Population axiology concerns how to evaluate populations in regard to their goodness, that is, how to order populations by the relations \is better than" and \is as good as". This eld has been riddled with para- doxes and impossibility results which seem to show that our considered beliefs are inconsistent in cases where the number of people and their welfare varies. All of these results have one thing in common, however. They all involve an adequacy condition that rules (...) out Derek Par t's Repugnant Conclusion. Moreover, some theorists have argued that we should accept the Repugnant Conclusion and hence that avoidance of this conclusion is not a convincing adequacy condition for a population axiology. As I shall show in this chapter, however, one can replace avoid- ance of the Repugnant Conclusion with a logically weaker and intuitively more convincing condition. The resulting theorem involves, to the best of my knowledge, logically weaker and intuitively more compelling con- ditions than the other theorems presented in the literature. As such, it challenges the very existence of a satisfactory population ethics. (shrink)

Population axiology concerns how to evaluate populations in regard to their goodness, that is, how to order populations by the relations “is better than” and “is as good as”. This field has been riddled with “paradoxes” which seem to show that our considered beliefs are inconsistent in cases where the number of people and their welfare varies. Already in Derek Parfit’s seminal contribution to the topic, an informal paradox — the Mere Addition Paradox — was presented and later contributions (...) have proved similar results.1 All of these contributions, however, have one thing in common: They all involve an adequacy condition that rules out Parfit’s Repugnant Conclusion: The Repugnant Conclusion: For any perfectly equal population with very high positive welfare, there is a population with very low positive welfare which is better, other things being equal.2 A number of theorists, however, have argued that we should accept the Repugnant Conclusion and hence that avoidance of this conclusion is not a convincing adequacy condition for a population axiology. Torbjörn Tännsjö, for example, argues that the Repugnant Conclusion is not at all repugnant but rather “an unsought, but acceptable, consequence of hedonistic utilitarianism”:3.. (shrink)

The repugnant conclusion can be formulated as follows: For any population consisting of people with very high positive welfare, there is a better population in which everyone has a very low positive welfare, other things being equal. As the name indicates, this conclusion appears unacceptable. Yet it has proven to be surprisingly difficult to find a theory that avoids it without implying other very counterintuitive conclusions. Moreover, the conclusion is a problem not just for total utilitarians or (...) those committed to welfarism but for all moral theories according to which welfare matters at least when all other things are equal, which arguably is a minimal adequacy condition for any moral theory. And, not the least, how to deal with it has implications for the present generations’ duties to future generations and intergenerational justice. The question as to how the repugnant conclusion should be dealt with has thus become one of the cardinal challenges of modern ethics, and the inquiry into what it shows about the nature of ethics has opened up many new avenues for research. This chapter covers the different suggestions in the literature on how to do deal with the conclusion, both on the axiological and on the normative levels. Moreover, the conclusion and different ways of deriving it are explained in detail. (shrink)

Population axiology concerns how to evaluate populations in regard to their goodness, that is, how to order populations by the relations “is better than” and “is as good as”. This field has been riddled with impossibility results which seem to show that our considered beliefs are inconsistent in cases where the number of people and their welfare varies.1 All of these results have one thing in common, however. They all involve an adequacy condition that rules out Derek Parfit’s (...) Repugnant Conclusion: The Repugnant Conclusion: For any perfectly equal population with very high positive welfare, there is a population with very low positive welfare which is better, other things being equal.2 1 The informal Mere Addition Paradox in Parfit (1984), pp. 419ff is the locus classicus. For an informal proof of a similar result with stronger assumptions, see Ng (1989), p. 240. A formal proof with slightly stronger assumptions than Ng’s can be found in Blackorby and Donaldson (1991). For theorems with much weaker assumptions, see my (1999), (2000b), and especially (2000a), (2001), and (2009). 2 See Parfit (1984), p. 388. My formulation is more general than Parfit’s apart from that he doesn’t demand that the people with very high welfare are equally well off. Expressions such as “a population with very high positive welfare”, “a population with very low positive welfare”, etc., are elliptical for the more cumbersome phrases “a population consisting only of lives with.. (shrink)

Non-Archimedean population axiologies – also known as lexical views – claim (i) that a sufficient number of lives at a very high positive welfare level would be better than any number of lives at a very low positive welfare level and/or (ii) that a sufficient number of lives at a very low negative welfare level would be worse than any number of lives at a very high negative welfare level. Such axiologies are popular because they can avoid the (Negative) (...) Repugnant Conclusion and satisfy the adequacy conditions given in the central impossibility result in population axiology due to Gustaf Arrhenius. I provide a novel argument against them which appeals to the way that good and bad lives can intuitively outweigh one another. (shrink)

The Repugnant Conclusion served an important purpose in catalyzing and inspiring the pioneering stage of population ethics research. We believe, however, that the Repugnant Conclusion now receives too much focus. Avoiding the Repugnant Conclusion should no longer be the central goal driving population ethics research, despite its importance to the fundamental accomplishments of the existing literature.

