By Simon Knutsson
Version from April 15, 2024, posted online April 19, 2024, addition made to acknowledgements June 15, 2024
Comments are very welcome to

Readers might have heard a story about population ethics that goes something like this: Population ethics is exceptionally difficult and important. There are paradoxes and the Repugnant Conclusion, and every position in population ethics has counterintuitive implications. Still, all things considered, it is paramount to ensure the existence of enormous populations of happy beings in the future. So the story goes.

My take on population ethics is different. For instance, I do not think that population ethics is especially difficult, and I think largely correct answers in population ethics were published a long time ago. There are details one can debate and refine, and some practical questions remain, but much of the answer has already been given.

This essay is mainly about the state of population ethics and narratives about it. Among other things, I will talk about answers from the 1990s and earlier that have gotten too little attention, debatable judgments that have contributed to the rejection of certain answers and to the conclusion that there is no satisfactory theory, and reasons why population ethics is talked about in certain ways. I hope that this essay will help to give the reader a more informed understanding of which ideas and works are out there, and contribute to the reader being in a better position to assess whether they agree with different takes on population ethics.

The most important work in population ethics where one can read much of the answer includes, in my opinion, Vetter (1969; 1971), Wolf (1996; 1997; 2004), Benatar (1997), and Fehige (1998). For example, Wolf (1997, sec. III) presents a theory about which outcomes are better and worse. According to this theory, outcomes are first ranked based on how much misery they contain. Outcomes that contain more misery are worse. If several outcomes contain the same amount of misery, then other principles can be used for further refinement to differentiate among those outcomes, but the ordering of outcomes based on misery is lexically prior. Although many non-experts have probably never heard of Wolf’s work, it might be the most spot-on academic work in population ethics, I think. There are also much older ideas in traditions such as the Epicurean tradition and 19th-century German philosophy that I think essentially give the answers in population ethics.[1]

I believe the most reasonable position in population ethics is this: Adding beings never makes things better in itself, and we have no moral reason or duty to create a being for that new being’s sake. A population size of zero is the best possible population size.[2] Positive welfare can never counterbalance illbeing (in fact, there is no such thing as positive welfare). It is always morally prohibited to try to increase positive welfare, including by enabling the existence of more beings, at the expense of increased illbeing. Considerations that speak against creating or enabling the existence of new beings include their future illbeing, the harm they will or might cause, the risks they are subjected to by existing, and their lack of consent to being created.

As mentioned, some people say that population ethics is exceptionally difficult, that there is no satisfactory theory, and that all theories have counterintuitive implications. Others, like me, disagree. The main basis for why people disagree about whether proposed answers in population ethics are satisfactory is probably differences in judgments, intuitions, and background ideas. For example, some people think that positive welfare can counterbalance others’ illbeing, and that a satisfactory theory must allow that. An example is Arrhenius’ impossibility theorems. The theorems essentially say that no theory satisfies various adequacy conditions. Most of his theorems assume that a satisfactory theory must say that an increase from positive to higher positive welfare among some individuals can counterbalance someone else’s negative welfare.[3] In my opinion, and most likely in many others’ opinions, such increases in positive welfare at the expense of someone else’s negative welfare would be immoral, and it is definitely not a feature a theory must have to be satisfactory. It is rather the opposite: a theory or view should not favour such tradeoffs. At least in part because of disagreements like that, all of Arrhenius’ impossibility theorems are non-issues for views like mine. The theorems do not show that the project of finding a satisfactory view in population ethics has gloomy prospects.

To understand why population ethics is talked about in certain ways and why some publications on it look the way they do, it seems important to consider the social, professional, and advocacy aspects related to population ethics. A simple example is self-selection effects that plausibly result in that those who choose to publish research in population ethics tend to find the topic unsolved, or they might be drawn to the topic to do academic advocacy.

Finally, are there any important remaining research questions in population ethics? Yes. If my position in population ethics is accepted, or something roughly like the positions of the aforementioned authors (Vetter, Wolf, Benatar, and Fehige), then the main direction in population ethics seems settled, yet there can still be some issues to investigate. The perhaps most important questions concern which particular behaviours related to population sizes are morally right or permissible. An example is in policy-making when one consideration is the creation or existence of future beings. Such decisions might concern international relations, the allocation of resources to the prevention of extinction, as well as new technologies with potential benefits and risks.

1 Introduction

Population ethics deals with ethical issues related to the number of beings and their welfare and identities (and perhaps other issues).[4] For example, a much-discussed matter in population ethics is the value of different populations of different sizes and with different levels of welfare. Other questions in population ethics include: Are there moral reasons to create or not create a being, considering only the welfare the created being would have? Can someone be harmed or benefited by being created?[5]

Much work in population ethics is centred around purported problems and paradoxes, and population ethics is said to be so difficult and unsolved at least in part due to such purported problems.[6] Plenty of purported problems in population ethics hinge on what is supposed to be intuitive and counterintuitive, and on particular assumptions, rather than on convincing arguments. But, of course, people have very different intuitions and make different assumptions. Some authors find the options on the table counterintuitive while other authors think that there are reasonable, intuitive options that essentially could or should be accepted. I belong to the camp that thinks there already are good, satisfactory answers in population ethics.

This essay is mainly about my take on the history and state of population ethics, as well as narratives about population ethics, although small parts of the essay are future-oriented, such as when I talk about promising future research and remedies to problems. My aim is neither to exhaustively explain arguments for and against different views in population ethics nor to argue for the views I favour.[7] I will not try to rehash the content of introductions to population ethics. Rather, I will try to give space to points that people might be unaware of and might not easily encounter elsewhere.

There is a parenting book in Sweden titled Grow Not Obey (my translation), and that title captures how I think we should approach students, beginners, and young people when it comes to population ethics. We should encourage them to read critically, think independently, and not accept appeals to authority or what “most people” think. It helps if they know relevant history, how a field works, and what interests others have in influencing them. We want them to be aware of a wide range of perspectives from diverse sources.

It has been my ambition to write in that spirit, with an emphasis on points the reader who is somewhat familiar with population ethics might have missed. I have given more space to ideas and information that I think are a combination of the most neglected, reasonable, and important, so this text is more of a complement to other texts that the reader might have read (it is not meant to be an introduction to the standard population ethics content).

I will first briefly talk about the early days of population ethics (in Section 2). Next, I give examples of what I essentially take to be the answers in population ethics (Section 3). Broadly speaking, the answers are not fond of existence or of adding new beings, and especially not of enabling more lives with more positive welfare at the expense of others’ illbeing. These answers were, to a substantial extent, published already in the first few years of population ethics in 1967–1971, and in some ways much earlier. By the 1990s, elaborate, good answers in population ethics had been published, but too little attention has been paid to these answers, in my opinion.

It seems that personal judgments and intuitions are among the main explanations as to why various authors have rejected those answers and paid little attention to some of them. Some authors are generally favourable to existence and adding beings, and hold that there is positive and negative welfare that can be traded off among different individuals. Section 4 is about such judgments, intuitions, and background ideas (hereafter, I will often merely write ‘judgments’ instead of the cumbersome phrase ‘judgments, intuitions, and background ideas’). In brief, one should at least be aware of such judgments, their roles in population ethics, and the fact that they are questionable, and one should actively assess them.

Section 5 deals with some social, professional, and advocacy aspects related to population ethics. These shed light on matters such as the history and state of population ethics, and why some texts directed at non-experts look the way they do. I then turn to remaining questions in population ethics (Section 6), and I briefly conclude in Section 7. There are also two appendices. The first appendix is about consequentialism, utilitarianism, value, and the delineation of population ethics. The second appendix concerns Arrhenius’ impossibility theorems.

Readers should not just take my word for what I write. I recommend reading original sources, including those from the 1960s to the 1990s, thinking critically for oneself, and not relying on someone else’s judgments or narrative about population ethics. I try to link to sources when they are free, and I quote a lot from the original works.

2 The early days of population ethics

How one understands the history of population ethics presumably depends in part on what one takes population ethics to be (see Appendix 1). A question is which ideas and texts in the literatures on, for example, intergenerational justice, optimum population, ethics of procreation, and antinatalism should be included in population ethics.[8] My approach in this section and essay is to focus on what is commonly talked about as ‘population ethics’, but I also try to convey that the range of ideas and texts that pertain to ethics and population is wide and sprawling.

It has been said that population ethics was born with Narveson’s article “Utilitarianism and New Generations”, which was published in 1967.[9] If I had to pick one text that marks the starting point of population ethics, I would also pick this text by Narveson. In the next few years, Narveson’s article was discussed by Sprigge (1968) and Vetter (1969; 1971). All those works talk about population issues related to utilitarianism.

Soon after Narveson’s article, there were plenty of seemingly independent publications talking about obligations to future generations from other angles (e.g., Golding 1968; 1972; Callahan 1971; Delattre 1972). There has been talk about justice, responsibility, rights, and other topics related to population and future generations at least since the 1970s.[10]

That said, the spirit of many works in what we might think of as ‘population ethics’ has seemingly mostly been in the utilitarian tradition in which Narveson and Sprigge wrote during the 1960s.[11]

3 Published answers in population ethics

Again, I think many of the answers in population ethics were published a long time ago. Here are some examples.

Already in the first text in population ethics (Narveson 1967b, 72), we can read about how there is no moral point in the existence of a human race, as such, and about a universe containing people not being morally better off than one without people.[12] Vetter (1969) reasonably accepts the consequence that as far as the utility of a potential child and the parents is concerned, it is morally preferable not to have children.[13] And Vetter (1971, 302) was right, I think, about the existence of mankind not being a value in itself:[14]

the existence of mankind is not a value in itself. On the contrary, if mankind ceases to exist, all suffering is extinguished perfectly, which no other human endeavour will be able to bring about.

Wolf (1996; 1997; 2004) correctly recognises the importance of misery and illbeing, in my opinion. His theory of obligation “forbids the purchase of bliss for some at the price of misery for others”.[15] If someone says we need a principle or theory for ordering all possible populations and outcomes with regard to their value, then even just a part of Wolf’s theory would do. Order populations and outcomes only based on how much illbeing they contain. The best population and outcome is the one with the least illbeing.[16]

Benatar (1997) talks about how children cannot be brought into existence for their own sakes, how it is impossible to get consent from people to bring them into existence, how coming into existence is a great harm, and why we might be deceiving ourselves about how things are for us.[17]

Fehige (1998, 521) writes about how “nothing can be better than an empty world”. He also provides an illuminating discussion of existence with all preferences satisfied versus existence with one frustrated preference:

It would be surprising indeed if one tiny frustration could turn a decidedly good thing into a bad thing. It can’t. Instead, the existence of the person with all her satisfied preferences is morally neutral, and one tiny preference frustration is one tiny departure from neutrality towards badness. Think of a barrel that is filled with water right to the rim. Can removing just one glass of water make the barrel less full than it could be? The answer is yes…. You can’t do any better than having no frustration, and the person who will have just one does only a little worse, just like the barrel of water is only a little emptier if you take out just one glass.[18]

Similar ideas about pleasure and happiness can be found much earlier, for example, in the Epicurean tradition and among German philosophers in the 19th century. In those literatures, we find the following ideas: Pleasure is the absence of distress, fear, irritation, pain, regret, trouble, and so on. The satisfaction of a need is never a plus, and happiness is negative in the sense of being the removal of a privation or stilling of a pain.[19] It is seemingly a small step to go from such ideas about preferences, pleasure, and happiness to answers in population ethics: there is no positive welfare, and, at least as far as the welfare of new beings goes, adding beings does not make things better and no population can be better than an empty population.

Answers in population ethics are also given by other writings on a created individual being exposed to harm, risks, and the new being’s lack of consent, as well as the harm a created being will or might cause.[20]

Of course, people disagree about whether the ideas I have mentioned in this section are correct, and there are objections.[21] I will not try to list all objections and explain why I think they are unconvincing, which would be quite a big project. Nor will I list arguments for the ideas I favour, although one could do that.[22] Rather, I will focus on what I take to be the main source of disagreements, namely different judgments. The extent to which one thinks that the ideas presented in this section are answers in population ethics, or at least that an appealing view or theory can easily be assembled from these kinds of existing ideas, probably depends to a large degree on one’s judgments. We turn to these matters in the next section.

4 Opposing judgments, intuitions, and background ideas

In this section, I will look at a few judgments, intuitions, and background ideas in population ethics. These concern whether procreation is wrong (Section 4.1), whether an empty population is the best population (Section 4.2), whether some people’s positive welfare can counterbalance someone else’s negative welfare (Section 4.3), and the assumed existence and role of positive welfare (Section 4.4).

Academic publications have typically contained optimistic judgments on these matters. That is, authors have usually judged that procreation should generally be permissible, that an empty population is not the best one, that positive welfare can counterbalance someone else’s negative welfare, and that positive welfare exists and is important.

I think those optimistic judgments have led to complications and obstacles to finding solutions in population ethics. Moreover, the existence of the judgments and the roles they play might not be obvious. Sometimes the judgments are explicit, but they can also seemingly take the form of implicit assumptions and frameworks.

Being aware of the existence of these judgments and the roles they play, as well as having critically assessed the judgments, seem to be important ingredients of having an informed view on population ethics. Depending on which judgments one agrees with, one might reach the conclusion that population ethics is unsolved or largely solved, or that there was not even much of a problem to be solved in the first place.

4.1 Creating people and antinatalism

Some speak as if it is a problem for an idea in population ethics if it implies that it is wrong to procreate. But if one finds that implication acceptable or even appropriate, there is no need to reject theories or views in population ethics because they imply antinatalism.

An early example of two authors making very different judgments, including about producing children, is Sprigge and Vetter. I have already mentioned Vetter’s ideas that it is morally preferable not to have children and that the existence of mankind is not a value in itself. Vetter (1969, 445) makes a reasonable point when he talks about not making “the admissibility of producing children a condition of adequacy for any ethics”.

