In a recent thought-provoking article, Patrick Kaczmarek and S. J. Beard argue that intentionally causing human extinction would be wrong because it wrongs past people by making their sacrifices less morally worthwhile. They begin with a compelling example:
Liver Transplant. Through no fault of his own, Jeff is very sick. He desperately needs a liver transplant. Though he is not obliged to do so, a stranger called Michael gives Jeff part of his liver at the cost of reducing his own lifespan by ten years. After the procedure, Jeff drinks heavily, and he dies from cirrhosis four months later.Footnote 1
The authors contend that the shortening of Michael's life is a bad thing, despite being morally justified, and that this bad thing is made worse by the fact that Jeff subsequently drinks himself to death. This is because Jeff's actions post-transplant fail to realise the full extent of the benefits made possible by Michael's sacrifice. They argue that ‘although our subsequent actions cannot prevent the harms that are involved in making a sacrifice, they can thus make this state better or worse all-things-considered by making these harms worthwhile’ (201) and therefore that ‘worthwhileness appears to alter the reasons we have for acting to varying degrees’ (201). They call this the Moral Worthwhileness Intuition (MWI): if a recipient makes the sacrifice not morally worthwhile, they wrong the giver.
Their contention is that for anyone who subscribes to the No Complainants Claim – an act cannot be wrong unless there is or will be someone whom this act wronged – and feels the force of MWI, there is a reason to prevent human extinction. They argue that this reason is present across a variety of moral theories and explicitly deny that their arguments depend on any one in particular.
The crux of their argument against human extinction is:
Even if it would not wrong any future people if ours was to be the last generation of humans, it still seems to wrong past people who had anticipated and made grave sacrifices for the benefit of future generations and the long-term future of our species. Only if future generations actually exist, and enjoy lives that are worth living, will these sacrifices be worthwhile. (201)
In the article Kaczmarek and Beard raise several potential objections to their view and while I am not fully satisfied by their replies, for space considerations, I will limit the focus of my comments here to two main areas: (1) there is an ambiguity about what makes a sacrifice morally worthwhile; (2) the authors’ conclusions rely on the unacknowledged and unsupported assumption that existential benefits exist and are of moral importance.
When is a sacrifice morally worthwhile?
The authors argue that a sacrifice is not morally worthwhile if the beneficiary fails to ‘realise the full benefits of the sacrifice’.Footnote 2 However, there is an ambiguity in what it means to realise the full benefits of a sacrifice, leaving open three possible interpretations, each of which is suggested at different points in the article.
i. When the benefits are at least equal to the amount sacrificed
Kaczmarek and Beard write:
Michael did the right thing because he judged that Jeff could expect to get much more than the ten years of additional life that Michael himself had sacrificed. He trusted Jeff to realize this full benefit from his sacrifice, making it, in other words, worthwhile. However, Jeff's actions post-surgery meant that he actually benefited a lot less than Michael had lost. (201; my emphasis)
The final sentence of this paragraph suggests that Jeff wrongs Michael by benefiting less than Michael sacrificed. On this interpretation, if Jeff did not die of cirrhosis until at least ten years after his transplant, Michael's sacrifice would be morally worthwhile and no wrong would have been done because Jeff did not benefit less than Michael sacrificed; the benefits and sacrifice were equal.
ii. When benefits are greater than the sacrifice
However, Unfinished Business – ‘If actor p reasonably judges performing a supererogatory act ϕ at great sacrifice to herself will enable beneficiary q to achieve a greater good, then failure to promote the good made possible by ϕ wrongs p’ (202; my emphasis) – and the first sentence in the paragraph quoted above suggest a different interpretation. This is that the wrong comes from the fact that the benefits to Jeff are not more than the sacrifice Michael makes. On this view if Jeff dies of cirrhosis at exactly ten years post-transplant, he does wrong to Michael, but if he lives at least one day beyond that, he does not.
iii. When benefits are maximised
Later in the article, however, Kaczmarek and Beard imply that it is not enough even that the benefits are more than the sacrifice; rather, they should be the maximum possible. For example, they say: ‘Michael could reasonably expect Jeff to refrain from drinking, and even to dedicate himself to some higher good, as a result of sacrificing his liver’ (202; my emphasis). This reference to Michael's legitimate expectation that Jeff would dedicate himself to a higher good suggests that the authors think that in order for Michael's sacrifice to be morally worthwhile, and for Jeff not to have wronged him, it is still not enough that Jeff simply lives at least ten more years (equal to the number of years Michael loses). Rather, Jeff needs to do even more than that – dedicate his life to some noble cause. If Jeff lived forty years, but never left the house or contributed to society, he would have wronged Michael by failing to make Michael's sacrifice morally worthwhile. In other words, for a sacrifice to be morally worthwhile, the benefits (to the recipient or to others) need to be maximised.
