译者：王宇琪& 何翔宇 & 张力文
The end of us
Only since the Enlightenment have we been able to imagine humans going extinct. Is it a sign of our maturity as a species?
In 1844, the Russian prince Vladimir Odoevsky wrote a short story in which a future humanity, stricken with overpopulation and resource-depletion, welcomes a ‘Last Messiah’ who instructs a jaded mankind to commit omnicide by blowing up the planet. Earlier, in 1836, the Italian poet Giacomo Leopardi proclaimed that, if the human species were to be extinguished, ‘the Earth’ wouldn’t ‘feel that there is anything missing’. Three decades prior, the Marquis de Sade characteristically decreed that ‘nothing would be more desirable than the total extinction of humankind’. Earlier still, in 1756, the influential French naturalist Comte de Buffon envisioned another lifeform inheriting our crown as apex cogitator should ‘the human species be annihilated’.
1844年，俄罗斯王子弗拉基米尔·奥多耶夫斯基（Vladimir Odoevsky）写了一个短篇故事，讲述未来的人类因为饱受人口过剩和资源枯竭之苦，迎来了“最后的救世主”，他引领着精疲力竭的人类炸毁了地球、走向了灭绝。此前，在1836年，意大利诗人贾科莫·利奥帕尔迪（Giacomo Leopardi）就曾宣称，如果人类灭绝，“地球”并不会“觉得少了什么”。再往前推三十年，萨德侯爵（Marquis de Sade）也以颇具其个人特色的方式宣布：“没有什么比人类的彻底灭绝更令人向往的了。”更早的1756年，颇具影响力的法国博物学家布丰伯爵（Comte de Buffon）也曾设想，如果“人类物种被消灭”，另一种生命形式将继承我们的王冠，成为自然最高的统治者。
As ideas go, human extinction is a comparatively new one. It emerged first during the 18th and 19th centuries. Though understudied, the idea has an important history because it teaches us lessons on what it means to be human in the first place, in the sense of what is demanded of us by such a calling. For to be a rational actor is to be a responsible actor, which involves acknowledging the risks one faces, and this allows us to see today’s growing responsiveness to existential risks as being of a piece with an ongoing and as-yet-unfinished project that we first began to set for ourselves during the Enlightenment. Recollecting the story of how we came to care about our own extinction helps to establish precisely why we must continue to care; and care now, as never before, insofar as the oncoming century is to be the riskiest thus far.
Indeed, despite the tone of Leopardi’s or Odoevsky’s forecasts, this story is not at all one of doom and gloom. Around the same time that the first mentions of the risk of our extinction began to emerge throughout the 1700s, so too did the first projections of plausible mitigations. These range from Lord Byron’s 1824 vision of humanity averting incoming comets by means of planetary ballistic-defence systems, to Jean-Baptiste Cousin de Grainville’s 1805 notion of gigantic geoengineering ‘machines’ working to extract diminishing nutrition from a collapsing biosphere by levelling mountain ranges and shifting seas, to Benoît de Maillet’s anticipation, as early as the 1720s, of planetary-scale terraforming and irrigation efforts designed to offset the desiccating heat of an expanding Sun and stave off the ‘total Extinction of Mankind’.
事实上，尽管利奥帕尔迪或奥多夫斯基预测时的语气有些悲观，但这个故事一点也不阴郁。大约在同一时期贯穿整个十八世纪，人类灭绝的风险首次被提及，同时第一批貌似合理的解决方法预测也出现了。其范围从拜伦勋爵（Lord Byron）在1824年想象人类通过行星导弹防御系统躲避彗星，到格兰维尔的让-巴蒂斯特·库辛（Jean-Baptiste Cousin）在1805年构想庞大的地质工程“机器”以通过夷平山脉、搬运海洋来从崩溃的生物圈中提取营养，再到伯努瓦·徳·梅耶（Benoît de Maillet）早在1720年代对行星大规模改造和灌溉的预期，以抵消不断膨胀的太阳带来的干热，避免“人类的彻底灭绝”。
The story of the discovery of our species’ precariousness is also the story of humanity’s progressive undertaking of responsibility for itself. One is only responsible for oneself to the extent that one understands the risks one faces and is thereby motivated to mitigate against them. It was the philosopher Immanuel Kant who defined ‘Enlightenment’ itself as humanity’s assumption of self-responsibility. The history of the idea of human extinction is therefore also a history of enlightening. It concerns the modern loss of the ancient conviction that we live in a cosmos inherently imbued with value, and the connected realisation that our human values would not be natural realities independently of our continued championing and guardianship of them.