In contrast, Sprigge (1968, 341) is favourable to the production of children and increasing the number of happy people:

I can see nothing particularly odd in the view that increasing the population and adding to happiness simply by adding to the number of happy people might be a morally good thing. Why should one not favour (in a moral way) there being more people to enjoy life, so long as life is enjoyable?

Sprigge talks about avoiding “the absurd consequence that production of children is almost bound to be wrong” (p. 341).

More recently, some authors speak similarly to Sprigge: as if it would be a problem for an idea in population ethics if it leads to antinatalism.[23] Frick’s (2014, 129–30) comments on the matter seem typical: If affirming an idea in population ethics forced us to embrace an argument for antinatalism, “this would be a serious strike against” the idea, “since Anti‑Natalism strikes most people as implausible”. Of course, everyone is free to make such judgments about whether antinatalism should be avoided or welcomed, but even if antinatalism would strike most people as implausible, that would be close to no argument for the position that implying antinatalism is a problem. The stance that theories in population ethics should not imply antinatalism seems more like an assumption that one can (and many do) disagree with.

I think that creating beings, such as by having children, involves so serious moral drawbacks that it should not be seen as a flaw of a theory or idea if it implies that doing so is wrong.[24] When formulating a theory or view in population ethics, there is no need to go through any trouble to formulate it so that it makes creating beings permissible in usual circumstances. There is no need to limit the range of satisfactory answers in population ethics because they imply antinatalism.

4.2 Empty populations

Similarly to the case of creation just mentioned, some seemingly want to avoid the implication that an empty population is the best population; at least essentially that implication is sometimes mentioned as an objection in population ethics.[25] Huseby (2012) defends sufficientarianism and mentions the objection that it “includes an empty world in the set of the best worlds conceivable (as far as welfare goes[)]”, and says “I do not find this very troubling. It follows from a view of welfare that I find defensible and plausible” (p. 197). I essentially agree with Huseby. I think it is not a problem for a theory or idea in population ethics if it implies that an empty population or world is the best population or world. On the contrary, it seems to be a correct verdict.

4.3 Some people’s positive welfare counterbalancing others’ illbeing

A common, crucial, and (in my opinion) implausible idea in population ethics is that some individuals’ positive welfare can counterbalance others’ illbeing. Here are two important roles that this idea of counterbalancing plays in population ethics: First, several impossibility theorems assume that some people getting higher rather than lower positive welfare can counterbalance someone else’s negative welfare. So, when someone says that impossibility theorems show that all theories in population ethics have counterintuitive implications, insofar as the speaker has these theorems in mind, the speaker seemingly considers such counterbalancing intuitive. Those of us who reject such counterbalancing do not have any problems due to those impossibility theorems; those theorems are not an obstacle to having a reasonable view in population ethics.

Second, views in population ethics that allow positive and negative welfare to simply be traded off between persons face objections such as the Very Repugnant Conclusion, while other objections have been levelled against views like mine that reject such tradeoffs. I think such objections, and more generally, tradeoffs between purported positive welfare and ills, constitute the perhaps most important issue in population ethics.[26]

The rest of this section delves further into these two roles of the idea of counterbalancing, starting with impossibility theorems.[27]

4.3.1 Arrhenius’ impossibility theorems

It has been said that the most important impossibility results are due to Arrhenius (Carlson 2022, 204). Roughly speaking, Arrhenius’ impossibility theorems say that it is impossible to satisfy different adequacy conditions. The conditions are inconsistent. Of course, the importance of an impossibility theorem hinges on whether a view in population ethics really needs to satisfy all the adequacy conditions in the theorem. I, for example, do not think so, and hence Arrhenius’ theorems are non-issues for my view.

More specifically, there is talk of Arrhenius’ six impossibility theorems (see Carlson 2015; 2022; Thomas 2016; 2018). The two first theorems, which I will discuss in Section 4.4, assume that a population with high positive welfare is at least as good as a larger population with low positive welfare. The other four theorems assume that some individuals’ increase in positive welfare can counterbalance someone else’s negative welfare. If, as I think, positive welfare cannot counterbalance an increase in negative welfare, then the last four theorems are non-issues. This includes Arrhenius’ sixth theorem, which he, according to Carlson (2015; 2022, 204), considers to be his strongest. (I talk about the impossibility theorems in more detail in Appendix 2.)

4.3.2 The Very Repugnant Conclusion and similar conclusions

Views in population ethics that embrace the idea that some individuals’ positive welfare can counterbalance others’ severe illbeing face objections of the following kind: it is implausible or even unacceptable to favour increases in positive welfare at the expense of the existence of hellish lives. Two such objections are the Very Repugnant Conclusion and Creating Hell to Please the Blissful.[28] Here is a formulation of the Very Repugnant Conclusion.

The Very Repugnant Conclusion: For any perfectly equal population with very high positive welfare, and for any number of lives with any very negative welfare, there is a population consisting of the lives with negative welfare and lives with very low positive welfare which is better than the high welfare population, other things being equal.[29]

In other words, according to the Very Repugnant Conclusion, a population with many lives in lifelong unbearable torment and many lives with very low positive welfare is better than a population in which everyone is very well off, as long as there are enough lives with very low positive welfare. If this statement is implausible (as I and plenty of others think), then it serves as an objection to the views in population ethics that imply it.

The related objection Creating Hell to Please the Blissful is what it sounds like. Essentially, it says that it is implausible that it would be an improvement to add a smaller population of maximally hellish lives and bring a vast population of almost maximally blissful lives to maximal bliss (Vinding 2021).

These questions of counterbalancing hellish lives with additional beings with purportedly positive welfare are crucial but talked about too little. For example, if a theory accepts the just-mentioned conclusions about positive welfare counterbalancing hellish lives, then that is really noteworthy. It might be the most important kind of challenge to the theory and it deserves a corresponding level of attention.

Another example is if a theory is claimed to not imply the aforementioned conclusions while it still allows some tradeoffs of positive and negative welfare between individuals. Such a theory might hold that hellish lives can be counterbalanced by additional awesome lives but neither by lives with very low positive welfare nor by increases in welfare from blissful to even more blissful. That kind of theory should presumably be scrutinised like other theories that allow some but not all tradeoffs (such as theories holding that the mildest ills but not horrible lives can be counterbalanced by positive welfare).[30] And even if a theory holds that lives need to be special and awesome to counterbalance others’ hellish or miserable lives, I would still find that counterbalancing strongly objectionable.

That said, some would strongly object to my view because it never allows purported positive welfare to counterbalance ills, and one should also question whether my view is acceptable, of course.[31]

In sum, my main points in this subsection have been to highlight the common acceptance of the idea that positive welfare can counterbalance someone else’s misery, mention serious objections to that acceptance which should be talked about more, and emphasise how crucial I think debates on such tradeoffs are for population ethics.

4.4 The assumed existence and role of positive welfare

Much has been written on issues in population ethics that concern higher versus lower positive welfare. For example, the non-identity problem, the Mere Addition Paradox, and the Repugnant Conclusion are about different levels of positive welfare.[32] The two first of Arrhenius’ six impossibility theorems also concern higher versus lower positive welfare.[33]

For someone like me who holds that there is no positive welfare, these are non-issues.[34] And so is the Asymmetry in population ethics, in its typical formulation, which is about adding lives with positive versus negative welfare.

I will now mention three ideas (or intuitions) about positive welfare that seemingly lead to supposed problems or paradoxes in population ethics.  In brief, it looks like puzzles are being created where there need not be any.

The first idea is that causing the existence of someone does not harm and is not bad for that individual as long as that individual’s lifetime welfare is positive if the alternative is that this individual never exists.[35] The created individual does not have a complaint.[36] The second idea is that adding beings with positive welfare results in a population of at least the same value (or it does not make a population worse).[37] The third idea is that it is morally important that people have higher rather than lower positive welfare.[38]

Talking about these ideas thoroughly would require much more space, so I will just make the following brief remark: In population ethics, typically when low versus high positive welfare is described a bit concretely (as opposed to the abstract term ‘low positive welfare’), the persons with low positive welfare tend to suffer, have disorders, get a bad start in life, or have low welfare due to the depletion of natural resources.[39] In other descriptions of lives with low positive welfare that do not mention things like disorders explicitly, it is still plausible that the person with supposedly low positive welfare experiences ills such as dissatisfaction and boredom. When one takes into account the ills that are commonly taken to be ingredients in lives that are said to have lower positive welfare, it seems understandable how adding them could be unethical and make the population worse, and that it matters morally that we avoid such ills.[40] If, on the other hand, we take lives with lower and higher positive welfare to contain no ills, then we could perhaps compare hypothetical completely problem-free lives with pleasant experiences to lives with even more pleasant experiences (although I reject the idea of experiences being more or less positively pleasant, see Knutsson (2022a)). Then the issues of lower versus higher positive welfare in population ethics seemingly have less of a claim to being morally and practically significant challenges, both because such problem-free lives seem unrealistic and because purported differences in welfare between completely problem-free lives seem relatively unimportant.

5 Social, professional, and advocacy aspects

In some ways, reading texts related to population ethics is similar to reading news stories or reports by a think tank. Suppose we read a news story and we have no information about how the creation and dissemination of news work, and no information about the source’s aims and incentives. Then we are probably in a worse position to critically consume that piece of news compared to if we had more context. In this section, I aim to write about some of the context for population ethics.

When we read population ethics, we should pose critical questions such as the following:

  • Why does the writer present that narrative and history of population ethics?
  • Why are certain authors, ideas, and objections mentioned but not others?

More specific questions that come to my mind include:

  • Why do people say things like that every theory in population ethics has counterintuitive implications? (And whose intuitions are they talking about?)
  • Why are the works that seem to me to give much of the answer in population ethics mentioned so little? (E.g., the works by Wolf and Fehige that I mentioned in Section 3.)
  • Why do some people talk about the Repugnant Conclusion instead of stronger objections such as the Very Repugnant Conclusion?
  • Why was a given textbook and syllabus written and why do they look the way they do?

Of course, these are a fair number of questions and the answer to each might be complicated and have many parts. Still, it seems we can at least reason about plausible partial answers to such questions.

In this section, I will distinguish between two groups of phenomena related to population ethics, although the line between them can be blurry: The first group concerns structures in academic philosophy that probably affect what we see from regular academic philosophers and others who publish research. The structures presumably contribute to how the whole research literature on population ethics looks. This is the topic of Section 5.1. The second group of phenomena concerns more strategic influence methods, which I will turn to in Section 5.2.

To be clear, my aim in this section is not to attack specific individuals. Rather, I am concerned with how things work, and I think of this section’s content as important information to be aware of. When I talk about problems, I hope that doing so can help remedy them.

5.1 Structures and mechanisms in population ethics research

There is clearly a self-selection mechanism that affects what is published in population ethics. Who chooses to write their PhD dissertation on population ethics? Who wants to spend a substantial part of their career trying to publish research in population ethics? Such a person can have different characteristics. One characteristic can be that the person finds it to be a genuinely important philosophical task that warrants being worked on. Another characteristic can be that the person thinks population ethics to be an important area for advocacy, including by academics, because large welfare amounts are at stake. It might be instrumentally important to “work” on population ethics, write about it, teach it, try to become an authority and expert on it, and influence what is published and paid attention to.

In addition to who chooses to write on the topic, we can ask similar questions about what gets published and what is considered publishable. This can lead to researchers adjusting what they write because of their beliefs about what will be publishable. In my experience, being a student and publishing in peer-review philosophy journals is much about pleasing those in a position of power over whether one’s writings are approved of or not: examiners, supervisors, anonymous reviewers, editors, and so on. I guess it is similar with applications for funding of research projects. (See also, e.g., Nesse on mechanisms in the academic world inhibiting diversity of thought and criticism of established dogmas.) Works in population ethics often appeal to intuitions, and my impression is that it is easier to get others’ approval if they share those intuitions, and if one writes as if there is a vexing problem that one is addressing.

Moreover, the history of population ethics strikes me as being to a substantial extent about who got various academic employments, who had the health, money, and desire to publish their views over and over, and who was in the right network and became talked about.

Taking into account what I have mentioned so far, one would expect to find plenty of examples of the following in the research literature:

  • emphasis on the importance of population ethics and talk as if there is a big challenge to address;
  • writings in line with the judgments and frameworks of gatekeepers;
  • advocacy and rhetoric;
  • authors with total utilitarian tendencies (who are attracted to the topic in part because of the astronomical stakes);
  • certain texts and ideas getting disproportionate attention seemingly in part because of the person behind them rather than purely because of the content (and vice versa, texts and ideas with important content getting little attention in part because the wrong person was behind them).

Of course, this is exactly what we see examples of in the research literature on population ethics.[41]

5.2 Strategic influence methods

From which perspectives can it be very important to influence what people think about population ethics? One group of perspectives are those that say things like that the existence of a billion times as many happy beings is a billion times as good (all else being equal), and they might also say that the existence of vast populations in the far future enables other purported goods such as a flourishing civilisation and scientific discoveries.[42]

Okay, but could one from that perspective not simply teach people about the putatively important issues in population ethics in a respectable way? Sure, one can imagine that. But let us also ask from which ethical perspectives it can make sense to be liberal with the truth, tendentious, and uncharitable to opposing ideas. And from which perspectives does it make sense to strategically omit information, and to try to reach novices first and give them a favourable impression of one’s own view? An answer is ethical perspectives that prescribe such behaviours in real-world scenarios when sufficient amounts of value or future welfare are at stake (whether it be positive or negative value or welfare).

