1.1 Palaeolithic: The first counterfactual

In 1939, J.R.R. Tolkien defined what he called a ‘eucatastrophe’, articulating it as an unexpected yet joyous turn: ‘a sudden and miraculous grace’. Like a catastrophe, being an unprecedented break from the prior course of events – but for the better.Footnote ⁴

Eighteen years later, the Harvard astronomer Harlow Shapley similarly spoke of the ‘Great Moments’ of history, defining them similarly. His candidates included the Big Bang – which led to the formation of the matter we are made from – alongside the evolution of photosynthesis on Earth and the accumulated accidents allowing the first animals to leave the ocean for the land.Footnote ⁵

Here’s another candidate for a eucatastrophe, or, a great turning in the course of the world. Somewhere within Africa, probably tens of thousands of years ago, potentially hundreds of thousands, a string of sounds fell from the lips of one of our forebears. It expressed, for the first time, what properly could be called a counterfactual.

It might have been expressed in awe, in urgency, in annoyance. We will never know. The utterer will forever remain nameless and unsung. But it was the first linguistic utterance, articulated on this planet, describing something not currently actual. Instead, it was about something else: the way world could be or could become. It was the entrance of the future into our linguistic world. It was the birth of all our tomorrows.

Counterfactuals are part of modal discourse. Modal discourse is the family of locutions expressing states of affairs that are not currently actual, or, in other words are irrealis. They empower a language to express modalities: phrases tracking which things are possible or impossible, contingent or necessary, permissible or impermissible, and conditional one upon another.

Of course, anticipation exists across life’s tree, with evidence of prevision stretching from horse to hymenopteran. In one sense, a nervous system just is a machine for predicting one’s environment. Forms of foresight clearly have evolved piecemeal and multiply across life’s tree. But humans are uniquely empowered when it comes to predicting the future.

Psychologists talk about ‘mental time travel’: the ability to recall the past and predict the future.Footnote ⁶ This affords us capacity not only to keep track of our biographies, but, also, to a degree, to actively author them. It allows us to learn from yesterday, so as to pursue preferable tomorrows. Our unique aptitude at ‘mental time travel’ rests, almost certainly, on human language and its unique capacity to talk about a world that is otherwise than the one currently, immediately perceived.Footnote ⁷

Inventing the whole suite of linguistic aptitudes required for this would not have been one clean event. Nonetheless, though anatomically modern humans have existed for something like 300,000 years, behaviourally modern humans emerged around 70,000 years ago. The former looked like us; the latter acted like us. They planned, danced, created symbols, told stories, and began accumulating traditions. Nobody today knows exactly why this happened, but it’s easy to imagine it was caused by – or itself helped cause – an expansion in what our language was capable of expressing.

Perhaps hominids had long been accumulating rich vocabularies of declaration and denotation: anchored purely in the here and now, picking out immediately present objects or events. Perhaps innovations were thereafter made, enabling the embedding of such denotive exclamations within modal constructions. Any shared, complex language presumably needs such constructions, because they allow rules – and, thus, what’s correct and incorrect, or grammatical and ungrammatical – to be articulated and maintained. Rules express what ought to be: in excess of what’s actual, irrespective of whether they are always followed; and no amount of declarations of fact can capture this unique, motivating aspect to their meaning.

Such irrealis constructions, moreover, would have initiated our species into a world of right and wrong – or, at least, where these are recognisable concepts, in addition to guttural feelings, because they are now explicable. The difference between what ‘ought’ and ‘is’ rests, after all, in the fact that former doesn’t need to exist to be meaningful. Norms will have existed long before creatures could talk about them – in some diffuse way, as appetites or conventions – but now they could be discussed, contested, disputed, discarded. Pragmatically, this would have impressively empowered those vocabularies of diplomacy necessary for better cooperation: for resolution of dispute and division of labour.

What’s more, being able to talk about what isn’t (yet) real is likely attached to ‘mental synthesis’: the capacity for stitching together images in one’s imagination, into a combination not previously perceived. Combining a wooden stick with a knapped stone, for example, plucks a hatchet from inexistence.Footnote ⁸

Investing in better tools and cooperating more fluidly mean more surplus time and energy. This diminishes current pressures on survival, opening room for luxuries such as planning more and further ahead, freeing up more resources for further invention. It’s a loop. Thinking about the future caused more thinking about the future.

By the point this delaminates imaginative horizons from a single lifetime, this would also galvanise the precept of passing recipes and techniques forward – via teaching and tutelage. A stock of insight starts building across generations, rather than resetting with the passing of each one, meaning wisdom instead becomes an intergenerationally building stock. Anthropologists call this ‘cumulative culture’.Footnote ⁹

By being able to talk about how things ought to be – in excess of how they merely are – human beings could come not only to declare things about the world but also to assess the accuracy of such declarations. A totalitarianism of sensation became accountability to a reality. Indeed, if an utterance or internal state cannot even be said to be wrong, how can it purport to have a world in view: to describe it by being held accountable to it?

Whenever and wherever all this came fell into place, our species dislocated itself from the barricades of the cloistered present – from the absolutism of the actual – in a fashion more intense than any species before. Our kind stepped forth into the spacious world of what’s merely possible: of what-could-have-been; of what-could-yet-be.

The cumulation of the first modal utterances embarked our species on an adventure. Though they couldn’t have foreseen it, the heirloom they bequeathed hoisted Homo sapiens out of the pressing present, eventually coaxing the human mind not only into the deepest past and furthest future but also towards reverse engineering the very workings of the world. And knowing how to imagine the world otherwise is the first step towards making it otherwise. The future is made from motivation as much as prediction.

Our ancestors, when they first started talking this way, began drifting from somewhere and somewhen towards less parochial vantages, and we have been drifting ever since – becoming disoriented and dislocated from the concrete present, but freer in the process. The Horizon of Contingency could begin to expand beyond the fleeting present, forcing unfolding encounters with the truth that the world is chancy and its future is undecided, in ways applying outside the confines of a single, fleeting life.

At the limit, being able to discuss the contingent truth of our claims ultimately opened out into acknowledgement of the contingency of truth-seeking and claim-making itself: eventually flowing into modern awareness that nothing about the human mind is a necessary feature of independent nature. Or, in other words, awareness our species – and everything it cares about – can go extinct, never to return.

Whether all this proves a ‘eucatastrophe’ or a ‘catastrophe’ is yet to be decided. The decision, in the main, is down to us and those coming next.

1.2 Ancient: That the World Is All It Can Be

Piercing the absolutism of immediacy, seeing a world of expanded possibility beyond, modal speak bequeathed to our ancestors a way of negotiating the world that wasn’t governed by the exigencies of sensation nor tethered to the overwhelming present. It cleaved open the room to step back from what is, in order to assess what could – and should – be.

This explains why humans developed agriculture, eventually encouraging urban centres to tumesce, sometime around 10,000 years ago. These advances can be seen as amongst the first widescale, albeit ad hoc, attempts at mitigating and distributing risk – oriented, by definition, at protecting tomorrow’s interests.

Efforts to predict, and thus control, the future remained limited to related techniques for the majority of recorded history. That is, as extemporaneous buffers against unpredictable nature: dams and dikes to protect against flooding; stockpiling and crop rotations to prevent famine; city walls and guards to defend against invasions. This, for the longest time, was the cutting-edge technology for manipulating the future.

During the Twelfth Dynasty of Egypt’s Middle Kingdom, Amenemhat III dammed the entire Nile. After fires in Rome in AD 6, Emperor Augustus set up a citywide force of firefighters. These evidence anticipation of risks and coordinated attempts to mitigate them. But these were all post hoc preparations for familiar catastrophes: calamities already within the record; disasters that were known to have happened. They evince responsivity to the precedented, not yet the unprecedented.

This connects to a truth summarised by the American historian Robert Heilbroner. He reflected, of the ‘first stratified societies’, that ‘dynastic dreams were dreamt and visions of triumph or ruin entertained’:

This observation appears to be true. It seems odd to us now: but the idea humanity’s future could be not only radically different but also different in unpredictable ways is a shockingly recent addition to worldviews.

One plausible explanation for this is simple. There just wasn’t yet enough recorded history for anyone to notice such change can happen. It is, after all, the historic record that provides determinate proof that human values and views transform over time. But, without a sufficient evidential chronicle available, it wouldn’t be clear this happens.

Sometimes called the oldest book in the world, the Ancient Egyptian Instructions of Ptahhotep, composed 4000 years ago, makes it clear that it ‘is good to speak to posterity’.Footnote ¹¹

Ancient Egyptians argued the best accomplishments are those that become lasting monuments. With their towering pyramids, they evidently aimed to leave a lasting impression. This implies concern for an extended future. However, it is unclear whether they fretted much about whether distant future generations – that is, us – would look upon these monuments the same way they looked upon them. It’s unlikely the architects of the pyramids considered posterity might come to scrutinise and study their works – to interpret or misinterpret them – through the unfamiliar eyes of an unrecognisably alien epoch. There’s scant evidence they suffered any anxiety of interpretation: angst about their beliefs not standing the test of time. Such monuments, indeed, can be read as evidence of precisely the opposite.

Point being, in the long millennia since, humanity’s collective memory has expanded. With the cumulative increase in chronicling and compiling of records, people have progressively come to appreciate the past really is a foreign country. It’s very simple. As recorded time has gone on, there’s been more evidence for the truth of this: and building recognition that things have been different dovetails into building anticipation that they may become different again. (Which nurtures awareness – and anxiety – that the future might look back on your present with very different eyes.)

Relatedly, before a global archaeological and fossil record was compiled, cross-referenced, and communicated across continents – rather than remaining constrained within one – it wasn’t possible to falsify hunches that human history has been cycling on Earth, without definitively beginning, throughout boundless ages.

As we shall later see, such a planetwide record would only begin being pieced together much later: throughout the 1700s and 1800s. Accordingly, for most of human history, people were liable to assume that human history has been going, much in the same way, forever, and would so continue. That everything they were witnessing on their landmass had already been chronicled or achieved elsewhere, on uncontacted continents, or in forgotten aeons. Again, there was not yet evidence to disqualify such assumption.

Accordingly, the Ancient Greeks and Romans, for example, tended to assume that time was eternal and that the future would thus, in the longer term, look like the past. It was invariably assumed that humanity’s combined possibilities – the total space of human potential – were small enough, and the time or space available comparatively large enough, that this entire set of possibilities would exhaustively manifest and thereafter recur and repeat without limit.

