Population Ethics

This paper responds to Theron Pummer’s distinction between Sorites arguments and repugnant conclusion arguments by presenting a Sorites overpopulation argument. Also I present a Sorites argument in favour of myths of genius.

Extensive measurement is the standard measurement-theoretic approach for constructing a ratio scale. It involves the comparison of objects that can be "concatenated" in an additively representable way. This paper studies the implications of extensively measurable welfare for social choice theory. We do this in two frameworks: an Arrovian framework with a fixed population and no interpersonal comparisons, and a generalized framework with variable populations and full interpersonal comparability. In each framework we use extensive measurement to introduce novel domain restrictions, independence (...) conditions, and constraints on social evaluation. We prove a welfarism theorem for the resulting domains and characterize the social welfare functions that satisfy the axioms of extensive measurement at both the individual and social levels. The main results are simple axiomatizations of strong dictatorship in the Arrovian framework and classical utilitarianism in the generalized framework. We conclude by drawing some lessons regarding the utilitarian significance of Harsanyi's aggregation theorem. (shrink)

Variable-Value axiologies propose solutions to the challenges of population ethics. These views avoid Parfit's Repugnant Conclusion, while satisfying some weak instances of the Mere Addition principle (for example, at small population sizes). We apply calibration methods to Variable-Value views while assuming: first, some very weak instances of Mere Addition, and, second, some plausible empirical assumptions about the size and welfare of the intertemporal world population. We find that Variable-Value views imply conclusions that should seem repugnant to anyone who opposes Total (...) Utilitarianism due to the Repugnant Conclusion. So, any wish to avoid repugnant conclusions is not a good reason to choose a Variable-Value view. More broadly, these calibrations teach us something about the effort to avoid the Repugnant Conclusion. Our results join a recent literature arguing that prior efforts to avoid the Repugnant Conclusion hinge on inessential features of the formalization of repugnance. Some of this effort may therefore be misplaced. (shrink)

Our universe is both chaotic and (most likely) infinite in space and time. But it is within this setting that we must make moral decisions. This presents problems. The first: due to our universe's chaotic nature, our actions often have long-lasting, unpredictable effects; and this means we typically cannot say which of two actions will turn out best in the long run. The second problem: due to the universe's infinite dimensions, and infinite population therein, we cannot compare outcomes by simply (...) adding up their total moral values - those totals will typically be infinite or undefined. Each of these problems poses a threat to aggregative moral theories. But, for each, we have solutions: a proposal from Greaves let us overcome the problem of chaos, and proposals from the infinite aggregation literature let us overcome the problem of infinite value. But a further problem emerges. If our universe is both chaotic and infinite, those solutions no longer work - outcomes that are infinite and differ by chaotic effects are incomparable, even by those proposals. In this paper, I show that we can overcome this further problem. But, to do so, we must accept some peculiar implications about how aggregation works. (shrink)

Is the overall value of a world just the sum of values contributed by each value-bearing entity in that world? Additively separable axiologies (like total utilitarianism, prioritarianism, and critical level views) say 'yes', but non-additive axiologies (like average utilitarianism, rank-discounted utilitarianism, and variable value views) say 'no'. This distinction is practically important: additive axiologies support 'arguments from astronomical scale' which suggest (among other things) that it is overwhelmingly important for humanity to avoid premature extinction and ensure the existence of a (...) large future population, while non-additive axiologies need not. We show, however, that when there is a large enough 'background population' unaffected by our choices, a wide range of non-additive axiologies converge in their implications with some additive axiology -- for instance, average utilitarianism converges to critical-level utilitarianism and various egalitarian theories converge to prioritiarianism. We further argue that real-world background populations may be large enough to make these limit results practically significant. This means that arguments from astronomical scale, and other arguments in practical ethics that seem to presuppose additive separability, may be truth-preserving in practice whether or not we accept additive separability as a basic axiological principle. (shrink)

It has been known for quite a while that traditional ethical theories have very counterintuitive and paradoxical implications for questions concerning procreation and our moral duties to future generations. Classical Utilitarianism, for example, seems to imply that we have a moral duty to procreate and that we should try to have as many off-springs as possible. More disturbingly, it implies Derek Parfit’s well-known Repugnant Conclusion.