We find the intersection of these perspectives in longtermism and existential risk circles and in parts of the effective altruism landscape.[43] Moreover, in these circles, there is talk of “information hazards”. I speculate that at least some of the ideas that I think make up the answers in population ethics are considered information hazards (or something close to information hazards) in these circles. Presumably, from this perspective, people getting information about these ideas might make it less likely that vast amounts of value and huge populations will be realised in the future. This might be considered a “hazard” or “risk” in the broad (and, in my opinion, strange) sense of failing to realise vast amounts of value or welfare in the far future. Therefore, it is unsurprising if this perspective can lead to strategic omissions of ideas in population ethics when someone is producing texts and syllabi.[44]

In addition, in these circles, we find the further contributing ingredients of money; accessible labour; organisational capacity; and public relations, marketing, and media strategies. There are quite a lot of relevant actors in this space, including some academic moral philosophers and organisations.

The strategic playbook seemingly has many parts, but the following seem to be some of the more important parts:

  • Reach young and uninitiated people who might be impressionable and influential in the future. So, for example, produce tendentious textbooks, introductions, syllabi, and reading lists; target students at certain universities; and edit relevant Wikipedia articles.
  • Omit information and shield the audience from undesirable information. It is preferable that the target audience does not read widely and consider what might be appealing about competing views. Use a “nothing to see here” message for competing views. Omit the strongest objections to the views being advocated. Direct readers to an ally that gives the same picture and that in turn directs the reader to further allies that reinforce the narrative. Keep the target audience in that bubble. Prevent undesirable posts in forums and try to silence writers with opposing views.
  • Be tactical about framings, rhetorics, narratives, optics, and the like for the purposes of recruitment, influence, promotion, and so on. The toolbox for furthering the agenda is rich and ranges from subtle to brazen.

Plenty has already been written about these kinds of phenomena (Knutsson 2019; Vinding 2022e; Gleiberman 2023a; 2023b; Torres 2022), and I will not go through all that. In the rest of this section, I will merely do two things: First, I will give a brief update on the secret coordination involving, among other things, which ideas and texts to mention and which ideas to keep quiet about. The update is how accepted this behaviour is at least in the academic population ethics and philosophy circles that I am most familiar with. Second, I will look at a few recent texts about population ethics and talk about related influence methods.

Let us start with the first point. As I have already written about elsewhere, some people created and spread non-public communication guidelines as a “coordinated effort” (Knutsson 2019). Even though I was employed at a public university and not any of the involved organisations, I was encouraged “to follow these guidelines for all forms of public communication, including personal blogs, social media, essays, books, talks, meetups, and scholarly publications”. Among other things, the guidelines discourage writing about or promoting the idea that the future will likely be bad. I was also told essentially that I could likely get funding in the future if I were to follow these guidelines. Around the time, one of the involved organisations made a $1,000,000 grant to another involved organisation. It looks like the recipient organisation was paid a million dollars in part to tone down its pessimism and to lobby academic and independent researchers to discourage us from writing about various ideas.

One of the two documents with guidelines says:

Written by Nick Beckstead with input and feedback from various community members and several EA organizations. These guidelines are endorsed by the following organizations and individuals:

80,000 Hours, CEA, CFAR, MIRI, Open Phil, Nick Bostrom, Will MacAskill, Toby Ord, Carl Shulman

Hilary Greaves, Will MacAskill, Toby Ord, and Nick Beckstead were listed as trustees or board members of the Centre for Effective Altruism (CEA) around the time I was encouraged to play along.[45] My impression around the time was that someone had communicated with Hilary Greaves about guidelines. All of them are moral philosophers who have written about population ethics. In the guidelines I was supposed to follow, I was encouraged to reference, among other works, texts by these same philosophers—texts that tend to be of low quality but that are favourable to the total utilitarian view in population ethics (i.e., roughly speaking, the view that the value of a population or state of affairs is calculated by taking positive welfare minus negative welfare), to the importance of extinction or existential risk reduction, and to space colonisation.[46]

As I understand the message in the guidelines and the cooperation, if I had played ball and followed the guidelines (which I never have), I should not speak favourably about the kinds of ideas one finds in, for example, Vetter (1969; 1971), Wolf (1996; 1997; 2004), Benatar (1997), and Fehige (1998), or German 19th-century pessimism for that matter. Instead, I should avoid them. Yet those are, as I have mentioned, the works in which I think much of the answer in population ethics has been published.

This way of making deals and lobbying behind the scenes and using money and favours to influence which ideas and texts in moral philosophy, including population ethics, are mentioned and argued for is shameful and weirdly brazen. It has been interesting to see how accepted this behaviour is at least in the academic population ethics and philosophy circles that I am most familiar with (based on the information I have). As far as I have seen, one can, without facing any consequences, just go ahead and make secret deals to promote and discourage philosophical ideas and get citations. Obviously, one should still not do it.[47]

I now turn to my second task in this subsection, namely talking about some influence methods related to a few recent texts about population ethics. In essence, it is much of the same old.

The following texts seem so similar in certain respects that we can talk about them all at the same time: the recent books The Precipice by Ord (2020) and What We Owe the Future by MacAskill (2022); the web page on population ethics that is a part of the “online textbook” by Chappell, Meissner, and MacAskill (2023); and the Wikipedia article on population ethics (and, to some extent, Greaves’ (2017) article “Population Axiology”). There are critiques and reviews of some of these texts,[48] and I will limit myself to merely making some brief remarks about the texts as a group (although not every remark I make necessarily applies to every text). Of course, all of the texts discuss population ethics and they are all directed at beginners. The authors seem to be allies, setting the author-less Wikipedia article aside, although it looks like it was largely written by allies. Why even mention the Wikipedia article in this group of texts? Most, perhaps all, of the authors I have just mentioned are involved in effective altruism, longtermism, and existential risk, and in such circles, it is most likely a strategy to edit relevant Wikipedia articles to promote ideas, persons, and organisations.[49] The Wikipedia article also to an absurd extent highlights and points the reader to these authors, their pet ideas, their organisations, their allies, and so on.

These texts can be used as case studies of advocacy that one can critically analyse, but they should not be used in teaching as regular literature.[50]

If we were to imagine an instruction manual for writing these kinds of texts, it could read something like this:

  • When it comes to the philosophical positions, the overall message should include selling a total view in population ethics. (The total view is also called ‘totalism’ or ‘total utilitarianism’, as in a total utilitarian population axiology.)
  • Talk about how all views have counterintuitive implications. This makes it easier for the audience to accept the total view despite its counterintuitive implications.[51]
  • Discuss the Repugnant Conclusion, which is a comparatively weak objection, as the main objection to the total view, and mention reasons why this conclusion can be acceptable. Omit stronger objections such as the Very Repugnant Conclusion or mention them only in notes or further reading where they are not so visible.[52]
  • Present person-affecting views as the main competitors. When talking about them and the Asymmetry, do so in terms of “intuition” or “slogan”, and talk about how problematic such views are.[53]
  • Omit ideas and works such as those of Wolf (1996; 1997; 2004) and Fehige (1998) that are sort of the opposite of the total view being advocated.
  • Use unspecific and unsubstantiated talk of “most people” and talk of opposing views in terms such as “extreme” and “too nihilistic and divorced from humanistic values to be worth taking seriously.”[54]
  • Mention longtermism, existential risk, and effective altruism. Point the reader to like-minded organisations, allies, and resources. Try to spread syllabi and course outlines that will bring the message to students via other teachers. Funnel readers further into the carefully crafted activism environment for deeper involvement, persuasion, and recruitment.[55]

I think it would be better if experts in the field of population ethics and neighbouring fields took a clear stance against the problematic behaviours that I and others have mentioned, even if the behaviours occur among coauthors or members of the same institution or project.

Non-experts should approach texts, videos, and the like related to population ethics with a very critical eye, similar to how one would approach texts written by a lobbyist. Of course, there are plenty of authors who seem fine and texts that one can point people to,[56] but it might be hard for a non-expert to tell whether a text is more like an ideological marketing brochure or not. Given the mix of misleading advocacy and good scholarship on the topic, it seems that a general critical approach is advisable for those who do not already know enough to be able to peer-review texts on population ethics.

6 Remaining questions

The most important remaining questions related to population ethics seemingly concern what is morally right and permissible in real life when the stakes in terms of population size and welfare are especially high (Section 6.1). In contrast, theoretical questions about weighing bads against one another do not seem especially important (Section 6.2).[57]

6.1 Practical questions about what should be done

Because I think much of the answer in population ethics was given long ago, the most important remaining questions seem to concern what to do in real life when many empirical facts and ethical considerations can come into play. I do not mean population policies that aim to change the size or composition of various populations, and I do not have in mind individual procreation decisions or policies on, for example, abortion.

In part, we get to the basic practical question of how to best reduce and alleviate severe suffering and other ills, which people have written about.[58] The effectiveness aspect of that question is perhaps not a question of ethics, but insofar as the question of how to best reduce ills includes what one should do, it becomes partly an ethical question. Yet it is such a general question that I am not sure one should call it a question especially related to population ethics.

Perhaps more closely related to population ethics (and population size and welfare, in particular), is what should be done in a wide range of situations when different considerations need to be balanced against one another and when at least one of the considerations is the creation or existence of future beings. Policy-making is one such situation but there are others. The stakes are presumably high when acts matter for ending up with one instead of other, very different scenarios such as there being a population of zero, a population that will be limited to what Earth can sustain, or astronomical numbers of beings. Relevant decisions might include those that concern international relations, biotechnology, risk, space colonisation, and many other things. Of course, different decisions, policies, and the like often have pros and cons, and how to take into account, for example, the existence and number of future beings seems to be one important consideration.

When it comes to risks of astronomical suffering (s-risks), some has been written on whether we should focus on such risks and on how to best reduce them (e.g., Baumann 2022), but I cannot think of any research on which particular behaviours (and perhaps intentions and the like) related to s-risks are morally permissible, wrong, or right. One can analyse similar ethical issues related to at least keeping our population within the boundaries of Earth (i.e., not colonising space) or the scenario of ending up with a population of zero.[59] To be clear, when I talk about what is permissible, I do not mean what one can morally get away with. Rather, I have in mind that in societies, there seems to be moral room for people to act in line with their different values and ideas (within limits).

This kind of practical work related to population ethics seems promising, might be area-specific, and might benefit from empirical expertise in relevant areas such as international conflicts, biotechnology, and regulation of space.

6.2 Weighing bads

There is a question of how to weigh different bads against one another for axiological and moral purposes. For example, one question is whether a large population with barely negative welfare is worse than a smaller population with very negative welfare (see the Reverse Repugnant Conclusion in Blackorby et al. 1998; Carlson 1998).[60] An alternative formulation of this question which avoids the debatable term ‘negative welfare’ is whether many experiences of daily-life unpleasantness can be worse than fewer horrible experiences. But a much more important question is whether purportedly good things can outweigh ills, and that question is already settled, in my opinion. I doubt that it is theoretically or practically important to do much further work on how to weigh bads against one another, for the following three reasons:

First, as a matter of theory, the perhaps simplest way to weigh bads, namely to say that all bads can be traded off against one another, seems acceptable enough. It is not my view, but it still seems pretty defensible.

Second, there seem to be reasonable theoretical approaches that imply a limitation on tradeoffs among bads (see, e.g., Vinding 2022b; 2020b; 2020a; Knutsson 2021; Nebel 2022).

Third, in practice, it is not clear that it matters significantly whether one holds that a sufficiently large number of “mildly” unpleasant experiences can be worse than a smaller number of horrible experiences, since the practical implications may be largely the same either way (see, e.g., Vinding 2022a).

7 Concluding remarks

Population ethics does not seem especially difficult, and good answers have been around for a long time. The research literature and texts about population ethics look like organisms that grow with their own dynamics. Although the resulting body of texts is not uniform—it ranges from solid scholarship to brazen influence tactics—there seems to be a prevalent surface where narratives and broad statements are put forth and framed. Often, these are seemingly presented from a point of supposed authority with little opportunity for the reader to easily vet them. It is crucial to question narratives and claims, and check whether they hold up to scrutiny. When I scrutinise, I find, among other things, that many supposed problems and paradoxes in population ethics hinge on implausible judgments and assumptions.

If only one thing related to population ethics could be scrutinised and given special attention, it should perhaps be omissions (including intentional, unintentional, defensible, and indefensible omissions). When someone talks about population ethics and, for example, its history and state, it seems that omissions play a key role. A history is presented that puts some authors, ideas, and works front and centre while others are not mentioned. Similarly, an overview of the different positions in population ethics might present a selection that omits some positions. One of the presented positions might sound more appealing because the strongest objection to it is omitted, while another position sounds less appealing because points in favour of it are omitted. Unfortunately, to notice omissions, one might already need to know about the thing that is omitted. To this and other ends, it is advisable to read widely beyond what is standardly presented to readers. Even an author’s implicit and perhaps standard delineation of population ethics might lead to important works and ideas about ethics and populations being excluded because they do not fall within that rather narrow notion of population ethics. For a fuller picture of ethics related to populations, one should probably also read outside of what is commonly called ‘population ethics’ (I talk about this in Appendix 1).[61]

Appendix 1: The delineation of population ethics and its relation to consequentialism, utilitarianism, and axiology

On the one hand, there is a consequentialist and utilitarian air over many works in what is often talked about as ‘population ethics’. The high degree of utilitarian tendencies in that literature might even be surprising. When population ethics is approached in a narrow, utilitarian-oriented, axiological way, one should remember to have a critical attitude toward claims about its practical and theoretical importance. On the other hand, one can reasonably think of this line of work as merely one strand or one approach to population ethics. The range of important ideas and texts that pertain to ethics and populations is much wider and more diverse, regardless of whether we label them ‘population ethics’. There is more to ethics and populations than one might think when reading about ‘population ethics’.