This is why Thucydides, writing around 400 BC, thought that chronicling his local history was indefinitely instructive for the future: precisely because possibilities are ‘repeated’, such that ‘human nature’ never truly changes.Footnote ¹²

But another explanation for Heilbroner’s observation rests in language itself. After all, accumulating insight about the world comes not only from accumulated encounters with it but from clarifications in the ways we talk about it. Refinements in our awareness of what it is our languages are doing when we describe the world, and what they aren’t doing, allow our languages to better model that world. And, as with all other forms of discovery, this takes time.

Thucydides’s sentiment can be tied, that is, to a conception of possibility prevalent throughout the premodern world, which defined it as ‘that which sometimes happens’. This was by contrast to necessity, defined as ‘that which always happens’, and impossibility, as ‘that which never happens’.

This has been called the ‘statistical interpretation of modality’. It tethers modal definitions to ‘temporal frequency’, or, concrete realisation in time.Footnote ¹³ Put differently, it’s the same as saying ‘nothing that’s possible never happens’. Though this basic assumption pre-existed him, it was first made explicit by Aristotle, who was the first to attempt to clarify what we actually mean when we deploy modal language.Footnote ¹⁴ In the Metaphysics, for example, Aristotle evidenced his assumption by declaring that ‘evidently it cannot be true to say ‘this is capable of being but will not be’’.Footnote ¹⁵ This formulation thus limits possibility to what is called a ‘diachronic’ conception: tethering it to what actually happens in time, thus blunting conception of entirely unrealised possibilities. Across his corpus, Aristotle consistently defines ‘impossible’ as what is never the case; ‘necessary’, as what is always the case; and ‘possible’, as what is sometimes the case.Footnote ¹⁶

Though elegantly intuitive, this formulation obstructs articulation of possibilities that have never once happened before.Footnote ¹⁷ It blunts sensitivity, in other words, to entirely unprecedented potentials. Writing in De Caelo, Aristotle revealingly reasoned that nothing which has always existed can be ‘destructible’, because the possibility of its destruction would, necessarily, have already come to pass.Footnote ¹⁸ Combined with his belief in the eternity of the past, this becomes the uninspected assumption that there is no such thing as a genuine unprecedented possibility.

Aristotle – and other premodern thinkers – readily applied this to wider nature as much as to human history, assuming things simply cycle limitlessly, and everything that can happen already has happened.Footnote ¹⁹ Hence, they lacked the idea that the further future – at the largest and most systemic scales – could come to look drastically different from the extended past. This, understandably, would have gelled comfortably with their lived experience: wherein material conditions didn’t visibly alter – in undeniably novel ways – during a single lifetime.

Given assumption of a limitless past, Aristotle therefore concluded ‘each art and science has often been developed as far as possible and has again perished’, such that the ‘same opinions appear in cycles among men’. He held this had happened ‘not once nor twice nor occasionally but infinitely often’.Footnote ²⁰ Within ‘the multitude of years’, he insisted, ‘everything has been found out’.Footnote ²¹ Aristotle even elsewhere claimed the aim of inquiry is merely to rectify ‘defects’ in knowledge – that is, the recollection of what’s forgotten.Footnote ²² Tellingly, the Greek word ‘encyclopaedia’ contains the word ‘cylcos’, implying knowledge is a returning circle.

Assuming time is ‘vast and immeasurable’, Plato also claimed the past is of ‘an infinitely long period of time’: such that, in his eyes, countless civilisations have ‘come into existence’, and just ‘as many’ have ‘perished’. From this, he reasoned, their social and political arrangements have been of every possible kind. Every permutation of human ‘goodness’ and ‘badness’, he assumed, must have already been passed through innumerably many times.Footnote ²³

By the same token, he believed all possibilities would, inevitably, be manifested again, unceasingly throughout the measureless future, regardless of what happens now. Assuming this meant assuming that no human potentials can ever be permanently lost, or irreversibly disappear from existence, including the potential for human existence as such. Indeed, Plato spoke of the

But he also clarified that ‘the human race has often been destroyed in various ways – as it will be in the future too’.Footnote ²⁴ The supposition therefore being that, even if humankind should be entirely extinguished, it would simply endlessly return. Other thinkers, like Xenophanes, had already made similar claims.Footnote ²⁵

This is why the premodern world lacked our modern concept of extinction: which, by definition, involves irreversibility. There simply wasn’t yet the collated evidence to determine that once species are wiped out to the final member, they are gone forever. In absence of contrary proof – which, again, wouldn’t arrive until a global picture of the fossil record was pieced together – it was, again, impossible to banish presumption that eradicated species would simply, eventually, always return. Given ancient definitions of modality, after all, all possibilities – including species themselves – sometimes are not and sometimes are.Footnote ²⁶

More precisely, on this view, no genuine influences from the present persist into the further future, because the future will be a repeat of the past regardless of what happens now. Nothing can be lost, nothing gained. It was for this reason that, around 50 BC, Cicero claimed there was little point in seeking to impart legacies that are ‘diuturnam’, or durable, much less ones that are indelible.Footnote ²⁷

Indeed, Cicero and many others, following Plato’s initial conjectures, believed that catastrophes regularly destroyed civilisation – wiping away all accumulated learning – such that human history could all play out again, in unending cycle. This is why Lucretius entertained the possibility that everything he was witnessing in his own life – all unfolding achievements – were ‘things’ which had ‘happened before’: it’s simply that countless earlier ‘races of human beings perished in great conflagration’ and their achievements ‘were razed by a mighty convulsion of the world’.Footnote ²⁸ Once more, ahead of sizeable evidence to the contrary, there wasn’t yet the combined evidence to disprove such suspicion.

But what of Plato’s Republic? Surely, he was thinking of something unprecedented when delineating his utopian vision for ideal society. Not so: midway through the dialogue, Plato has Socrates explicate he is envisioning a situation that ‘has been’ in the ‘infinite time past’ – or, otherwise, is ‘now’ in some ‘region far beyond our ken’ – such that we can also be sure it will inevitably return again ‘hereafter’.Footnote ²⁹

For the ancient world, therefore, given limitations of compiled evidence as much as limitations of language, possibility was inherently tethered to prior manifestation, such that cogently articulating the entirely unprecedented was stymied. This is why, as Heilbroner observed, the premodern universe lacked our modern conception of the future: as undecided and undetermined and populated by what’s unprecedented and unpredictable. Indeed, Aristotle readily affirmed that ‘it is of actual things already existing that we acquire knowledge’: which is the same as denying we concretely can know anything about things which haven’t yet existed.Footnote ³⁰ If we can’t talk of things that aren’t already actual, then the only way we can talk of the future is as a loop of the past.

Given available knowledge, on balance, it was – back then – safer to assume time was eternal and all possibilities simply cycle, such that the future would, in the longer term, be a repeat of the past and all present influences be laundered away. The Horizon of Contingency was, thus, limited in scope to one’s own lifetime and, at most, one’s own polis or nation. Beyond that, it was impossible to verify new things can happen and old things can be irreversibly lost across an undetermined, undecided future. The future remained shallow.

1.3 Medieval: That the World Could Have Been Otherwise

Similar definitions of possibility – and, thus, assumptions about the future – persisted well into the Medieval Era. Glossing Aristotle around AD 1100, the Arabic philosopher Ibn Rushd explained that ‘the term ‘possible’ is used’ to talk either of that which ‘happens more often than not’ or ‘less often than not’.Footnote ³¹ Modality remained tied to diachronic definitions and to manifestation in time: subtly precluding the possibility of the entirely unprecedented; reducing contingency to variations upon what’s already been.

This keyed into a wider feature of much premodern belief: the assumption that the world is inherently reasonable. For if all possibilities at some point come to pass, the only things that are never actual must be so for demonstrable reasons of logical incoherence or contradiction – rather than by dint of brute facticity or arbitrariness. This is the same as assuming that our world is maximally rational. Or, that things are the way they are for entirely demonstrable reasons – exhaustively amenable to deductive analysis – such that they couldn’t justifiably have been made otherwise than they are. (Note that this is incompatible with the modern notion of a ‘law of nature’: as a parameter or constraint that could plausibly have been otherwise; or, is the way it is for weaker reasons than lack of logical contradiction.)Footnote ³² This, in turn, underwrote a perennial Scholastic platitude: ‘ens est bonum convertuntur’, or, ‘being and good are convertible terms’. As Aristotle originally had it, ‘in all things, we affirm, nature always strikes for the better’.Footnote ³³

In a yet broader sense, such belief was again consequent upon narrow definitions of modal terms. Insofar as their usage was restricted to straightforward descriptions of events within the world, their more subtle application – as evaluations of our conceptual frame upon that world – remained implicit and undeployed. Put simply, if contingency narrowly refers only denotatively to things, it has not yet been critically applied to our concepts about things. Prior to the elaboration, explication, and deployment of this meta-descriptive dimension of concepts like contingency, as picking out the limitations and uncertainties of rational judgement itself, it was thus natural for thinkers to fail to catch sight of the distinction between our moral expectations and independent reality.Footnote ³⁴

Nonetheless, the introduction – and eventual ascendency – of Abrahamic religion had introduced an ‘alien intrusion’ within the pagan worldview.Footnote ³⁵ With the spread of Christianity and, later Islam, across the European and Arabic worlds, there arrived a sense of crisp direction in time: stretched between the twin extremities of Genesis and Judgement. The Hellenistic sense of eternalism was eventually toppled by Abrahamic belief in universal chronology.

On the one hand, eternity still saturates these creeds. Worldly time was conceived of as but a brief hiatus, environed by two eternities: a vanishing ‘vale of tears’ cleft between the boundless precedent of an uncreated divinity and, afterward, the unending afterlife promised for the souls He created.

On the other hand, the ‘intrusive’ element was immense. Jesus’s crucifixion on Golgotha split history in two. For his disciples, at least, it introduced a crisp ‘before’ and ‘after’: absolving all humans of their sins – everywhere – thus being incapable of precedent, reversal, or repetition. Everything afterward – that is, the future – would be different.

Previously, there was no universal reference point against which to orient ‘now’. Indeed, Aristotle had once reasoned that, if history cycles, we cannot properly say we come after our ancestors, because, in another sense, we also come before them.Footnote ³⁶ For believers in the new Abrahamic creeds, such reasoning could no longer apply. God can only sacrifice himself once, after all. If one time was not enough to get the job done then the act – of universal salvation, of the saving of the souls of everyone, everywhere – wouldn’t have been fulfilled. Divinity, being omnipotent, doesn’t work in half-measures.