But if human extinction was first spoken about in the 18th century, where was the notion prior to this point? What about the perennial tradition of end-of-the-world scenarios coming from religion? For a start, prophecies concerning religious apocalypse provide us with a final revelation upon the ultimate meaning of time. Prognoses concerning human extinction, instead, provide us with a prediction of the irreversible termination of meaning within time. Where apocalypse secures a sense of an ending, extinction anticipates the ending of sense. They are different in kind – not degree – and therefore different in their origins.
So, why was human extinction and existential catastrophe not a topic of conversation and speculation prior to the Enlightenment?
In the 1930s, the American historian of ideas Arthur Lovejoy noticed an assumption, which he called the ‘Principle of Plenitude’, spanning Western philosophy from Aristotle to G W Leibniz. Put simply, the Principle holds that all legitimate possibilities must eventually be realised. Formulated slightly differently, there are no unjustifiable absences in existence. There are no things that could be, but simply just are not, without any justification. Accordingly, something as unjustifiable as an extinction (inasmuch as it is an unaccountable gap in nature’s space of realisations) was forbidden. This effectively made the extirpation of any species (whether human or nonhuman) meaningless and temporary, because it entails that the possibility of it returning will, inevitably and eventually, be fulfilled. Even if it is wiped out somewhere, each species will someday re-emerge. This Principle prevented an appreciation of species extinctions from the antiquity to the Enlightenment.
20世纪30年代，美国思想史学家阿瑟•洛夫乔伊（Arthur Lovejoy）注意到了一种涵盖了从亚里士多德到莱布尼茨的西方哲学的假设，他称之为“丰饶原则”(Principle of Plenitude)。简而言之，这一原则认为，所有合理的可能性最终都必将实现。换个说法即是，没有不合理的不存在。没有任何事情可以在没有任何理由的情况下被证明是不可能的。因此，像灭绝这样不可理喻的事情（因为它是自然实现空间中一个不可解释的分歧）是被禁止的。这有效地使任何物种（无论是人类还是非人类）的灭绝都变得毫无意义，而且是暂时的，因为这意味着它们最终将不可避免地复活。每个物种即使在某个地方灭绝了，总有一天会重新出现。这一原则阻止了对从古代到启蒙时期对物种灭绝的认识。
Such assumptions led the Roman philosopher Lucretius, during the 1st century BCE, to confidently claim that ‘nothing in creation is the only one’ and, hence, nothing can really die out. Centuries later, in 1686, the French scientist Bernard Le Bouyer de Fontenelle proclaimed with identical conviction that no species ‘can totally perish’ because, even if our planet is destroyed or our Sun dies, a new world will eventually be repopulated somewhere with the exact same species. The 18th-century French philosopher Denis Diderot confirmed that, within the churning cosmic immensity, nothing can ever truly be lost. When asked whether Homo sapiens would one day go extinct, Diderot reportedly answered ‘yes’, but immediately qualified that, during another stellar cycle, and after ‘several hundreds of millions of years of I-don’t-know-whats’, the ‘biped animal who carries the name man’ would re-evolve. Only within such a framework could the poet Alexander Pope’s oft-quoted line ‘And now a bubble burst, and now a world’ be read as a sign of creation’s jubilant magnanimity rather than of its malignancy.