Here are two different ways to think of population ethics:

  1. The first way to think about population ethics is that most discussions in population ethics have focused on the value of populations and that population ethics represents the efforts of consequentialism-oriented authors. Population ethics deals with certain questions such as: What is the value of different possible populations with different numbers of individuals and levels of welfare? Do we have a moral reason to create a being merely due to the welfare the new being would have? The questions and topics in focus are limited and many important ethical issues related to populations are largely set aside. Population ethics is narrower and less interesting than one might have thought (although Vetter (1969; 1971), Wolf (1996; 1997; 2004), and Fehige (1998) still fall within population ethics even on this narrow conception of population ethics).
  2. The second way to think about population ethics is that the scope of population ethics is much wider and simply covers all ethical questions related to population (as the term ‘population ethics’ suggests). Many topics are relevant, such as consent, coercion, rights, voluntariness, subjecting others to risk, and the moral significance of causing harm and exposing someone to harm. On this conception, it seems to me that the literature overall does not look so consequentialism-oriented and most discussion has probably not concentrated on how to evaluate populations in regard to their goodness. Population ethics is broader and more widely relevant and important, but the relevant literature is huge and sprawling.

We could use the term ‘population ethics’ in either of the two ways (or in other ways). Some may try to use it in the way that best suits their interests, and it would be unsurprising to see a publication proposing a definition of ‘population ethics’ that helps that author’s agenda. Anyway, when the term ‘population ethics’ is used, it seems important to be cognisant of what it does and does not cover in that instance.

In the rest of this appendix, I will talk in some more detail about how population ethics is related to consequentialism, utilitarianism, and axiology.

Here are a few statements that are in line with the aforementioned first narrow way of thinking about population ethics as being closely related to consequentialism and axiology: According to Roberts (2015, 399),

Population ethics represents the efforts of theorists who are happy to accept many consequentialist tenets but worry that traditional formulations—for example, classical utilitarianism—miss the mark when it comes to cases that involve distinct populations.

Similarly, Frick (2014, 3) says that “much of the literature in population ethics is written by consequentialists or those friendly to the consequentialist perspective”.[62] According to Arrhenius (2004, 201), ‘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 focus makes some sense if something like consequentialism is assumed because, according to one description of consequentialism, moral properties such as wrongness depend only on the value of outcomes. Indeed, Arrhenius (2004, 203) writes:

As a matter of fact, most of the population theories presented in the literature explicitly or implicitly include some form of consequentialism as a bridging principle from the axiological level to the normative level.

Such talk of population ethics as being so related to consequentialism and axiology might in part be a matter of one’s notion of population ethics.

When we look at historical works in typical population ethics, all the way from the beginning until today, we tend to see a broadly utilitarian framework. A substantial part of that literature almost looks like an internal utilitarian or consequentialist debate.[63]

In the 1960s, Narveson wrote favourably about utilitarianism,[64] and he dealt in part with how utilitarianism is to be formulated or interpreted.[65] (Although he later “became persuaded of the unworkability of utilitarian theory”.[66]) In his essay from 1967 said to have started population ethics, he sort of talks about the topic as an internal utilitarian matter:

there is some difference of opinion about the way in which the utilitarian theory is to be formulated… [Some] are assuming that according to the utilitarian, there is a certain sort of mental state called “pleasure” or “happiness”, of which it is our obligation to produce as much as possible, by whatever means…. But it is obviously not the one which Bentham and Mill had in mind. Their formulations, as everybody knows, have it that the “greatest happiness of the greatest number” is the end of morality…. [T]hat we are to aim at the greatest happiness of the greatest number, does not imply that we are to aim at the greatest happiness and the greatest number. In order to make this perfectly clear, note that the classical utilitarians’ view may be put this way: everyone should be as happy as possible. Cast into modern logical form, this reads, “For all persons x, x should be as happy as possible”, and this is equivalent to, “if a person exists, he should be as happy a[s] possible”. This last shows clearly that the classical formulation does not imply that as many happy people as possible should be brought into existence. (Narveson 1967b, 62–63)[67]

Sprigge also wrote favourably about utilitarianism and Vetter (1971, 301) wrote “I agree with the utilitarian premisses Narveson is using”.

Bayles’ (1976) book Ethics and Population is interesting. It contains reprinted and new papers by different authors. The second part of the book is titled “Utilitarianism and Population Policies” and it consists of three papers: a reprint of a paper by Narveson from 1973, a new paper by Singer, and a new paper by Parfit. These papers and authors that Bayles sorts under “Utilitarianism and Population Policies” are probably what many think of when they hear ‘population ethics’. In this book, Parfit says he owes a great deal to Narveson’s article from 1967,[68] while Narveson says he owes “to discussions with Derek Parfit, and those attending his classes in Trinity term 1971 at Oxford.”[69]

In Bayles’ book from 1976 that I just mentioned, Parfit said that Narveson and Singer faced difficulties and remarked: “Such difficulties may seem to face only utilitarians. This is not so. They face most of those who give any weight to a utilitarian principle.”[70] Similar and stronger statements have been made since. For example, Arrhenius (2004, 214) writes that “the paradoxes of population ethics … are a problem for any moral theory” (see also Arrhenius 2017, 5). However, I think that claims about the relevance and importance of various purported problems in population ethics would really need to be argued for and scrutinised. One reason is that sometimes such claims are simply false. Another reason is that it seems like a big task to say to what extent various purported problems in population ethics matter for different ethical views. And even if something matters it might be a minor consideration among much more important ones or it might be irrelevant in practice.

Finally, as one can tell from the sources I mentioned in Sections 2 and 3, non-utilitarian and non-axiological approaches to ethics and populations have been around for a long time, and they are well worth some more attention.

Appendix 2: Arrhenius’ impossibility theorems

Most of the theorems discussed below are from Arrhenius’ PhD dissertation published in 2000 (Arrhenius 2000). Arrhenius (2017) seemingly overstates what the theorems establish and the acceptability of the theorems:

Many different theories have been proposed over the years, all of which claim to avoid the classical theories’ absurd results. The problem, however, is that the theories that avoid these results have other strange implications that are at least as absurd and counterintuitive. We know this for sure through a number of so-called impossibility theorems, which are among the more important results of my research and presented in the book. The proofs of these theorems show that there is no theory that fulfils a number of intuitively compelling adequacy conditions – conditions which everyone seems to agree that a reasonable moral theory must fulfil.

In this section, I will go through Arrhenius’ six impossibility theorems, and say why I find them to be unconvincing and non-issues for my kind of view. The first two theorems concern different levels of positive welfare, and the last four assume that some people getting higher rather than lower positive welfare can counterbalance someone else’s negative welfare.[71]

The first impossibility theorem

Arrhenius (2000, 157) states his first theorem as follows:

The First Impossibility Theorem: There is no population axiology which satisfies the Quality Condition, the Egalitarian Dominance Condition, and the Quantity Condition.

According to Arrhenius (2000, 151), “The first theorem illustrates the tension between the Quality and the Quantity Condition.”

The quality and the quantity conditions are (quoted from Arrhenius 2000, 155–56):

The Quality Condition: There is at least one perfectly equal population with very high positive welfare which is at least as good as any population with very low positive welfare, other things being equal.

The Quantity Condition: For any pair of positive welfare levels A and B, such that B is slightly lower than A, and for any number of lives n, there is a greater number of lives m, such that a population of m people at level B is at least as good as a population of n people at level A, other things being equal.

Here is my attempt to explain these quality and quantity conditions, Arrhenius’ first theorem, and his proof of it. The Quality Condition essentially says that there exists a population with very well-off people that is at least as good as any population with very low positive welfare, regardless of how large the population with low welfare is. Quality trumps quantity in that case, regardless of how large the quantity is. (And the Quality Condition says that there are positive welfare ranges.[72])

A contrasting idea can be found in the other condition (the Quantity Condition), namely that a larger population with lower positive welfare is at least as good as a smaller population with slightly higher welfare. An increase in the number of lives (the quantity) here counterbalances a lowering of the level of welfare (the quality).

In his proof of this first theorem, Arrhenius (2000, 157–58) takes populations of different sizes and different levels of positive welfare, uses the conditions in the theorem, and derives that a population B is better than another population A1 while A1 is at least as good as B, which he takes to be a contradiction. The conditions in the theorem entail a contradiction so no axiology can satisfy all of them.

I reject the Quantity Condition, so I think it is unproblematic if it is impossible to satisfy all the conditions in the theorem. I would say, contrary to this condition, that a larger population with lower welfare cannot be least as good as a smaller population with higher welfare. I also reject the ideas of different levels of positive welfare that figure in the quality and quantity conditions and in the proof (since I reject the idea of positive welfare).

The second impossibility theorem

Arrhenius’ (2000, 159) second theorem reads:

The Second Impossibility Theorem: There is no population axiology which satisfies the Quality Condition, the Inequality Aversion Condition, the Egalitarian Dominance Condition, and the Dominance Addition Condition.

Arrhenius (2000, 151) says, “The second theorem is a version of the Mere Addition Paradox but with logically weaker and intuitively more plausible conditions than those used elsewhere in the literature.”

The two key conditions for our purposes are the Quality Condition and the Dominance Addition Condition. The Quality Condition was found in the first theorem above and I stated it there. The Dominance Addition Condition is (quoted from Arrhenius 2000, 159):

The Dominance Addition Condition: An addition of lives with positive welfare and an increase in the welfare in the rest of the population doesn’t make a population worse, other things being equal.

I take the essence of this condition to be that adding huge numbers of beings with low positive welfare always results in a population that is at least as good as the original population, as long as the original population with positive welfare gets higher positive welfare in the process. This sounds similar to the Quantity Condition in the first theorem. Of course, the Dominance Addition Condition concerns adding lives with positive welfare, which I take to be impossible. So I reject the presumption in the condition.

The proof of the second theorem looks similar to the proof of the first. In his proof of the second theorem, Arrhenius (2000, 159–61) takes populations with different levels of positive welfare and different sizes, uses the conditions, and derives that one population is not worse than another while the second population is better than the former, which he takes to be a contradiction. In his proof, Arrhenius uses different levels of positive welfare, which I deny the existence of.

All in all, I take Arrhenius’ second impossibility theorem to be unproblematic and a non-issue for my kind of view for essentially the same reasons why the first impossibility theorem is a non-issue.

The third impossibility theorem

Here is the third impossibility theorem by Arrhenius (2000, 163):

The Third Impossibility Theorem: There is no population axiology which satisfies the Egalitarian Dominance, the Inequality Aversion, the Non-Extreme Priority, the Non-Sadism, and the Weak Quality Addition Condition.

Arrhenius (2000, 151) comments: “The third theorem involves less controversial assumptions than the first two…. This theorem shows that the on-going project of constructing an acceptable population axiology has gloomy prospects.”

The Non-Extreme Priority condition assumes that an increase from positive to higher positive welfare among some individuals can counterbalance someone else having negative welfare. The condition reads as follows (Arrhenius 2000, 162):

The Non-Extreme Priority Condition: There is a number n of lives such that for any population X, a population consisting of the X-lives, n lives with very high welfare, and a single life with slightly negative welfare, is at least as good as a population consisting of the X-lives and n+1 lives with very low positive welfare, other things being equal.

I disagree with this condition. I do not think that the population with the individual with negative welfare is at least as good as the population in which everyone has positive welfare. I gather Wolf (1997), Fehige (1998), Benatar, Vinding (2020c, chap. 3), and many others would also disagree with the Non-Extreme Priority condition. So this third impossibility theorem is not a problem, and it does not show that the project of constructing an acceptable population axiology has gloomy prospects.

The fourth, fifth, and sixth impossibility theorems

Arrhenius’ fourth, fifth, and sixth impossibility theorems are similar to the third in that they also assume that some people getting higher rather than lower positive welfare can counterbalance someone else’s negative welfare. More specifically, the fourth, fifth, and sixth impossibility theorems assume the General Non-Extreme Priority Condition.

Here are the theorems:[73]

The Fourth Impossibility Theorem: There is no population axiology which satisfies the Egalitarian Dominance, the Non-Elitism, the General Non-Extreme Priority, the Weak Non-Sadism, and the Weak Quality Addition Condition.

The Fifth Impossibility Theorem: There is no population axiology which satisfies the Egalitarian Dominance, the Non-Elitism, the General Non-Extreme Priority, Avoidance of the Very Repugnant Conclusion, and the Dominance Addition Condition.

The Sixth Impossibility Theorem: There is no population axiology which satisfies the Egalitarian Dominance, the General Non-Extreme Priority, the Non-Elitism, the Weak Non-Sadism, and the Weak Quality Addition Condition.

And here is the General Non-Extreme Priority Condition that these impossibility theorems assume:

The General Non-Extreme Priority Condition: There is a number n of lives such that for any population X, and any welfare level A, a population consisting of the X-lives, n lives with very high welfare, and one life with welfare A, is at least as good as a population consisting of the X-lives, n lives with very low positive welfare, and one life with welfare slightly above A, other things being equal.

Roughly speaking, this condition says that it would be at least as good if the worst-off individual with negative welfare were even worse off as long as other people with positive welfare would instead have higher positive welfare. Again, I disagree with that, as would, I presume, Wolf (1997), Fehige (1998), Benatar, Vinding (2020c, chap. 3), and many others. I think an increase in positive welfare to higher positive welfare for others does not at all counterbalance a worsening for the worst-off individual with negative welfare.

According to Arrhenius, this condition implies a more general acceptance of tradeoffs to the effect that any number of lives with very negative welfare can be counterbalanced by others’ increases from low to high positive welfare. Arrhenius (2000, 102) says:

In conjunction with the transitivity of the relation “at least as good as”, however, the General Non-Extreme Priority Condition has an implication that some theorists with a negativist inclination might find bothersome. It implies, as we shall show in chapter 10, that for any given number of lives with very negative welfare, there is a (much) greater number of lives with very high welfare such that a population consisting of these two groups of lives is at least as good as a same sized population consisting of lives with slightly positive welfare. Let’s call this implication bad lives for very good lives.