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)

Plausibly, one important part of a good life is doing work that makes a contribution, or a positive difference to the world. In this paper, however, I explore contribution pessimism, the view that people will not always have adequate opportunities for making contributions. I distinguish between three interestingly different and at least initially plausible reasons why this view might be true: in slogan form, things might become too easy, they might become too good, or we might be too late. Now, (...) one response to these problems might be to deliberately attempt to undo them. However, I claim that this solution is intuitively misguided, and argue that explaining this supports a holistic approach to the value of contributions. Finally, I argue that if contribution pessimism is correct, it could provide an explanation of some widely held intuitions about issues in population ethics, with implications about the practical issue of how much priority we should give to addressing risks of human extinction. (shrink)

In carrying out cost-benefit or cost-effective analysis, a discount rate should be applied to some kinds of future benefits and costs. It is controversial, though, whether future health is in this class. I argue that one of the standard arguments for discounting (from diminishing marginal returns) is inapplicable to the case of health, while another (favouring a pure rate of time preference) is unsound in any case. However, there are two other reasons that might support a positive discount rate for (...) future health: one relating to uncertainty, and the other relating to the instrumental benefits of improved health. While the latter considerations could be modelled via a discount rate, they could alternatively be modelled more explicitly, in other ways; I briefly discuss which modelling method is preferable. Finally, I argue against the common claims that failing to discount future health would lead to paradox, and/or to inconsistency with the way future cash flows are treated. (shrink)

Given the deep disagreement surrounding population axiology, one should remain uncertain about which theory is best. However, this uncertainty need not leave one neutral about which acts are better or worse. We show that as the number of lives at stake grows, the Expected Moral Value approach to axiological uncertainty systematically pushes one towards choosing the option preferred by the Total and Critical Level views, even if one’s credence in those theories is low.

According to Longtermism, our acts’ expected influence on the expected value of the world is mainly determined by their effects in the far future. There is, given total utilitarianism, a straightforward argument for Longtermism due to the enormous number of people that might exist in the future, but this argument does not work on person-affecting views. In this paper, we will argue that these views might also lead to Longtermism if Prudential Longtermism is true. Prudential Longtermism holds for a person (...) if and only if our acts’ overall influence on that person’s expected well-being is mainly determined by the acts’ effects in the far future. We argue that (due to a small chance of anti-ageing and uploading) there could be an enormous amount of prudential value for some contemporary person in the far future and that value may be so large that it dominates their overall expectation of lifetime well-being. (shrink)

The following seems to be a truism in modern day philosophy: No agent can have had other parents (IDENTITY). IDENTITY shows up in discussions of moral luck, parenting, gene editing, and population ethics. In this paper, I challenge IDENTITY. I do so by showing that the most plausible arguments that can be made in favor of IDENTITY do not withstand critical scrutiny. The paper is divided into four sections. In the first, I document the prevalence of IDENTITY. In the second, (...) I examine a defense of IDENTITY on the basis of genetic considerations. In the third, I examine a defense of IDENTITY that I call gamete essentialism. In the fourth, I return to genetic considerations to wrap up the paper. (shrink)

The pessimistic hypothesis is the hypothesis that life is bad for us, in the sense that we are worse off for having come into existence. Suppose this hypothesis turns out to be correct — existence turns out to be more of a burden than a gift. A natural next thought is that we should stop having children. But I contend that this is a mistake, because in fact it would often be permissible to create new people even if the pessimistic (...) hypothesis turned out to be correct. Roughly, this is because we are often in a position to know that future people will approve of having been created, and our respect for their attitudes towards their own creation can permit us to create them. Crucially, future people’s attitudes are worthy of respect, because it is not irrational or otherwise inappropriate for them to approve of having come into existence — even if having come into existence is bad for them. (shrink)