Which is to say, Jesus’s crucifixion was, to his disciples, undeniably an event that had never once happened before. Precisely the same applied, for early Muslims, to the arrival of the Prophet Muhammad’s teachings around a half-millennium later.

These beliefs would – slowly but surely – disband elder conviction that the future must also be a closed-off repeat of the extended past. But this, as yet, was far from an acceptance of historic contingency: that is, sensitisation to the fact that the past could have played out differently, thus leading up to an unrecognisable present; nor that the future can play out multiply, depending upon what happens now.

This was because, for Muslims and Christians alike, the arc of events – from Creation to Judgement – was exhaustively orchestrated, from outside worldly time, by divine diktat. In its broadest brushstrokes, history’s unfolding was considered predetermined, which, again, was highly compatible with a solely ‘diachronic’ conception of possibility. The things that can happen exhaust the things that will happen: hence, determinism.

Apocalypse was thus conceived of as the ultimate – unavoidable – culmination of God’s infallible judgement, inscrutable though this may remain for mortals. It is important here to note that apocalyptic prophecy is distinct from the modern art of prediction, though they both are oriented towards the future, in that only the latter embeds awareness of its own corrigibility. The former does not – indeed, this is its very appeal – such that it cannot be sensitive to possibilities beyond its ken, or, indeed, assent.

This, again, appealed to the wider belief that ours is a maximally rational universe: where everything is the way it is – and not otherwise – for revealable reasons. Such conviction was inherited from Aristotelianism and sustained into Christian Scholasticism and Islamic Kalām. As Anselm of Canterbury proclaimed around 1080 AD: ‘whatever is, is right’.Footnote ³⁷

But it also played into to a view that, though worldly things could change, they couldn’t do so in meaningful nor multifarious ways. In the words of Nicholas of Autrecourt, ‘nothing in the universe, either in particular or in general, can be useless, for, if it were, then it would be better for it not to be than to be’.Footnote ³⁸ Such conviction, again, prohibits irreversible loss. Because, if any existent thing ceases to be permanently, it leaves a gratuitous gap in creation, where something could be, but simply never is again. This was simply incompatible with underlying conviction the universe itself is maximally just, as it would introduce an unjustifiable chasm in creation’s fabric. By the same token, a genuine novelty would reveal what was previously an imperfection – a vacuity of value, an empty vessel.

The uninspected assumption was that what seems morally unjustifiable must be naturally impossible. Thus, having declared that ‘we feel displeasure when we believe that a thing has become non-existent’, Nicolas of Autrecourt further reasoned that the universe must, across time, contain an equal amount of its possibilities, insofar as it needs to be ‘always perfect to the same extent’. It must, over time, house an invariant ‘complement of good’.Footnote ³⁹ Variation in overarching ‘good’, after all, would introduce imperfection into creation. In other words, the aggregate ‘goodness’ in the universe is not contingent, is not a variable that can alter contingent upon local events or happenstances. If something bad happens here, something good happens over there, balancing out the whole. Again, this ties into definitions of possibility as that which sometimes happens and sometimes doesn’t, which block appreciation of irreversibly wasted opportunities, frustrated potentials, and irrecoverable harms. Put simply, on such a view, the world, at large, cannot get better, or worse, in the same way we now acknowledge it can. Indelible stains on the human record or unprecedented progressions over past oppressions were unthinkable.

Evidently, this also made the extinction of species – and, even more so, of mind – inconceivable. As Saint Bonaventure, again glossing Aristotle around 1200 AD, declared: the cosmos ‘cannot exist without men, for in some sense all things exist for the sake of man’.Footnote ⁴⁰ Writing later, Aquinas likewise claimed that it is an ‘impossible supposition’ to envisage a world without intellects in it.Footnote ⁴¹

But, more profoundly, it stultified all sense of meaningful world-historical change – or, large-scale historic shifts for better or worse. Given ours was considered a maximally rational world, God was on pains to maintain its invariant goodness over time, throughout all its shifting permutations. The total ‘bonum’ in the universe was considered indestructible and invariable: globally conserved through all interactions and local shifts. Again, limiting possibility to narrowly ‘diachronic’ usage – as describing that which comes and goes, but only ever as a return of what’s come or gone before – means that it can only describe trivial rearrangements rather than irrecuperable losses or genuine novelty.

As Augustine put it, ‘variable good’ is governed, in the last instance, by ‘immutable good’.Footnote ⁴² Meaning that the ‘goodness’ of created beings can, locally, ‘be augmented and diminished’; but, globally speaking, all variations must ultimately average out as ‘good because their author is supremely good’.Footnote ⁴³ This, again was essentially continuous with the elder, pagan view, which was aptly summed up by Lucretius, who claimed that the ‘aggregate of things palpably remains intact’, because every death or disappearance is necessarily matched by compensatory birth or renewal:

Thus, beyond the implacable and divinely orchestrated countdown to apocalypse, when it came to secular affairs and to human expectation, the medieval outlook – by and large – wasn’t too far from the elder view of cycling stasis. Local changes of fate were feasible, but never any shift from the view of the globe: nothing irreversibly destroyed, nothing genuinely novel; always a revolving, never a rupture. Indeed, certain – albeit heterodox – believers happily made pagan eternalism compatible with their Christian faith, such as Siger of Brabant, who in the 1200s professed that nothing is truly unprecedented, such that

Though deemed heretical, Siger’s opinion was not far from the words of Ecclesiastes:

Indeed, despite the fact that Abrahamic religion taught of a crisp beginning to worldly time, there was no consensus during the Middle Ages about the span from then until the present.Footnote ⁴⁷ Many assumed this duration was, to all intents and purposes, immeasurable: and, thus, readily compatible with Classical teaching that everything humanly achievable must, by necessity, have already been achieved, such that our future could not come to look drastically divergent from its past.

This outlook came to be embodied in the Medieval metaphor of the ‘wheel of fortune’ – the Rota Fortunae made popular by Boethius – whose attraction was adroitly captured by Reinhart Koselleck. The ‘circling wheel’, Koselleck wrote, ‘pointed to the iterability of all occurrence, which in spite of all ups and downs could not introduce anything which was, in principle, new to the world before the time of the Last Judgement’.Footnote ⁴⁸

But this outlook would begin being dissolved from within by the acidic notion of divine omnipotence. During the later Middle Ages, a string of theologians – both Islamic and Christian – became eager to buttress their conviction that Deity was free to have made our world completely otherwise. This motivated them to develop logical definitions of possibility unmoored and unanchored from all precedent, or, manifestation within time. Indeed, in buttressing Divinity’s omnipotence this way, they were led to rejecting that our world exhausts all the ways it could be. This not only evacuated our world of rational structure – where everything is the way it is for a deducible reason – but also opened the door to sensitisation to all the ways our world itself could become otherwise, in ways unprecedented. The future began trickled into the frame, eventually becoming a torrent, then a deluge.

Scholasticism made it to the Middle East during the Islamic Golden Age, dating roughly from AD 700 to 1300. Here it blossomed into the teachings of the Muʿtazilite falāsifa (i.e. philosophers) who sought to elucidate the rational necessity of the cosmos along Aristotelian lines. This triggered a counter-reaction from what came to be known as Ashʿarism. The Ashʿarites instead foregrounded God’s limitless will, forging a position known as voluntarism. They reproached the Aristotle-inspired encroachments of the Muʿtazilites, for leveraging chains of logical and deductive demonstration over divine decision. In order to exalt God’s freedom and omnipotence over such rationalist straightjacketing, they asserted the centrality of divine will in every worldly happenstance and sought to strip the cosmos of any inherent, indwelling rational order.

A prominent example comes from al-Ghazālī and his Tahāfut al-Falāsifah of 1095. Here, the Sunni theologian wanted to dismantle the Peripatetic faith in the demonstrability of the connection between cause and effect. As such, he presaged Hume, by saying that the link could not be logically demonstrated.Footnote ⁴⁹ He did this by conjuring up unrealised, yet logically plausible, events that could disrupt regular causality.Footnote ⁵⁰ This, in many ways, may have been philosophy’s first true conception of catastrophe: a grasp of the purely unprecedented, based upon a higher order acceptance of the disunity of human reason and wider existence.

As such, Islamic and Christian voluntarist theologians moved away from elder definitions of ‘contingent’ as that which doesn’t happen at one moment but does happen another. Instead, it began being deployed to express plausible alternates to what happens at one moment, which thus never have to otherwise come to pass. In so doing, they divorced the concept of possibility from realisation within time, emancipating and liberating its range from the known, familiar, and established course of events.

Though it was already tacit in Augustine’s fifth-century proclamation that ‘potuit sed noluit’ – that is, there are worlds God could have made, but simply didn’t – this new, properly ‘synchronic’ definition of possibility was first explicitly articulated by Duns Scotus. Writing near the opening of the fourteenth century, Scotus announced:

Scotus here made explicit what was implicit in prior thinkers from al-Ghazālī to Peter Damian, finally consummating a separation of possibility from precedent or eventual manifestation. ‘In the late medieval modal theory’, writes Hintikka, ‘the domain of possibility is accepted as an a priori area of conceptual consistency [which is then] divided into different classes of compossible states of affairs of which the actual world is one’. In other words, this new conception explained possibility as delineating a space of conceptual consistency carved up by abstract relations of compatibility, rather than barricaded and gerrymandered by the fickle horizons of established human experience. Duns Scotus, in other words, had unwittingly provided the logical seedbed of the modern sense of the future as the domain of the entirely unprecedented.

Bewitched by omnipotence, late Medieval theologians started excitedly pondering the ways in which this world could be otherwise. The historian Amos Funkenstein wrote of ‘schoolmen [driven] by an almost obsessive compulsion [to] devise orders of nature [different] from the one admittedly existing’.Footnote ⁵¹ This became ensconced in the popular distinction between ‘potentia dei absoluta et ordinata’ – or, between God’s absolute power and ordained power – an important bifurcation baptised by Alexander of Hales, to describe the order God upholds within this world (‘potentia ordinata’), as opposed to the totality of what he could make manifest (‘potentia absoluta’).

