Gone to the Dogs

Science fiction has often questioned humanity’s will and ability to survive into the distant future. It has also explored an obvious possible alternative: that ultimately we may be replaced by another species here on Earth. In this blog, I take a look at narratives of post-human animal evolution and what they can tell us about ourselves - would another intelligent species arise if humanity vanished?

Note: I’m going to set aside for now examples of individuals or entire species deliberately “uplifted” (i.e. enhanced in intelligence) which are actively supervised by humans or in direct competition with them, which is arguably a different topic, and focus on examples of evolution (natural or otherwise) which are sufficiently distant that humanity has disappeared, that are unintended or have origins lost in the mists of time.

Distant Cousins

 Given our awareness of our own descent from primordial ape-ancestors, a natural assumption might be that if humanity were removed, another primate species might arise to fill the gap. Primates have the same agile fingers and (to a greater or lesser extent) the same opposable thumbs as humans, and already display tool use and cooperate behaviour in groups. Most also have the vocal structures, but not the neurological complexity, necessary for complex human speech; it's not impossible for such an ability to evolve over sufficient time.

This was, of course, the premise of the enormously successful 1968 film Planet of the Apes, based on the 1963 novel of the same name by Pierre Boulle, together with its sequels, spin-offs and remakes, and its abundant parodies. Here a human astronaut lands on a world where a primitive tribe of humans is enslaved by intelligent bipeds apparently descended from chimpanzees, orangutans and gorillas, with the former providing most of the intellectuals, and the latter portrayed mostly as warriors and combatants. It is famously not until the end of the first film that the astronaut realises that this is not a planet with closely-parallel evolution to our own, but instead a post-apocalyptic Earth on which human culture was destroyed in the distant past. Various of the sequels to the original work further explored the culture of the ape-descendants, as well as possible rebellions by the remnant of humanity.

However this idea was not new. In his epic 1930 novel Last and First Men, Olaf Stapledon guides the reader through not just multiple civilisations but no less than eighteen entirely separate species of Man, as well as various off-shoots and mutations. Over the ten million years after the First Men are wiped out by an industrial accident, leaving a few dozen survivors in the arctic, a second species evolves. However we’re told that

When the Second Men had penetrated further into Africa they came to a forest region where companies of diminutive monkeys resisted their intrusion. It was soon evident that any interference with the imbecile and passive sub-humans in this district was resented by the monkeys. And as the latter made use of a primitive kind of bow and poisoned arrows, their opposition was seriously inconvenient to the invaders. The use of weapons and other tools, and a remarkable co-ordination in warfare, made it clear that in intelligence this simian species had far outstripped all creatures save man. Indeed, the Second Men were now face to face with the only terrestrial species which ever evolved so far as to compete with man in versatility and practical shrewdness.

After enslaving a sub-human offshoot of the Second Men, the monkeys become obsessed with metal, and attempt to wipe out humanity with plagues, but are ultimately limited in their ability to evolve a more complex society or thought patterns, and decline again into obscurity and oblivion.

This brief mention, as well as others, in stories such as Sons of Japhet by Richard Wilson (Infinity magazine, Dec 1956), tends to show descendants of primates or simians as ultimately limited in their capacity for evolution and also too close to home and thus doomed to repeat humanity’s mistakes. This is also a theme picked up by Isaac Asimov, in his short story No Connection (Astounding, June 1948). This centres on the viewpoint of intelligent ursines (descended from bears) who populate the post-atomic Americas and live individualistic lives in loose and cooperative communities. However the peace of an archaeologist investigating the ‘primordial primate’ is disturbed by the arrival of a group of chimpanzee-descendants from what is evidently the Old World, who are far closer in both society and mindset to the long-gone humanity.

Man’s Best Friend

Setting aside the success of Planet of the Apes, perhaps the most frequently imagined successor to humanity is a species which has been nurtured and shaped by its interactions with us over its evolution: dogs. As mammals, they share the warm-blooded advantages possessed by primates in terms of adaptability to different environments and energy availability. However they lack the manipulative digits and flexible limbs that have played such a big part in the development of human technologies. They also have brains with substantial processing power dedicated to scent rather than sight, potentially giving them a very different mentality to humans, if that capacity were to develop.