Longtermism is the view that the most urgent global priorities, and those to which we should devote the largest portion of our resources, are those that focus on (i) ensuring a long future for humanity, and perhaps sentient or intelligent life more generally, and (ii) improving the quality of the lives that inhabit that long future. While it is by no means the only one, the argument most commonly given for this conclusion is that these interventions have greater expected goodness (...) per unit of resource devoted to them than each of the other available interventions, including those that focus on the health and well-being of the current population. In this paper, I argue that, even if we grant the consequentialist ethics upon which this argument depends, and even if we grant one of the axiologies that are typically paired with that ethics to give the argument, we are not morally required to choose an option that maximises expected utility; indeed, we might not even be permitted to do so. Instead, I will argue, if the argument's consequentialism is correct, we should choose using a decision theory that is sensitive to risk, and allows us to give greater weight to worse-case outcomes than expected utility theory does. And, I will show, such decision theories do not always recommend longtermist interventions. Indeed, sometimes, they recommend exactly the opposite: sometimes, they recommend hastening human extinction. Many, though not all, will take this as a reductio of the consequentialism or the axiology of the argument. I remain agnostic on the conclusion we should draw. (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)

In the face of an impossibility result, some assumption must be relaxed. The Mere Addition Paradox is an impossibility result in population ethics. Here, I explore substantially weakening the decision-theoretic assumptions involved. The central finding is that the Mere Addition Paradox persists even in the general framework of choice functions when we assume Path Independence as a minimal decision-theoretic constraint. Choice functions can be thought of either as generalizing the standard axiological assumption of a binary “betterness” relation, or as providing (...) a general framework for a normative (rather than axiological) theory of population ethics. Path Independence, a weaker assumption than typically (implicitly) made in population ethics, expresses the idea that, in making a choice from a set of alternatives, the order in which options are assessed or considered is ethically arbitrary and should not affect the final choice. Since the result establishes a conflict between the relevant ethical principles and even very weak decision-theoretic principles, we have more reason to doubt the ethical principles. (shrink)

The case for longtermism depends on the vast potential scale of the future. But that same vastness also threatens to undermine the case for longtermism: If the universe as a whole, or the future in particular, contain infinite quantities of value and/or disvalue, then many of the theories of value that support longtermism (e.g., risk-neutral total utilitarianism) seem to imply that none of our available options are better than any other. If so, then even apparently vast effects on the far (...) future cannot in fact make the world morally better. On top of this, some strategies for avoiding this problem of “infinitarian paralysis” (e.g., exponential pure time discounting) yield views that are much less supportive of longtermism. In this chapter, we explore how the potential infinitude of the future affects the case for longtermism. We argue that (i) there are reasonable prospects for extending risk-neutral totalism and similar views to infinite contexts and (ii) many such extension strategies will still support the case for longtermism, since they imply that when we can only effect (or only predictably affect) a finite, bounded part of an infinite universe, we can ignore the unaffectable rest of the universe and reason as if the finite, affectable part were all there is. (shrink)

Many philosophers are attracted to a complaints-based theory of the procreation asymmetry, according to which creating a person with a bad life is wrong (all else equal) because that person can complain about your act, whereas declining to create a person who would have a good life is not wrong (all else equal) because that person never exists and so cannot complain about your act. In this paper, I present two problems for such theories: the problem of impairable-life acceptance and (...) an especially acute version of the problem of improvable-life avoidance. I explain how these problems afflict two recent complaints-based theories of the procreation asymmetry, from Joe Horton and Abelard Podgorski. (shrink)

One prominent welfarist axiology, critical-level utilitarianism, says that individual lives must surpass a specified ‘critical level’ in order to make a positive contribution to the comparative status of a given population. In this article I develop a new dilemma for critical-level utilitarians. When comparatively evaluating populations composed of different species, critical-level utilitarians must decide whether the critical level is a universal threshold or whether the critical level is a species-relative threshold. I argue that both thresholds lead to a range of (...) axiological puzzles and objections as yet undiscussed within the literature, and therefore conclude that critical-level utilitarianism should not be taken as a morally plausible welfarist axiology. I show that certain competitive formulations of critical range utilitarianism are subject to the argument too, and that further attempts to relativise critical levels to a particular group or category of welfare bearer are unsustainable. (shrink)