Variable-Value axiologies avoid Parfit’s Repugnant Conclusion while satisfying some weak instances of the Mere Addition principle. We apply calibration methods to two leading members of the family of Variable-Value views conditional upon: first, a very weak instance of Mere Addition and, second, some plausible empirical assumptions about the size and welfare of the intertemporal world population. We find that such facts calibrate these two Variable-Value views to be nearly totalist, and therefore imply conclusions that should seem repugnant (...) to anyone who opposes Total Utilitarianism only due to the Repugnant Conclusion. (shrink)

This article articulates and defends a dissolution of the so-called repugnant conclusion, which focuses on the notion of life worth living figuring both in Parfit's formulation of the repugnant conclusion and in most responses to such a conclusion. The proposed dissolution demonstrates that the notion of life worth living is plagued by multiple ambiguities and that these ambiguities, in turn, hamper meaningful debate about both the issue of whether the repugnant conclusion can be avoided and the issue (...) of whether the repugnant conclusion is actually repugnant. This result does not exclude that some modified versions of the repugnant conclusion may yield valuable insights about the value of populations and the tenability of different axiological/ethical theories. Still, if the proposed dissolution is correct, then the repugnant conclusion rests on an ill-defined notion and we lack the information required to assess the merits of the repugnant conclusion. (shrink)

The spectre of the repugnant conclusion and the search for a population axiology that avoids it has endured as a focus of population ethics. This is in part because the repugnant conclusion is often interpreted as a defining problem for totalism, while the implications of averagism and related views are taken to illustrate the theoretical cost of avoiding the repugnant conclusion. However, we show that this interpretation cannot be sustained unless one focuses only on a (...) special case of the repugnant conclusion: namely, the subset of instances of the repugnant conclusion where there is no portion of the population unaffected by the choice between population outcomes (as in Derek Parfit’s original illustration). To avoid an inappropriate focus on only this proper subset of instances of the repugnant conclusion, we formulate a general characterization of the repugnant conclusion. We then prove formally that all leading welfarist axiologies imply this conclusion, including averagism and Ng’s Theory X0 , including probabilistic and ‘very repugnant’ variants that involve the addition of negative lives. We then prove that the full range of axiologies considered by population ethics each imply an extended version of the repugnant conclusion, including axiologies that are incomplete, intransitive, rank-dependent, person-affecting, and/or pluralist. The upshot is that the repugnant conclusion does not ultimately tell against any approach to axiology, and the methodological requirement to avoid the repugnant conclusion should be dropped from population axiology. (shrink)

Problems concerning future populations help us better understand what it is for one possible future, or world, to be morally better than another. The repugnant conclusion challenges traditional forms of consequentialism, including utilitarianism. A key issue is whether, per the traditional view, we make things morally better by creating additional people whose lives are worth living and by creating nonidentical better-off people in place of less well-off but distinct people. Or can we, instead, make things morally better only by (...) making things better for some particular person or another? Is the structure of morality aggregative in nature or instead person-affecting in nature? While the latter, non-traditional view may tempt us, it also seems to give rise to the nonidentity problem and various inconsistency objections. Can those problems be resolved? Questions raised by Parfit and others decades ago remain unsettled today but as critical as ever. (shrink)

It is notoriously difficult to find an intuitively satisfactory rule for evaluating populations based on the welfare of the people in them. Standard examples, like total utilitarianism, either entail the Repugnant Conclusion or in some other way contradict common intuitions about the relative value of populations. Several philosophers have presented formal arguments that seem to show that this happens of necessity: our core intuitions stand in contradiction. This paper assesses the state of play, focusing on the most powerful of (...) these ‘impossibility theorems’, as developed by Gustaf Arrhenius. I highlight two ways in which these theorems fall short of their goal: some appeal to a supposedly egalitarian condition which, however, does not properly reflect egalitarian intuitions; the others rely on a background assumption about the structure of welfare which cannot be taken for granted. Nonetheless, the theorems remain important: they give insight into the difficulty, if not perhaps the impossibility, of constructing a satisfactory population axiology. We should aim for reflective equilibrium between intuitions and more theoretical considerations. I conclude by highlighting one possible ingredient in this equilibrium, which, I argue, leaves open a still wider range of acceptable theories: the possibility of vague or otherwise indeterminate value relations. (shrink)