In other words, according to Arrhenius (2000, 173), the General Non-Extreme Priority Condition implies what he calls Condition δ. I take the gist of that condition to be that any number of lives at any negative level of welfare, even a huge number of hellish lives, can be counterbalanced by that others would get higher rather than lower positive welfare. I find that extremely implausible.

In sum, Arrhenius’ fourth, fifth, and sixth impossibility theorems are non-issues for my kind of view. Arrhenius considers his sixth theorem to be his strongest, according to Carlson (2015; 2022, 204). If this is the strongest impossibility theorem by the author who has produced the most important impossibility theorems in population ethics, then the state of impossibility theorems in population ethics is underwhelming. Even the supposedly strongest theorem makes at least one really implausible assumption, and so does not create any problems for formulating or accepting a reasonable theory in population ethics.


Ajantaival, Teo. 2021. ‘Minimalist Axiologies and Positive Lives’. Center for Reducing Suffering (blog). 2021.

———. 2022. ‘Minimalist Extended Very Repugnant Conclusions Are the Least Repugnant’, October.

Algander, Per. 2013. ‘Harm, Benefit, and Non-Identity’. Doctoral thesis, Uppsala University.

Algander, Per, and Katharina Berndt Rasmussen. 2019. ‘Asymmetry and Non-Identity’. Utilitas 31 (3): 213–30.

Arrhenius, Gustaf. 2000. ‘Future Generations: A Challenge for Moral Theory’. PhD, Uppsala University.

———. 2003. ‘The Very Repugnant Conclusion’. In Logic, Law, Morality: Thirteen Essays in Practical Philosophy in Honour of Lennart Åqvist, edited by Krister Segerberg and Rysiek Sliwinski, 29–44. Uppsala: Department of Philosophy, Uppsala University.

———. 2004. ‘The Paradoxes Of Future Generations And Normative Theory’. In The Repugnant Conclusion: Essays on Population Ethics, edited by Torbjörn Tännsjö and Jesper Ryberg, 201–18. Library Of Ethics And Applied Philosophy. Dordrecht: Springer Netherlands.

———. 2005. ‘Superiority in Value’. Philosophical Studies 123 (1–2): 97–114.

———. 2009. ‘One More Axiological Impossibility Theorem’. In Logic, Ethics and All That Jazz: Essays in Honour of Jordan Howard Sobel, edited by Lars-Göran Johansson, Jan Österberg, and Rysiek Sliwinski, 23–37. Uppsala: Department of Philosophy, Uppsala University.

———. 2017. ‘Précis Population Ethics’. Ars Vivendi Journal, no. 8/9: 3–6.

Arrhenius, Gustaf, Krister Bykvist, Tim Campbell, and Elizabeth Finneron-Burns, eds. 2022. The Oxford Handbook of Population Ethics. Oxford Handbooks. Oxford, New York: Oxford University Press.

Arrhenius, Gustaf, Jesper Ryberg, and Torbjörn Tännsjö. 2022. ‘The Repugnant Conclusion’. In The Stanford Encyclopedia of Philosophy, edited by Edward N. Zalta and Uri Nodelman, Winter 2022. Metaphysics Research Lab, Stanford University.

Baier, Annette. 1981. ‘The Rights of Past and Future Persons’. In Responsibilities to Future Generations: Environmental Ethics, edited by Ernest Partridge, 171–83. Buffalo, NY: Prometheus Books.

Baumann, Tobias. 2022. Avoiding the Worst: How to Prevent a Moral Catastrophe.

Bayles, Michael D., ed. 1976. Ethics and Population. Cambridge, Mass.: Schenkman.

———. 1980. Morality and Population Policy. University: University of Alabama Press.

Benatar, David. 1997. ‘Why It Is Better Never to Come Into Existence’. American Philosophical Quarterly 34 (3): 345–55.

———. 2013. ‘Still Better Never to Have Been: A Reply to (More of) My Critics’. The Journal of Ethics 17 (1–2): 121–51.

———. 2015. ‘The Misanthropic Argument for Anti-Natalism’. In Permissible Progeny?, edited by Sarah Hannan, Samantha Brennan, and Richard Vernon, 34–64. New York: Oxford University Press.

———. 2017. The Human Predicament: A Candid Guide to Life’s Biggest Questions. New York: Oxford University Press.

Blackorby, Charles, Walter Bossert, David Donaldson, and Marc Fleurbaey. 1998. ‘Critical Levels and the (Reverse) Repugnant Conclusion’. Journal of Economics/ Zeitschrift Fur Nationalokonomie 67 (1): 1–15.

Broome, John. 1992. Counting the Cost of Global Warming. Cambridge: White Horse.

Callahan, Daniel. 1971. ‘What Obligations Do We Have To Future Generations?’ American Ecclesiastical Review 164 (4): 265–80.

Carlson, Erik. 1998. ‘Mere Addition and Two Trilemmas of Population Ethics’. Economics and Philosophy 14 (2): 283–306.

———. 2015. ‘On Some Impossibility Theorems in Population Ethics’. Draft.

———. 2022. ‘On Some Impossibility Theorems in Population Ethics’. In The Oxford Handbook of Population Ethics, edited by Gustaf Arrhenius, Krister Bykvist, Tim Campbell, and Elizabeth Finneron-Burns, 204–25. Oxford University Press.

Chappell, R.Y., D. Meissner, and W. MacAskill. 2023. ‘Population Ethics’. In Utilitarianism.Net.

Delattre, Edwin. 1972. ‘Rights, Responsibilities, and Future Persons’. Ethics 82 (3): 254–58.

Fehige, Christoph. 1998. ‘A Pareto Principle for Possible People’. In Preferences, edited by Christoph Fehige and Ulla Wessels, 508–43. Berlin: De Gruyter.

Feinberg, Joel. 1974. ‘The Rights of Animals and Unborn Generations’. In Philosophy & Environmental Crisis, edited by William T. Blackstone, 43–68. Athens, GA: University of Georgia Press.;

Finneron-Burns, Elizabeth. 2015. ‘What We Owe to Future People: A Contractualist Account of Intergenerational Ethics’. DPhil, University of Oxford.

———. 2017. ‘What’s Wrong with Human Extinction?’ Canadian Journal of Philosophy 47 (2–3): 327–43.

———. 2024. What We Owe to Future People: A Contractualist Account of Intergenerational Ethics. Oxford, New York: Oxford University Press.

Forrester, Katrina. 2019. In the Shadow of Justice: Postwar Liberalism and the Remaking of Political Philosophy. Princeton: Princeton University Press.

Fox, Joshua Isaac. forthcoming. ‘Does Schopenhauer Accept Any Positive Pleasures?’ European Journal of Philosophy.

Frick, Johann. 2020. ‘Conditional Reasons and the Procreation Asymmetry’. Philosophical Perspectives 34 (1): 53–87.

Frick, Johann David. 2014. ‘“Making People Happy, Not Making Happy People”: A Defense of the Asymmetry Intuition in Population Ethics’. Doctoral dissertation, Harvard University.

Gleiberman, Mollie. 2023a. ‘Effective Altruism: Doing Transhumanism Better’. Institute of Development Policy | University of Antwerp, The IOB Working Paper Series, , March.

———. 2023b. ‘Effective Altruism and the Strategic Ambiguity of “Doing Good”’. IOB Discussion Papers, IOB Discussion Papers, , April.

Golding, M. P. 1968. ‘Ethical Issues in Biological Engineering’. UCLA Law Review. University of California, Los Angeles. School of Law 15 (2): 443–79.

———. 1972. ‘Obligations to Future Generations’. The Monist 56 (1): 85–99.

Greaves, Hilary. 2017. ‘Population Axiology’. Philosophy Compass 12 (11): e12442.

Green, Ronald Michael. 1976. Population Growth and Justice: An Examination of Moral Issues Raised by Rapid Population Growth. Harvard Dissertations in Religion 5. Missoula, Mont.: Scholars Press.

Gustafsson, Johan E. 2023. ‘Against Negative Utilitarianism’.

Hallich, Oliver, and Michael Hauskeller. 2022. ‘Introduction’. The Journal of Value Inquiry 56 (1): 1–4.

Heyd, David. 1998. ‘Population and Ethics’. In Routledge Encyclopedia of Philosophy, 1st ed. London: Routledge.

Huseby, Robert. 2012. ‘Sufficiency and Population Ethics’. Ethical Perspectives 19 (2): 187–206.

Knutsson, Simon. 2019. ‘Problems in Effective Altruism and Existential Risk and What to Do about Them’. 2019.

———. 2020. ‘In Support of Talking about Pessimism, Antinatalism, Negative Utilitarianism, Etc.’ 30 May 2020.

———. 2021. ‘Many-Valued Logic and Sequence Arguments in Value Theory’. Synthese 199: 10793–825.

———. 2022a. ‘Undisturbedness as the Hedonic Ceiling’.

———. 2022b. ‘Permissible Moderate Paths to Human Extinction’. 8 May 2022.

———. 2022c. ‘Philosophical Pessimism: Varieties, Importance, and What to Do’. The Blog of the American Philosophical Association (blog). 13 September 2022.

———. 2022d. ‘On the Results of Oxford-Style Effective Altruism, Existential Risk, and Longtermism – Simon Knutsson’. 29 December 2022.

———. 2023. ‘My Moral View: Reducing Suffering, “How to Be” as Fundamental to Morality, No Positive Value, Cons of Grand Theory, and More’. 23 August 2023.

Lougheed, Kirk. n.d. ‘Anti-Natalism’. In Internet Encyclopedia of Philosophy. Accessed 30 August 2023.

MacAskill, William. 2022. What We Owe the Future: A Million-Year View. London: Oneworld Publications.

Magnusson, Erik. 2022. ‘On Risk-Based Arguments for Anti-Natalism’. The Journal of Value Inquiry 56: 101–17.

McMahan, Jeff. 2022. ‘Introduction’. In Ethics and Existence: The Legacy of Derek Parfit, edited by Jeff McMahan, Tim Campbell, James Goodrich, and Ketan Ramakrishnan, 1–12. Oxford University Press.

Meyer, Lukas. 2021. ‘Intergenerational Justice’. In The Stanford Encyclopedia of Philosophy, edited by Edward N. Zalta, Summer 2021. Metaphysics Research Lab, Stanford University.

Millgram, Elijah. 2018. ‘Hypophilosophy’. Social Philosophy and Policy 35 (2): 138–57.

Mogensen, Andreas. forthcoming. ‘The Weight of Suffering’. The Journal of Philosophy.

Morioka, Masahiro. 2021. ‘What Is Antinatalism? Definition, History, and Categories’. The Review of Life Studies 12: 1–39.

Narveson, Jan. 1963. ‘The Desert-Island Problem’. Analysis 23 (3): 63–67.

———. 1967a. Morality and Utility. Baltimore: Johns Hopkins University Press.

———. 1967b. ‘Utilitarianism and New Generations’. Mind 76 (301): 62–72.

———. 1973. ‘Moral Problems of Population’. The Monist 57 (1): 62–86.

———. 1978. ‘Future People and Us’. In Obligations to Future Generations, edited by Richard I. Sikora and Brian M. Barry, 38–60. Cambridge: The White Horse Press.

Nebel, Jacob M. 2022. ‘Totalism Without Repugnance’. In Ethics and Existence: The Legacy of Derek Parfit, edited by Jeff McMahan, Tim Campbell, James Goodrich, and Ketan Ramakrishnan, 200–231. Oxford University Press.

Ord, Toby. 2020. The Precipice: Existential Risk and the Future of Humanity. New York: Hachette Books.

Parfit, Derek. 1976. ‘On Doing the Best for Our Children’. In Ethics and Population, edited by Michael D. Bayles, 100–115. Cambridge, Mass.: Schenkman.

———. 1986. Reasons and Persons. Oxford University Press.

Plant, Michael. 2023. ‘William MacAskill, What We Owe The Future: A Million-Year View (One World Publications, London, 2022), Pp. 246.’ Utilitas 35 (4): 333–38.

Roberts, M. A. 2015. ‘Population Axiology’. In The Oxford Handbook of Value Theory, edited by Iwao Hirose and Jonas Olson, 0. Oxford University Press.

———. 2021. ‘Anonymity and Indefinitely Iterated Addition and Reversal’. In Studies on Climate Ethics and Future Generations, edited by Joe Roussos and Paul Bowman, 4:221–38. Working Papers 2021:11-23. Stockholm: Institute for Futures Studies.

———. 2022. ‘The Nonidentity Problem’. In The Stanford Encyclopedia of Philosophy, edited by Edward N. Zalta and Uri Nodelman, Winter 2022. Metaphysics Research Lab, Stanford University.

Roberts, Melinda A. 2013. ‘Population’. In The International Encyclopedia of Ethics. John Wiley & Sons, Ltd.

Rulli, Tina. 2016. ‘The Ethics of Procreation and Adoption’. Philosophy Compass 11 (6): 305–15.

Ryberg, Jesper. 1996. ‘Is the Repugnant Conclusion Repugnant?’ Philosophical Papers 25 (3): 161–77.

Schopenhauer, Arthur. 2009. ‘Prize Essay on the Basis of Morals’. In The Two Fundamental Problems of Ethics, edited and translated by Christopher Janaway, 113–258. The Cambridge Edition of the Works of Schopenhauer. Cambridge: Cambridge University Press.

———. 2014. Parerga and Paralipomena: Short Philosophical Essays. Edited and translated by Sabine Roehr and Christopher Janaway. Vol. 1. The Cambridge Edition of the Works of Schopenhauer. Cambridge: Cambridge University Press.