In some cases the historical association between dogs and humani is mentioned only briefly, as, for example in William Tenn’s satirical short story Null-P (Worlds Beyond, Jan 1951). Here humanity rejects exceptionalism and elitism, and instead breeds itself towards mediocrity, resulting in the eventual collapse of civilisation. Since any deviation from the average becomes seen as ugly and distasteful, the resultant breed of humans are near-identical and placid to the point of docility. As we’re told,

The reign of homo abnegus endured for a quarter of a million years. It was disputed finally—and successfully—by a group of Newfoundland retrievers who had been marooned on an island in Hudson Bay when the cargo vessel transporting them to new owners had sunk back in the twentieth century. These sturdy and highly intelligent dogs, limited perforce to each other’s growling society for several hundred millennia, learned to talk in much the same manner that mankind’s simian ancestors had learned to walk when a sudden shift in botany destroyed their ancient arboreal homes—out of boredom.

 In the final few paragraphs of the story, these dogs domesticate and breed humans as stick-throwing tools, before eventually replacing them with robots and allowing them to go extinct.

A more serious and harsh view is effectively evoked in a very short story, Survivors, by Arthur Dekker Savage (Imagination, May 1952). This is set in the aftermath of a nuclear war. The two protagonists describe a society divided between those living as wild hunters and those living off buried supplies of ‘gods’ in the ruins of cities, and subject to the dangers of radioactivity. As one notes:

“I've come to believe that it's useless to follow in the footsteps of the gods—that we must wait, and think, and work, each in his own way, until we learn what is possible for us through our own trials and the further development of our simple tools. We've learned much from the god-things, slowly, over the years. But we also know that we're mutants, changed by the radiation of the great war areas, breeding true at last, and that we are different from the Wild Ones. True, we're superior, but—we're not gods."

It’s only in the last few lines that it becomes clear that this is not a society of human survivors but instead a developing culture of mutated dogs. In hindsight, both the scavenging and hunting behaviour becomes more recognisable as canine characteristics.

A similarly brief, but less bleak view can be found in another short story, Earth’s Gone to the Dogs! by William J McLelland (published in Imagination, Oct 1954). Here a government official, holidaying with his pet ‘dog’, is interrupted by an archaeologist with disturbing news: the discovery of a rare pre-atomic war book, the first one found with pictures.

Ruskin took the book and stared curiously at a picture showing a dressed up dog sitting in a chair patting a human on the head. The caption read: MAN'S BEST FRIEND GETS REWARD.

Ruskin glanced back at Bigelow.

"I don't understand," he said slowly. "Is it some kind of joke-book?"

Bigelow grinned narrowly.

"A very bitter joke, Commissioner. A joke of Mother Nature's."

"I'm still not sure I understand...."

"I think you do, Commissioner," Bigelow countered quickly. "Now so many of the things we couldn't understand become clear to us. The naked animal on the floor in the picture is our ancestor, and the hairless thing in the chair is our dog!"

 The commissioner is left with the dilemma of how best to prioritise the well-being and mental health of his society in the light of this news. The interactions between individuals here, and their reactions, are all too human, suggesting that in this scenario the physical differences between species are less important than the social context and history the canines have inherited.

Other writers have created far more complex and intricate histories for future dog civilisations. The 1952 novel City by Clifford D Simak was a fix-up of eight connected short stories [1], given a bridging story in the form of academic notes from doggish scholars who are debating the historicity of the mythic stories, and whether Man ever really existed. Indeed, it begins with an “Editor’s Preface”:

“What is Man?” they’ll ask.

Or perhaps: “What is a city?”

Or: “What is a war?”

There is no positive answer to any of these questions. There are suppositions and there are theories and there are many educated guesses, but there are no answers.

The stories describe the decline and replacement of humanity on Earth, starting with abandonment of the cities for bucolic rural living (enabled by quick, effective long distance travel), progressing through a growing agoraphobia and boredom to an escape into a utopian life in transformed form on Jupiter [2], with the last handful of humans on Earth ultimately sealed involuntarily into the domed city of Geneva, for the sake of allowing their successors to take over. Those successors are dogs which descend from a small group initially altered by a human experimenter to have a modified throat and vision, giving them speech and the ability to read, and equipped with personal robots to provide them with hands. However the stories make it clear that, while a few physical traits are modified by humanity, the intelligence, mindset and potential of the dogs were there all along and simply awaiting expression. Over the course of more than ten thousand years, much of it isolated from human interaction and guided gently by an elderly robot, the dogs develop their own culture and worldview, which includes the ability to perceive, and ultimately move between parallel worlds. The dogs eventually abandon their Earth-of-origin, leaving it to the ants (on which more later) and then to the field-mice.