There is a question about the source of even a pro tanto wrong here. Briefly, the sentence after the paragraph cited above reads ‘Jeff thus betrayed Michael's trust and thereby wronged him’ (201). This sentence suggests that the wrong comes from Jeff betraying Michael's trust. One question is what it is that Michael trusted Jeff to do. Was it to live at least ten years, live more than ten years, or live forty years and also dedicate his life to curing cancer? However, it is not clear to me why trust is relevant here at all. The wrong in breaking trust seems to be in failing to do something you said you would do, rather than in weighing sacrifices and benefits. If Jeff had promised Michael that he would not drink so that he could live as long as possible, then it would be a betrayal of trust to drink himself to death four months later, but this would not be because he lived fewer additional years than Michael sacrificed or failed to maximise the benefits of Michael's sacrifice; it would be because he said he wouldn't drink. It does not seem to me that unilaterally placing my trust in someone else can result in a wrong to me if they do not do what I trusted them to do. If I trust my neighbour to feed my cats when I go on vacation, it is not a betrayal of my trust or a wrong to me when I come home to hungry cats since my neighbours never said they would feed them in the first place. Or, more analogously to Liver Transplant, if I give my neighbour 1 million dollars, trusting them to spend it on their children's education, they have not betrayed my trust or wronged me if they choose to spend it on home renovations instead unless they agreed to spend it on education in the first place. In any case, there is no such agreement between Michael and Jeff in Liver Transplant and indeed the two parties are set up as strangers, so the source of wrongness being found in a betrayal of trust is peculiar.
Although there is an ambiguity, I think the third interpretation (maximising benefits) is the one intended by the authors. The choice of the phrase – which they repeat multiple times in the article – ‘realise the full benefits/value of the sacrifice’ suggests to me the maximisation view. But it is very important to be clear on this, and not just because precision is a crucial part of philosophical writing. It is also important because if I am correct that the authors intend the latter interpretation, there are two problems. First, the authors never justify why benefits need to be maximised as opposed to simply at least equal to the sacrifice, and their core argument against human extinction depends on it. Second, it leaves undefined how much Jeff needs to do in order to ‘fully realise the benefits’ of Michael's sacrifice, make it morally worthwhile, and therefore not wrong him. This then gives rise to several of the objections the authors do address in the article. The authors claim that our duties to maximise benefits are not unbounded and that they will address this later in the article. Unfortunately, I was unable to find any discussion that explained or justified these limits.
One objection they do consider is that the person making a sacrifice needs to have some intention to do a particular good in order for a failure of someone else to bring about that good to have wronged the sacrificer. The objection is that since our ancestors did not free the slaves (for example) in order to prolong humanity, moral worthwhileness does not preclude extinction. The authors argue that the objection misunderstands what we learn from Liver Transplant. They say that in Liver Transplant the harm to Michael from his donation is even more worthwhile if Jeff cures cancer. They claim that this assessment would not change just in case Michael never imagined this result when he donated his liver; in his mind he was just sacrificing ten years of his life so Jeff could have forty.
Table 1 shows how the two cases compare in terms of the reason for the sacrifice and the outcomes/benefits.
Reasons for and outcomes of sacrifice
In Liver Transplant we see that Jeff gains forty years of life, and those forty years of life allow him the time to create the additional benefit of discovering a cure for cancer. On the authors’ view, ‘the moral reason Jeff has to realise the upper bound of value made possible by Michael's sacrifice does not appear to be constrained in some way by the mere fact that Michael has wildly underestimated the value of his organ donation’ (204). In the case of humanity as a whole, our ancestors ended slavery, and the added, unanticipated ‘benefit’Footnote 3 could be that humanity continues for a long time with good lives.