这样的假设导致公元前1世纪的罗马哲学家卢克莱修（Lucretius）自信地宣称：“造物中没有哪样是唯一的”，因此，也没有任何东西可以真正灭绝。几个世纪后的1686年，法国科学家伯纳德·勒·布耶尔·德·方特内尔（Bernard Le Bouyer de Fontenelle）以同样的信念宣布，没有任何物种“能完全消失”，因为即使我们的星球毁灭、我们的太阳熄灭，一个新世界最终也会在某个地方重新繁衍出完全相同的物种。18世纪的法国哲学家丹尼斯·狄德罗（Denis Diderot）确信，在翻腾的宇宙浩瀚之中，没有任何东西可以真正失去。据传闻，当被问及智人是否有一天会灭绝时，狄德罗的回答是“会”，但他立刻断定，在另一个恒星周期中，经过“数亿年我未知的事情”之后，这种“被叫做人类的两足动物”将会重新进化。只有在这样的想法之下，诗人亚历山大•蒲伯（Alexander Pope）常被引用的那句“泡沫破裂，世界新生”，才能被解读为造物慷慨欣荣的象征，而不是其恶毒。
Belief in Plenitude, moreover, provoked the future American president Thomas Jefferson to argue, in 1799, in the face of mounting anatomical evidence to the contrary, that specimens such as the newly unearthed Mammuthus or Megalonyx represented species still extant and populous throughout the unexplored regions of the Americas. Even when scientists could no longer deny that organisms had previously gone extinct, the same set of ideas remained irresistible to the Scottish geologist Charles Lyell, who declared in the 1830s that iguanodons, ichthyosauri and pterodactyls would, in the distant future, return and reclaim the Earth. The disappearance of entire genera, he pronounced, is a mere ‘interval of quiescence’. It was due to similar presumptions, indeed, that we did not even notice the demise of the Mauritian dodo more than a century after it disappeared sometime in the 1690s. We humans have been wiping out other species at a large scale since the Pleistocene, but we only began noticing this during the late 1700s.
此外，对丰饶原则的信念，也促使了未来的美国总统托马斯·杰斐逊（Thomas Jefferson）在1799年面对越来越多的解剖学证据时，仍提出了相反的观点：新出土的猛犸象或巨爪地懒等标本，代表了这些物种仍然大量存在于整个美洲未开发的地区内。即使当科学家们无法再否认有些生物已经灭绝的事实时，同样的想法仍然让苏格兰地质学家查尔斯·莱尔（Charles Lyell）坚持在19世纪30年代宣称，禽龙、鱼龙和翼手龙在遥远的将来会返回地球、重称霸主。他认为整个物种的消失只是一段“平静的间隔”。事实上，正是由于类似的假设，我们甚至在一个多世纪之后才注意到毛里求斯渡渡鸟在1690年代左右就已灭绝。自更新世（Pleistocene）以来，我们人类一直在大规模地导致其他物种的灭亡，但我们直到18世纪末才开始注意到这一点。
Long-standing belief in the ‘Principle of Plenitude’ blocked understanding of the stakes involved in extinction such that it became almost unworthy of observation – let alone forecast or mitigation. Whether human or animal, dying out was, after all, but a mere interval of quiescence.
A related issue obstructed thinking on human extinction. This was the conviction that the cosmos itself is imbued with value and justice. This assumption dates back to the roots of Western philosophy and is, moreover, intimately connected to belief in Plenitude. For believing that ‘all legitimate possibilities are eventually realised’ is the same as believing that ‘reality is as legitimate as it possibly can be’. Or, simply, to be is to be just. Thus, dying out can only be temporary or local.
We see this most clearly in Leibniz’s notion that we live in ‘the best of all possible worlds’, but it is long-preceded by the Platonic doctrine of the Idea, which teaches that reality is intelligible precisely because it is essentially intellectual in nature.
Where ‘being’ is presumed inherently rational, reason cannot itself cease ‘to be’, such that the termination of human rationality can have no real sting. Correlatively, when Aeschylus, Hesiod or Plato long ago recounted Zeus’ plan to ‘destroy this race of mortals’, such a mythic episode is not an ‘extinction scenario’ or ‘existential catastrophe’ in the modern sense because it is not an end of sapient value. Even if humans are smitten by Zeus, human-like value indefinitely lives on in the creator. Presuming the Universe to be inherently judicial trivialises the stakes involved in what we think and do.
