitarianism imply the Repugnant Conclusion: Theory X does not exist. However, since the Repugnant Conclusion is really compelling, the Impersonal Total Principle should be adopted for impartial comparisons concerning future generations. Nevertheless, where our own interests are affected, we may yet choose to be partial, trading off our concern for future goodness with our self-interests. Theory X' meets all Parfit's requirements except the Mere (...) Addition Principle in less compelling cases. (shrink)

Temkin presents a new way of thinking about equality and inequality that challenges the assumptions of philosophers, welfare economists, and others, and has significant implications on both a practical and theoretical level.

_ Source: _Page Count 28 Recent debates over climate change policy have made it clear that the choice of a social discount rate has enormous consequences for the amount of mitigation that will be recommended. The social discount rate determines how future costs are to be compared to present costs. Philosophers, however, have been almost unanimous in endorsing the view that the only acceptable social rate of time preference is zero, a view that, taken literally, has either absurd or extremely (...) radical implications. The first goal of this paper is to show that the standard arguments against temporal preference are much less persuasive than they are usually taken to be. The second goal is to explore two different avenues of argument that could be adopted, in order to show that temporal discounting of welfare may be permissible. The first involves simply an application of the method of reflective equilibrium, while the second involves consideration of the way that our abstract moral commitments are institutionalized. (shrink)

KATIE McSHANE | : Taking the Fifth Assessment Report of the Intergovernmental Panel on Climate Change as representative, I argue that animal ethics has been neglected in the assessment of climate policy. While effects on ecosystem services, biodiversity, and human welfare are all catalogued quite carefully, there is no consideration at all of the effects of climate change on the welfare of animals. This omission, I argue, should bother us, for animal welfare is not adequately captured by assessments of ecosystem (...) services, biodiversity, or human welfare. After describing the paper’s assumptions and discussing the role of the IPCC’s Assessment Reports in climate policy, I consider the presentation of climate impacts in the IPCC’s Fifth Assessment Report, noting the aspects of animal welfare that are considered there, and comparing the report’s treatment of animal welfare to its treatment of human welfare. Next, I argue that the concepts of ecosystem services, biodiversity, and human welfare do not adequately capture the welfare of animals. Finally, I discuss concerns about human responsibility for animal welfare and the practicality of including considerations of animal welfare among the climate impacts studied by the IPCC. | : En prenant le Cinquième Rapport d’évaluation du Groupe d’experts intergouvernemental sur l’évolution du climat à titre de cas représentatif, je soutiens que l’éthique animale a été négligée dans l’évaluation de la politique climatique. Alors que les effets sur les services écosystémiques, la biodiversité et le bien-être humain y sont tous soigneusement recensés, les effets du changement climatique sur le bien-être des animaux n’y sont aucunement pris en considération. Je soutiens que cette omission devrait nous préoccuper, étant donné que l’évaluation des services écosystémiques, de la biodiversité et du bien-être humain ne rend pas compte adéquatement du bien-être des animaux. Après avoir décrit les présupposés de l’article et réfléchi au rôle des Rapports d’évaluation du GIEC quant à la politique climatique, j’examine la présentation des effets climatiques dans le Cinquième Rapport du GIEC, en indiquant les aspects du bien-être animal qui y sont pris en considération, tout en comparant le traitement que fait le rapport du bien-être animal à celui qui est fait du bien-être humain. Ensuite, je soutiens que les concepts de services écosystémiques, de biodiversité et de bien-être humain ne reflètent pas adéquatement le bien-être des animaux. Enfin, je traite des problèmes potentiels liés à la responsabilité humaine relativement au bien-être des animaux ainsi que de la faisabilité d’inclure des considérations liées au bien-être animal parmi les effets climatiques étudiés par le GIEC. (shrink)