Extinction causes the painful death of billions, destruction of future generations, and loss of all value

Would it be wrong if humanity were to go extinct like most species that have so far existed? If so, how wrong, and for what reasons? The present paper aims to synthesize a wide range of arguments for why human extinction would be very bad, if not one of the worst things that could possibly happen. We will call this “Conclusion C.” Although there are some moral and axiological positions that see the extinction of humanity as desirable, such as Benatarian anti-natalism, our aim will be to show that there are multiple independent lines of reasoning that all converge upon Conclusion C, and thus imply that humanity ought to make the avoidance of extinction a top global priority this century and beyond. Here it is useful to distinguish between (E) the event or process of going extinct, and (S) the state or condition of being extinct. At the very least, all of the most prominent moral theories identify (E), if caused or allowed by moral agents, as wrong; other theories, however, affirm the moral badness of both (E) and (S), even going so far, in certain cases, to assert that most of what is bad about human extinction is the subsequent loss of value that could have been realized if only we had survived.

This topic is not one of mere philosophical curiosity. As one of us has elsewhere shown, the very idea of human extinction is a quite recent addition to our shared conceptual repertoire; e.g., not even Charles Darwin entertained the idea in his work on human evolution. Consequently, very little scholarly 3 attention has focused on the ethical implications of either (E) or (S). Yet the most informed probability estimates of human extinction occurring this century suggest that this could be the most dangerous moment of our species’ 200,000-year history. For example, Nick Bostrom (2005) estimates that the likelihood of extinction before 2100 is not less than 20 percent; an informal survey of experts at the Future of Humanity Institute (FHI) yields a median probability of 19 percent (Sandberg and Bostrom 2008); and Toby Ord conjectures a 1-in-6 chance of extinction before 2100 (see Wiblin 2017; author). For ease of discussion, we can call this the “unique hazards hypothesis,” defined as follows:

Unique hazards hypothesis: Humanity finds itself in a period of historically unprecedented dangers to our survival.

If this hypothesis is even remotely accurate, then the question of whether and to what extent Conclusion C is well-supported by cogent philosophical argumentation is not only of paramount importance but extremely urgent as well. Thus, the present paper aims to fill-in a significant lacuna in the contemporary 4 literature on existential risks, offering a robust point-of-departure for future discussions of whether and to what extent human extinction would be tragic.

This paper will proceed as follows: Section 2 examines five potential reasons why human extinction might be tragic. Section 3 explores how the four main classes of moral theories would evaluate these reasons. Section 4 addresses the issue of normative uncertainty in the context of human extinction. It should become clear by the end of this fairly exhaustive tour through a philosophical labyrinth of argumentation that one need not espouse any particular moral or axiological perspective to see human extinction as a tragedy of immense proportions. Indeed, some lines of reasoning that converge upon Conclusion C are not only independent but mutually exclusive, meaning that people with incompatible moral or axiological commitments can still agree that ensuring our survival into the far future should constitute a global priority for human civilization.

Section 2. Five Potential Tragedies of Human Extinction

There are at least five aspects of human extinction that moral and axiological theories could appeal to in arguing that such an event would constitute a tragedy of the highest order. These are:

2.1 Human extinction will very likely harm those alive at the time. Although no scientific surveys of normative beliefs about human extinction have been conducted, there are reasons for suspecting that most people would pre-theoretically see (E) as tragic for at least one morally relevant reason, namely, that it would entail the death of ~7.6 billion people (as of this writing); yet many would also see this as only slightly worse than a catastrophe that kills a much smaller number of people. Even more, most probably wouldn’t view (S) as being bad at all.5 Taking these in reverse order, many philosophers and non-philosophers alike hold “person-affecting” intuitions according to which we should care most, or only, about the effects of our actions on currently existing people and consequently little, or not at all, about those who will only exist in the future. Thus, since no one will be around to bemoan the non-existence of humanity, who cares? On the other hand, while many agree that any bodily or psychological harm that going extinct causes would be bad, the badness of such harm does not scale multiplicatively as the number of deaths increases due to cognitive biases like “scope neglect” and “psychophysical numbing” (see Slovic 2017). The first bias refers to our inappropriate emotional responses to large numbers and the second denotes the rapid decline in compassion for other humans as the absolute number of casualties rises above one. Thus, most people interpret the difference between 0 and 1 deaths as greater than the difference between 2,154,489,204 and 2,154,489,205 deaths; most people would rather spend some quantity of resources to prevent a single death rather than to prevent 2,154,489,204 deaths from becoming 2,154,489,205. Yet there is no reason why this should be carried over into our moral evaluations as such, and once we evaluate human extinction according to the actual number of people who will die it seems that, even if we do hold person affecting views, an extinction event would still be one of the worst things that could ever happen.

Furthermore, even if people preserve such biases, there remains the fact that an event of this sort could, depending on the timing, cause the death of oneself or living creatures that one cares about, such as parents, siblings, friends, pets, or celebrities. Consider that if the risk of human extinction were only 0.1 percent per year—a relatively conservative estimate—and if the only life one cared about was one’s own, then one should still be willing to take precautions against such extinction that are at least as costly as those one takes against dying in a road traffic accident, since the chance of death from both causes would be comparable (Global Challenges Foundation 2017; author) But death itself isn’t the only personal harm 6 that the scenario above could entail. People often seek to acquire a form of “vicarious immortality” by contributing in some way to culture, sports, academia, and so on; the thought of such accomplishments, or “traces,” persisting through time give many people a deep sense of meaning in life. Or, as Wilhelm Ostwald’s put it in 1906, “every man leaves after his death certain things in the world [that are] changed by his influence,” adding that “there is a very general desire in mankind to leave such impressions.” Along 7 these lines, Ernest Partridge (1981) argues that human beings manifest a

desire to extend the term of one’s influence and significance well beyond the term of one’s lifetime—a desire evident in arrangements for posthumous publications, in bequests and wills, in perpetual trusts (such as the Nobel Prize), and so forth. In such acts and provisions, we find clear manifestations of a will to transcend the limits of personal mortality by extending one’s self and influence into things, associations, and ideals that endure.8

This gestures at yet another idea that Janna Thompson (2009) calls “lifetime-transcending concerns,” or “interests concerning states of affairs that will, or could, occur in the future beyond one’s lifetime.” It follows that merely believing that humanity will go extinct in the foreseeable future could lead to a sense of despondency by undercutting the promise of vicarious immortality. In the words of Allen Tough (1991), if humanity fails to survive, “then most other values and goals will lose their point. No other goals are more important than humanity’s survival at a satisfactory level.” Elsewhere he writes that “if humanity goes out of existence or back to the caves, then our personal efforts and achievements also disappear. Career success, national prestige, battlefield victories, business as usual, books, paintings, and children will not provide any of us with long-lasting benefits if human civilization destroys itself.”9 Thus, not only would human extinction entail actual mortality, but it would also eliminate vicarious immortality.

2.2 Human extinction will cause a great loss in the quantity of human welfare and other values. Many of the scholars and philanthropists who are most committed to averting human extinction are motivated not only by the harm of (E), but also by considerations of the lost value inherent in (S). There are several possible routes to this conclusion depending on one’s interpretation of the astronomical value thesis:

Astronomical value thesis: The potential value of the future could be astronomically huge, if only

we play our cards right.

The question immediately arises as to what “value” means, and one answer is: “Whatever you would like it to mean.” The point is that if humanity survives and spreads through the universe, there could be far more of whatever one values in the future than in the contemporary world. In fact, philosophers have argued that, insofar as one genuinely values a property P, one should strive to ensure its continued existence into the future, if not work to multiply the number of instances of the universal (see Scheffler 2007, 2018). It follows that one should see human extinction as bad not just because of the possible bodily and 10 psychological harm that going extinct could cause, but because of the loss of potentially astronomical amounts of value that we could actualize. In this way, given what it means to value something and that 11 people do value thing, the descriptive proposition of the astronomical value thesis yields the normative proposition of Conclusion C.