A running theme through the stories is the difficulty human beings face in maintaining and developing their culture, given a tendency to indolence and self-obsession, and the intrinsic tendency to violence underlying it. Both the guardian robot Jenkins and the human who decides to seal Geneva are desperate to protect the dogs from contamination by this human character. Indeed the canine scholars in the notes struggle to interpret even the meaning of the word “war”. However Simak doesn’t imply that all alternatives are necessarily better. Left alone, the dogs develop a brotherhood of wild things, forbidding predation by mammals and introducing yeast-based foods, but face an overpopulation problem as a result, which necessitates forced emigration to parallel worlds.

City is often considered Simak’s masterpiece. Unlike many of the shorter examples, it does capture the origin story of a very non-human culture, and certainly makes for compelling reading. It’s fascinating to see how the two species left behind by humanity - dogs and robots - end up working cooperatively to some extent. On the other hand, the timescales here are short (compared, for example, with the quarter-million years of Null-P), such that it’s never clear how big the speaking dog population is (with the majority restricted to a very small region around their original home), let alone how other mammals develop the ability to speak. The idea that dogs could be straightforwardly modified within a single generation for speech and reading, and then pass on that modification to future generations, is biologically implausible. And while efforts are made to keep doggish culture uncontaminated, the very existence of the mythic stories gives evidence that humanity (and the almost-human robot Jenkins) left a substantial and lasting influence on their mindset.

Walking Alone

A natural alternative to dogs in this role can be found in the form of another of humanity’s companion species: cats. A central character in the television sitcom Red Dwarf (TV series, 1988-1999 and revivals) is a humanoid descended over millions years from Dave Lister’s pet cat, after the humans aboard are wiped out by a radiation leak. Simply known as Cat, he is the last survivor of a technological civilisation, albeit one arising on the titular mining ship in deep space, rather than on Earth. Most of his behaviour is shown as effectively human, although he is notable for his conceit and pride and enjoys playing with his food (all recognisable feline traits).

Back in the Solar System, an amoral industrialist, Dollard, is frozen in an effort to escape plague-ridden Earth and revived in the distant future in the short story Deep Freeze by Robert Donald Locke (Imagination, Jan 1953). As we’re told by a narrative voice:

Hardiest of all forms of life, as proved in the last days of the reptilian age, are the carnivorous mammalian orders; these members are generally the most adaptable, intelligent and ubiquitous of living types. And by their conquest of their stubborn environment, they have proven themselves equally the fiercest.
Thus, it was not surprising that eventually the derelict spaces between the inner planets of Sol were once again the scene of traffic; not bristling traffic perhaps, but sufficient to present concrete proof a new intelligent race had developed on Terra.

Dollard’s approach to his rescuers is far from conciliatory:

“Now, I've got you pegged," he went on. "You're just a specimen of what a jacked-up tiger would turn out to be, burned under a few million volts of hard radiation. You may be civilized, you and your people—but I bet it took you a million years of high-speed evolution to do it. If it hadn't been for mankind's work with mutable bacteria, you'd still be chasing your tails under the palm trees—”

Given his arrogance and contemptuous approach, as well as the contempt of the Tegurians for primate primitives, Dollard’s otherwise horrifying fate comes across as rather well-deserved. As Locke notes, carnivorous mammals like cats (as well as dogs) may have some advantages when it comes to adaptation - meat provides a more abundant energy supply than vegetation, and carnivores require the ability to analyse and predict their prey's behaviour. It's interesting however that Locke also forsees the probable need for an intervention beyond that of pure random mutation, in the form of the radiation and biological weapons legacy of mankind, to bring about feline civilisation on such a timescale.