My thesis demonstrates that, despite a number of impossibility results, a satisfactory and coherent theory of population ethics is possible. It achieves this by exposing and undermining certain key assumptions that relate to the nature of welfare and personal identity. I analyse a range of arguments against the possibility of producing a satisfactory population axiology that have been proposed by Derek Parfit, Larry Temkin, Tyler Cowen and Gustaf Arrhenius. I conclude that these results pose a real and significant (...) challenge. However, in the absence of further evidence I reject the conclusion that they imply that the value of populations is either not precise or not transitive. Instead, I expose some fundamental assumptions behind these results. One key assumption is that something can only make a life better or worse if it makes that life better or worse for the person living it, i.e. it raises or lowers the ‘welfare level’ of that life. Although intuitively highly plausible, this assumption ignores the possibility that perspectives other than that of the person living a life may be relevant for evaluating the components of that life and that these should be incorporated into our all things considered judgements. I argue that episodes within a person’s life that are strongly psychologically connected may have a special normative significance, particularly if these episodes involve such things as the enjoyment of ‘the best things in life’ or the experience of great suffering. We have reason to assign an all things considered value to such strongly psychologically connected phases of a person’s life, where this value is not exhausted by the contributions these make to the welfare level of that person’s life as a whole. It follows that our all things considered evaluations of populations are often underdetermined by information about the welfare levels of the lives they contain. However, in certain cases, most notably in that of ‘the Repugnant Conclusion’, there is nevertheless sufficient information provided by the welfare levels of persons’ lives to allow us to infer facts about these components that make an all things considered difference to these evaluations. I argue that a failure to acknowledge these facts is the cause of the aforementioned impossibility results and that once they are taken into account it is possible to produce a satisfactory theory of population ethics. (shrink)

Population axiology includes two major arguments. The first is the repugnant conclusion, which was originally formulated by Derek Parfit to criticize total utilitarianism. The second is the sadistic conclusion. In this study, I demonstrate that no additively separable principle can avoid both repugnant and sadistic conclusions if individual moral values have no upper bound. This impossibility holds not only for utilitarian principles but also for any population principles that guarantee the separability of people’s well-being. I emphasize (...) the importance of examining non-separable principles in population ethics. (shrink)

The implications of the repugnant conclusion for consequentialist theories, such as total utilitarianism, have been extensively discussed since the work of Derek Parfit. These discussions make the paradoxes of population ethics depend on welfarist conditions, like the dominance condition (or the Pareto Principle). Thus, one might think that the repugnant conclusion is not a practical problem for deontologists, who deny that we always ought to do what produces the most aggregate welfare. In this study, we offer two (...) impossibility results using what we call the limit aggregation property. This states that when welfaristic and non-welfaristic considerations conflict, there is a threshold number of persons such that the former can override the latter as long as more people than the threshold number can enjoy increases in well-being levels. We argue that this property should be accepted even by deontologists, insofar as they do not commit themselves to the implausible absolutist position that fails to assign any moral weight to aggregate welfare. Our results therefore state that any normative population theory that is not absolutist entails (a variant of) the repugnant conclusion or some other implausible conclusion. Therefore, the repugnant conclusion must be taken seriously even by non-absolutist deontologists, not just consequentialists. (shrink)

Formal arguments have proven that avoiding the Repugnant Conclusion is impossible without rejecting one or more highly plausible population principles. To many, such proofs establish not only a deep challenge for axiology, but also pose an important practical problem of how policymaking can confidently proceed without resolving any of the central questions of population ethics. Here we offer deflationary responses: first to the practical challenge, and then to the more fundamental challenge for axiology. Regarding the practical challenge, (...) we provide an overview of recent literature that explores the implications for public policy of the Repugnant Conclusion and related puzzles within population ethics, and shows that there is more commonality in the implications of different population axiologies than is generally recognized. The upshot is that uncertainty about population ethics presents no important problem for policymaking, and the importance of population ethics to policymaking has been overstated. We then turn to more fundamental issues about axiology, and describe a new series of formal proofs that undermine the idea that any plausible axiology could avoid the Repugnant Conclusion, including those that are assumed to avoid it in the literature. The philosophical upshot is that the Repugnant Conclusion cannot plausibly be avoided, and so it is a mistake to assume as a constraint on a plausible axiology that it must be avoided, as is assumed by most of the literature in population ethics, including by all of the fundamental impossibility theorems. (shrink)

In the posthumously published ‘Future People, the Non-Identity Problem, and Person-Affecting Principles’, Derek Parfit presents a novel axiological principle which he calls the Wide Dual Person-Affecting Principle and claims that it does not imply the Repugnant Conclusion. This paper shows that even the best version of Parfit's principle cannot avoid this conclusion. That said, accepting such a principle makes embracing the Repugnant Conclusion more justifiable. This paper further addresses important questions which Parfit left unanswered concerning: the relative importance (...) of individual and collective goodness, comparisons involving unequal outcomes, how to understand individual goodness, and whether incomparability at the level of individual goodness implies incomparability at the level of overall goodness. (shrink)