This essay introduces a new type of measure of social welfare, where populations are evaluated by their resemblance to an optimum population, which is an (in principle) possible population with the highest degree of social welfare, relative to some circumstances. Here it is argued to be the largest possible population where everyone fares maximally well. The new measure is responsive to quality of welfare, equality of welfare, and the number of people. It satisfies dominance and negative monotonicity, and it avoids (...) both the repugnant conclusion and a reverse repugnant conclusion for comparisons relative to our future on earth. (shrink)

Particular persons have claims against being made worse off than they could have been. The literature, however, has focused primarily on only two-option cases; yet, these cases fail to capture all of the morally relevant factors, especially when a person’s existence is in question. This paper explores how to assess claims in multiple-option choice sets. We scrutinize the only extant proposal, offered by Michael Otsuka, which we call the Weakening View. In light of its problems, we develop an alternative: the (...) Combining View. The Weakening View holds that a person’s claim against a loss of well-being relative to one distribution is weakened by the availability of further alternatives relative to which the person gains well-being. By contrast, our view holds that a person has an overall claim for or against a certain distribution relative to the whole option set, where overall claims are second-order functions of the different pairwise claims. Finally, we defend the Combining View by exploring its implications for the impact of a person’s possible non-existence on their overall claims, and we develop a proposal for how the number of distributions relative to which a person gains or loses welfare influences the strength of their overall claims. (shrink)

According to the procreation asymmetry, we have strong pro tanto reason to do what prevents someone from coming into a miserable existence—an existence so bad that it would be rational to prefer having never been born—solely because it prevents them from coming into a miserable existence, but we do not have strong pro tanto reason to do what allows someone to come into a happy existence solely because it allows them to come into a happy existence. At best, the fact (...) that an act would create a happy person merely offsets the reasons we have to avoid that act—i.e., an act that would be impermissible because it brings a miserable person into existence could be rendered permissible if it also brought into existence enough happy people. In this paper, I first argue that there is an intuitive asymmetry in the offsetting weight of happy humans and the offsetting weight of happy animals: the offsetting weight of happy animal lives vis-à-vis miserable animal lives appears to be greater than the offsetting weight of happy human lives vis-à-vis miserable human lives. This is the Procreation Asymmetry Asymmetry. I then argue that there is no Procreation Asymmetry Asymmetry. The best explanation of why happy human lives have only weak offsetting weight implies that happy animal lives also have only weak offsetting weight. (shrink)

ABSTRACT Average utilitarianism and several related axiologies, when paired with the standard expectational theory of decision-making under risk and with reasonable empirical credences, can find their practical prescriptions overwhelmingly determined by the minuscule probability that the agent assigns to solipsism—that is, to the hypothesis that there is only one welfare subject in the world, namely, herself. This either (i) constitutes a reductio of these axiologies, (ii) suggests that they require bespoke decision theories, or (iii) furnishes an unexpected argument for ethical (...) egoism. (shrink)

This thesis consists of a series of papers in population ethics: a subfield of normative ethics concerned with the distinctive issues that arise in cases where our actions can affect the identities or number of people of who ever exist. Each paper can be read independently of the others. In Chapter 1, I present a dilemma for Archimedean views in population axiology: roughly, those views on which adding enough good lives to a population can make that population better than any (...) other. In Chapter 2, I extend Gustaf Arrhenius’s famous impossibility theorems in population axiology into the domain of choices under risk. My risky impossibility theorems dispense with the assumption that welfare levels are finitely fine-grained, and so tell against lexical views in population axiology. In Chapter 3, I present objections to critical-level and critical-range views in population axiology. I then sketch out what I call the ‘Imprecise Exchange Rates View’ and argue that it is an attractive alternative. In Chapter 4, I address critical-level and critical-range views again. This time, I note that they are vulnerable to objections from biographical identity: identity between lives. I suggest that these objections give us reason to reject critical-level and critical-range views and embrace the Total View. In Chapter 5, I argue that objections of the same form – objections from personal identity – tell against person-affecting views in population ethics. In Chapter 6, I draw out some counterintuitive implications of two recent complaints-based theories of the procreation asymmetry. (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)