The extent to which feline physiology and instincts might lead to a different society from that of humans isn't really considered in the examples above. Again, though, a more detailed study of a cat-descended successor to Man has appeared in novel form. André Norton’s Breed to Come (novel, 1972) is set in a future some five centuries after the last of humanity vanished from Earth. In doing so they left behind vast empty cities and a weight of mythology. To the feline People, humanity are “demons”, many of whom fled to the stars, while the remainder were driven mad by a disease which led them to destroy each other. The same disease enhanced the intelligence and self awareness of the People, Barkers, Tusked Ones and Rattons, descended from domesticated cats, dogs, pigs and lab rats respectively. It also reshaped their bodies, leading to a gradual loss of fur, a shift towards bipedalism and development of more flexible digits. The four competing species can communicate through sign language and symbols, but each have their own separate cultures, with the cat-descendants living in small clans, centred around breeding females and their young, but with far-roving warriors supporting and protecting them (an understandable extrapolation from the behaviour of today's cats). The protagonist’s clan is cave dwelling, and makes use of metal claws, carried on a tool belt, to enhance their natural claws when climbing or hunting.

The more independent nature of the People is contrasted with a more pack-based mentality amongst the cruel Rattons and aggressive Barkers, and the boar-dominated family clan of the Tusked Ones. Of them all, only the pig-descendants show little interest in trying to recover some of the lost technologies left behind by the demons. However all are at threat when a craft carrying a small group of humans returns to Earth, driven by the need for a solution to self-caused disaster, particularly when these also prove vulnerable to the madness which killed their predecessors.

As might be expected, the cat descendants in science fiction are typically less awed by or respectful of lost-humanity than are the dogs, and more interested in how their own interests can be advanced by what was left behind than uncovering the truth of the past.

Let Others Try

Other narratives in the science fiction canon have considered alternative lines of descent for our successors.

 While the Rattons in Breed to Come are portrayed as vicious and little more than savages (although intelligent), an advanced rodent civilisation appears in The Eternal Wall by Raymond Z Gallun (Amazing Stories, Nov 1942), where a million-years-hence archaeologist revives a mummified human being and then faces the puzzle of what to do with him as the human is promptly driven mad by the enormous cognitive dissonance of his situation.

Still more distant is the scenario in Later than You Think by Fritz Leiber (Galaxy, Oct 1950), in which the archaeologists uncovering a long-lost civilisation on Earth are octopoids, and we learn at the end that the species they were uncovering was not humanity at all, but instead our rodent successors. As octopus are now recognised as having a form of consciousness parallel to, but independently evolved from, that of mammals, and have better adapted limbs for fine manipulation, some might argue that this sequence could be inverted.

Just as far from any mammalian descendant but also common in other areas of science fiction, is the idea that insects, and particularly ants, might have the potential for civilisation if humanity were not in the way. The intelligence and cooperation of insect colonies is very different to that of mammals, as are the physical constraints involved.

In Let the Ants Try, a short story by Frederik Pohl (Planet Stories, Winter 1949, as by James MacCreigh), Dr Salva Gordy, a physicist in the grieving aftermath of nuclear war determines the physical characteristics of ants that have prevented their development as an intelligent civilisation, focusing on the poor efficiency of their respiratory system. Modifying these, he uses his newly-invented time machine to transport the mutant ants back through forty million years of history.

Gordy stood with his hand on the control wheel, thinking about the ants. Assuming that they survived—assuming that in 40,000,000 years they grew larger and developed brains—what would happen? Would men be able to live in peace with them? Would it—might it not make men brothers, joined against an alien race?

Might this thing prevent human war, and—his thoughts took an insane leap—could it have prevented the war that destroyed Gordy's family!

As this implies, Gordy’s aim is to provide an enemy force that will give humanity a reason to unite and avoid internecine conflict. Instead on his return to the present, he finds bipedal ant descendants in the cities, and realises that he has caused the end of humanity, as well as dictating his own fate. Here the ants are shown as aggressive, ruthless, silent and ultimately unknowable.

Equally unknowable and relentless, but ultimately less overtly hostile, are the ants who provide a counterpart to the dog civilisation already discussed in Clifford Simak’s City. At the same time as a human is experimenting with giving dogs a voice-box, early in the sequence, another (long-lived mutant) human decides that only the cold of winter, with its enforced dormancy, dying-off and loss of intergenerational knowledge, has prevented ants from developing a culture of their own. Building a protective dome over an ant-hill, and heating it through the winters, he soon discovers that the ants are using simple tools and even showing evidence for smelting small quantities of metal. In that segment of the narrative, the ants’ benefactor tires of the game and tries to destroy the anthill with a careless foot. But in the later stories, the rebuilt anthill gradually spreads, until it ultimately becomes a world-spanning structure which forces the gentle dogs to leave their home world (amongst the parallel multiverse) to the vast but never-seen, never-heard-from ant civilisation.