We report on the mechanisation of (preference-based) conditional normative reasoning. Our focus is on Åqvist's system E for conditional obligation, and its extensions. Our mechanisation is achieved via a shallow semantical embedding in Isabelle/HOL. We consider two possible uses of the framework. The first one is as a tool for meta-reasoning about the considered logic. We employ it for the automated verification of deontic correspondences (broadly conceived) and related matters, analogous to what has been previously achieved for the modal logic (...) cube. The equivalence is automatically verified in one direction, leading from the property to the axiom. The second use is as a tool for assessing ethical arguments. We provide a computer encoding of a well-known paradox (or impossibility theorem) in population ethics, Parfit's repugnant conclusion. While some have proposed overcoming the impossibility theorem by abandoning the presupposed transitivity of ‘better than’, our formalisation unveils a less extreme approach, suggesting among other things the option of weakening transitivity suitably rather than discarding it entirely. Whether the presented encoding increases or decreases the attractiveness and persuasiveness of the repugnant conclusion is a question we would like to pass on to philosophy and ethics. (shrink)

According to the Repugnant Conclusion: Compared with the existence of many people who would all have some very high quality of life, there is some much larger number of people whose existence would be better, even though these people would all have lives that were barely worth living. I suggest some ways in which we might be able to avoid this conclusion. I try to defend a strong form of lexical superiority.

Is it better if more people live? This chapter examines the effects of population growth on existing people, overpopulation, whether a decline in the quality of life could always be made up for by a sufficient increase in the number of people living. It discusses a repugnant conclusion and the level at which lives cease to be worth living.

Lexical views in population axiology can avoid the Repugnant Conclusion without violating Transitivity or Separability. However, they imply a dilemma: either some good life is better than any number of slightly worse lives, or else the ‘at least as good as’ relation on populations is radically incomplete. In this paper, I argue that Archimedean views face an analogous dilemma. I thus conclude that the lexical dilemma gives us little reason to prefer Archimedean views. Even if we give up (...) on lexicality, problems of the same kind remain. (shrink)

Critical-Range Utilitarianism is a variant of Total Utilitarianism which can avoid both the Repugnant Conclusion and the Sadistic Conclusion in population ethics. Yet Standard Critical-Range Utilitarianism entails the Weak Sadistic Conclusion, that is, it entails that each population consisting of lives at a bad well-being level is not worse than some population consisting of lives at a good well-being level. In this paper, I defend a version of Critical-Range Utilitarianism which does not entail the Weak Sadistic (...) Conclusion. This is made possible by a fourth category of absolute value in addition to goodness, badness, and neutrality. (shrink)

In population ethics, some appeal to certain lexical and critical level total views to avoid the repugnant conclusion. Since the very repugnant conclusion is a weaker adequacy condition, we may think that these views will also allow us to avoid this conclusion. In this paper I argue that this is not the case. First, I show that the idea that some popular lexical total views could allow us to avoid the very repugnant conclusion is mistaken. (...) Then I demonstrate that the same is true of critical range total views. Finally, I clarify which views allow us to avoid this conclusion. (shrink)

On the Total Principle, the best state of affairs (ceteris paribus) is the one with the greatest net sum of welfare value. Parfit rejects this principle, because he believes that it implies the Repugnant Conclusion, the conclusion that for any large population of people, all with lives well worth living, there will be some much larger population whose existence would be better, even though its members all have lives that are only barely worth living. Recently, however, a (...) number of philosophers have suggested that the Total Principle does not imply the Repugnant Conclusion provided that a certain axiological view (namely, the ‘Discontinuity View’) is correct. Nevertheless, as I point out, there are three different versions of the Repugnant Conclusion, and it appears that the Total Principle will imply two of the three even if the Discontinuity View is correct. I then go on to argue that one of the two remaining versions turns out not to be repugnant after all. Second, I argue that the last remaining version is not, as it turns out, implied by the Total Principle. Thus, my arguments show that the Total Principle has no repugnant implications. (shrink)

Two related asymmetries have been discussed in relation to the ethics of creating new lives: First, we seem to have strong moral reason to avoid creating lives that are not worth living, but no moral reason to create lives that are worth living. Second, we seem to have strong moral reason to improve the wellbeing of existing lives, but, again, no moral reason to create lives that are worth living. Both asymmetries have proven very difficult to account for in any (...) coherent moral framework. I propose an impersonal population axiology to underpin the asymmetries, which sidesteps the problematic issue of whether or not people can be harmed or benefited by creation or non-creation. This axiology yields perfect asymmetry from a deliberative perspective, in terms of expected value. The axiology also yields substantial asymmetry for large and realistic populations in terms of their actual value, beyond deliberative relevance. (shrink)