Buttressing God’s freedom in selecting between worlds involved pushing the claim that it is not the way it is for any binding reason nor logical necessity, but is so purely because of arbitrary choice. This eventually led to the claim, articulated most prominently by William of Ockham in the 1300s, that none of the dictates of reason could restrict what reality can be. Motivated by conviction that our mental categories (universals, abstractions, sensations, species, propositional structures) cannot place limits upon what God can do, Ockham imagined existence completely voided of all such mental contents. He did this by deploying the recently strengthened modal logic to put this evacuation into counterfactual relief. That is, arguing that only singulars truly exist, because categorial structures cannot impinge on God’s will, Ockham imagined counter-to-fact worlds wherein all such mental categories are procedurally eliminated from the universe, thus abrading reality to its mind-independent kernel. Referring to this as the ‘Principle of Annihilation’, he imagined universes where everything is removed – ‘toto mundo destructo’ – except for one singular object, in pure autonomy of all cognitive generalisations or phenomenal contents.Footnote ⁵² This way, Ockham became the first to properly propose a possible world entirely without intellects within it.

In other words, this was the origin of our modern conception of ‘scientific realism’ or ‘robust mind independence’. It’s no coincidence that, writing centuries later, Galileo deployed a similar vocabulary of annihilation, pondering the counterfactual erasure of experience: ‘I think that tastes, odours, colours, and so on are no more than mere names so far as the object [is] concerned … Hence, if the living creature were removed, all these qualities would be wiped away and annihilated.’Footnote ⁵³ Again, by definition, putting reality’s mind-independence into relief requires the emancipation of conceptions of possibility from prior human experience. The fact existence will continue without minds like ours can only be articulated counterfactually – that is, insofar as mind like us persist. Hence, why such articulations would have to wait for the late Medieval liberation of possibility from precedent. Ockham’s thought experiments – providing the first robust benchmark of mind independence – are the primal scene of all future articulations of our potential extinction.

Much has been written on how this provided the crucible for the birth of modern science.Footnote ⁵⁴ The ‘compulsion’ of earlier theologians to imagine worlds entirely otherwise than the apparent one was prologue to the later discovery of scientists that the world in fact is otherwise than it intuitively appeared.

Indeed, as already hinted at, imagining hypothetical objects entirely outside of all conceptual or experiential relations, as Ockham did, lies at the root of the Early Modern distinction between ‘primary’ and ‘secondary’, or mind-independent and mind-dependent qualities. Funkenstein, moreover, notes Galileo’s employment of entirely counterfactual scenarios, analogous to Ockham’s own, to arrive at the unobservable, and because physically impossible, limit cases (i.e. a frictionless plane) that were required to formulate counterintuitive laws like that of inertia.Footnote ⁵⁵ Oakley and Milton point out the centrality of such thought to the discovery of the modern idea of a ‘law of nature’ itself.Footnote ⁵⁶ That is, as a parameter that could have been otherwise, in ways blind to the demonstrative approach of Scholasticism, but nonetheless carves up the limits of what can happen within this world. Such regularities, being arbitrary and contingent, cannot be rationally deduced from afar, but instead must be investigated by close-up encounters with the world – or, in other words, empirically and inductively.

In this way, modern science can be seen as a fortuitous ‘exaptation’ of late Medieval obsession with omnipotence. (Where an exaptation is a trait evolved for one purpose, potentially now defunct, fortuitously becomes adaptive for another.)Footnote ⁵⁷ But, aside from generating the intellectual conditions enabling scientific inquiry, it also fomented a growing sense of the future. The two go hand in hand: by enabling the vocabularies required to reverse engineer the nomological structure of the universe, and thus beginning technoscience’s accelerating transformation and restructuring of our material conditions, these same vocabularies allowed people to capture the burgeoning sense that genuine change was afoot within one’s own lifetime.

Ultimately, in making the world arbitrary, omnipotence stripped it of indwelling reason. Hans Blumenberg called this the ‘Ordungsschwund’, or, loss-of-order, that stood at the late Medieval threshold to modernity. The laceration of the old, traditional worldview is what opened the floodgates on the future.

It should be noted here, also, that the late Medieval invention of ‘synchronic’ possibility, as the selection between simultaneous alternates, may also have been upstream of the development of both of the major modern systems of ethics: utilitarianism and deontology. Ancient and Medieval normative theories were broadly aretalogical, or, centred on performing the virtues. This again was often rooted in precedent, or replicating the habits and prior example of admirable people. This, clearly, fits with a ‘diachronic’ conception of possibility: wherein, as all possibilities eventually come to pass regardless, and can never become forever frustrated, the aggregate of good in the universe over time cannot be affected. Utilitarianism appeals to the idea that the aggregate of good in the cosmos is variable, in potentially unprecedented ways, and teaches that we should select between our actions based on maximising that aggregate. Selecting between alternate actions, some of which may remain forever unrealised, thus plausibly alters that aggregate – in meaningful and lasting ways – because not all possible permutations are guaranteed to come to pass regardless. Deontology, likewise, appeals to a rule of conduct which is meaningful even though it may have never been fully obeyed by any limited, finite being. It is very consciously not rooted in precedent or prior actions. This way, the late Medieval development of new modal logics may have paved the way for, centuries later, the invention of modern systems of ethics too.Footnote ⁵⁸

What’s more, by stripping reality of dependence on mental structures, this inculcated sensitivity to things and events falling beyond all current conceptual categorisation. This lubricated responsivity to the cosmos’s non-responsivity to semantic capture and moral expectation: manifesting as new openness to the unexpected, inexplicable, catastrophic, and anomalous. Of course, humans have always dealt with these things, but now new concepts had been developed through which to express and model them.Footnote ⁵⁹

In short, by starting to encourage ways of thinking about how the universe could have been otherwise than they believed, people started to realise it already is otherwise, the realisation of which – snowballing into an undeniable break with the past – lent momentum to a burgeoning sense things can and will become otherwise in ways unscripted by Deity’s predetermination.

Of course, this would not happen overnight. Expectations on the future remained shallow. This was, primarily, because of widespread belief that history was much nearer its end than its beginning. Each generation assumed it might be the last. Jesus himself had told his disciples as much. Indeed, most believers, during the Middle Ages, actively wanted the end to come. It would liberate them, they believed, of their Earthly suffering and consecrate the final sorting of Good from Evil. Existence was considered irredeemably alloyed with sin; the only way to purify it was to end it.

In the thirteenth century, towards the end of the Middle Ages, the English polymath Roger Bacon recorded his hopes for the future. He believed ‘individuals, cities, and whole regions can be changed for the better’ through study and education. But, nonetheless, Bacon still assumed he was living nearer the end, adding that ‘it is believed by all the wise that we are not far from the times of the antichrist’.Footnote ⁶⁰

In 1493, the German writer Hartmann Schedel set out to compile a chronicle of time in its total compendium – stretching from creation to apocalypse. At the end of the book, he left blank pages for his readers to fill in and record history’s remaining episodes themselves. The entire volume was roughly three hundred pages long. Schedel left only six blank pages for time’s remaining episodes.Footnote ⁶¹

What’s more, again, what unfolded over those remaining blank pages was considered prewritten and predetermined. Even the voluntarists believed that God had selected ours as the best of all possible worlds, wherein value and life are invariant and indestructible qualities, sealed away from vicissitude. Though local change could be affected, the aggregate ‘bonum’ of the universe was maintained by God and couldn’t be meaningfully altered by humans. ‘Mind’ and ‘life’ were not yet subsumed within the Horizon of Contingency as historical variables: they were not thought of as emerging from nature nor of as potentially disappearing from it. Instead, all the regions of the premodern cosmos were thought of as populated with spiritual agents – whether angelic or demonic or human – across time and space. The Ptolemaic universe had no unoccupied regions. There was no acknowledgement that nature has an autonomous history, wherein vast regions in time and space can be unpopulated and abiotic. Whether through deity or directionless repeats, an invariant baseline of ‘justice’ or ‘life’ was thought of as maintained from start to end.

But then, by good chance, someone discovered how to measure chance, thus allowing the unpredictable nature of the future to – finally – become an object of study.

2.1 Early Modern: That We Can Make the World Otherwise

The historian of ideas Ian Hacking once remarked at how curious it is that, despite the fact almost all other fields of mathematics find their first flourishing in the ancient world, the study of probability remained a ‘absent’ until the dawn of modernity.Footnote ⁶² There is long-running mystery over probabilism’s belated birth: or, why ‘probability calculus was so long developing’.Footnote ⁶³

One reason for this, which has yet to be noticed, is the lack of ‘synchronic’ definitions of possibility prior to Duns Scotus. Conceiving of each throw of the dice as the expression of a wider space of simultaneous alternatives is requisite for grasping probability. Without grasp of ‘synchronic’ possibility, there could be no such understanding.

Of course, in sortition, divination, casting of lots, and astragali (heel bones used as dice), and cleromancy, there is a ‘prehistory of randomness’ and ‘luck epistemics’ going back deep into the ancient world.Footnote ⁶⁴ Yet this was apprehended as inscrutable ‘fortuna’, rather than anything formally tractable: until, that is, Gerolamo Cardano’s Liber de Ludo Aleae, which was written around 1550 and published posthumously in 1663.Footnote ⁶⁵

In this pathbreaking work, Cardano – a polymath who often resorted to gambling to support himself financially – conducted the ‘first real experiments in the mathematics of chance’.Footnote ⁶⁶ Cardano’s breakthrough, now deceptively intuitive yet at the root of the entire edifice of the modern world, was in conceptualising each dice-throw as the expression of a larger set of possibilities, thus developing the notion of a synchronic possibility space (which Cardano entitled the ‘circuit’ of the die). In deploying numeral notations to track frequencies within this reference class, Cardano invented the modern field of probability and made the future enumerable. Indeed, by 1654, Pascal – in his correspondence with Fermat – deployed the method to robustly measure future outcomes: computing the cascading number of possible results from an interrupted game of chance so as to properly allot winnings between players, given likelihoods each player would have won had the game concluded.Footnote ⁶⁷

This, in important ways, provided the threshold of ‘advanced modernity’, leading the way to our modern ‘world of speed, power, instant communication, and sophisticated finance’.Footnote ⁶⁸ Indeed, the word ‘risk’ first entered the English language throughout the 1600s, percolating first through the professional vocabulary of maritime traders and their insurance underwriters. With the coincident explosion of financial markets, and speculation thereof, futures had become profitable and risk a lucrative business. The future began bleeding into the present, by being carved at the joints – and thus made tangible and tradeable – by Cardano’s seismic innovation.

By this time, moreover, worldly time was swelling beyond the bookends prescribed by apocalyptic prophecy. The promised end kept failing to arrive. The more the years continued to accumulate, and the more frustrated their apocalyptic conclusion became, the more there could arrive a growing sense of the autonomy of secular history from divine dictatorship. As apocalyptic expectation became increasingly frustrated, that is, worldly time began to seem increasingly untouched by orchestrations from beyond.