To argue their point against the objection, the authors claim that even though Michael did not donate his liver with the intention that Jeff cure cancer, once Jeff has the opportunity to cure cancer, he ought to do so at pains of wronging Jeff by not realising the ‘upper bound of value made possible by Michael's sacrifice’ (204). Similarly, in order not to wrong our ancestors, we ought to realise the upper bound of value made possible by their sacrifice in ending slavery. Failing to continue humanity for as long as possible would only wrong our ancestors if the wrong comes from failing to realise the full value of any sacrifice. Although I also disagree with the authors’ core claims here,Footnote 4 my point is to show that their response to the objection depends on a particular interpretation of the distinction above. In this case, benefits must be maximised in order not to wrong those who made the sacrifices. If it is not required to maximise the benefits made possible by a sacrifice, then there is no further requirement to continue the human species. If all we had to do to avoid wronging past people were to ensure that the benefits were at least as great as the sacrifice made, then there would be no duty for us at all since the benefits of there being an end to slavery are surely already greater on their own than the sacrifice it took to end the practice.
The objections that we are being extorted by past people (204–05) and the concern for bodily integrity (205–07) both arise from the anticipated worry that the requirement to maximise the benefits made possible through past people's sacrifices non-consensually constrains current people's freedom, including the freedom to decide whether or not to have children. The underlying thought behind these objections seems to be that people should not be morally required to organise their lives and activities around maximising benefits that they never asked for, and that there is essentially no limit to what they may be required to do. If the authors intended interpretations (i) or (ii) these worries would be much less serious as there is a clear limit on how much can be required – you must ensure benefits are as much/at least as much as the sacrifice. Of course, if the authors did that, the strength of their core argument that allowing harmless extinction is wrong would be seriously weakened.
What is the benefit in prolonging humanity?
Kaczmarek and Beard argue that prolonging human history allows our successors to experience more of the best things in life, making the sacrifices made by our ancestors morally worthwhile. Giving examples of such sacrifices, they write: ‘our ancestors fought for democracy, freed slaves, built the infrastructure that serves us, struggled through the Black Death and so forth’ (204).
A relatively minor objection here is to reject the idea that these were sacrifices at all, at least according to the meaning the authors seem to impute, because on multiple occasions in the article they describe the sacrifices relevant to the article in general, and in Unfinished Business specifically, as being supererogatory.Footnote 5 I find it implausible that freeing slaves was supererogatory, and therefore a ‘sacrifice’. Rather, it was (certain of) our ancestors’ moral obligation to give up something to which they were not entitled in the first place. Surviving the Black Death was not something people did for some greater good, but because they themselves wanted to live. Fighting for democracy and building infrastructure may be supererogatory, but unlike Michael's donation, they were at least partly self-interested acts. It is true that both benefit current and likely future people, but they also benefited the people at the time. When French citizens stormed the Bastille they were clearly willing to die for the sake of democracy for others – after all, if they died, they would not benefit from democratic change. But they also certainly fervently hoped they would live and enjoy that democracy themselves. The same is true of infrastructure building. People build schools, hospitals, roads, etc. so that present people and future people can enjoy them. Especially given the much-lamented short-term focus of successive governments, it would be unusual for a large infrastructure project to be delivered solely for the benefit of those in, say, a hundred years’ time. Indeed, this is a large part of the reason why we have so far failed to do anything significant in the way of climate change mitigation. Nonetheless, let us be charitable and assume that the authors were just too hasty with their examples of our ancestors’ sacrifices, and assume that they did indeed make sacrifices for our sake.Footnote 6 Who was the sacrifice for?
In Liver Transplant there is a clear beneficiary of Michael's sacrifice – Jeff. For the extinction case to be analogous to Liver Transplant, humanity itself must benefit from past people's sacrifices. How could humanity benefit from past people's sacrifices?
The authors seem to think that there are benefits in humanity continuing for as long as possible. Just as Jeff should maximise his benefits by surviving for as long as possible, so too must humanity maximise its benefits by surviving as long as possible. Of course, the way humanity survives longer is through the creation of more people. Without more people, humanity ‘dies’. For an individual person like Jeff, the benefit in surviving for as long as possible is in having time to do the things you enjoy, whether it be spending time with family, finishing personal projects, engaging in hobbies, etc. How may a longer ‘life’ be a benefit to humanity itself?