According to Finite Fine-grainedness (roughly), there is a finite sequence of intuitively small differences between any two welfare levels. The assumption of Finite Fine-grainedness is essential to Gustaf Arrhenius’s favored sixth impossibility theorem in population axiology and plays an important role in the spectrum argument for the (Negative) Repugnant Conclusion. I argue that Theravāda Buddhists will deny Finite Fine-grainedness and consider the space that doing so opens up—and fails to open up—in population axiology. I conclude with a (...) lesson for population axiology that generalizes beyond the Buddhist context: to plausibly deny Finite Fine-grainedness, we must locate a welfare good—such as the good of awakening (bodhi)—with some rather esoteric axiological properties. (shrink)

Fred Feldman has proposed a desert-adjusted version of utilitarianism,, as a plausible population axiology. Among other things, he claims that justicism avoids Derek Parfit's. This paper explains the theory and tries to straighten out some of its ambiguities. Moreover, it is shown that it is not clear whether justicism avoids the repugnant conclusion and that it is has other counter-intuitive implications. It is concluded that justicism is not convincing as a population axiology.

According to Critical-Level Views in population axiology, an extra life improves a population only if that life’s welfare exceeds some fixed ‘critical level.’ An extra life at the critical level leaves the new population equally good as the original. According to Critical-Range Views, an extra life improves a population only if that life’s welfare exceeds some fixed ‘critical range.’ An extra life within the critical range leaves the new population incommensurable with the original. -/- In (...) this paper, I sharpen some old objections to these views and offer some new ones. Critical-Level Views cannot avoid certain Repugnant and Sadistic Conclusions. Critical-Range Views imply that lives featuring no good or bad components whatsoever can nevertheless swallow up and neutralise goodness or badness. Both classes of view entail that certain small changes in welfare correspond to worryingly large differences in contributive value. -/- I then offer a view that retains much of the appeal of Critical-Level and Critical-Range Views while avoiding the above pitfalls. On the Imprecise Exchange Rates View, the quantity of some good required to outweigh a given unit of some bad is imprecise. This imprecision is the source of incommensurability between lives and populations. (shrink)

This article explores the main similarities and differences between Derek Parfit’s notion of imprecise comparability and a related notion I have proposed of parity. I argue that the main difference between imprecise comparability and parity can be understood by reference to ‘the standard view’. The standard view claims that 1) differences between cardinally ranked items can always be measured by a scale of units of the relevant value, and 2) all rankings proceed in terms of the trichotomy of ‘better than’, (...) ‘worse than’, and ‘equally good’. Imprecise comparability, which can be understood in terms of the more familiar notions of cardinality and incommensurability, rejects only the first claim while parity rejects both claims of the standard view. -/- I then argue that insofar as those attracted to imprecise comparability assume that all rankings are trichotomous, as Parfit appears to, the view should be rejected. This is because imprecise equality is not a form of equality but is a sui generis ‘fourth’ basic way in which items can be ranked. We should, I argue, understand imprecise equality as parity, and imprecise comparability as entailing ‘tetrachotomy’ – that if two items are comparable, one must better than, worse than, equal to, or on a par with the other. Thus those attracted to the idea that cardinality can be imprecise should abandon trichotomy and accept parity and tetrachotomy instead. -/- Finally, I illustrate the difference between Parfit’s trichotomous notion of imprecise comparability and parity by examining how each notion might be employed in different solutions to the problem posed by the Repugnant Conclusion in population ethics. I suggest that parity provides the arguably more ecumenical solution to the problem. (shrink)

When Derek Parfit in Reasons and Persons, examined whether the Non-Identity Problem could be solved with the Impersonal Total Principle, he assumed perfect equality in the future population outcomes under his consideration. His thinking was that this assumption could not distort his reasoning, but would make it more simple and clear. He then reasoned that the best future population outcome, according to the Impersonal Total Principle, would be an enormous population, whose members have lives only barely worth (...) living, as a slight lowering in quality of life, according to the principle, can always be more than compensated for by an increase in the number of future people. He found this result impossible to believe and dubbed it the Repugnant Conclusion, concluding that his attempts had ended in failures and that the Non-Identity Problem continues to undermine our beliefs of our obligations to the future. The purpose of this paper is to examine the implications of the Impersonal Total Principle in real-world circumstances where the inevitability of inequality is taken into account. What, if anything, will this imply regarding the Repugnant Conclusion, the indirect version of the Non-Identity Problem and our abilities to ground our moral responsibilities to posterity in an ethical theory? (shrink)

Parfit’s Repugnant Conclusion argues, against intuition, that for any world A, another world Z with higher population and minimal well-being is better. That intuition is incorrect because the argument has not considered resources that support well-being. Z must have many more resources supporting well-being than A does. Z is repugnant because it spreads those resources among too many people; another world with Z’s resources and fewer people, if available, would be far superior. But Z is still better (...) than A; it is worth accepting its very large population to get the resources needed to support their well-being. (shrink)

A vcry important question raised by Dcrck Parfit in the part 0i` Reasons and Persons which dcals with population ethics is how t0 compare thc future outcomes 0i` those policies which differ in thc way they afTcct population growth} Such comparisons arc complicated by the fact that thcsc 0utcomcs may differ not only in thc avcragc Icvcls 0f well-being they gcncratc but also in thc identity and number 0i` thc persons who cxist.