Is animal farming permissible when animals would have a positive welfare? The happy animal farming problem represent the paradigmatic problem in population ethics, because its simple structure introduces the most important complications of population ethics. Three new population ethical theories that avoid the counter-intuitive repugnant and sadistic conclusions are discussed and applied to the animal farming problem. Breeding farm animals would not be permissible according to these theories, except under some rather unrealistic conditions, such as those farm animals being so (...) happy that they themselves would prefer a continuation of animal farming. Given the fact that many people believe that most farm animals are not so happy and the fact that one can formulate reasonable population ethical theories that condemn happy animal farming, it can be concluded that it is better to avoid animal farming and the consumption of animal products in general. (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)

The evolutionary process involved the suffering of quadrillions of sentient beings over millions of years. I argue that when we take this into account, then it is likely that when the first humans appeared, the world was already at an enormous axiological deficit, and that even on favorable assumptions about humanity, it is doubtful that we have overturned this deficit or ever will. Even if there’s no such deficit or we can overturn it, it remains the case that everything of (...) value associated with humanity was made possible by our evolutionary history and all that animal suffering. It can seem indecent to regard all that past suffering as having been worth it simply because it was a causal precondition for our existence. But when we consider the realistic alternatives to the way evolution in fact unfolded, there is nevertheless a conditional case for regarding past sentient suffering as a kind of necessary evil. (shrink)

Discussions of the non-identity problem presuppose a widely shared intuition that actions or policies that change who comes into existence don't, thereby, become morally unproblematic. We hypothesize that this intuition isn’t generally shared by the public, which could have widespread implications concerning how to generate support for large-scale, identity-affecting policies relating to matters like climate change. To test this, we ran a version of the well-known dictator game designed to mimic the public's behavior over identity-affecting choices. We found the public (...) does seem to behave more selfishly when making identity-affecting choices, which should be concerning. We further hypothesized that one possible mechanism is the notion of harm the public uses in their decision-making and find that substantial portions of the population seem to each employ distinct notions of harm in their normative thinking. These findings raise puzzling features about the public’s normative thinking that call out for further empirical examination. (shrink)

The topic of this thesis is how we should treat tiny probabilities of vast value. This thesis consists of six independent papers. Chapter 1 discusses the idea that utilities are bounded. It shows that bounded decision theories prescribe prospects that are better for no one and worse for some if combined with an additive axiology. Chapter 2, in turn, points out that standard axiomatizations of Expected Utility Theory violate dominance in cases that involve possible states of zero probability. Chapters 3–6 (...) discuss the idea that we should ignore tiny probabilities in practical decision-making. Chapter 3 argues that discounting small probabilities solves the ‘Intrapersonal Addition Paradox’ and thus helps avoid the Repugnant Conclusion. Chapter 4 explores what the most plausible version of this view might look like and what problems the different versions have. Chapter 5 focuses on one type of problem, namely, money pumps. The Independence Money Pump, in particular, presents a difficult challenge for those who wish to discount small probabilities. Finally, Chapter 6 discusses the implications of discounting small probabilities for the value of the far future. (shrink)

I argue that the possibility of posthumous harm ought to be rejected. My argument centers on a kind of repugnancy case involving posthumous harm. Supposing the existence of posthumous harm, a person whose wellbeing was extremely high while she was alive could incur small posthumous harms over a long enough period such that it is true of that person that she had a life not worth living. I respond to various objections and in the end conclude that rejecting posthumous harm (...) is preferable to all other options. (shrink)

Current ecological threats, such as the sixth mass extinction or climate change, highlight the need to evaluate the moral implications of changing populations, both human and non-human. The paper sketches a non-anthropocentric and multispecies sufficientarian account of population ethics. After discussing several other options for multispecies population ethics, the paper proposes a two-level account of multispecies sufficientarianism, according to which the value of populations depend on two kinds of sufficientarian thresholds. First, there is a species-relativized individual-level threshold for what species-specific (...) flourishing is for an organism. Second, there is a population-level threshold for a sufficiently viable population enough to support the species-specific flourishing of the current and future members of that population. The paper concludes by discussing some of the practical implications and concerns raised by the two-level account suggested. (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)