So, human extinction could become meaningful (and thus a motivating target for enquiry and anticipation) only after value was fully ‘localised’ to the minds of value-mongering creatures. We had to realise that the Universe was not inherently a cradle of justice and morality. ‘Value’ and ‘fact’ had to be disentangled before we truly came to appreciate the potential fact of the end of value. Only through this were we first motivated to forecast, in order to redoubt human justice against an extrajudicial nature. It is such a dynamic that, across modernity, drags our concerns further and further into futurity, and continues to do so.
The process through which we came to this understanding, though it properly began with the emergence of nominalism in the late-medieval era, culminated in the 18th century. This was due to the consolidation during the Enlightenment of a number of new scientific fields of enquiry: geology, demography and probabilism.
Geology saw its beginnings in hypotheses formulated by Royal Society polymaths during the latter decades of the 17th century. The English scientists Robert Hooke and Edmond Halley proposed the first recognisably ‘geohistorical’ conjectures by injecting naturally caused vicissitude and change into their theoretical models of Earth systems. They both produced the first unequivocal endorsements of the idea that previous species had gone extinct. Following this, fossil evidence slowly built up throughout the 18th century until the French palaeontologist Georges Cuvier in 1796 established undeniable evidence for the irreversible disappearance of prehistoric animals (by applying comparative anatomy to mammoth molars).
这种理解始于17世纪后期的地质学界，当时皇家学会的学者们提出了一个假设。英国科学家罗伯特·胡克（Robert Hooke）和爱德蒙·哈雷（Edmond Halley）首次明确提出“地理历史”猜想，即向地球系统的理论模型中引入自然变迁和变化。他们首次明确认可了之前的物种灭绝了这一说法。在此之后的整个18世纪，化石证据逐渐成型。1796年，法国古生物学家乔治·库维尔（Georges Cuvier）为史前动物不可逆转的消失提出了无懈可击的证据（通过用比较解剖学对猛犸臼齿进行分析）。
Cuvier’s overarching theory of Earth history was aptly called ‘catastrophism’ because of its reliance upon pyrotechnic and earth-shuddering disasters. It is telling that its influence can be found in the first literary and imaginative works that engage the topic of human extinction. These come from a circle of Romantic authors and poets: Lord Byron’s poem ‘Darkness’ (1816) extrapolates the sterilisation of our biosphere by way of heat dissipation; Percy Bysshe Shelley’s Prometheus Unbound (1820) contains a vision of previously extinct fauna, laminated throughout the planet’s crust, and dramatises the threat of humanity joining this fossil pantheon; and Mary Shelley would go on to write Last Man (1826), the first full-length novel depicting the truly global scope of an existential catastrophe. She had, however, already alluded to existential catastrophe in Frankenstein(1818). She invoked the monster’s demographic potential – should Victor Frankenstein make it a female companion – to trigger humanity’s extinction via outbreeding it as a competing species.
居维叶包罗万象的地球历史理论被贴切地称为“灾变说”，因为它依赖于枪火和地球战争灾难。事实上，它影响了第一批涉及人类灭绝主题的浪漫主义文学和虚构作品：拜伦勋爵的诗《黑暗》（Darkness，1816）通过烧成灰烬来推断人类的灭绝; 珀西·比希·雪莱（Percy Bysshe Shelley）的《解放了的普罗米修斯》（Prometheus Unbound，1820）通过早已灭绝了的动物群的视角（这些动物被塑封在整个地球的地壳上），戏剧化地展现了人类面临加入这个化石名人堂的威胁；玛丽·雪莱（Mary Shelley）的《最后的人》（Last Man，1826）本会是首部描绘真正在全球范围内发生的有关人类生存的长篇灾难小说。然而，她已经在《弗兰肯斯坦》（Frankenstein，1818）中影射了关乎人类生存的灾难。她描写了这个怪物在人口方面的潜力 – 如果维克多·弗兰肯斯坦（Victor Frankenstein）给它制造一个女性伴侣，让其作为一个竞争物种去远离人群的地方繁殖，会引发人类的灭绝。
This brings us to the second key context: ‘political arithmetic’ or demography. One of the first texts to engage in demography, written by the French philosopher Baron de Montesquieu, is likewise one of the first to mention the plausibility of the cessation of humanity as a biological species. In his Lettres persanes (1721), or Persian Letters, Montesquieu declares that global population has diminished since antiquity and, having undertaken ‘calculations as exact as possible’, he then proclaims that ‘if this trend continues, within 10 centuries the Earth will be nothing but an uninhabited desert’.