Recently, Derek Parfit has offered a novel solution to the “Repugnant Conclusion” that compared with the existence of many people whose quality of life would be very high, there is some much larger number of people whose existence would be better but whose lives would be barely worth living. On this solution, qualitative differences between two populations will often entail that the populations are merely “imprecisely” comparable. According to Parfit, this fact allows us to avoid the Repugnant Conclusion (...) without violating the transitivity of better than. In this paper, I argue that Parfit’s view nevertheless implies two objectionable conclusions. The first is an alternative version of the Repugnant Conclusion that, Parfit suggests, may not be all that repugnant. The second is a revised version of the first that is nearly identical to the Repugnant Conclusion. I conclude that Parfit’s view offers no escape from repugnance. (shrink)

The passage of Mill’s Utilitarianism that sets out the condition in which one pleasure has a superior quality than another stokes interpretive controversy. According to the Lexical Interpretation, Mill takes one pleasure, P1, to be of a superior quality than another, P2, if, and only if, the smallest quantity of P1 is more valuable than any finite quantity of P2. This paper argues that, while the Lexical Interpretation may be supported with supplementary evidence, the passage itself does not rule out (...) qualitative superiority without lexical dominance, as it only requires P1 to be more valuable than any quantity of P2 that it is possible for someone to experience. Some will object that this concession to opponents of the Lexical Interpretation still renders Mill’s condition for qualitative superiority too demanding to be plausible. However, if Mill’s qualitative rankings apply to higher-order pleasures taken in modes of existence as such rather than to the pleasures of different activities chosen from within these modes, the objection loses much of its force. One upshot is that Mill may have more to contribute to debates in contemporary population axiology than is usually acknowledged. (shrink)

Two objects of valuation are said to be incommensurable if neither is better than the other, nor are they equally good. This negative, coarse-grained characterization fails to capture the nuanced structure of incommensurability. We argue that our evaluative resources are far richer than orthodoxy recognizes. We model value comparisons with the corresponding class of permissible preference orderings. Then, making use of our model, we introduce a potentially infinite set of degrees of approximation to better, worse, and equally good, which we (...) interpret as degrees of commensurability.One payoff is the solution our approach provides to a paradox in population ethics, generated by Parfit's “Continuum Argument”. Parfit imagines a sequence of populations, starting with one consisting of excellent lives and, by a sequence of apparent improvements, reaching a much larger population of lives barely worth living. What he dubs “the Repugnant Conclusion” is that the final population is better than the first. Developing Parfit's response, we argue that some of the populations in the sequence are merely almost better than their immediate predecessors. Almost better is not transitive (unlike better). We offer analogies to other ‘spectrum arguments’, Condorcet's paradox, and to developments in formal epistemology. (shrink)

One of Derek Parfit’s greatest legacies was the search for Theory X, a theory of population ethics that avoided all the implausible conclusions and paradoxes that have dogged the field since its inception: the Absurd Conclusion, the Repugnant Conclusion, the Non-Identity Problem, and the Mere Addition Paradox. In recent years, it has been argued that this search is doomed to failure and no satisfactory population axiology is possible. This chapter reviews Parfit’s life’s work in the field and (...) argues that he provided all the necessary components necessary for a Theory X. It then shows how these components can be combined together and applied to the global challenges Parfit argued matter most: preventing human extinction, managing catastrophic risks, and eradicating global poverty and suffering. Finally, it identifies a number of challenges facing his theory and suggests how these may be overcome. (shrink)

In Chapter 17 of his magnificent Reasons and Persons, Derek Parfit asks what he describes as an ‘awesome question’: ‘How many people should there ever be?’ For a utilitarian like me, the answer seems simple: there should be however many people it takes to make the world best. Unfortunately, if I answer Parfit's awesome question in this way, I may sink myself in a quagmire of axiological confusion. In this paper, I first describe certain aspects of the quagmire. Then I (...) introduce and explain some of the elements of a novel axiological view – ‘justicism’. Justicism is derived from some ideas originally suggested by Franz Brentano. It was developed in an effort to solve certain other problems confronting utilitarianism – problems explicitly about justice. I think, however, that as a sort of happy by-product, justicism also generates a plausible answer to Parfit's awesome question. This may come as a bit of surprise, since justicism is a form of totalism, and it is widely thought that no totalistic theory can provide a satisfactory answer to Parfit's question. After presenting and explaining my proposed solution, I address some objections. (shrink)

