Extinction is the worst possible impact by eradicating all current and possible value---it’s profoundly evil, even if they win all of their arguments

But claiming that there should not be any more people does not imply that the population should be zero. As already stated: life-extension technologies could enable people to live indefinitely long lives – that is, to attain what I call “functional immortality”, whereby one lives until she either succumbs to injury, commits suicide, or perishes due to the heat death of the universe.8 This gestures the “dual policy” at the heart of no-extinction anti-natalism: first, we should stop procreating entirely (anti-natalism), and second, we should develop safe and effective life-extension technologies (pro-immortalism). This should appeal to Benatar himself given his anti-Epicurean view that death is (often) bad and, as such, one ought to (typically) avoid it. The reason is that, when evaluating an outcome, any harm at all “will be decisive”. Since “we (usually) have an interest in continuing to exist…death may be thought of as a harm, even though coming into existence is also a harm” (Benatar 2006, 213). This links to an important distinction between “lives worth starting” and “lives worth continuing”. Although life is much worse than most of us realise, many lives are not so bad as to warrant suicide. Thus, they are worth continuing even though they were not worth starting, much like a movie that is worth finishing but not having started. (If only you had known the movie was bad, you would have stayed home rather than venturing out to the theatre.)

But just as there are human lives worth continuing, there are arguments for why human existence is worth continuing, even if it would have been better for our evolutionary lineage never to have been. The strongest argument against human extinction, if sound, comes from total utilitarianism. The first to articulate this idea was Henry Sidgwick [1874] 1962, although more recent versions proceed by calculating how many people could come to populate Earth or our future light cone, with some claiming that up to 10^46 “human lifetimes” could exist per century within our galactic supercluster (Ćirković 2002). Since people are the substrate or “containers” of well-being (or value), the more people there are with net positive amounts of well-being, the better things will go from the “point of view of the universe”. But creating new lives is incompatible with anti-natalism, so this line of argumentation is a non-starter in the present context. There is, however, an alternative approach that focuses not on the total number of people but on the quality of their lives – rather than merely “lives not so bad as to warrant suicide”, there could exist future life conditions that are extremely good and hence very much worth continuing.

Why believe that life in the future could improve? There are at least two reasons. First, there is at least some evidence that violence has declined over the past several centuries, if not longer (see Ferguson 2012 for criticisms). Since the middle of the twentieth century, the rights of many groups has expanded in the West, including women, minorities, LGBTQ people, and non-human animals – a process driven by what Steven Pinker (2011) names the “moral Flynn effect”. If this trend continues, we should expect the world to become even more peaceable and tolerant in the future; as Martin Luther King Jr. (1958) hypothesised, “the arc of the moral universe is long, but it bends toward justice”. Second, some transhumanists argue that radical human enhancements could significantly improve the human condition by augmenting core human capacities like cognition, emotion, wisdom, and morality (Bostrom 2008; Persson and Savulescu 2012). Transhumanist philosophers tell us that such enhancements could create a posthuman condition that is far superior in uncontroversial ways than the present human condition, which is marked by pervasive ignorance, violence, foolishness, and iniquity. Together, these two trends could greatly decrease the “magnitude”, to borrow Benatar’s term, of harm in the world. In doing so, they would yield a future situation marked by far more well-being than there is today, which is good from a total (and average) utilitarian perspective.

But one need not embrace utilitarianism to strongly oppose human extinction. I have elsewhere explored these arguments in great detail, so I will here offer only some brief summaries, directing readers to my prior work. The point is to underline that there are multiple lines of argumentation that (a) are compatible with Benatarian anti-natalism, and (b) independently converge on the conclusion that human extinction, if it were to occur, would constitute an immense tragedy. A few of these are:

(i) The argument from unfinished business. This states that, to quote Edmund Burke (1790, 359), civilisation is “a partnership not only between those who are living, but between those who are living, those who are dead, and those who are to be born”. That is to say, humanity is “building something” over time – a morally better society, a complete scientific picture of the universe, a world with no more scarcity, and so on – such that it behoves us not to end up being the failing link in the chain of generations.