Amongst other insects-will-inherit-the-Earth stories, Arthur C Clarke's The Next Tenants (short story, Satellite Science Fiction, Feb 1957) is interesting in its quiet ambivalence. One of his Tales of the White Hart, it has the raconteur Harry Purvis telling an anecdote of his meeting with a quiet and rational Japanese scientist who was patiently providing tools and a method of communication to colonies of termites, which have a collective organisation and are effectively immortal. This Professor Tokata, a man whose family died at Nagasaki, has founded his termite experiment on a Pacific island, both to protect it from the atomic devastation he considers inevitable, and to ensure that the termites will not spread until and unless they reach a high level of technology. The question that the story leaves hanging is whether this is a sane and reasonable response to humanity's rush to self-destruction, or whether something should be done to end the experiment.

After Us

 So why does the idea of another species inheriting the world from humanity so fascinate us?

An obvious motivator of such stories, and one which reappears frequently - as, for example, in No Connection, Let the Ants Try or Earth’s Gone to the Dogs! - is the way in which the threat of nuclear war loomed large over the writers of the mid-twentieth century. For the first time there appeared to be a realistic prospect that humanity could wipe out not just the population of a town or region, but its own entire species. That such an event would likely also trigger mutations which might benefit other species was a corollary that led pleasingly to speculation regarding animals with intelligence and physical changes (although negative mutations are far more likely in the real world). These stories mixed the fear and pathos of nuclear war and human extinction with a fundamentally optimistic hope that, even if we destroyed ourselves, some part of the natural world might survive us. It is interesting to note, however, that even at the peak of the Cold War, the idea of mutually assured destruction was not universal - it’s striking that, far from imagining humanity’s death and destruction, Clifford Simak’s City saw Earth being abandoned to our successors through progress and growth out into the wider galaxy.

The ethics of nuclear brinksmanship are seldom shown in a positive light - in these stories or elsewhere - but the fiction discussed here challenges scientific ethics in another way. Despite the absence of humanity from the selected narratives, a significant fraction of these stories discuss the possibility that the species in question were significantly changed by their predecessors. The radiation-driven mutants in these stories (or biological weapon-mutated in the case of Breed to Come) are more common than those which arise naturally over eons after humanity’s departure. More interestingly, several of the species discussed were set on their path to sentience and culture by the actions humankind. Sometimes this is inadvertent, through the ruins and material relics left behind, which might accelerate technological development. Some of the societies mentioned infer the existence of prior civilisations more by the lack of accessible resources than their provision. However in a few cases, the species are developed deliberately by human scientists. This is part of a wider sub-genre of science fiction, which includes fiction of biomedical intelligence enhancement (as, for example, in David Brin’s Uplift series, or other human-contemporary stories), artificial intelligence (in software or automata) and artificial life (as in cloning or similar technologies). It questions the right of science to ‘play god’ by deliberate modification of other self-aware life, and the moral pathways that might lead to such an action. It also asks more fundamental philosophical questions: what is self-awareness, and how can we be certain it exists even in ourselves, let alone others? [3] 

However there are arguably other influences on this fiction that can shed light on its relationship with scientific developments other than weapons and scientific malpractice. Evolution has always been a poster child for science, with evidence for its effects on species forming a key aspect of the evolution of western society away from predominantly religious perspectives. For some writers, the proposal that other animals might evolve in similar ways is a way of challenging human exceptionalism, and putting us in our proper space with regards to our animal cousins and intrinsic pride as a species regarding our sentience, ability to communicate and potential for civilisation.

Much of this discussion can be framed in the context of the evolutionary biology debate between convergence (the recognition that the same trait has evolved many times on Earth in different lineages to address the same environmental challenges, as championed by Simon Conway Morris in Life's Solution, non-fiction, 2003) and contingency (the existence of rare innovations in the fossil record, and the importance of their combination, such as human hands and communication which have evolved together only once in Earth's history, as argued by Stephen Gould in Wonderful Life, non-fiction, 1989). The former position would suggest that if humans vacated their current niche, other intelligences would likely evolve to fill it. The latter suggests that other intelligent civilisations on Earth (or, by extrapolation, elsewhere!) may be relatively unlikely to occur and cannot be expected. The majority of the fictions discussed here (and science fiction in general) argue for the convergence position, explicitly so in some cases, such as Simak's City, with radiation or other driven-mutations merely accelerating an inevitable process [4].