Shiffrin, Seana. 1993. ‘Consent and the Morality of Procreation.’ PhD, University of Oxford.

Shiffrin, Seana Valentine. 1999. ‘Wrongful Life, Procreative Responsibility, and the Significance of Harm’. Legal Theory 5 (2): 117–48.

Singh, Asheel. 2012. ‘Furthering the Case for Anti-Natalism: Seana Shiffrin and the Limits of Permissible Harm’. South African Journal of Philosophy 31 (1): 104–16.

———. 2018. ‘The Hypothetical Consent Objection to Anti-Natalism’. Ethical Theory and Moral Practice 21 (5): 1135–50.

Spears, Dean. 2020. ‘The Asymmetry of Population Ethics: Experimental Social Choice and Dual-Process Moral Reasoning’. Economics & Philosophy 36 (3): 435–54.

Sprigge, Timothy L. S. 1968. ‘I. Professor Narveson’s Utilitarianism’. Inquiry (United Kingdom) 11 (1–4): 332–46.

Tännsjö, Torbjörn. 1996. ‘Classical Hedonistic Utilitarianism’. Philosophical Studies: An International Journal for Philosophy in the Analytic Tradition 81 (1): 97–115.

———. 1998. Hedonistic Utilitarianism. Edinburgh University Press.

———. 2004. ‘Why We Ought to Accept the Repugnant Conclusion’. In The Repugnant Conclusion, edited by Jesper Ryberg and Torbjörn Tännsjö, 219–37. Dordrecht: Kluwer Academic Publishers.

———. 2020. ‘Why Derek Parfit Had Reasons to Accept the Repugnant Conclusion’. Utilitas 32 (4): 387–97.

———. 2023. ‘Recension av William MacAskill: What We Owe the Future’. Tidskrift för politisk filosofi 27 (2).

The Yale Task Force on Population Ethics. 1974. ‘Moral Claims, Human Rights, and Population Policies’. Theological Studies 35 (1): 83–113.

Thomas, Teruji. 2016. ‘Reconstructing Arrhenius’s Impossibility Theorems’.

———. 2018. ‘Some Possibilities in Population Axiology’. Mind 127 (507): 807–32.

Tomlin, Patrick. 2022. ‘The Impure Non-Identity Problem’. In Ethics and Existence: The Legacy of Derek Parfit, edited by Jeff McMahan, Tim Campbell, James Goodrich, and Ketan Ramakrishnan, 0. Oxford University Press.

Torres, Émile P. 2022. ‘Selling “Longtermism”: How PR and Marketing Drive a Controversial New Movement’. Salon, 10 September 2022.

Vetter, Hermann. 1969. ‘The Production of Children as a Problem of Utilitarian Ethics’. Inquiry 12 (1–4): 445–47.

———. 1971. ‘Utilitarianism and New Generations’. Mind 80 (318): 301–2.

Vinding, Magnus. 2020a. ‘Clarifying Lexical Thresholds’. Center for Reducing Suffering (blog). 2020.

———. 2020b. ‘Lexical Views without Abrupt Breaks’. Center for Reducing Suffering (blog). 2020.

———. 2020c. Suffering-Focused Ethics: Defense and Implications. Copenhagen: Ratio Ethica.

———. 2021. ‘Comparing Repugnant Conclusions: Response to the “near-Perfect Paradise vs. Small Hell” Objection’. Center for Reducing Suffering (blog). 30 November 2021.

———. 2022a. ‘Lexical Priority to Extreme Suffering — in Practice’. Center for Reducing Suffering (blog). 2022.

———. 2022b. ‘Lexicality between Mild Discomfort and Unbearable Suffering: A Variety of Possible Views’. Center for Reducing Suffering (blog). 2022.

———. 2022c. ‘Reply to Gustafsson’s “Against Negative Utilitarianism”’. Center for Reducing Suffering (blog). 7 June 2022.

———. 2022d. ‘Reply to Chappell’s “Rethinking the Asymmetry”’. Center for Reducing Suffering (blog). 13 June 2022.

———. 2022e. ‘The Dismal Dismissal of Suffering-Focused Views’. 17 June 2022.

———. 2022f. ‘Comments on Mogensen’s “The Weight of Suffering”’. Center for Reducing Suffering (blog). 23 July 2022.

———. 2022g. ‘Critique of MacAskill’s “Is It Good to Make Happy People?”’ Effective Altruism Forum. 23 August 2022.

Wolf, Clark. 1996. ‘Social Choice and Normative Population Theory: A Person Affecting Solution to Parfit’s Mere Addition Paradox’. Philosophical Studies 81 (2–3): 263–82.

———. 1997. ‘Person-Affecting Utilitarianism and Population Policy; or, Sissy Jupe’s Theory of Social Choice’. In Contingent Future Persons, edited by Nick Fotion and Jan C. Heller, 99–122. Springer.;

———. 2004. ‘O Repugnance, Where Is Thy Sting?’ In The Repugnant Conclusion, edited by Torbjörn Tännsjö and Jesper Ryberg, 61–80. Library Of Ethics And Applied Philosophy 15. Springer Netherlands.

Zimmermann, Klaus F. 1989. ‘Optimum Population: An Introduction’. In Economic Theory of Optimal Population, edited by Klaus F. Zimmermann, 1–16. Microeconomic Studies. Berlin, Heidelberg: Springer.


[1] I talk about such ideas in Knutsson (2022a, sec. 1).

[2] I am here talking only about the value of the population itself, not the effects of it. Moreover, perhaps there could be populations of size greater than zero that are equal in value to an empty population so that those populations and an empty population would be tied for first place in terms of value.

[3] Here and elsewhere in this essay, I make short and hopefully readable statements about what most of Arrhenius’ theorems assume. For more precise formulations of the assumptions that I am talking about, see the Non-Extreme Priority Condition and the General Non-Extreme Priority Condition in Appendix 2, or check out what Arrhenius calls the “exact formulation” of these two conditions in Arrhenius (2000, 162, 166–67). See also Arrhenius’ (2000, 95–96) comments on talk of “gains” and “losses”.

[4] E.g., Roberts (2013, 1) writes: “The choices we make today have consequences for what life will be like for future people, how many future people there will be, and who those future people are. Such quality, quantity, and identity issues – and more besides – fall within the domain of population ethics.” Welfare is the same as quality of life. Another word for welfare is ‘wellbeing’. One can speak of positive and negative wellbeing or, as I do, say ‘illbeing’ instead of ‘negative welfare’ and ‘negative wellbeing’.

[5] According to McMahan (2022, 2), “The following are among the many foundational questions in population ethics. Can individuals be harmed or benefited by being caused to exist? Is there a moral reason not to cause individuals to exist if their lives would be miserable, or not worth living? Most of us believe there clearly is. But, if there is, is there also a moral reason to cause individuals to exist just because their lives would be worth living, or well worth living?” See also, e.g., Narveson (1967b).

[6] Arrhenius et al. (2022, 2) say that “what makes the task of formulating an adequate population ethics so difficult is that it is plagued by several very difficult problems and even paradoxes”. They continue: “The question of how to respond to the paradoxes in population ethics has spawned a huge, though largely inconclusive, literature” (p. 6). They similarly speak about “paradoxes” and “a formidable obstacle” (p. 9). Spears (2020, 435) says “Population ethics is widely considered to be exceptionally important and exceptionally difficult.” Arrhenius (2004, 214) writes that “the paradoxes of population ethics … are a problem for any moral theory”. Arrhenius (2017, 5) writes that proofs “show that there is no theory that fulfils a number of intuitively compelling adequacy conditions”. After having listed questions in population ethics, McMahan (2022, 3) writes, “All of the questions enumerated above are dauntingly difficult”.

[7] For examples of sources where one can find such arguments, see notes 21 and 22 at the end of Section 3.

[8] Meyer’s (2021) encyclopedia entry on intergenerational justice says:

Discussions of what we owe to future people go back to ancient times (Auerbach 1995: 27–35) and ancient philosophy provides resources and insights for intergenerational ethics (Lane 2012). Important contributions within the utilitarian tradition include the analysis of the moral status of future sentient beings (see, e.g., Sidgwick 1907 [1981: 414]), of optimal savings (Ramsey 1928, see entry on Ramsey and intergenerational welfare economics), and of obligations of reproduction (Narveson 1967; see §2.2). Within a theory of justice we owe the first systematic account of obligations to future people to John Rawls…

In an introduction to optimum population, Zimmermann (1989) writes:

One group of authors was concerned with the normative issue of the desired, ideal or optimal population size from the standpoint of society. (Page 2)

There is no ‘true father’ of the doctrine of optimum population. The idea can be traced back to works of Plato and Aristotle. Generally, Knut Wicksell (1910, 1913) and Edwin Cannan (1888, 1928, see also 1964, pp. 80-87) are each credited with independently originating the economic concept, although the actual progression of ideas is not apparent…. However, many distinguished economists had discussed the concept before or at the time Wicksell and Cannan introduced the doctrine. Among them there were Jean Charles Leonard Simonde de Sismondi, Henry Sidgwick, John Stuart Mill and Julius Wolf. Most notable are Mill (1848) and Wolf (1901, 1908), but also important are Wagner (1893, pp. 638-665) and Schmoller (1900, pp. 184-190). (Page 3)

The ethics of procreation is dealt with in, e.g., Rulli (2016), and the history of antinatalism is talked about in, e.g., Morioka (2021). Lougheed (n.d.) writes that “population ethics have had little to say about anti-natalism”, but an alternative take is that antinatalism is a stance within population ethics and that it is merely the case that some writers in population ethics have said little about antinatalism (while others like Benatar have said a lot).

[9] The article is Narveson (1967b). Forrester (2019, 183) says the following about Narveson’s article: “with Narveson’s essay, population ethics was born”. According to Heyd (1998, sec. Bibliography), Narveson’s article was “The first modern discussion of the problems of applying utilitarian principles to population issues”.

[10] Rights and claims are discussed in Callahan (1971) and Feinberg (1974, 64–66). The latter discusses whether future generations have a right to come into existence and whether voluntary childlessness leading to the end of our species would violate the rights of anyone. Bayles’ book Morality and Population Policy (1980) separates (1) utilitarianism and optimum population, (2) contractarianism and population principles, and (3) duties to future generations connected to rights (in appendices 1, 2 and 3, respectively). Here is an example of a contractarian account: Bayles writes on page 114 that “the most thorough contractarian account of population principles is by Ronald Green” (i.e., Green 1976). Delattre (1972) talks about responsibilities and

the question whether nonexistent persons have a right to existence, namely, whether we are obligated to create persons at all. Could we justifiably bring to a close the great entail of human life? Certainly there are conditions under which we should say yes to this last question, as for example if the environment could not possibly sustain either life or qualitatively worthwhile life. And even in the absence of such conditions, we should, I think, deny that nonexistent persons have a right to existence. (Page 255)

The Yale Task Force on Population Ethics (1974) lists alternative population policies and different values involved such as species survival, freedom, high wellbeing, rights, and justice.

[11] For comments on the relation between utilitarianism and population ethics, see Appendix 1. Recent exceptions to the broadly utilitarian tradition include Finneron-Burns’ work on contractualism and future people (Finneron-Burns 2015; 2017; 2024).

[12] This is the passage in Narveson (1967b, 72) that I am talking about: “There is one final question which might bring the whole issue into a sort of focus. This is: is there any moral point in the existence of a human race, as such? That is to say, would a universe containing people be morally better off than one containing no people? It seems to me that it would not be, as such, at any rate on utilitarian grounds. We might prefer, like Smart, a universe containing people to one that does not contain them, particularly since we presumably would not be able to occupy the second one ourselves; but is this, then, a moral preference? It seems to me, again, that it is not, and that the effort to make it one is a mistake.”

[13] Vetter (1969, 445) says: “It is shown that the basic postulate of utilitarianism does not work when we must decide whether a person should be brought into existence. Utilitarianism must be supplemented by further axioms. Those proposed lead to the consequence that as far as the potential child’s utility is concerned, it is morally preferable not to produce children at all. This consequence is accepted. It is still recommended when parents’ utility is taken into account.”

[14] However, in this passage, Vetter seems to ignore the non-human suffering that would remain even if there were no humans around.

[15] Wolf (1997, 119).

[16] One can debate whether there are other bads, and whether, say, very many instances of daily life unpleasantness can be worse than a few instances of unbearable suffering. But compared to clarifying the focus on preventing bads over creating purported goods, these seem more like details beyond what an acceptable and satisfactory theory or view needs to include.

[17] The following are quotes from Benatar (1997): “Children cannot be brought into existence for their own sakes” (p. 351). “Given that it is not possible to obtain consent from people prior to their existence to bring them into existence…” (p. 352). “If coming into existence is as great a harm as I have suggested, and if that is a heavy psychological burden to bear, then it is quite possible that we could be engaged in a mass self-deception about how wonderful things are for us” (p. 352). “One implication of my view is that it would be preferable for our species to die out. It would be better if there were no more people. Many people, but not I, find such a prospect inherently intolerable” (p. 353). One can read Benatar’s later works instead of his article from 1997, but I highlight the article from 1997 to illustrate how long his ideas have been published.

[18] Quote from Fehige (1998, 523).

[19] I talk more about such historical ideas and mention sources in Knutsson (2022a, sec. 1) . See also the quotes of Schopenhauer at the beginning of Fox (forthcoming), such as the following from Schopenhauer (2009, 202): “pain, suffering – which includes all lack, privation, need and even every wish – is what is positive, what is immediately felt. The nature of satisfaction, pleasure, or happiness, by contrast, consists only in a privation’s being removed, a pain’s being stilled. So they have an effect negatively.” And from Schopenhauer (2014, 1:355): “the nature of all enjoyment and all happiness is negative, whereas that of pain is positive.”