Derek Parfit has famously pointed out that ‘total’ utilitarian views, such as classical hedonistic utilitarianism, lead to the conclusion that, to each population of quite happy persons there corresponds a more extensive population with people living lives just worth living, which is better. In particular, for any possible population of at least ten billion people, all with a very high quality of life, there must be some much larger imaginable population whose existence, if other things are (...) equal, would be better, even though its members have lives that are barely worth living. This world is better if the sum total of well-being is great enough, and it is great enough if only enough sentient beings inhabit it. This conclusion has been considered by Parfit and others to be ‘repugnant’. (shrink)

Derek Parfit defends the Imprecise Lexical View as a way to avoid the Repugnant Conclusion. Allowing for ‘imprecise equality’, Parfit argues, makes it possible to avoid some well-known problems for the Lexical View. It is demonstrated that the Lexical View has stronger implications than envisaged by Parfit; moreover, his assumption of Non-diminishing Marginal Value makes the Lexical View collapse into a much stronger view, which lets the two appear incompatible. Introducing imprecise equality does not address the latter problem. But (...) it does makes it possible for the Imprecise Lexical View to soften the discontinuities it would otherwise face, at the cost of blurring the difference between options.However, if Non-diminishing Marginal Value is rejected, the remaining complications for the resulting most plausible version of the Imprecise Lexical View, including a confrontation with Arrhenius’ Non-Elitism Condition, may be within a range where the view largely remains defensible. (shrink)

As the title of this paper indicates, I’m going to discuss what we ought to do in situations where our actions affect future generations. More specifically, I shall focus on the moral problems raised by cases where our actions affect who’s going to live, their number and their well being. I’ll start, however, with population axiology. Most discussion in population ethics has concentrated on how to evaluate populations in regard to their goodness, that is, how to order populations (...) by the relations “is better than” and “is as good as”. This field has been riddled with “paradoxes” which purport to show that our considered beliefs are inconsistent in cases where the number of people and their welfare varies. Derek Parfit’s Mere Addition Paradox is a case in point. The main question of my paper concerns the implication of such axiological paradoxes for normative theories. Do the axiological paradoxes translate into paradoxes for normative theories or will they, as some believe, disappear if we switch to a normative framework? (shrink)

Totalism is the view that one distribution of well-being is better than another just in case the one contains a greater sum of well-being than the other. Many philosophers, following Parfit, reject totalism on the grounds that it entails the repugnant conclusion: that, for any number of excellent lives, there is some number of lives that are barely worth living whose existence would be better. This paper develops a theory of welfare aggregation—the lexical-threshold view—that allows totalism to avoid the (...) repugnant conclusion, as well as its analogues involving suffering populations and the lengths of individual lives. The theory is grounded in some independently plausible views about the structure of well-being, identifies a new source of incommensurability in population ethics, and avoids some of the implausibly extreme consequences of other lexical views, without violating the intuitive separability of lives. (shrink)

Arrhenius’s impossibility theorems purport to demonstrate that no population axiology can satisfy each of a small number of intuitively compelling adequacy conditions. However, it has recently been pointed out that each theorem depends on a dubious assumption: Finite Fine-Grainedness. This assumption states that there exists a finite sequence of slight welfare differences between any two welfare levels. Denying Finite Fine-Grainedness makes room for a lexical population axiology which satisfies all of the compelling adequacy conditions in each (...) theorem. Therefore, Arrhenius’s theorems fail to prove that there is no satisfactory population axiology. In this paper, I argue that Arrhenius’s theorems can be repurposed. Since all of our population-affecting actions have a non-zero probability of bringing about more than one distinct population, it is population prospect axiologies that are of practical relevance, and amended versions of Arrhenius’s theorems demonstrate that there is no satisfactory population prospect axiology. These impossibility theorems do not depend on Finite Fine-Grainedness, so lexical views do not escape them. (shrink)

A set of arguments shows that either the Repugnant Conclusion and its variants are true or the better-than relation isn't transitive. Which is it? This is the most important question in population ethics. The answer will point the way to Parfit's elusive Theory X.