This fed into, and was fed by, building conviction that genuinely unprecedented things were being invented and wrought by human agency and activity. History seemed on the move, with human ingenuity – rather than divinity – increasingly with its hands on the rudder. This led some to begin asking, in new ways, where they stand within this story. None other than Gerolamo Cardano, writing around 1570, remarked that his position in the generations seems improbable given he appeared to have been born during an uncommonly pacey time of innovation: wherein printing, gunpowder, and the compass had all become widespread in Europe.Footnote ⁶⁹

But many Renaissance thinkers continued to assume that, though there might be local direction to human history – applying within one’s nation or continent – there may be only aimless cycling and recurrence at the level of the globe. They tended to assume that all novel inventions had already been invented elsewhere and elsewhere, and, by implication, will be discovered again should their civilisation be lost or forgotten. Again, there was not yet the evidence sufficient to disprove this: in absence of a global fossil record it remained underdetermined as to whether human history had a proper beginning such that it can admit of genuine novelties and irreversible transitions.

For example, in 1651’s Leviathan, Thomas Hobbes spoke of the shift from a warring ‘State of Nature’ to that of the ‘Social Contract’. This might now sound like what we understand as the transition from prehistory to history. We envision a time before which no humans, anywhere, practised farming or writing, and a time after which some started. But this wasn’t what Hobbes had in mind. He clarified he believed the precivilisational state ‘was never generally so, over all the world’.Footnote ⁷⁰

This betrays assumption that human history – at the level of the globe – could simply represent the cycling of a set of states simultaneously manifested in space, rather than a chronology of genuine firsts and lasts irreversibly punctuating time. A revolving, never a rupture. Regions might slither between states, but, from the global perspective, nothing genuinely novel ever happens or is permanently lost. Every ‘civilised’ region will have previously been in the ‘State of Nature’ and every wild region will previously have experienced ‘Social Contracts’, potentially without limit.

Hobbes’s view was far from unorthodox. Many other Early Modern thinkers also understandably erred cautiously when it came to the question of extremities to human history. Writing in his 1513 Discourses, Machiavelli again entertained the possibility there have been countless human civilisations, its just the records of them have been ‘blotted out by various causes’. Like Plato before him, he endorsed a cyclical view wherein civilisation repeatedly grows to a certain point – that is, ‘when human craft and malice have gone as far as they can go’ – before everything is destroyed, clearing the way for a reset.Footnote ⁷¹

Various commentators remarked that, though new things appeared to be being invented, they couldn’t disprove lingering suspicion all these feats hadn’t already been innumerably achieved before – by forgotten civilisations, in unknown regions, throughout time immemorial.

Accordingly, by the Early Modern period, the Horizon of Contingency still didn’t extend far beyond one’s landmass or continent. Nonetheless, this didn’t deter growing feeling that human ingenuity – rather than divine dictatorship from the heavens – seemed, increasingly, to be steering history’s course. So, too, did a suspicion begin building that time is open-ended: that is, that it can take various different tracks, depending on accident and agency flowing from human affairs.

So mused the French polymath Blaise Pascal sometime around 1650: had ‘Cleopatra’s nose’ been different, making her less attractive, then ‘the whole face of the earth would have been different’.Footnote ⁷² That is, should Mark Antony not have fallen for Cleopatra’s distinctive visage, subsequent events would have also been unrecognisable. With this clever quip – bundled with a pleasing pun – Pascal captured an emerging, very modern attitude towards time.

We may be accustomed to such counterfactual conjectures at global scale now; back then, however, they were newfangled. Our grasp of history’s contingencies, and of the future’s forking paths, has continued growing ever since: an ever-expanding halo of unrealised possibilities fanning out from the merely actual.

Nonetheless, Pascal himself held to the old belief that the space of historical possibility was small enough that everything that can happen already has happened, such that true unprecedented change – in secular affairs – remained unthinkable to him. As he memorably put it, writing in his Pensées: ‘the nature of man is not to be always going’. In Pascal’s eyes, human history evidently ‘has its goings and comings’. ‘It is the same with human inventions from age to age’, Pascal concluded, ‘and the same with the goodness and wickedness of the world in general’.Footnote ⁷³ In other words, he also believed nothing truly unprecedented happens within worldly history.

Nonetheless, new tools for making the future tractable were being developed. Namely, the mathematics of calculus, developed independently by Isaac Newton and Gottfried Wilhelm Leibniz in the latter 1600s. This allowed the computation of changing rates of change: meaning that anything that can be plotted with a curve – parabolas of orbital paths as much as fluctuations in markets or populations – could suddenly yield to being converted into numbers. These nonlinear processes, formerly intractable to computation, could now be translated into tractable formulas, amenable to retrodiction and prediction. The future yielded to calculation: thanks to offloading our imaginations from imprecise language to the rigour and rule of number. The first triumph of this method was procured by Edmond Halley, who, in 1705, used it to compute the path of the comet that now bears his name. He correctly forecast its future return in 1758, proving long-range numerical prediction of nature’s trajectories was possible.

Though its roots go back to the aforementioned Medieval arguments of Duns Scotus and others, Leibniz is also famous for developing the theory of ‘possible worlds’ in his Théodicée of 1710. But, crucially, these evanescent possibilities were hermetically sealed from our world. Leibniz, again, believed ours, by necessity, the best. Accordingly, when it came to worldly history, he held a very providentialist view: remarking – after considering some critical counterfactuals – that the ‘instants of when things should happen’ are, ultimately, ‘set by God’.Footnote ⁷⁴

What’s more, in a fragment penned in 1715, the German polymath set out to gauge the total set of human historic possibilities, with an eye to calculating the interval of time before worldly history resets and repeats itself.

Beginning with the premise that one can ‘determine the number of all possible books of a given size composed of meaningful and meaningless words’, Leibniz noted this number is finite. Supposing, therefore, that ‘a public annual history of the earth can be sufficiently related’ in a book containing ‘100 million letters’, he concluded it is ‘clear that the number of possible public histories of the earth’ is ‘limited’, because the number of meaningful combinations of 100,000,000 letters is finite. Accordingly, given enough time, human possibilities will ‘exhaust’ and repeat. Leibniz remarked that the monarchs of his day – from Emperor Leopold I to King Louis XIV – will ‘return’.

Going even further, he pronounced that the same calculation can be conducted for our own ‘private’ histories. Supposing a ‘thousand million humans’ alive on Earth, he guessed that a book with 100,000,000,000,000,000 characters could exhaustively chronicle every experience of every human over the course of a year. Again, given that the number of meaningful permutations of a book of this length nonetheless remains finite, Leibniz pronounced that every individual life is bound to repeat, down to the smallest minutiae. ‘I myself, for example, would be living in a city called Hannover’, he mused, ‘writing letters to the same friends with the same meaning’.Footnote ⁷⁵

Leibniz wasn’t explicit on the interval of time required for this recurrence to occur, but he was certain it could be meaningfully numbered. Notably, at the time, the entire span of Earth history was often measured in thousands of years, with some outliers admitting the possibility of tens or hundreds of thousands of years.

Indeed, it also remained orthodox to assume the world would last a further several centuries. This sense, of living nearer to history’s conclusion than its beginning, affected peoples’ sense of ambition and hope for the future ahead. Writing in 1658, Sir Thomas Browne perfectly captured this overriding sentiment. ‘’Tis too late to be ambitious’, he declared:

The great mutations of the world are acted, or time may be too short for our designes.Footnote ⁷⁶

But, by this point, in the wake of the Copernican revolution, people could now look beyond the Earth, to other planets, as the places where our history would repeat and recur without limit.

Indeed, Copernicus’s revolution made people feel small, but it didn’t initially make them feel lonely. Far from it. Responding to the cosmic vastitudes revealed throughout the 1600s, Pascal famously admitted the ‘silence of these infinite spaces terrifies me’.Footnote ⁷⁷

But people forget what else he said. What terrified him wasn’t the prospect we were alone, but the opposite. He hated the ignominy of being unnoteworthy, or, the idea of countless populated globes that ‘know nothing of us’ because Pascal assumed all worlds host the same animals Earth houses – down to the ‘mites’ – such that all Earthly things must cosmically recur ‘without end and without cessation’.Footnote ⁷⁸ What alarmed him was how mundane this extramundane churn of living globes makes us.

Pascal was far from alone. Confronted by a universe far larger, in space and time, than had previously been permitted by limited imaginations, people simply assumed it lacked limits entirely. Contemporaries, like the Cambridge Platonist Henry More, concluded there will be ‘endless’ Earths and humankinds. Dizzyingly, he pictured infinite Adams coupling with innumerable Eves. Nothing in infinity is unique, nothing mortal.Footnote ⁷⁹

Indeed, the belief that the universe is so overflowingly full of living planets made some feel comfortable in proclaiming that the destruction of one must be for the benefit of all, given this provides room for renewal. Retrofitted for the new Copernican cosmology, the old idea of invariant and indestructible ‘goodness’ – from the level of the cosmic whole – persisted. As the Earl of Shaftesbury wrote in 1711, the idea that all evil is necessarily compensated by equal good, elsewhere or elsewhen, applies to entire planetary systems: whereby ‘the evil of one private system is the good of others’, such that the destruction of one ‘contributes still to the good of the general system’, particularly when ‘one planetary system … swallows up another’. The harm to a destroyed system, he continued, ‘is not really bad in itself, any more than the pain of cutting new teeth is bad in a system of body which is so constituted that without this episode of pain it would suffer worse by being defective’.Footnote ⁸⁰ Again, historic, irreversible, or unprecedented fluctuations in the aggregate goodness of creation were considered impossible.

So, again, from the perspective of the cosmic whole, there is only constant equilibrium: never any genuine loss or novelty, never any true history. What’s more, in such vastitudes, all achievements must necessarily already have been achieved, such that nothing on Earth is truly novel. The Ancient belief – that all historical possibilities have already limitlessly been passed through – had simply receded from other landmasses to other planets.

This way, initially, Copernicus’s revolution didn’t shrink humanity’s ego. It inflated it to cosmic catchments. But figuring out where we find ourselves in time – more specifically, within the chronology of our own planet – slowly but surely, unravelled this.

2.2 Enlightenment: Subsuming Earth within Contingency’s Horizon

But then, throughout the 1700s, naturalists began looking to the Earth itself, rather than scripture, to answer the question of the present’s location in time. Geology had begun consolidating as a science.

The geological record of superposed strata, each containing different fossils – a ledger of the past – would seem clearly to imply direction. Nonetheless, for a while, naturalists resisted: trying to resolve building evidence of systemic direction into cycles of wider directionlessness and recurrence.