这将我们带入第二个关键背景：“政治算术学”或人口统计学。法国哲学家孟德斯鸠（Baron de Montesquieu）最早在文章中提到人口学以及人类作为一个生物物种而灭绝的合理性。在他的《波斯人信笺》（Lettres persanes，1721）中，孟德斯鸠宣称自古以来全球人口已在减少，他做了尽可能精确的“计算”，并宣称“如果这种趋势持续下去，地球将在10个世纪内变成一个无人居住的沙漠”。
Throughout the next century, the emerging field of population science produced numerous similar extrapolations. Aside from wielding the newfound understanding that numbers can be applied to reality in order to predict its longterm future course, the rise of demography was a crucial factor in growing receptivity to our existential precariousness because demography cemented humanity’s awareness of itself as a biological species. Following the English naturalist John Ray’s work in the 1680s, ‘species’ had become defined as an organic form fixed, across time, by sexual propagation: thus, through focusing attention upon humanity as a reproductive community, political arithmetic inculcated ‘taxonomic self-awareness’. This was consecrated in the Swedish botanist Carl Linnaeus’s inclusion, in 1758, of the genus Homo in his system of nature. It was during this century that we began referring to ourselves as ‘the human species’. Thinking of ourselves as a species, we became capable of thinking of our dying out as a species.
在整个19世纪，新兴的人口科学领域涌现了许多类似的推断。人们有了新的认识，即数字可以用于预测现实的长期走向，除此之外，因为人口学增强了人类对自身作为生物物种的认识，人口学的兴起也是促使我们接受人类生存的不稳定性的关键因素。在17世纪80年代，英国博物学家约翰·雷（John Ray）的作品发表之后，“物种”开始被定义为一种随着时间的推移、通过性传播而变得稳定的有机形式：因此，通过强调人类是可繁殖的群体，政治算术将“生物分类学上的自我意识”灌输给了社会。1758年，瑞典植物学家卡尔·林奈（Carl Linnaeus）把它纳入自然系统中的早期人类范畴，将其神圣化。本世纪，我们开始将自己称为“人类物种”。把自己看作是物种之一，我们开始能将自己看成是一个会灭绝的物种。
In his Lettres persanes, Montesquieu had already acknowledged a dizzying surfeit of natural disasters that could bring humanity ‘within a hair’s breadth of extinction’. Any number of factors ‘may be at play’ that could decimate us, he warned. We dwell in an ‘uncertain state’. This brings us to the third key context, that of the consolidation of a rigorous and modern notion of risk and uncertainty.
Political arithmetic had appeared on the scene due to the application of early probability theory to census data. It was during the 17th and 18th centuries that mathematicians, from Blaise Pascal in France to Jacob Bernoulli in Switzerland, first began tackling probabilism and the problem of the numerical measurement of future outcomes. It was not long before probabilities were leveraged to compute the odds of what is now called a ‘global catastrophic risk’.
由于早期概率论在人口普查资料中的应用，政治算术学应运而生。17世纪和18世纪，从法国的布莱斯•帕斯卡(Blaise Pascal)到瑞士的雅各布•伯努利(Jacob Bernoulli)，数学家们开始研究概率问题，并对未来结果进行数值预测。不久之后，概率方法被用来计算“全球灾难性风险”的概率。
In 1773, the French astronomer Jérôme Lalande was the first to apply probabilism to the question of existential threat. He predicted the odds of Earth’s intersection with a comet as 1/76,000. Sensationalised reporting of this provoked panic on the streets of Paris. Thereafter, the French scholar Pierre-Simon Laplace proclaimed that, though small, the likelihood of such an encounter would compound over the ages. And, by 1810, the German astronomer Wilhelm Olbers had converted Laplace’s ‘long succession of ages’ into a precise timeframe, computing a stretch of 220 million years per collision. (For comparison, contemporary calculations put extinction-level collisions at once every 500,000 years.)