[20] Shiffrin (1999) talks about consent, harm, and risk. There is also Shiffrin (1993). Benatar (2015, sec. Abstract) argues that “we have a presumptive duty to desist from bringing into existence new members of species that cause vast amounts of harm”. Discussions of harm and consent can also be found in Singh (2012; 2018). Risk related to bringing beings into existence is talked about by Benatar (2017, chap. 4) and Magnusson (2022).

[21] Here are a few examples of published objections. There are plenty of replies to Benatar (as one can see in, e.g., Benatar 2013; Hallich and Hauskeller 2022). Replies to Fehige (1998) include Arrhenius (2000, sec. 5.2), Ryberg (1996, 165–66), and other sources listed at Frick (2014, 135–41) replies to Shiffrin (1999). Wolf has received much too little attention, in my opinion. I mention objections to the idea that undisturbedness is the hedonic ceiling in Knutsson (2022a).

[22] Examples of recent sources that might give a sense of some of the arguments in the debate include Ajantaival (2022), Knutsson (2022a; 2023, sec. 7), Gustafsson (2023), Mogensen (forthcoming), and Vinding’s (2022c; 2022f) replies to Gustafsson and Mogensen.

[23] One example is Frick (2014, 129–30, 152). Another example is Algander (2013, 152) who writes: “It might be claimed that the easiest way to defend the asymmetry would be to deny that benefits provide reasons under any circumstances. However, this view is very counter-intuitive. It suggests, for example, that the balance of reasons is almost always against creating people”. Algander speaks similarly on pp. 154–55. Wolf (1997, 117) lists the Anti-Natalist Objection as a common objection. The objection seems to be that a theory implies that we are obliged to never have children, and this is seemingly considered implausible or unacceptable. Roberts’ (2021, 222–23, 225, 228–30) reasoning about antinatalism is also interesting.

[24] The complications include the severe illbeing the created being will almost certainly experience, the eventual death of the created being, the risks that the being will be exposed to by existing, the lack of consent from the created being, the harm the created being will likely cause, and the opportunity costs in terms of helping existing beings and preventing future suffering.

[25] Examples of authors who have talked about similar matters include Huseby (2012), Wolf, Fehige, and Mogensen. Wolf (1996, 277) writes:

There is a more serious objection that may be raised against a view like the one I have outlined here. It might turn out that the best way to minimize suffering and deprivation in future generations would be to see to it that there will be no future generations at all. The principle defended here places no value on the existence of persons per se, but only disvalue on suffering and want.

Fehige (1998, 521–22) discusses the claim that “Nothing can be better than an empty world (a world without preferences, that is).” Mogensen (forthcoming) says that “the greatest cost of accepting LTNU [lexical threshold negative utilitarianism] is surely that it appears to support the desirability of human extinction or the extinction of all sentient life”, and Vinding (2022f) replies. See also note 26 about Parfit and a variant of the Absurd Conclusion.

[26] In addition, Parfit’s discussion of a variant of the Absurd Conclusion that he calls “(A)” is relevant to the present and previous sections since this variant is about empty populations and positive welfare counterbalancing others’ illbeing (Parfit 1986, 415–17). Parfit seems to hold that a future in which some suffer and many more have lives worth living is not worse than a future with no people. This assumption might have had a role in Parfit’s failure to find a theory that meets his requirements (Parfit 1986, 443).

[27] The two roles are related. For example, Thomas (2016, 1–2) presents Arrhenius’ impossibility theorems in terms of conclusions such as the Very Repugnant Conclusion, and Arrhenius’ (2003, 173) fifth impossibility theorem explicitly involves “Avoidance of the Very Repugnant Conclusion”.

[28] See also, e.g., the Ultra Repugnant Conclusion: “In order to improve, in a sub-noticeable way, the well being of a great many people, who already live happy lives, we may have to torture one person” (Tännsjö 2004, 220). Tännsjö (1996; 1998, chap. 5) also talks about the Ultra Repugnant Conclusion. Of course, one could formulate this conclusion in terms of ‘population’ and ‘better’, as in the case of the Very Repugnant Conclusion. Vinding (2021) formulated Creating Hell to Please the Blissful.

[29] This formulation of the Very Repugnant Conclusion is a quote from Arrhenius, Ryberg, and Tännsjö (2022). Earlier, Fehige (1998, 534–35) formulated the Very Repugnant Conclusion.

[30] This scrutiny can involve objections such as sequence arguments and objections to sharp and non-sharp thresholds, like for various other views that restrict tradeoffs. I talk about sequence arguments and mention literature in Knutsson (2021). In general, I find Ajantaival (2022) useful for thinking about the Very Repugnant Conclusion and similar conclusions.

[31] I mentioned sources with objections in notes 21 and 22.

[32] Various other formulations are also used instead of ‘positive welfare’. Roberts (2022) speaks in terms of ‘existences worth having’, e.g., in the following passages: “Assuming (here and throughout) that existence is worth having”. “As before, an assumption of the argument is that the existences under consideration are worth having. We should understand, however, that at least in theory a particular existence can be less than worth having: a child will be brought into existence who is made so miserable…”. Arrhenius et al. (2022, 2–3) explain the non-identity problem in terms of lives worth living. Frick (2020) talks about the non-identity problem in terms of creating a moderately happy life or a very happy life. Algander and Rasmussen (2019, 213) “distinguish two versions of the non-identity problem: one involving positive well-being and one involving negative well-being”, but my impression is that the non-identity problem is usually formulated in terms of only positive wellbeing and that this feature (the feature that the lives in question explicitly have positive wellbeing) is considered an important part of the non-identity problem.

[33] I talk about these theorems in more detail in Appendix 2.

[34] Arrhenius’ (2000, 16) PhD dissertation says:

Admittedly, the intuitive force of examples that we are to discuss is linked to our understanding of lives with positive and negative welfare. And if we were to radically revise these notions – for example by claiming (implausibly) that there are no lives worth living – then many of these examples would lose their force and many of the adequacy conditions that we are to propose would lose their relevance.

Of course, I would not speak in terms of “radically revise” and “implausibly”. Rather, if those who have claimed that there is no positive welfare are right, or if these ideas are the most reasonable, then, yes, many of the examples Arrhenius talks about lose their force and the adequacy conditions he proposes lose their relevance.

Similarly, Arrhenius, Ryberg, and Tännsjö (2022) write the following in their encyclopedia entry on the Repugnant Conclusion:

The above discussion of the Repugnant Conclusion presumes that there are possible lives with a very high quality of life. However, Christoph Fehige (1998) and David Benatar (2006) have suggested that there are no lives enjoying positive welfare. Benatar claims that it is always worse for a person to begin to exist than never to have existed. According to Fehige, only frustrated preferences count, and they count negatively, whereas satisfied preferences have no positive value. These “Schopenhauerian” theories imply that there are no possible lives with positive welfare. On the contrary, most lives have negative welfare and the best possible lives only have neutral welfare.

Would the truth of such a theory of welfare make the Repugnant Conclusion acceptable? Yes in a way, since it would neutralise the Repugnant Conclusion by making it an empty truth.

Similarly, regarding the non-identity problem, Rulli (2016, 308) writes that “Benatar’s view avoids the Non-identity Problem since he thinks no lives are worth living.”

[35] E.g., according to Roberts (2022): ‘Three intuitions are at stake in the nonidentity problem…. The second intuition is that an act that confers on a person an existence that is, though flawed, worth having in a case in which that same person could never have existed at all in the absence of that act does not make things worse for, or harm, and is not “bad for,” that person. In other words, conferring the existence that is unavoidably flawed and yet not so flawed that it is less than worth having does not make things worse for, or harm, and is not “bad for,” the person whose existence it is.’

[36] Tomlin (2022, 94–95) describes the non-identity problem partly in terms of ‘complaint’: “The non-identity problem arises when an agent faces a choice of whether to bring into existence a person who will be well off, or to bring into existence a different person who will be less well off. On the one hand, it seems intuitive there’s at least some moral reason to bring into existence the well off person. On the other, since one is choosing which of two people (or groups of people) to bring into existence, neither choice is worse for or better for any particular person (assuming all will have lives worth living). Since nobody is made worse off, arguably, nobody has any complaint about the choice.”

[37] E.g., in a section on the Mere Addition Paradox, Arrhenius et al. (2022, 4) write: “Comparing the value of the populations in the sequence leads to the following observations. A+ seems at least as good as A since A+ is a mere addition of positive well-being; it contains some extra people with positive well-being and the well-being of the A population is not affected. More generally, it seems that a mere addition of positive well-being is always at least as good as no mere addition (Parfit 1984).” Similar ideas are assumed in Arrhenius’ first and second impossibility theorems (see Appendix 2).

[38] E.g., the non-identity problem involves the idea that it would be wrong to create a being with lower positive welfare than another being with higher positive welfare. See, e.g., Roberts (2022) and Arrhenius et al. (2022, 2–3).

[39] See, e.g., Roberts (2022, sec. 2) and other literature on the non-identity problem.

[40] Ideas similar to mine can be found in Vinding (2022d, sec. Do the “intrinsically awesome lives” contain suffering or other bads?)

[41] I have written about relevant mechanisms and have pointed to sources in Knutsson (2020; 2022c). In addition to what I mention there, Millgram (2018, 138) writes that “philosophy today is a thoroughly corrupt discipline”. Millgram says: “Academics spend a good deal of time reviewing one another’s work; when referee reports enforce a party line, they are corrupt” (p. 153). And “citations are too often tit-for-tat arrangements, attempts to curry favor with those higher in the pecking order, or a means of placating potential reviewers. To engage in or to overlook these little dishonesties is to be a participant in the crass form of corruption that pervades academic philosophy today” (p. 154). Regarding population ethics in particular, Tännsjö (2020, 388) writes that “The rhetoric in the area of population ethics is rich”. I agree and there seems to be plenty of rhetoric that is not about truth, the merits of arguments, and the like. A minor observation is that in academic philosophy related to population ethics, one can hear things like the following rough and anonymised quotes: “I owe this to other philosopher X” and “You may want to cite the same philosopher X so that philosopher X might pay attention to you.”

[42] The case is in some ways similar but in other ways dissimilar for perspectives that only say that the existence of a billion times as many hellish lives is a billion times as bad (all else being equal). The concern for the astronomical stakes is similar and parts of population ethics are relevant to both, but a dissimilarity is that the idea about the value or moral importance of astronomical numbers of blissful lives seems to be challenged more in the population ethics literature, so those favourable to huge future populations might have a stronger interest in influencing what people think about population ethics so as to protect that controversial view. Ideas and texts in population ethics are probably seen as obstacles to the realisation of astronomical future populations. In contrast, the idea about the badness of vast numbers of hellish lives does not seem to be in as much need of protection from criticism and competing ideas in population ethics. So it seems, at least based on this dissimilarity alone, that people with merely the concern about hellish lives would have a weaker interest in influencing what people think about issues in population ethics.

[43] I call a prominent strand of this kind of effective altruism ‘Oxford-style’ effective altruism in Knutsson (2022d).

[44] Other factors probably include that ideas of “moral trade” and game-theoretic “cooperative” behaviour in these circles contribute to authors adjusting what they write as a matter of trade, compromise, and cooperation. For example, a pessimistic author omits certain pessimistic ideas in population ethics and mentions the potential flourishing far future, while an optimistic author in turn mentions the risk of suffering in the future and cites the pessimistic author’s text on that issue. A “win-win” from the authors’ perspectives that results in public texts looking different and more like a compromise.

[45] They were listed as trustees or board members of CEA on April 29, 2019, here, and on February 20, 2020, here.

[46] E.g., I was encouraged to reference “Greaves & Ord: Moral uncertainty about population axiology” and “Beckstead: On the Overwhelming Importance of Shaping the Far Future”. In addition, I was encouraged to reference “MacAskill (2014): Normative uncertainty”, which says that we have strong reasons to prevent the extinction of the human race (pp. 238–46). The texts by Greaves, Ord, and Beckstead are of low quality in my opinion, but I have not spent enough time on MacAskill’s to evaluate its overall quality.

[47] Here are some of the reasons why one should not do it: (1) It goes against seemingly widespread and reasonable ideas about how scholarship is supposed to work (where merit, ideas, and intellectual openness are supposed to be central, not secret deals, money, and exchanging favours). (2) It erodes trust in what people say and write. (3) It is a disservice to the readers because they become less informed, and it could, relatedly, be paternalistic. (4) It is not transparent. (5) It distorts the landscape of ideas, authors, and works so that some of them are artificially cited and mentioned more while others are cited and mentioned less. (6) The behaviour might very well have other morally problematic aspects. After all, outsiders react to it with words such as ‘corrupt’, ‘slimy’, and ‘manipulative’. (7) The field of moral philosophy, including value theory, can lose credibility, appeal, and integrity when some of those involved are moral philosophers. (8) The behaviour might violate existing rules. A person knowledgeable about research ethics said that this does not look good, that research should not be conducted like that, and that it was among the strangest things they had heard of. The person also floated the idea that a couple of researchers in Sweden could be reported for merely knowing about the secret coordination but keeping quiet. Participating in the deal would seemingly be even more at risk of being an official violation of research integrity. (It puzzles me how this is allowed at Oxford University, if indeed it is.) Encouraging researchers to participate in the deal would seemingly be to encourage such a potential violation. When talk of future money to a current public university employee is involved, as in my case, we might get into the territory of a foreign person or organisation secretly using money as a carrot to make a government researcher change their research output, which sounds potentially serious.