Ahead of digging into the planet, the first geologists assumed they might find proof of nothing really changing throughout Earth’s history. They expected remains of everything currently alive on the surface to be located even in the deepest strata. Some predicted that, if we dug to Earth’s core, we would find human remains. Thus wrote the French diplomat Benoît de Maillet, speculating in the 1720s:

Ahead of evidence to the contrary, naturalists assumed the evidences of excavation would eventually reveal a lack of directionality across geologic history. But, when scientists began peeling Earth open, revealing the fossil record’s testimony, this isn’t what they found. Not only did the eldest strata lack organic remains entirely, they also noticed the skeletons change drastically – becoming less familiar – the deeper you get.

Nonetheless, since at least 1700, scientists had been accumulating evidence of undeniable directionality in Earth’s past. In the shape of vestiges of a beginning. As early as 1669, geologist Nicholas Steno recorded strata ‘free of all [organic] material’, implying a period of Earth’s history ‘when animals and plants had not yet appeared’.Footnote ⁸²

Moreover, no sign of fossilised humans could be found in the lower beds. Candidates for ancient humans were soon proven to be mistaken, such as one giant salamander fossil, which was briefly mischaracterised as human, by Johann Jakob Scheuchzer in 1726.

By putting a clear backward stop on previous human history, alongside implying the recency of all humanity within a much elder Earth system, this meant that it became much more plausible to suggest that not everything humanly achievable has already been achieved throughout an unbounded past.

This, in turn, fed into a sense that – rather than being a closed-off repeat of what’s come before – the future ahead could be open-ended: containing novel achievements as well as unprecedented challenges.

Thus, rather than being made up of directionless returns, resets, and amnesias gyrating through boundless time, human history – as a global whole – could begin to gain an overarching shape: involving determinate firsts and unidirectional transitions between differing states.

As early as Reference Lomonosov1763, the Russian polymath Mikhail Lomonosov had begun explicitly dismissing the prior attempts of ‘Christian chronologists’ to gauge the size of Earth’s past, before hinting that the testimony of the Earth itself must trump that of the Bible. After all, our planet, Lomonosov explained, is the ‘most senior Chronicler of all’. Lomonosov concluded the Earth ‘appears to be greater’ than previous calculations had indicated.Footnote ⁸³

Having put the question to the rocks, it wasn’t long before scientists were widely accepting the Earth had been around for leagues longer than was previously expected. Thousands of year estimates swelled into tens of thousands. Unsurprisingly, it became natural to expect that it might stick around – into the future – for a similar length of time. So, the question was asked: can geological evidence tell us how long is left ahead for Earth?

The time was ripe for the first physical theory comprehensively predicting both the past and future of the Earth system. This came from the French polymath Georges Buffon in the 1770s. Theorising the Earth was created from molten matter ejected from the sun, Buffon inferred it would eventually dissipate its internal heat and freeze, killing all life. A molten birth, hurtling inexorably to frozen death.

Retreating to his basement forge in Burgundy, Buffon heated iron balls then measured their cooldown times, before scaling them up to the globe’s size. From this, he estimated Earth was around 74,832 years old; that life emerged upon it 35,983 years ago; and that it would remain habitable for another 93,291 years.Footnote ⁸⁴ (Rounding wasn’t yet scientific convention.)

This might seem paltry now, but it was fathoms greater than previous estimates. Indeed, given that time’s prior limits seemingly were bursting, some once again saw evidence of limitlessness. Eternity recurred.

Not long after Buffon’s investigations, the Scottish geologist James Hutton riposted. He argued that, in explaining Earth’s features, only currently observable causes should be conscripted. This was sensible – designed to excise unverifiable explanations from geological science – but Hutton overapplied it wildly.

Hutton became convinced our planet had never looked drastically different from how it looks today, nor can it change in future. This keyed into his famous declaration that geologists find ‘no vestige of a beginning, no prospect of an end’.Footnote ⁸⁵ Bewitched by the aeons required to sculpt vast mountains and canyons using only mundane processes – like erosion or sedimentation, which work at piecemeal pace – Hutton became convinced the past and future of the Earth system was not just enormously long but, instead, limitlessly long. He applied this to the future as much as the past. Sometimes hailed as the ‘discoverer of deep time’, nothing could be further from the truth. Hutton was drunk on boundlessness, not deep time.

This way, eternity briefly recurred: by ceding ground and receding from human history to the mists of geological time. But, despite Hutton’s efforts, Buffon’s view – that Earth’s biography has determinate bookends in time – slowly won the day, as evidence of an epoch before all life became undeniable.

The habitable planet had thus gained a definitive beginning and a bounded future: providing the ambit, the extremities, within which human history could be understood as unfolding, and as unfolding in a way that – because of the boundedness – could admit of persistence, genuine firsts, and irreversible losses. Eventually, this would come to replace the default assumption that global human history unfolds as a limitlessly reversible and retraceable meandering through time immemorial.

Because of this, there emerged a sense of time ahead, bounded yet capacious, within which novel things could be achieved and persistently accumulated. But, by the same token, this also meant that what might be lost, in the event of planetary disaster, could also begin to become articulable.

Given the new knowledge won by geology, the Horizon of Contingency had expanded to circumscribe the entire planet, bequeathing it the temporal bookends within which history’s contingencies could gain bite, insofar as there was no longer a guarantee all outcomes would come to pass regardless. Though Duns Scotus, back around 1300, had invented his logic of possible worlds in order to say how things could have been otherwise, this same logic was now being leveraged to reveal how things – at planetary scale – can become dramatically otherwise.

2.3 Evolution: Subsuming Species within Contingency’s Horizon

Nonetheless, contingency didn’t yet enter the picture. In 1777, Buffon himself once speculated what would happen if all life was wiped out globally:

He imagined that, after this, there ‘could not fail’ to be reproduced ‘a new living Nature’. Furthermore, he made explicit that he thought:

Why did Buffon assume this? The answer is because there was not yet any clear understanding of how species originate, such that there could be no grasp of what precisely is lost when their populations are destroyed to the last member. There was no consensus that, once lost, they are gone forever.

Many assumptions regarding origination of species – prior to Darwin – actively obstructed grasping this. Going back centuries, one prevalent theory – affirmed also by Buffon – held that each species ‘pre-exists’ all its manifestations, as invisible ‘seeds’, diffused through the atmosphere. These were assumed ‘indestructible’: i.e. they always have existed and always will. All that was needed, it was believed, were welcoming conditions and the ‘seeds’ would simply germinate into fully adapted species, without need of parents.

This means that a species can persist even if it has no living members. Such a theory makes the origin of species effortless, in that such origination lacks any timespan or stringency of circumstances, because it bypasses all the steps we now know are required – to be traced through, from simpler to less simple forms – in order to forge a complex lifeway.

There’s no multiplicity of prior states the world needs to have passed through for species to pass from inexistence to existence; the corollary of this is assuming that, if a population dies out here and now, it’s hard to see what would obstruct it from later reappearing elsewhere.

In the earlier 1700s, de Maillet rallied this theory to explicitly deny the irreversibility of extinction:

As late 1819, the influential German biologist Lorenz Oken conjectured that humanity was first generated in such a way: gestated from ‘slime’ in sea shallows, without descending from prior forms. He even speculated, sincerely, as to how the first generation of children fed and fended for themselves, given there were no parents to show them the ropes.Footnote ⁸⁹

Put simply, belief in the spontaneous generation of complex things, without the need of any prior histories, neuters the consequences of their eradication: because there’s no stringency of states, the universe must retrace to produce identical, or similarly complex, classes of entities again.

Falsifying the presupposition that annihilated species could return required the testimony of the fossil record: wherein lost fauna never return. And, again, not just on one landmass or continent but spanning them. This, however, is precisely what scientists had been piecing together from the early 1700s onwards.

By 1800, the scientific community accepted the reality of irreversible extinction.Footnote ⁹⁰ A few decades later, sequence started to be accepted: a succession of fauna over time, with earlier forms more unfamiliar and later forms more closely resembling those extant today. Naturalists hypothesised an initial ‘Era of Fish’, then an ‘Era of Reptiles’, followed by today’s ‘Era of Mammals’.

Nonetheless, the causes behind this faunal succession remained unclear. Many simply assumed that each era’s fauna were ‘fresh creations’: that they aren’t descended from the creatures of prior periods, nor are related to them in any ‘material’ way.

Some, as late as the 1840s and 1850s, argued that not a single organism has ever passed offspring between past epochs. They held that, each time, the Earth is wiped entirely clean of life – by some cataclysm – before entirely unrelated, novel animals are simply ‘called into existence’, entirely from scratch, whether by divine intervention or nature’s inherent creativity.Footnote ⁹¹

As late as the 1840s, Louis Agassiz – an immensely influential biologist – was still insisting that life’s succession proceeds this way and ‘is not the consequence of a direct lineage between the faunas of different ages’. ‘There is nothing like parental descent connecting them’, he ordained.Footnote ⁹²

Today, we now recognise that the smallest possible number of steps required to assemble a complex mammal from unorganised matter – entirely from scratch and without the help of pre-existing parents – is something on the order of four billion years of uninterrupted evolution. That is, the shortest pathway to the biosphere’s current richness demands an ancestry billions of years deep.

But, if you don’t see this, assuming contrarily something as exquisite as an entire ecosystem can simply be forged ‘afresh’, each time the world is wiped clean, it’s much harder to see the weight of what might be lost in planetary disaster.

We now know species are historical entities – they cannot simply spawn independently of myriad prior states of the world holding true. This is why, should they be lost, they cannot effortlessly reappear. It was, of course, Darwin who allowed the world to see this. With his Reference Darwin1859 Origin of Species, he demonstrated that complex lifeways are only ever wrought by stringent, long-winding histories. Accordingly, members of a species cannot spawn anywhere, anytime, effortlessly, because they need a connection to a shared past, in the form of parents and countless ancestors.

Darwin was himself conclusive:

Organic complexity thus becomes a kind of stock, built only over time: it doesn’t just require one prior state to hold, it requires myriads, in unbroken chains of cumulative inheritance, stretching back eons. Without the ‘shortcut’ of already procreating parents, there is no way of skipping these steps.

Solely upon apprehending this could it become truly apparent how historically consequential any destruction or loss of that planetary stock might be. Though it would take a few more generations for adherents of Darwin’s theory to truly realise what this entails concerning the scope of the contingency of every Earthly species. So, in the years following Origin of Species, life’s lineages themselves began being subsumed within the Horizon of Contingency: as products of events which didn’t have to have happened, as therefore contingent and definitively destructible.