I think there are two ways we might try to make sense of this ‘benefit’. The first is to deny that ‘humanity’ is itself something that can be benefited, in the same spirit as Margaret Thatcher said ‘there is no such thing as society. There are individual men and women’ (Keay Reference Keay1987). On this view, we would say that the benefit is not to humanity itself, but to the individuals who get a chance to exist who would not have existed if human extinction had happened sooner. There are two problems this interpretation poses for the article's argument. The first is that it is no longer analogous to Liver Transplant. In the transplant case, the benefit is clearly a personal benefit for the individual person Jeff. In the case of humanity, the benefit is not to humanity per se but to its constituent members. There is no equivalent in Liver Transplant unless we see survival as only beneficial to particular constituent parts of Jeff, a view that would raise all sorts of metaphysical difficulties.
We need to ask what is driving the thought that humanity continuing is a good thing or benefit that makes past people's sacrifices morally worthwhile. I suspect that Kaczmarek and Beard would not consider it better if only one human existed for 2 billion years than for 6 billion people to exist for each of 5,000 years. In the former case, humanity ‘survives’ for longer, but in the latter, more people live to make past people's sacrifices morally worthwhile. If my suspicion about Kaczmarek and Beard's view on the case is correct, their underlying assumption must be that there is something good about more people getting to exist that makes past sacrifices more beneficial and thus more morally worthwhile.
But this raises the second problem, which is that their argument depends on the claim that people are benefited by being brought into existence, or that it is a good thing for there to be more people, depending on whether one takes a personal or impersonal interpretation of their view. However, both of these views are rejected by many philosophers (e.g. see Narveson Reference Narveson1967; Benatar Reference Benatar2006; Weinberg Reference Weinberg2015). Although space precludes a defence of this position, it is important to note that Kaczmarek and Beard's arguments will not be convincing to anyone who denies existential benefits, including contractualists – the view the article purports to persuade (Weinberg Reference Weinberg2008; Finneron-Burns Reference Finneron-Burns2016).
The other way we might think humanity itself benefits from longevity is if it is just a good thing for it to survive for as long as possible. The benefit or value here is impersonal since humanity is not a person for whom things can go better or worse. However, relying on the impersonal or intrinsic goodness of humanity's continuation begs the question and is therefore unpersuasive to those moved by the No Complainants Claim (199). It is a matter for debate whether there actually is any impersonal value in humanity's continued existence, and claiming that there is, is a substantive moral claim, again one that does not move contractualists (Finneron-Burns Reference Finneron-Burns2017).
However, those who do accept the idea of existential benefits may not agree that they influence the worthwhileness of past sacrifices in the way Kaczmarek and Beard's argument requires. Returning to Liver Transplant, it is not clear to me why it is the extra amount (length) of life that Michael's donation grants Jeff that is important in determining the worthwhileness of Michael's sacrifice. Rather, what seems to matter most is the total extra quality of life (or happiness/well-being if you prefer) that Jeff is afforded by Michael's sacrifice, and this need not be determined by the number of extra years he lives. If Michael's sacrifice allows Jeff to live an additional forty long years of misery, is that really more worthwhile than if he lived four additional months of pure bliss found at the bottom of many bottles of the finest champagne?
With respect to Liver Transplant, the authors at times do include non-longevity benefits in the determination of moral worthwhileness, such as when they claim that Michael's sacrifice would be even more worthwhile if Jeff found a cure for cancer (201). However, they do not consider that the same may be true with respect to humanity as a whole. One plausible way humanity could benefit from the sacrifices of past generations is not through surviving a long time, but through humanity's constituent parts – people – enjoying extraordinarily high-quality lives, perhaps even higher than would have been enjoyed by those who would exist if the sacrifices had not been made. Imagine that the sacrifices of past people allowed each of us the opportunity to live for 1,000 superb years, but at the cost of not being able to have children. It might reasonably seem that we would make the sacrifices of past generations less worthwhile if we failed to take up this opportunity, even though it would ultimately shorten the ‘lifespan’ of humanity as a whole.Footnote 7
Ultimately, I find the intuition about moral worthwhileness unique and very thought-provoking. However, for the reasons outlined above, I do not yet find it persuasive as a reason to prevent human extinction, particularly for those who do not consider it to be a benefit for there to be more people.
Acknowledgements
Thanks to two anonymous reviewers and Dale Miller for very helpful comments on previous versions of this article, and to Charles Jones and Richard Vernon for illuminating discussions about the topics in it. Work on the article was done with the generous support of Riksbankens Jubileumsfond.
Competing Interests
The author declares none.