In his restriction of prioritarianism to cases in which the same people would exist in all the possible outcomes, Parfit stakes out an unstable position, both for himself and more generally. There is no plausible rationale for a prioritarianism that is so restricted, which is consistent with the key features of Parfit’s elaboration and defence of this view and his other commitments. The principles that might be appealed to, in an attempt to justify such a restriction, give rise to a (...) different view—one that is sensitive to the presence or absence of the competing claims of different individuals, where both the existence and the magnitude of these claims are determined by gains and losses to individuals in a manner that is not fully captured by Parfit’s prioritarian weighting. (shrink)

Ethics in the tradition of Derek Parfit’s Reasons and Persons is riddled with sorites-like arguments, which lead us by what seem innocent steps to seemingly false conclusions. Take, for example, spectrum arguments for the Repugnant Conclusion that appeal to slight differences in quality of life. Several authors have taken the view that, since spectrum arguments are structurally analogous to sorites arguments, the correct response to spectrum arguments is structurally analogous to the correct response to sorites arguments. This sorites analogy is (...) here argued against. There are potential structural disanalogies between spectrum arguments and sorites arguments. But even if these arguments are relevantly structurally analogous, they differ in their content in ways that show the sorites analogy to be implausible. Two content-based disanalogies are here explored—one is inspired by Parfit’s work on reductionism, and the other involves hypersensitivity. The chapter concludes with a methodological lesson. (shrink)

Separability is roughly the principle that, in comparing the value of two outcomes, one can ignore any people whose existence and welfare are unaffected. Separability is both antecedently plausible, at least as a principle of beneficence, and surprisingly powerful; it is the key to some of the best positive arguments in population ethics. This chapter surveys the motivations for and consequences of separability. In particular, it presents an ‘additivity theorem’ which explains how separability leads to total utilitarianism and closely related (...) axiological views. It then examines systematically how this family of views can avoid the Repugnant Conclusion by incorporating lexicality, a critical level, or a neutral range. (shrink)

This chapter presents several arguments related to Parfit's notion of evaluative imprecision and his imprecisionist lexical view of population ethics. After sketching Parfit's view, it argues that, contrary to Parfit, imprecision and lexicality are both compatible with thinking about goodness in terms of positions on a scale of value. Then, by examining the role that imprecision is meant to play in defusing spectrum argument, it suggests that imprecision should be identified with vagueness. Next, it argues that there is space for (...) robust moral realists to think of evaluative vagueness as a semantic phenomenon, illustrating this view with a version of conceptual role semantics on which the precisifications of betterness are correctness conditions for the precisifications of preference. Finally, it gives a probability-based argument against the imprecisionist lexical view. (shrink)

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)

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)

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)

The non-identity problem is that some actions seem morally wrong even though, by affecting future people’s identities, they are worse for nobody. In this paper, I further develop and defend a lesser-known solution to the problem, one according to which when such actions are wrong, it is not because of what they do or produce, but rather just because of why they were performed. In particular, I argue that the actions in non-identity cases are wrong just when and because they (...) result from, or reflect in those who have performed them, a morally dubious character trait. (shrink)

What are the prospects for using population policy as tool to reduce carbon emissions? In this paper, we review evidence from population science, in order to inform debates in population ethics that, so far, have largely taken place within the academic philosophy literature. In particular, we ask whether fertility policy is likely to have a large effect on carbon emissions, and therefore on temperature change. Our answer is no. Prospects for a policy of fertility-reduction-as-climate-mitigation are limited by population momentum, a (...) demographic factor that limits possible variation in the size of the population, even if fertility rates change very quickly. In particular, a hypothetical policy that instantaneously changed fertility and mortality rates to replacement levels would nevertheless result in a population of over 9 billion people in 2060. We use a leading climate-economy model to project the consequence of such a hypothetical policy for climate change. As a standalone mitigation policy, such a hypothetical change in the size of the future population-much too large to be implementable by any foreseeable government programme-would reduce peak temperature change only to 6.4°C, relative to 7.1°C under the most likely population path. Therefore, fertility reduction is unlikely to be an adequate core approach to climate mitigation. (shrink)