A foundational problem in population ethics is the “repugnant conclusion", introduced by Derek Parfit in Reasons and Persons. It holds that for any possible population of at least ten billion lives of very high positive welfare, there is some larger possible population of lives of very low positive welfare whose existence would be better, if other things are equal. I call this claim RC1. In this article, I argue that by carefully considering the nature and variety (...) of possible lives of very low positive welfare, and distinguishing RC1 from a related but stronger claim I call RC2, we can show that RC1 is more acceptable than it first appears. It has been claimed that perfectionism— that is, a special concern for the best things in life—is a reason to reject the repugnant conclusion. I argue that although perfectionism gives us a reason to reject RC2, it does not give us any reason to reject, and might in fact support, RC1. In his last two papers on the subject, Parfit develops a strategy for avoiding the repugnant conclusion that appeals in part to perfectionism. In the final part of this article, I argue that Parfit’s strategy can help us avoid RC2 but not RC1. If I am right that RC1 is more acceptable than RC2, this may not be an unwelcome result. (shrink)

Population axiology concerns how to evaluate populations in terms of their moral goodness, that is, how to order populations by the relations “is better than” and “is as good as”. The task has been to find an adequate theory about the moral value of states of affairs where the number of people, the quality of their lives, and their identities may vary. So far, this field has largely ignored issues about uncertainty and the conditions that have been discussed mostly (...) pertain to the ranking of risk-free outcomes. Most public policy choices, however, are decisions under uncertainty, including policy choices that affect the size of a population. Here, we shall address the question of how to rank population prospects—that is, alternatives that contain uncertainty as to which population they will bring about—by the relations “is better than” and “is as good as”. We start by illustrating how well-known population axiologies can be extended to population prospect axiologies. And we show that new problems arise when extending population axiologies to prospects. In particular, traditional population axiologies lead to prospect-versions of the problems that they praised for avoiding in the risk-free settings. Finally, we identify an intuitive adequacy condition that, we contend, should be satisfied by any population prospect axiology, and show how given this condition, the impossibility theorems in population axiology can be extended to (non-trivial) impossibility theorems for population prospect axiology. (shrink)

Recently, in his Rolf Schock Prize Lecture, Derek Parfit has suggested a novel way of avoiding the Repugnant Conclusion by introducing what he calls “imprecision” in value comparisons. He suggests that in a range of important cases, populations of different sizes are only imprecisely comparable. Parfit suggests that this feature of value comparisons opens up a way of avoiding the Repugnant Conclusion without implying other counterintuitive conclusions, and thus solves one of the major challenges in ethics. In this (...) article, I try to clarify Parfit's proposal and evaluate whether it will help us with the paradoxes in population ethics. (shrink)

Values are incommensurable when they cannot be measured on a single cardinal scale. Many philosophers suggest that incommensurability can help us solve the problems of population ethics. I agree. But some philosophers claim that populations bear incommensurable values merely because they contain different numbers of people, perhaps within some range. I argue that mere differences in how many people exist, even within some range, do not suffice for incommensurability. I argue that the intuitive neutrality of creating happy people is (...) better captured by a version of average utilitarianism. But this view is problematic. So I suggest a version of total utilitarianism that avoids the repugnant conclusion by appealing to incommensurable dimensions of wellbeing. (shrink)

A set of arguments shows that either the Repugnant Conclusion and its variants are true or the better-than relation isn’t transitive. Which is it? This is the most important question in population ethics. The answer will point the way to Parfit’s elusive Theory X.

Jan Österberg is one of the pioneers in the field of population ethics. He started thinking about this issue already in the late 60s and he has developed one of the most original and interesting population axiologies.1 I’ve discussed the problems and drawbacks of Österberg’s theory elsewhere, and I don’t think that this is the place and time to discuss them again.2 Rather, I shall show that Österberg’s theory has a feature in common with the population axiologies (...) of such luminaries like Plato, Aristotle, Kant, Nietzsche, Wittgenstein and Heidegger, had they developed such a theory: None of these theories simultaneously satisfy five weak adequacy conditions. We shall show this by proving that no population axiology satisfies these five conditions. As a fringe benefit, this theorem also shows that the on-going project of constructing an acceptable population axiology has very gloomy prospects. 3. (shrink)

Parfit (2017) proposed a novel principle for outcome betterness in different people and different number choices. It is claimed to solve the Non-Identity Problem while avoiding the Repugnant Conclusion, and it shall do so in person-affecting rather than in impersonal terms. According to this Wide Dual Person-Affecting Principle, one of two outcomes would be (i) in one way better if this outcome would together benefit people more, and (ii) in another way better if this outcome would benefit each person (...) more. I argue that a plausible construal of this principle has two features that make it vulnerable to objections. First, the most plausible interpretation of the second part of the principle turns out to incorporate an average function. Although this helps to avoid the Repugnant Conclusion, it implausibly implies that it can be better to add further people with less bad but still miserable lives to populations consisting only of lives full of suffering. Second, the principle is not based on a comparative but on an intrinsic notion of benefit. This allows to solve the Non-Identity Problem, yet it accounts only for a weak sense of person-affecting rather than for the more substantive person-affecting intuition that it is morally significant that particular people are made better (or worse) off. Eventually, I highlight what we can, nevertheless, learn from Parfit’s idea of combining different ways in which outcomes might be better. (shrink)