A popular moral interpretation of the axiological component of the astronomical value thesis comes from what is called the “Total View.” This identifies value as a property of individual lives, 12 where “value” can be defined in very many ways including hedonistic, desire-satisfaction, or objective list-theoretic terms. The central idea is that morally good acts are those that increase the total amount of value across all lives, present and future. A weaker interpretation of “astronomical value” arises from what is called the “Simple View.” On this view, value is still a property of individual lives, but one is not necessarily committed to maximizing it. Rather, all this view implies about morally good acts is that some lives are “good” and that the addition of any of these lives would always be in itself good and make the world better in at least one way. It follows that, on either of these views, since human extinction would 13 permanently preclude the realization of potentially vast amounts of future value, “to end the human race would be about the worst thing it would be possible to do,” a sentiment that goes back at least to Henry Sidgwick (1907). From this perspective, the difference between 99 and 100 percent of humanity dying out is far greater than the difference between 1 and 99 percent perishing (Parfit 1984). The reason is that, as H.G. Wells—the founder of future studies —put it in 1902, is that 14

all the past is but the beginning of a beginning, and that all that is and has been is but the twilight of the dawn. It is possible to believe that all that the human mind has ever accomplished is but the dream before the awakening. We cannot see, there is no need for us to see, what this world will be like when the day has fully come. We are creatures of the twilight.

Indeed, according to Carl Sagan, if humans remain on Earth with an average lifespan of 100 years, there could come to exist 500 trillion humans in the future. But it appears likely that, if we survive the next few centuries, humanity will spread into the cosmos, which could vastly increase the total number of people— and thus the total amount of well-being in the universe. For example, Bostrom (2003b) calculates that if a single star can sustain ~10 billion people, then the Virgo Supercluster could house ~100 sextillion future humans per century; yet there are about 10 million superclusters in the observable universe and 1 billion trillion stars in total. (We will leave it to readers to do the math!) Even more, if mind-uploading is possible, then based on calculations of the computational capacity of planets that are converted into giant supercomputers, there could exist ~100 decillion (or 1038) people per century in the Virgo Supercluster alone, although Milan Ćirković (2002) puts the number even higher at 10 quattuordecillion (or ~1046). If such people have worthwhile lives, then the potential well-being that our descendants could realize in the future could be truly astronomical. Notice here that even if one highly discounts future lives, the sheer 15 number that could come into existence still suggests that existential risk reduction ought to be highly prioritized.

2.3 Human extinction will cause a great loss in the quality of human welfare and other values. The astronomical waste thesis, though, does not need to be understood solely in terms of the total number of people with worthwhile lives that could come to exist in the future. Indeed, it should also take account of the potential for people in the future to acquire lives that are not merely worthwhile but extraordinarily, perhaps unimaginably (from our current vantage point), good. There are two trends worth mentioning here, the first being societal: As Steven Pinker (2011) outlines in great detail, humanity has made significant moral progress throughout history, and especially since the end of World War II. One happy symptom of this is the steady, if uneven, decline of violence. According to Pinker, humanity is not only in the midst of the “Long Peace” but also the “New Peace,” during which organized conflicts of all kinds—civil wars, genocides, repression by autocratic governments, and terrorist attacks—[have] declined throughout the world.” Although Pinker does not extrapolate these trends into the future, there are some reasons for expecting them to continue. For example, Pinker identifies the primary driver of moral progress in recent decades as the Flynn effect, the long term increase in human intelligence observed during the twentieth century. While this appears to have slowed, stopped, or reversed in certain regions of the world (see, e.g., Bratsberg and Rogeberg 2018), it is very likely that future innovation will yield safe and effective cognitive and moral enhancements. If the former augments our capacity for “abstraction from the concrete particulars of immediate experience,” which is “the cognitive skill that is most enhanced in the Flynn effect,” then we might expect a further expansion of our circles of moral concern (Pinker 2011). There could be similar gains from moral bioenhancement, which Ingmar Persson and Julian Savulescu (2012) describe as any biomedical intervention that augments our moral dispositions of altruism and a sense of justice (or fairness). The first consists of empathy—the cognitive property that Pinker focuses on—and sympathetic concern—the motivational element of moral action. Although Persson and Savulescu’s proposal has proven to be controversial for both philosophical and practical reasons (see author), it is not unthinkable that future breakthroughs yield highly effective mostropics, i.e., morality-boosting drugs, and that these drugs become as commonly ingested as fluoride is via the public drinking water.