This was a far cry from the Medieval worldview, wherein the universe could not suffer a single loss or annihilation, insofar as this would denude the ‘complement of good’ housed within it.

3.1 Thermodynamic: Subsuming the Sun within Contingency’s Horizon

But how much longer did life have left? What further development might be possible? Answering this question involved estimating how long it had taken for life to arrive at its current grandeur and diversity, so as to gauge how much further diversification could be cumulated in the time left ahead.

By the mid 1800s, due to the birth of thermodynamics – the mathematics which models the flow of energy and heat – the question of Earth’s future habitability was, by now, understood to hinge upon the sun’s remaining lifespan. As John Tyndall put it in 1863:

So, how long was left? Mid-century, physicists provide the first hypothetical model for how the sun was formed and produces its heat. Thermodynamic calculation was leveraged to estimate how long the sun had already been burning, as well as to forecast how many years of sunlight might be left.

At this time, however, it was uncertain how our star produces its outpouring. Scientists had already decided it couldn’t be combusting, like a gigantic coal, since a cinder the size of our sun would burn itself up far more rapidly than seemed plausible. This jarred with the timescales required to explain geological features on Earth.

Long before anyone alive had dreamed of liberating atomic energy, various explanations were proposed, assuming stars shine through some mechanical process. The most popular was that the sun produces its heat by languorously collapsing under its own vast weight. Grinding on its own matter as it compacts, outputting heat and light as the result.Footnote ⁹⁵

A proponent of this model, William Thomson produced the first prediction for the future output of the sun in 1854. He confidently announced:

By end of 1800s, physicists had, by and large, converged upon an estimate in the low tens of millions for Earth’s habitable future. As the US spectroscopist Charles Augustus Young relayed in 1881:

The past and future of the whole Solar System had thus become large but bounded, and, thus, subsumed within the Horizon of Contingency. The fates and fortunes of life within this zone were beginning to be acknowledged as irreversible and open to playing out, permanently, in different ways.

Nonetheless, many found the extent of future ahead, for life on Earth, dispiriting. Forecasts of 10,000 further years were admittedly much more commodious than Buffon’s earlier estimates, not to mention those of earlier Christians. However, in the century since Buffon, the sense of life’s unexplored potentials had grown – largely thanks to Darwin’s theories.

What’s more, the theory that the sun produces heat via collapsing on itself led physicists to conclude the ratio of ‘past spent’ to ‘future ahead’ was unforgiving. If it had started life as a diffuse cloud, our star – now relatively compact and dense – seemed at an advanced, geriatric stage of life’s arc. In the 1892 words of Robert S. Ball:

Accordingly, the placement of the present placement of ‘now’ – relative to established past and potential future – had returned to a position similar to that of the early Christians.

This predicament seemed depressing to many. There was a sense evolution had come thus far, but didn’t have time to go much further. People assumed life had passed its prime: that the future would be populated by increasingly simple life forms, withering on a diet of dwindling sunlight.

So, as the 1800s closed, there was a belief there wasn’t time nor available energy to see much more development, nor to care too urgently about the longer-run ramifications of our actions. A freezing death awaited in the not-too-distant future (see Figure 1).

Figure 1 Charles Joseph Mettais, ‘The Last Couple on Earth’, depicting the final human family succumbing to global cold.

From C. Flammarion, L’Astronomie Populaire (1880).

But, then, as the 1900s opened, an entirely new force of nature was discovered: blowing the ceiling off all previous upper bounds on the future. Having coined the word ‘radio-activité’, Marie Curie successfully isolated radium in 1902. Not long after, she proved that the element expels energy without itself losing heat. Radioactive atoms, she showed, were tiny furnaces. This reveals a titanic, previously unacknowledged, wealth of energy is locked up within mundane matter.

Moreover, given the extreme length of decay rates, it also provided the first reliable way of accurately measuring physical processes, past and future, stretching into the many billions of years. Timescales couldn’t help but expand.

Immediately, scientists started postulating that radioactive power somehow fuels the stars. Rather than languidly collapsing on itself, the sun now seemed like a self-heating furnace. Almost overnight, this drastically expanded estimates on upper bounds for solar lifespan, and, therefore, also for future habitability on Earth. As early as September of Reference Darwin1903, the geophysicist George Darwin celebrated Curie’s ‘unexpected’ discovery of this ‘new source of energy’. If the Sun powers itself by ‘liberating atomic energy’, he conjectured, rather than mere gravitational collapse, then we may have to expand the ‘cosmical time-scale’ by ‘some such factor as ten or twenty’.Footnote ⁹⁹

By 1907, the physicist Ernest Rutherford concurred, announcing we can expect solar ‘brilliancy’ for orders of magnitudes more than Kelvin’s considerations of no ‘more than 12 million years and probably much less’. Curie’s ‘new source of heat’, Rutherford wrote, probably suffices to power the ‘sun for a longer period’, thus vouchsafing a much greater ‘time for habitation of our globe’.Footnote ¹⁰⁰ By 1920, prominent physicist Arthur Eddington was venturing that our sun, powered by subatomic reservoirs, would be able to ‘maintain its output of heat for 15 billion years’ more. To hammer home his point, he referred to the gravitational theory of Kelvin and Helmholtz as a ‘corpse’.Footnote ¹⁰¹

Rather than living in a geriatric world, humankind suddenly seemed youthful. Within a generation, peoples’ sense of where they find themselves in terrestrial time had flipped: from believing they were living nearer the end, towards thinking they could be living during the dawn. Scientist quickly noted this means we should be more careful, remaining alert to the ways present action can scar or damage the expanding future. The Illinoisan geologist Thomas Chrowder Chamberlin put it best, proclaiming in 1903:

As the twenties roared, timescales continued to boom. By this time, physicists and cosmologists were predicting tens of billions of years of future habitability on Earth, some even a trillion. In the decades since, this has progressively been slashed downward, as it discovered our sun will expand, rather than contract, as it ages and was became understood how this expansion will interact with Earth’s atmosphere. Nonetheless, it remains testament to how much peoples’ sense of the possibilities and potentials of the future was expanding during the early 1900s.

But, during the 1930s, thanks to the work of Lise Meitner and others, understanding of nuclear fission coalesced. This led, ultimately, to the fateful uncorking of atomic energy, which, in turn, led to the development of atomic weapons: terrifying in their destructive potentials. Suddenly, the radically expanded prospect revealed by nuclear physics was being put in jeopardy by that very same force. As Freud put, already in 1931:

Yet, just as the Ancients and Early Moderns could point beyond their own landmass, in order to gesture beyond history’s horizon to the region wherein things will comfortingly repeat and recoup, so too ponderers in the early 1900s point beyond the Solar System – to other stars and systems – so as to conjecture that regardless of humanity’s fate here on Earth, there will always and forever be abundant ‘other humanities’ spread throughout the limitless cosmos. This provided assurance, as well as insurance.

This is why, as the French astronomer Camille Flammarion emotively put it in 1868 the starry expanses are ‘the future regions of our immortality’ as the ‘number of our body doubles is infinite in time and space’.Footnote ¹⁰⁴ Later, in 1888, he reiterated this point, claiming that our sun will one day ‘disappear to leave room for other systems of worlds, other suns, other earths, other humanities, other souls, – successors in universal and eternal history’. This, essentially, was a return to earlier, Lucretian views: of a universe unlimited in space and time, wherein everything is a repeat or return. (As Lucretius himself had said, writing nearly a millennium before, there will always be, ‘in other parts of the unverse’, worlds ‘inhabited’ by ‘many different peoples’.)Footnote ¹⁰⁵ For Flammarion’s part, he continued his argument, declaring:

Flammarion’s compatriot, the socialist Louis-Auguste Blanqui put this position strongest. In his 1872 L’Eternité par les astres, he pronounced:

These ‘doubles’, he clarified, are ‘body-double’ in ‘flesh and bone, even in trousers and vest, in crinoline and chignon’. He also added that this means ‘there is no progress’, cosmically speaking, but only ‘vulgar reissues’ and ‘repetitions’.Footnote ¹⁰⁷

Such belief was attached to related assumptions about the origination of life itself. Indeed, many theorised that in a cosmos without a beginning, life itself also need not be historical, in the sense of never having properly ‘originated’ anywhere or anywhere, such that it also can never properly have an ‘end’.

This took the form of the theory of ‘panspermia’, popular during the decades straddling 1900, which argued that life doesn’t originate or emerge – at a certain place or time – but simply circulates unendingly from system to system, and always has done, in the form of ‘cosmic spores’ or ‘astroplankton’. As the German biologist August Weismann stated in 1881, the corollary of panspermia is that

Moreover, panspermia meant that, on average and over time, the amount of life in the eternal cosmos will remain invariant. One planet may die, another may be germinated, but these average out in the longest term. The Swedish astronomer Svante Arrhenius made this clear in his 1908 World in the Making, proclaiming that this means organic evolution ‘can continue in an eternal cycle, in which there is neither beginning nor end, and in which life may exist and continue forever and undiminished’.Footnote ¹⁰⁹ Again, this was not a far cry from elder, Medieval notions of a world wherein all the losses and gains, all victories and defeats, equal out into an historically invariant aggregate of ‘value’.

3.2 Cosmical: Subsuming the Universe within Contingency’s Horizon

Accordingly, even though Darwin’s theory made it wildly improbable, people could still seek immortality for our species in the stars. Given an eternity of chances, even the most unlikely confluence of conditions will innumerably repeat. Hence, why, in the 1929 words of one Nobel-winning physicist, there will always be, somewhere, an ‘Earth’ – ‘it matters not which’ – upon which ‘some billion years hence the development of man still may be going on’.Footnote ¹¹⁰ In an eternal, infinite universe, such resurrection is inevitable. Such a thought was comforting, some began remarking, given that humans had begun messing with atoms.

But then the Universe itself started gaining bookends in time. Peering into the world’s largest telescope, around 1920, Edwin Hubble noticed something bemusing about other galaxies outside our Milky Way. They are flinging away from us, at quickening pace the further away they get. Our Universe is expanding.

Extrapolating backwards, this implied an explosive beginning. Inferring forwards, it implied a rarefied end, with matter and energy eventually centrifuging into nihility. The Universe – as one giant physical whole – was gaining a beginning and end.