[48] In a review of MacAskill (2022), total utilitarian Torbjörn Tännsjö (2023) writes that “the author [MacAskill] initially uses a demagogic trick” (my translation). The full original passage in Swedish is: “Man får nog säga att författaren initialt tillgriper ett demagogiskt trick för att få oss att gå med på att så är fallet. Redan bokens titel är förledande.” See also Vinding (2022e; 2022g), and St. Jules’ critical comments on’s population ethics article. Plant’s (2023) review of MacAskill’s book is the best academic review of that book that I have seen. Here are a few quotes from Plant’s review:

At times, I found the book uncomfortably polemical, as if MacAskill had set out to convince the reader, as effectively as possible, to share his conclusion, even if they would not fully understand the reasons for it and the challenges to them.

MacAskill presents his premises as simple and uncontroversial when they are not.

In framing the debate as being about future people, MacAskill has distractingly mauled a strawman.

I am unsympathetic to his portrayal of the Total View as uncontroversial.

Hence, it seems objectionable to describe the premises as simple and uncontroversial, especially when the readers are primarily non-philosophers who are liable to take MacAskill at his word.

Plant has also made sensible comments in the past, like the one below in response to the essay “Presenting the long-term value thesis” from late 2017 by Benjamin Todd, the CEO and co-founder of 80,000 Hours. I wrote about Plant’s comment in 2019 where I also mentioned that “the organisation 80,000 Hours, where MacAskill is President, is a part of CEA” (the Centre for Effective Altruism). I agree with Plant’s comment:

I found this woefully one-sided and uncharitable towards person-affecting views (i.e. the view we should ‘make people happy, not make happy people’). I would honestly have expected a better quality of argument from effective altruists…. 1. Your ‘summary of the debate’ was entirely philosophers who all agree with your view. This is poor academic form.

[49] I do not base my statement on the following source at all, but a reader might want to know about it: It seems to be written by one of the co-authors of Chappell, Meissner, and MacAskill (2023), which is a text I am discussing in this section (see

[50] Why should they not be used in teaching as regular literature? In a comprehensive answer, I would appeal to the content of this section and the sources I mention, and one could write a detailed motivation for each text. But here are some of the reasons, briefly stated: (1) The texts omit important ideas and works opposed to the authors’ view. (2) They look like they were written to influence rather than educate. (3) They tend to be rhetorical, one-sided, and uncharitable in a way that consistently favours the authors’ view. (4) They make sweeping, unsubstantiated statements in favour of the authors’ view, which is a practice students should not learn. (5) There are reasons to avoid using texts by authors who have been involved in secret coordination of the kind described earlier in this section. (6) When selecting texts representing the total utilitarian perspective, it is better instead to use texts that plainly and transparently argue for that view. When teaching, it seems much better to take the approach ‘here is a text by a total utilitarian that clearly explains and argues for that theory’ rather than the following approach: ‘Here is a text that purports to be a textbook but that in subtle and not so subtle ways appears designed to convince students of the total utilitarian view rather than to educate them. Be mindful of these rhetorical methods, uncharitable statements, omissions, and so on.’ (Unless, e.g., the teacher explicitly wants students to critically analyse advocacy methods in a purported textbook.)

[51] E.g., Ord (2020, 260) says that “the rivals to the Total View have their own counterintuitive consequences, and indeed there are celebrated impossibility results in the field which show that every theory will have at least one moral implication that most people find implausible. So we cannot hope to find an answer that fits all our intuitions and will need to weigh up how bad each of these unintuitive consequences is.” Chappell, Meissner, and MacAskill (2023) write the following in the section that defends the total view: “A final response is to note that counterintuitive implications are by no means unique to the total view. Several impossibility theorems prove that it is logically impossible for any population ethical theory to satisfy every intuitively desirable principle and axiom.” And at the end of their text, they write that “impossibility theorems prove that no population ethical theory can satisfy all the intuitive principles or axioms that we might have hoped for”. The Wikipedia article on population ethics states that “All major theories in population ethics tend to produce counterintuitive results”.

[52] E.g., Ord (2020, 260) says, “The main critique of the Total View is that it leads to something called the repugnant conclusion” and that book does not mention the Very Repugnant Conclusion, as far as I can see. Chappell, Meissner, and MacAskill (2023) puts the Repugnant Conclusion front and centre. They mention Spears and Budolfson as part of a defence of the total view, but not the counter by Ajantaival (2022). To their credit, they do mention the Very Repugnant Conclusion, but only in note 10 and among further reading, and then only a text by Arrhenius but not Fehige (1998). MacAskill (2022) talks plenty about the Repugnant Conclusion but I see nothing about the Very Repugnant Conclusion. See also Vinding (2022g) and Ajantaival (2021, sec. 3.3) .

[53] See, e.g., Ord (2020, 261–63). Chappell, Meissner, and MacAskill (2023) talk about person-affecting views in terms of “slogan” and “intuition” and write, e.g., the following about the procreative asymmetry: “While many find this principle intuitive, it is notoriously difficult to provide a principled basis for it. The procreative asymmetry also has several deeply problematic implications, stemming from its failure to consider positive lives to be a good thing.” Since this text is presented as a textbook, it should mention what the alternative bases for the asymmetry are and why one might not “consider positive lives to be a good thing”. For more examples of what they write in their section “Person-Affecting Views and the Procreative Asymmetry”, see note 54 below.

[54] See, e.g., Ord’s (2020, 260) usage of “most people” (see note 51 above). According to Ord (2020, 263), “Person-affecting views fit our intuitions well in some cases, but poorly in others. The case in question—whether extinction would be bad—is one where these views offer advice most people find very counterintuitive.” Ord (2020, 47) writes: ‘Some of the more extreme approaches to this relatively new field of “population ethics” imply that there is no reason to avoid extinction stemming from considerations of future generations—it just doesn’t matter whether these future people come into being or not.’ Chappell, Meissner, and MacAskill’s (2023) “textbook targeted at the undergraduate level” (which is rather an opinion and advocacy text) uses the following language in the section “Person-Affecting Views and the Procreative Asymmetry” that deals with views they oppose: “has several deeply problematic implications, stemming from its failure”, “falsely implies”, “clearly, we should prefer”, “even more misguided”, “most people would prefer”, “perversely”, “a deeper problem”, “perverse”, “seems wrong”, “too nihilistic and divorced from humanistic values to be worth taking seriously”, and “for all these reasons, utilitarians are largely united in rejecting person-affecting views”. These are, of course, merely isolated pieces of text that I have quoted. I suggest reading the whole source while critically paying attention to the language, including these example pieces of text and the surrounding text. See also Vinding (2022e) and St. Jules’ comment.

[55] E.g., for further reading, Ord (2020, 285–87) points the reader to authors with similar views and messages as Ord, such as Beckstead, Bostrom, Leslie, and Parfit. Ord’s book points to for further reading lists and course outlines (p. 285). The web page similarly mentions texts with the same ethical message as Ord, including MacAskill’s What We Owe The Future and an online text by Roser that says “I recommend ‘What We Owe The Future’, the new book by philosopher Will MacAskill” and “I recommend Toby Ord’s extraordinary book ‘The Precipice’. It is one of the most important books I have read.” The web page also says “The website lists a number of resources for further reading”. So the reader gets shuffled around to different websites. What is It is a website that seems to convey the same message as Ord and writes that “The Oxford philosopher Toby Ord summarises the moral significance of existential risks in his book The Precipice”. At the top of, it says

The Precipice by Toby Ord (2020)

This path-breaking book is a good place to start. It explores the science and philosophy behind the large-scale risks we face. It puts them in the context of the greater story of humanity: showing how ending these risks is among the most pressing moral issues of our time. And it points the way forward, to the actions and strategies we can take today to safeguard humanity’s future.

For a briefer introduction to the ideas in The Precipice, you can watch this 20-minute presentation, narrated by the author. If you prefer podcasts, we recommend this interview with Toby about why the long-term future of humanity matters more than anything else, and what we should do about it.

What We Owe The Future by William MacAskill (2022)

Who is behind It says “This site was made by Fin Moorhouse, a Research Scholar at the Future of Humanity Institute at Oxford University”, where Ord is a Senior Research Fellow, and if one goes to it says “I was a Research Scholar and assistant to Toby Ord”.

The web page presents “a sample syllabus on existential risk, intended as a helpful resource for people developing courses on existential risk — in schools, universities, independent reading groups, or elsewhere. It assumes that those participating have access to The Precipice, so takes this as the central text.” Of course, the syllabus should not be used by any respectable teacher or educational institution, and it looks like an attempt to try to spread the author’s opinions and ideas to students. As expected and as usual, the part about the ethics of existential risk in the syllabus is very one-sided and completely omits literature that would counter Ord’s take on that ethics. More specifically, the part “Ethics of existential risk” only lists Ord’s The Precipice, Bostrom’s “Astronomical Waste” article, two pages from Parfit’s Reasons and Persons where Parfit communicates essentially the same ethical message on extinction as Ord does, and “Annette Baier (1981). ‘The Rights of Past and Future Persons’” (this source is seemingly Baier 1981) that says that “Our duty to the past is to ensure that, short of catastrophe, there be future persons” (p. 181; see also pp. 177–78).

[56] Here are a few examples of philosophers who have written on population ethics and whose work I have a good impression of: John Broome, Erik Carlson, Elizabeth Finneron-Burns, Nils Holtug, Christopher Meacham, Wlodek Rabinowicz, Melinda A. Roberts, Torbjörn Tännsjö, and Clark Wolf. I know the philosophers and their work to different extents. For example, Carlson used to be my teacher, I have spent a lot of time on his work, and I have a great impression of it and him. Although I am not as familiar with everyone on the list, I have no particular reason to think that their work is problematic when it comes to integrity or strategic influence methods.

[57] A third example of a question that can remain is whether it can be permissible to procreate or create a being if, for example, the existence of the new being is expected to reduce extreme suffering and the new being is expected to have a relatively fortunate life. But this is not even close to the most important question to investigate, in my opinion. The question matters but further research on it does not seem to be as consequential for the world as other research that concerns ethics related to larger-scale events that could, for instance, lead to extinction or worlds that are much worse than our current world.

[58] E.g.,, and

[59] I have sketched thoughts on ethics related to a population of zero in Knutsson (2022b).

[60] Ajantaival (2022) contains figures that illustrate different “repugnant” conclusions. The topic of weighing bads (or goods) against one another seems older, broader, and more fundamental than questions about populations. For example, Arrhenius (2005, 97) talks about the ideas “Any amount of A is better than any amount of B” and “Some amount of A is better than any amount of B”, and says:

It is easy to find examples of these ideas in the literature. For example, early in the 20th century Franz Brentano claimed that ‘‘[i]t is quite possible for there to be a class of goods which could be increased ad indefinitum but without exceeding a given finite good’’.1 Likewise, W. D. Ross asserted that ‘‘[w]ith respect to pleasure and virtue, it seems to me much more likely to be the truth that no amount of pleasure is equal to any amount of virtue, that in fact virtue belongs to a higher order of value, beginning at a point higher on the scale of value than pleasure ever reaches…’’2 Similar views have been proposed by, among others, Roger Crisp, Jonathan Glover, James Griffin, Rem Edwards, Noah Lemos, Derek Parfit, and John Skorupski.3 Its lineage goes back to at least Francis Hutcheson in the early 18th century and of course John Stuart Mill in the mid 19th century.

[61] I am grateful for comments on earlier versions by Teo Ajantaival, Tobias Baumann, Erik Carlson, Michael St. Jules, and Clark Wolf. Magnus Vinding has been exceptionally helpful. Of course, all opinions expressed are my own and the fact that I thank someone does not imply that they agree with what I write. This essay is also published on the Center for Reducing Suffering (CRS) website. Writing this essay was a project during my part-time work for CRS.

[62] Huseby (2012, 187) says, “Most of the theories that have been discussed in the literature are versions of Utilitarianism.”

[63] See, e.g., Broome (1992, 27–28, 41, 132).

[64] E.g., in Narveson (1963), Narveson (1967b), and Narveson (1967a).

[65] See also Narveson (1978, 45–53; 1967a, 47–50).

[66] According to this biography.

[67] Relatedly, Narveson (1967a, 49) wrote: “The conclusion, then, is that there can be a moral reason (on utilitarian grounds, arising from hypothetical considerations about the happiness, or reverse, which would be the lot of children if produced) for not having children, but there cannot be such a reason for having them.”

[68] Parfit writes, ‘Though my remarks here are critical, I owe a great deal to Narveson’s first article, [“Utilitarianism and New Generations,” Mind 76 (1967): 62–72]’. Quote from Parfit (1976, 109), square brackets in the original.

[69] The fuller quote from Narveson (1973, 78) is: “I owe to discussions with Derek Parfit, and those attending his classes in Trinity term 1971 at Oxford, both the stimulus for considering the problem again and the way of formulating it that gives rise to Sec. IV.”

[70] Quote from Parfit (1976, 100). And Parfit (1976, 100) says, “All that I shall do here is sketch some of the difficulties still facing Narveson and Peter Singer”.

[71] I focus on the axiological theorems, as Arrhenius and others seemingly do. There are normative versions of the theorems (Arrhenius 2000, chap. 11), but they seem at least as vulnerable to the critical points I make in this appendix as the axiological theorems are.

[72] The Quality Condition I quote in this section says “There is at least one perfectly equal population with very high positive welfare”, which I deny because I deny the existence of positive welfare, and Arrhenius’ (2000, 156) exact formulation of the Quality Condition starts with “There are two positive welfare ranges R(u, v) and R(1, y), u > y”, which I also reject because there is no range of positive welfare levels (there are no positive welfare levels at all).

[73] These fourth, fifth, and sixth theorems are quotes from Arrhenius (2000, 167; 2003, 173; 2009, 30), respectively, except that I added ‘Impossibility’ in the name of the fourth theorem, and in the names of the fifth and sixth theorems, I added ‘Fifth’ and ‘Sixth’ to number the theorems.

Answers in population ethics were published long ago