The population ethics literature has long focused on attempts to avoid the repugnant conclusion. We show that a large set of social orderings that are conventionally understood to escape the repugnant conclusion do not in fact avoid it in all instances. As we demonstrate, prior results depend on formal definitions of the repugnant conclusion that exclude some repugnant cases, for reasons inessential to any "repugnance" (or other meaningful normative properties) of the repugnant conclusion. In particular, the literature traditionally formalizes the (...) repugnant conclusion to exclude cases that include an unaffected sub-population. We relax this normatively irrelevant exclusion, and others. Using several more inclusive formalizations of the repugnant conclusion, we then prove that any plausible social ordering implies some instance of the repugnant conclusion. This understanding-that it is impossible to avoid all instances of the repugnant conclusion-is broader than the traditional understanding in the literature that the repugnant conclusion can only be escaped at unappealing theoretical costs. Therefore, the repugnant conclusion provides no methodological guidance for theory or policy-making, because it does not discriminate among candidate social orderings. So escaping the repugnant conclusion should not be a core goal of the population ethics literature. (shrink)

Derek Parfit was one of the most important and influential moral philosophers of the late 20th and early 21st centuries. This Element offers a critical introduction to his wide-ranging ethical thought, focusing especially on his two most significant works, Reasons and Persons and On What Matters, and their contribution to the consequentialist moral tradition. Topics covered include: rationality and objectivity, distributive justice, self-defeating moral theories, Parfit's Triple Theory, personal identity, and population ethics.

In this essay I propose a new measure of social welfare. It captures the intuitive idea that quantity, quality, and equality of individual welfare all matter for social welfare. More precisely, it satisfies six conditions: Equivalence, Dominance, Quality, Strict Monotonicity, Equality and Asymmetry. These state that i) populations equivalent in individual welfare are equal in social welfare; ii) a population that dominates another in individual welfare is better; iii) a population that has a higher average welfare than another population is (...) better, other things being equal; iv) the addition of a well-faring individual makes a population better, whereas the addition of an ill-faring individual makes a population worse; v) a population that has a higher degree of equality than another population is better, other things being equal; and vi) individual illfare matters more for social welfare than individual welfare. By satisfying the six conditions, the measure improves on previously proposed measures, such as the utilitarian Total and Average measures, as well as different kinds of Prioritarian measures. (shrink)

The principle of Anteriority says that prospects that are identical from the perspective of every possible person’s welfare are equally good overall. The principle enjoys prima facie plausibility, and has been employed for various theoretical purposes. Here it is shown using an analogue of the St Petersburg Paradox that Anteriority is inconsistent with central principles of axiology.

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)

Nebel argues for the Repugnant Conclusion via the “Intrapersonal Repugnant Conclusion,” on which certainty of a mediocre life is better for individuals than a sufficiently small chance of an excellent life. In this article, I deny that acceptance of the Intrapersonal Repugnant Conclusion leads us to the Repugnant Conclusion. I point out that on many views which avoid the Repugnant Conclusion we should discount very small probabilities down to zero. If we do, then Nebel’s crucial premise of Ex Ante Pareto (...) fails, because discounting at the individual level can fail to match up with discounting at the population level. (shrink)

This paper develops transfinite extensions of transitivity and acyclicity in the context of population ethics. They are used to argue that it is better to add good lives, worse to add bad lives, and equally good to add neutral lives, where a life's value is understood as personal value. These conclusions rule out a number of theories of population ethics, feed into an argument for the repugnant conclusion, and allow us to reduce different-number comparisons to same-number ones. Challenges to these (...) arguments are addressed, including the issue of comparing existence and non-existence in terms of personal value, the possibility of minimal quanta of time and life, and the meaningfulness of measuring closeness between outcomes with different population sizes. An asymmetry is uncovered between transfinite cycles of worseness and betterness, supporting a version of the weak procreative asymmetry. Transfinite transitivity principles are also favourably compared to the better-known principles of continuity. (shrink)