1773年，法国天文学家杰罗姆·拉兰德(Jerome Lalande)率先将概率论应用于计算威胁人类存在的问题。他预测地球与彗星撞击的概率为1 / 76,000。这一耸人听闻的报道引发了巴黎街头的恐慌。此后，法国学者皮埃尔-西蒙·拉普拉斯(Pierre-Simon Laplace)宣称，地球发生碰撞的可能性虽然很小，但随着时间的推移会慢慢增加。而到了1810年，德国天文学家威廉·奥尔伯斯（Wilhelm Olbers）将拉普拉斯的“漫长的时间段”转变为一个精确的时间表，他计算出每2.2亿年发生一次碰撞。（为了与之比较，当代计算的结果为每50万年就会发生一次灾难级的碰撞。）
And so, given new awareness of the vicissitude of Earth history, of our precarious position within it as a biological species, and of our wider placement within a cosmic backdrop of roaming hazards, we were finally in a position to become receptive to the prospect of human extinction. Yet none of this could truly matter until ‘fact’ was fully separated from ‘value’. Only through full acceptance that the Universe is not itself inherently imbued with value could ‘human extinction’ gain the unique moral stakes that pick it out as a distinctive concept. Alongside descriptions of empirical fact, the discovery of human extinction demanded in-step self-reflections upon the proprieties (and precarities) of axiological value.
This final piece of the puzzle, therefore, came not from empirical science but from critical philosophy. It came from the revolution in philosophy initiated, in the 1780s, by Kant.
Kant realised that moral values are a question of self-legislation. They are maxims that we elect to bind ourselves by, and are accordingly constitutively dependent upon this election. Thus, they should not at all be considered part of the furniture of the natural world independently of our championship and upholding of them. And insofar as such values would not therefore be persistent features of the natural world independently of our ongoing stewardship, they thereby also demand our vigilant guardianship. In other words, ‘mind’ is entirely the responsibility of ‘minded agents’. We first realised that what we think and do matters, existentially so. It was this master idea of the Enlightenment that led us to appreciate the stakes involved in thinking.
Kant himself became increasingly preoccupied with the prospect of human extinction as he matured. Having once proclaimed that we ought ‘not lament’ the perishing of a world ‘as a real loss of Nature’, due to the age-old assumption that the Universe is maximally populated with moral worth and creatures like us, he slowly came to appreciate the precarity, and preciousness, of sapient values within the Universe. In his late works, the spectre of human extinction appears several times. During an essay on futurology, or what he calls ‘predictive history’, Kant’s projections upon humanity’s perfectibility are interrupted by the plausibility of an ‘epoch of natural revolution which will push aside the human race’. And this should come as no surprise, because Kant himself characteristically defined enlightening as humanity’s undertaking of self-responsibility: and human rationality assumes culpability for itself only to the exact extent that it progressively spells out the stakes involved in its precarious project, and stands steadfast in the face of them. This means that predicting increasingly severe threats is part and parcel of our progressive and historical assumption of accountability to ourselves. Only by articulating the stakes involved in our ignorance were we motivated to reason ever better, inasmuch as we realised that, should we not, we might never reason again.
In the 1980s, the German historian Reinhart Koselleck specified modernity as the increase in the ‘demands made of the future’, but we now know that it has ever also been the increase in the demands that the future made of us. We just didn’t quite know this yet. By recollecting the drama of how we came to answer this calling, through coming to care about our extinction, we see how today’s initiatives of prediction and mitigation (such as the Future of Humanity Institute in Oxford or the Centre for the Study of Existential Risk in Cambridge) are continuations and inheritors of this tenacious task: a project that we first began to set for ourselves during the Enlightenment. Though solemn, increasing concern with extinction gives us warrant to hope for our future on this planet and, possibly, beyond.