Also arguing for convergence, and an interesting inversion of the premise explored in this entry can be found in the Silurian species in television series Doctor Who; these are bipedal reptilian hominids who evolved on Earth at the time of the dinosaurs and were frozen in large complexes underground before the end-cretaceous mass extinction; whenever such a complex is disturbed, the Silurians find themselves in the same position with regard to humanity as that discussed here - replaced by life that evolved from small creatures which, in their own time, lacked sentience, and sometimes fighting it for resources. Still more so than post-human evolution stories, this is a reminder that humanity may not have a privileged place in time and space. It's interesting to note that, Doctor Who's Silurians have also inspired at least one study (Schmidt & Frank 2018) which considered whether the remnants of such a past civilisation would be visible in the fossil record, concluding that we might be able to determine if it had existed, but it might be hard to distinguish such a signature from other geological phenomena.

Such stories also touch on one of the more intriguing aspects of our own evolution: for most of its evolutionary history, humankind had cousins - fellow hominids (such as Neanderthals, Heidelbergensis and others) who almost certainly had their own cultures, worldviews, and ability to communicate. While it is impossible to know at this point how comparable those were to our own, there is certainly evidence for material culture, transmission of practical knowledge and ritual. While some of the narratives discussed above focus on evolution of a single species, many see a multi-species society as a likely outcome of our vacating our current position of superiority and allowing alternate sentient life to develop. Thus narratives such as Norton’s Breed to Come act as a thought experiment of how cultures with very different mindsets, motivations and morals might co-exist in a peaceable (or otherwise) society, particularly if their resource utilisation brought them into direct competition.

Whether through multiple species or a single breed of successor, the fiction of post-human evolution gave writers an opportunity to imagine aliens without the need for extraterrestrial life: characters with very different instincts and priorities to those common in human societies. Conceptions of how reproductive imperatives and breeding cycles might influence the evolution of cultures are seen, for example, in Breed to Come. As has been widely discussed in the context of writing extraterrestrial characters, however, it’s unclear whether any human-written story is capable of truly expressing a non-human viewpoint. It’s fair to say that the success of writers in this regard has been varied; characters in a number of these stories are essentially indistinguishable from human, while others are so heavily influenced by the material and cultural legacy of humanity (as, for example, in the dogs of City) that it’s hard to see the differences. Indeed some of the most convincing animal cultures are those that are never closely explored (as, for example, in City’s ants). Where such cultures are explored, they all too frequently show that the animals in question have inherited humanity’s flaws along with its planet: conflict, pride, arrogance and often self-destructive tendencies tend to be a recurring theme - although to what extent this is driven by authorial desire to make the characters relatable to readers, and to what extent it reflects their true belief of how such beings would act, remains unclear. 

For such a small sub-genre of fiction, it’s interesting just how many moral and philosophical questions stories of post-human evolution touch upon. Ultimately they ask the question of whether we are conscious, sentient beings because we are born Homo sapiens, whether that is necessary or sufficient, or whether others might aspire to that state. They ask how society might be driven by biological imperative, and how culture might have developed in different ways. And they ask whether we will destroy ourselves, and - if we do - whether we’ll leave behind a world in ruins, a better world, or one that is both at the same time.

At present, our ability to enhance the behaviour of other species has been demonstrated through breeding in both domesticated and lab animals. However this is always a slow process, and one that hits fundamental limits depending on the species in question. It may well not extend to intelligence. We are aware of some species which appear to be sentient, notably amongst the cephalopods and cetaceans, and of some which may have basic elements of material or societal culture (for example amongst primates or tool-using animals such as birds). However we do not know of any way to give a species the complex vocabulary or the manipulating digits which we believe to have been fundamental in the development of our own societies. Nor do we know of any robust culture-independent way to test for intelligence or sentience (as our current debate over artificial intelligence makes clear). As it stands, it is easy for us to speculate about the pathways by which a successor species might succeed humanity on Earth, and perhaps the pathways by which one might develop an advanced culture. It’s far harder to see how that might be brought about, and, still more so, whether it should be. Perhaps one day another species might be living in our ruins. Or - as in Later than You Think - even on an Earth which has long forgotten that humanity ever existed. Neither is impossible, or even implausible. And perhaps it’s comforting to think that, just maybe, whatever we do, life will find a way.