This leads to the second trend, which is transhumanist: Human enhancement technologies could enable a phase transition from humanity to posthumanity, where posthumans are beings with significantly augmented capacities in the broad domains of cognition, emotion, and healthspan (see Bostrom 2008). For example, nootropics, transcranial magnetic stimulation, brain-computer interfaces (BCIs), genetic modifications, iterated embryo selection, mind-uploading, and so on, could potentially increase our intellectual abilities, while advanced biotechnology and molecular nanotechnology could stop or even reverse aging, thus enabling people to live indefinitely long lives. The result could be a population of beings 16 who experience degrees of well-being that far exceed the intensity and amount that any current human could possibly attain. Even more, enhancement technologies could expand our “cognitive space” such that our posthuman progeny have mental access to concepts that are in principle beyond our ken (see author). It follows that, insofar as (say) some theory T requires a concept C to understand, and insofar as C falls outside of our current cognitive space but within the cognitive space of a species of posthuman, then that species could devise T—a theory about which we might be second-order ignorant, meaning that we can’t even know that we can’t know T. Thus, insofar as one values knowledge, there could be any number of marvelous new ideas in the future that forever linger beyond our epistemic reach.

This being said, people have been speculating about utopian futures in which people live qualitatively (much) better lives since at least the nineteenth century, and it has become natural to view these with a strong degree of skepticism. Yet 200 years ago, very few individuals were permitted the freedom of thought and self-expression that many now take for granted; violence, sickness, and disability where far more common than they are today; people’s understanding of the world around them was quite impoverished and their access to science, art, and technology almost unimaginably lower than such access is today. Even if twenty-first century utopian visions remain unrealized, the prospects for a qualitative improvement in future people’s lives, we would argue, ought not be underestimated. Thus, there both quantitative and qualitative aspects to, at the very least, a Totalist interpretation of the astronomical value thesis.

2.4 Human extinction will remove our rational/moral agency from the earth/universe. The physicist Enrico Fermi once observed that the sheer size of the universe should entail that interstellar civilizations are relatively common, and we should be able to detect them with our current technology, however so far we have found no real evidence of their existence. This is known as the “Fermi Paradox.” Yet there is a growing body of research that resolves (or dissolves) the paradox by arguing that intelligent life could be rare in the universe; at the extreme, humanity could be something of a cosmic hapax os, i.e., a “thing existing only once.” Peter Ward and Donald Brownlee (2000), for example, defend a version of the “rare 17 Earth hypothesis,” and a more recent analysis calculates that there is a 38 to 85 percent chance that humanity is alone in the observable universe and a 53 to 99.6 percent chance that humanity is alone in our galaxy (Sandberg et al. 2018). It follows that, as Toby Ord declares, “it’s very possible that we might be the most amazing and rare part of the whole universe, the only part of the universe capable of understanding the universe itself and appreciating its wonders” (quoted in Wiblin 2017).

For some, this observation provides additional support for the notion that humanities extinction would be a tragedy of cosmic proportions. As Derek Parfit (2016) argues,

if we are the only rational beings in the Universe, as some recent evidence suggests, 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, though failing to justify past suffering, would give us all, including some of those who have suffered, reasons to be glad that the Universe exists (emphasis added)18