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 poses a conundrum in population ethics that has evaded satisfactory solution for four decades. In this article, I show that the repugnant conclusion can be avoided without sacrificing any moral intuitions. The resulting framework satisfies Parfit's requirements for `theory X'. This is achieved using non-Archimedean orders, which admit the possibility of pairs of goods for which no amount of one is better than a single unit of the other. I show that with minimal assumptions, not only are (...) such goods sensible, they are compulsory. I show that utilitarianism and expected utility theory in their canonical forms are not in general suitable in this setting, and using these tools naively can lead to ethical errors that are arbitrarily serious. Multi-dimensional lexicographic expected utility representations may be required. I use fuzzy sets to show that there needn't be a clear boundary separating goods that are not Archimedean equivalent. This may be unavoidable due to intrinsic physical limits on the ability to discriminate between different goods arising from e.g. quantum mechanics. Limited discriminatory power causes preferences to be non-transitive, which can resolve problems related to so-called `fanaticism' and `recklessness' wherein `rational' decision-makers counterintuitively prefer arbitrary long shot bets to a guaranteed lesser outcome. (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)

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)

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)

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)

This thesis consists of several independent papers in population ethics. I begin in Chapter 1 by critiquing some well-known 'impossibility theorems', which purport to show there can be no intuitively satisfactory population axiology. I identify axiological vagueness as a promising way to escape or at least mitigate the effects of these theorems. In particular, in Chapter 2, I argue that certain of the impossibility theorems have little more dialectical force than sorites arguments do. From these negative arguments I move to (...) positive ones. In Chapter 3, I justify the use of a 'veil of ignorance', starting from three more basic normative principles. This leads to positive arguments for various kinds of utilitarianism - the best such arguments I know. But in general the implications of the veil depend on how one answers what I call 'the risky existential question': what is the value to an individual of a chance of non-existence? I chart out the main options, and raise some puzzles for non-comparativism, the view that life is incomparable to non-existence. Finally, in Chapter 4, I consider the consequences for population ethics of the idea that what is normatively relevant is not personal identity, but a degreed relation of psychological connectedness. In particular, I pursue a strategy based in population ethics for understanding the controversial 'time-relative interests' account of the badness of death. (shrink)

Consequentialism is thought to be in significant conflict with animal rights theory because it does not regard activities such as confinement, killing, and exploitation as in principle morally wrong. Proponents of the “Logic of the Larder” argue that consequentialism results in an implausibly pro-exploitation stance, permitting us to eat farmed animals with positive well- being to ensure future such animals exist. Proponents of the “Logic of the Logger” argue that consequentialism results in an implausibly anti-conservationist stance, permitting us to exterminate (...) wild animals with negative well-being to ensure future such animals do not exist. We argue that this conflict is overstated. Once we have properly accounted for indirect effects, such as the role that our policies play in shaping moral attitudes and behavior and the importance of accepting policies that are robust against deviation, we can see that consequentialism may converge with animal rights theory significantly, even if not entirely. (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)

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)

On person-affecting views in population ethics, the moral import of a person’s welfare depends on that person’s temporal or modal status. These views typically imply that – all else equal – we’re never required to create extra people, or to act in ways that increase the probability of extra people coming into existence. -/- In this paper, I use Parfit-style fission cases to construct a dilemma for person-affecting views: either they forfeit their seeming-advantages and face fission analogues of the problems (...) faced by their rival impersonal views, or else they turn out to be not so person-affecting after all. In light of this dilemma, the attractions of person-affecting views largely evaporate. What remains are the problems unique to them. (shrink)

Ruth Chang and Joseph Raz have both drawn far-reaching consequences for agency from the phenomenon of incommensurability. After criticizing their arguments, I outline an alternative view: if incommensurability is vagueness, then there are no substantial implications for agency, except perhaps a limited form of naturalistic voluntarism if our reasons are provided by desires.

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 (Theoria 82:110–127, 2016) responded to the Sequence Argument for the Repugnant Conclusion by introducing imprecise equality. However, Parfit’s notion of imprecise equality lacked structure. Hájek and Rabinowicz (2022) improved on Parfit’s proposal in this regard, by introducing a notion of degrees of incommensurability. Although Hájek and Rabinowicz’s proposal is a step forward, and may help solve many paradoxes, it can only avoid the Repugnant Conclusion at great cost. First, there is a sequential argument for the Repugnant Conclusion that uses (...) weaker and intuitively more compelling assumptions than the Sequence Argument, and which Hájek and Rabinowicz’s proposal only undermines, in a principled way, by allowing for implausible weight to be put on the disvalue of inequality. Second, if Hájek and Rabinowicz do put such implausible weight on the disvalue of inequality, then they will have to accept that a population A is not worse than another same sized population B even though everyone in B is better off than anyone in A. (shrink)

A major approach to the ethics of artificial intelligence is to use social choice, in which the AI is designed to act according to the aggregate views of society. This is found in the AI ethics of “coherent extrapolated volition” and “bottom–up ethics”. This paper shows that the normative basis of AI social choice ethics is weak due to the fact that there is no one single aggregate ethical view of society. Instead, the design of social choice AI faces three (...) sets of decisions: standing, concerning whose ethics views are included; measurement, concerning how their views are identified; and aggregation, concerning how individual views are combined to a single view that will guide AI behavior. These decisions must be made up front in the initial AI design—designers cannot “let the AI figure it out”. Each set of decisions poses difficult ethical dilemmas with major consequences for AI behavior, with some decision options yielding pathological or even catastrophic results. Furthermore, non-social choice ethics face similar issues, such as whether to count future generations or the AI itself. These issues can be more important than the question of whether or not to use social choice ethics. Attention should focus on these issues, not on social choice. (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)

I argue for the principle of Anonymity, according to which two populations are equally good whenever they have the same anonymous distribution of wellbeing. I first show that, given transitivity of the at-least-as-good-as relation, Anonymity is entailed by the ``Non-Identity Principle'', according to which the consequence of bringing better rather than worse lives into existence is, all else equal, better. I then argue for the Non-Identity Principle on the basis that if it were false, it would follow that we fail (...) to improve the world when we make existing people better off, while at the same time replacing worse-off future people with different better-off future people. Since this is implausible, we should accept the Non-Identity Principle, and therefore Anonymity as well. (shrink)

Traditional arguments for moral error theory are based on identifying a problem with the metaphysics of moral properties. I provide a new argument that is based on the inconsistency of first‐order moral judgments. I illustrate this using impossibility results in population axiology.

Sometimes we are interested in how groups are doing epistemically in aggregate. For instance, we may want to know the epistemic impact of a change in school curriculum or the epistemic impact of abolishing peer review in the sciences. Being able to say something about how groups are doing epistemically is especially important if one is interested in pursuing a consequentialist approach to social epistemology of the sort championed by Goldman. According to this approach we evaluate social practices and institutions (...) from an epistemic perspective based on how well they promote the aggregate level of epistemic value across a community. The aim of this paper is to investigate this concept of group epistemic value and defend a particular way of measuring it. (shrink)