(ii) The argument from cosmic uniqueness. According to a recent study that replaces the variables in the Drake equation with probability distributions, there is a very high probability that we are the only intelligent life forms in the Milky Way galaxy, if not the visible universe (Sandberg et al. 2018). To quote Parfit (2017, 437) once more:

if we are the only rational beings in the Universe…it matters even more whether we shall have descendants or successors during the billions of years in which that would be possible. Some of our successors might live lives and create worlds that…would give us all…reasons to be glad that the Universe exists.

(iii) The argument from normative uncertainty. There could be reasons, whether distinctly moral or not, for maintaining that human extinction would be extremely undesirable, but that the philosophical enterprise from the pre-Socratics to the present has not yet discovered. This gives us reason to hope that humanity does not go extinct, even if we believe that it should or that extinction would not ultimately be that bad. Tomorrow, a young genius could flip over a stone to find a novel insight that “radically changes the expected value of pursuing some high-level subgoal” (Bostrom 2014a).9

(iv) The argument from value-ladenness. Samuel Scheffler (2016; 2018) argues that most of us care about the continuation of our evolutionary lineage far more than we realise – that we have a “love for humanity”. This is supposedly revealed by the putative fact that most of us would become despondent if told, with certitude, that humanity would go extinct several decades after our deaths. As Scheffler writes, referring to future generations, “we have an interest in their survival in part because they matter to us; they do not matter to us solely because we have an interest in their survival” (Scheffler 2018, 57).

(v) The argument from final value. As Johann Frick (2017) observes, people commonly attribute “final value” (when something is valuable for its own sake) to a range of phenomena like languages, species, and cultures. This suggests, he argues, that humanity, “with its unique capacities for complex language use and rational thought, its sensitivity to moral reasons, its ability to produce and appreciate art, music, and scientific knowledge, its sense of history, and so on, should be deemed to possess final value” (Frick 2017, 359). Since it would be nonsensical to value things but “see no reason of any kind to sustain them or retain them or preserve them or extend them into the future” (Scheffler 2007, 106), we should conclude that “it would be very bad, indeed one of the worst things that could possibly happen, if, for preventable reasons, the end came much sooner rather than later” (Frick 2017, 344).

(vi) The argument from harm reduction in the wild. Some argue that there exists far more pain than pleasure in the natural world, in part because of r-selected species that give birth to tens or hundreds of offspring each reproductive cycle, only a relative few of which survive. If humanity exists long enough into the future, it could potentially develop ways to intervene in the ecosystem hierarchy to reduce the magnitude of harm in the biosphere.

Many more arguments for ensuring our survival could be adduced. In contrast, there are few compelling reasons for either indifference toward human extinction or seeing this outcome as desirable. Perhaps the two most notable are the argument from negative utilitarianism and the argument from anthropogenic destruction (which ties into Benatar’s misanthropic case for anti-natalism). The first claims that all that matters morally is the total amount of suffering in the world, independent of the total amount of well-being. Thus, if possible, one should become a “world-exploder” who destroys not just all sentient life on Earth, but the potential for sentient life to exist in our future light cone. (One realistic way of doing this might be to weaponise a particle accelerator. If the universe is in a “false vacuum” state, then it is theoretically possible to tip it into a “true vacuum” state by nucleating a “vacuum bubble” that expands in all directions at the speed of light, obliterating everything it encounters.10) The second claims that humans have destroyed so much of the biosphere that we deserve to perish. There are several fringe groups motivated by this view, such as the Gaia Liberation Front, that advocate for the involuntary annihilation of humanity; other groups, such as the Voluntary Human Extinction Movement (VHEMT), argue that humanity should voluntarily cease procreating for the sake of the “Gaian system”. (Thus, VHEMT are anti-natalists but for reasons unrelated to the harm-benefit asymmetry.)

Considering these for and against arguments together, there is, I believe, overwhelming reason to advocate for the continued existence of humanity. To quote Derek Parfit (1984, {452–453),

civilization began only a few thousand years ago. If we do not destroy [hu]mankind, these few thousand years may be only a tiny fraction of the whole of civilized human history. The difference between [nearly all and actually all people dying] may thus be the difference between this tiny fraction and all of the rest of this history. If we compare this possible history to a day, what has occurred so far is only a fraction of a second.