The Belgian physicist Georges Lemaître pieced it all together first. He theorised the Universe was birthed by titanic detonation. In 1931, Lemaître proposed our cosmos isn’t unborn and undying, but can be compared to a fireworks display.Footnote ¹¹¹ Standing on a ‘well-chilled cinder’, we peer into space, witnessing the explosion’s ember-scattering aftermath. In 1946, Lemaître published a book summarising his vision. Poetically, he wrote:

Just three years later, speaking on BBC Radio, the astronomer Fred Hoyle absentmindedly referred to Lemaître’s theory as the ‘Big Bang’. The name stuck.

It wasn’t long before this radical theory started winning over influential physicists, and it wasn’t much longer than that until they started extruding its entailments for life in general. The Russian-American physicist George Gamow was spelling it out, already, in 1941:

Around the same time, there were various important breakthroughs in origin-of-life research. Through the 1920s and 1930s, Russian biochemist Aleksandr Oparin had become the first to pose life’s origin as a specifically historical question. Previously, it was assumed either that life didn’t originate and simply eternally circulated (i.e. panspermia) or that it was constantly emerging from non-living matter (i.e. spontaneous generation). Both theories remove any significant factor of time.

Oparin reframed the problem by asking whether radically different atmospheric conditions in Earth’s past could have allowed gradual build-up of organic molecules from inorganic compounds. This, innovatively, brought history back into the picture: the reason we don’t see life emerging from non-life today is because these special conditions no longer hold.

Following Oparin’s conjectures, in 1952 the American chemist Stanley Miller replicated these conjectured young-Earth conditions in the lab, managing to synthesise organic monomers.Footnote ¹¹⁴ This leant credence to ‘abiogenesis’: the idea that life arose from non-living matter, potentially only once in the past, through a cumulative process. This new theory implied life was not some timeless, and thus universal, phenomenon, but the product of a specific confluence of past events.

Back in the earlier 1900s, it was still assumed – as one science writer summarised in 1920 – that we ought to ‘expect life to arise wherever the conditions exist’.Footnote ¹¹⁵ But, as the decades dragged on, even this position became less surefooted. Slowly, a new suggestion gained prominence: that life’s emergence, on Earth, may have been unlikely, an event birthed by luck or lottery. By the 1960s, writers were remarking we might do well to begin viewing life’s emergence ‘in terms of probability and chance rather than as the outcome of aim and effort’.Footnote ¹¹⁶ But, as far back as Reference Hopkins and Frederick1933, the biochemist Frederick Gowland Hopkins was already stressing that many of his colleagues were in agreement that ‘life’s advent’ on Earth might stand as one of the ‘most improbable’ events in the ‘history of the Universe’.Footnote ¹¹⁷

This began to imply that life, rather than being cosmically abundant across time and space, is a product of historical happenstance: the result of a series of flukes. Thus, it might well be cosmically scarce, perhaps even unique. Accordingly, what happens to Earth’s life in the future could no longer so surely seem a matter of triviality or warranting nonchalance.

Further, in 1964, two American astronomers – Arno Allan Penzias and Robert Woodrow Wilson – accidentally discovered the Cosmic Microwave Background Radiation. This is a faint hiss, coming at us from all angles. It is the omnipresent reverberation of the universe’s pyrotechnic beginning. This was received as overwhelming evidence for the so-called Big Bang Theory. It was tantamount to confirmation that the observable cosmos itself must have had a beginning and is finite in space.

This had subtle, yet profound, ramifications on our view of life’s place within the wider cosmos. The American anthropologist Loren Eiseley put it best in 1953:

Continuing, he stated:

In other words, in a universe with a beginning and a finite lifespan – no matter how large – it’s no longer feasible to fall back on the assumption that, regardless of what happens here and now, there always be other humanities and biospheres identical to our own, elsewhere and elsewhen. So, should we destroy any species – including ourselves – here and now, then these unique and unrepeatable products of terrestrial history are likely gone, from the entire universe, forever after.

Which is to say, the Horizon of Contingency had ballooned to cosmic catchments. Yet still, there remained one stubborn assumption obstructing full appreciation of the practical force of this realisation on our orientation towards our own future.

3.3 Extinction: Subsuming Sapience within Contingency’s Horizon

Going all the way back to Darwin, there persisted overriding assumption that something sapient was the inevitable outcome of macroevolution. Thus, if humanity died out here and now, then something like it would eventually re-emerge – and resume sapience’s project, so to speak – on Earth or elsewhere.

Darwin himself had been convinced that, in the main, species predominantly are pushed to extinction by their more adaptive descendants and competitors. In other words, it is a question of bad design, not bad luck.

For this reason, Darwin himself downplayed the role of planetary cataclysms that could decimate indiscriminately, wiping out even the most ‘successful’ lineages. He maintained that what looked like mass extinction events were just distortions of our incomplete view on the fossil record.

This underwrote a thoroughly progressivist view of macroevolution, where, in Darwin’s deeply influential words:

Of course, ‘perfection’ was here assumed to resemble something rational and humanoid. In an 1860 letter, Darwin went so far as to conjecture that rational beings would always inevitably re-evolve after being extinguished ‘if every Vertebrate were destroyed throughout the world’, except the humble reptiles, he conjectured, then, after ‘millions of ages’, they would inevitably ‘become highly developed on a scale equal to mammals’ – ‘possibly more intellectual’.Footnote ¹²⁰

Most of Darwin’s followers, for much of the 1900s, followed this lead. There was widespread assumption that extinction largely befell decrepit or spent lineages of life; such that, despite detours and delays, all macroevolution inexorably tends towards humanoid perfection.

Extinction was self-servingly assumed to only ever befall the deserving. This was applied particularly – sometimes with surprising spite – to the dinosaurs. Well into the century, the stereotypical view was that they died out due to sluggishness or stupidity, and were thus mercifully pruned from the world, so that we ‘superior’ and ‘intellectual’ mammals could take over. As one paleontological artist put it in 1946:

Though some dissented, it nonetheless remained common to assume that something like humanity was the inevitable outcome of macroevolution, here and elsewhere in the cosmos. At the 1969 centenary of Origin of Species, one scientist confidently pronounced the following:

Unsurprisingly, such assumption was applied not only to Earth’s future but also to planets beyond our Solar System. During the Cold War (indeed, because of the Cold War), it was often stated that, should humanity atomically self-destruct on Earth, there would at least be other rational beings, elsewhere, who would be able to give the world-riddle another shot. As the Hungarian essayist Arthur Koestler put it, musing in 1953,

Bluntly, calling humanity ‘necessitated’ is the opposite of accepting that it could easily – contingently – suffer a similar fate as the dinosaurs. In general, assuming extinction only happens to ‘the deserving’ was not only self-serving but it also obstructed sensitivity that it can befall lifeways which could otherwise have gone on, flourishing and diversifying.

But such a view would be dismantled in the latter decades of the century. As the 1980s opened, conclusive evidence began building, implying the dinosaurs were decimated by a chancy asteroid collision. Having been downplayed since Darwin – to the point of investigation being stymied – this went on to reveal the huge importance of chance, contingency, and mass extinction in shaping life’s history.Footnote ¹²⁴

Suddenly, it became highly plausible the dinosaurs didn’t die from ‘bad genes’, but from sheer ‘bad luck’: a comet, after all, cannot be rationalised away as the handmaiden of progress nor as adaptation’s invisible hand.

This had three, profound but subtle, consequences. First, the new view implied that, should the asteroid not have chanced upon Earth, we cannot assume that anything humanoid would have ever emerged. Or, in the 1983 words of the Polish polymath Stanisław Lem, none of us would be here if there hadn’t been, 66 million years ago, ‘a catastrophe in the form of an enormous, 3.5-to-4-trillion-ton meteorite’. We are, Lem concluded, the fluke product of the ‘roulette wheels that are galaxies’.Footnote ¹²⁵

Second, by demonstrating how the marks of contingency cast their legacies deep through evolutionary history, the impact hypothesis made much more salient the impacts of present-day human action upon life’s further future. Suggestions that we are altering everything to come – in ways which wouldn’t otherwise have come to pass – gained more force.

Tellingly, it was precisely around the same time, in the 1980s, that prominent scientists – such as Richard Leakey – first began asserting that we are living during the ‘sixth mass extinction’, triggered by human activities and decisions.Footnote ¹²⁶

For Leakey and others, it was clearly a recognition of the newfound role of contingence, in previous mass extinctions, which led him to insisting we take responsibility today. Indeed, prior generations of scientists – going back to Darwin – had made excuses for anthropogenic ecocide, explaining it away as part of nature’s inexorable search for the fittest.

Imputing culpability for a wrongdoing, after all, assumes that things could have played out differently had the wrongdoer acted differently. But long-held progressivist assumption had enabled prior intellectuals to pardon anthropogenic extinction as progress’s handmaiden. Again, ahead of strong contrary evidence, people have historically proven less that readily willing to extend the notion of genuine contingency far beyond human affairs, up to evolutionary and planetary scales. But the impact evidence forced such extension.

Third, and finally, the new view of mass extinction toppled any residual assurance that an animal as ‘adaptive’ as Homo sapiens won’t be succumbing to extinction any time soon. It demonstrated that even the most dominant and preeminent animals can perish: leaving no progenitors nor hope of a ‘replay’, entirely due to lottery or folly, rather than bad design or decrepitude.

For these reasons, its probably not a mere coincidence that, as Stephen Jay Gould liked to point out, research into the K-Pg impact dovetailed into the first serious research on the severity of nuclear winter:

It also no coincidence that the evolutionists who pioneered this new view of macroevolution were also amongst the first to apply the techniques of computer simulation to their field. This included the aforementioned Stephen Jay Gould – who communicated ideas of evolutionary contingency to wide audiences – alongside David M. Raup. Raup, in particular, had established himself, in the 1960s, by applying computer techniques to show how the shells of actual seasnails occupy only a small region within a much wider space of merely possible morphologies. Raup called this the ‘morphospace’: expressing all the living forms that could have been, but simply aren’t.

By the end of the millennium, the Horizon of Contingency had subsumed everything about humanity. Though he didn’t quite explicate it himself, and it took subsequent evolutionists like Gould to draw it fully out, this was one of the profounder upshots of what Darwin discovered. Species are forged by unrepeatable histories, which tether them, in time and space, to their place – and thus planet – of origin. All of Earth’s life forms are unique to Earth, just as island creatures are never found anywhere else, unless their ancestors migrated there. Therefore, bracketing the possibility of interstellar migration, should any species be wiped out or lost from Earth, here and now, we can be sure it will never be returning, anywhere, forever after. Extinction isn’t just an absence applying to all future moments of time, but to the entire spatial cosmic volume. These are the stakes of what happens next, during the age of the Sixth Mass Extinction.