How did we get here? How do we compare to other life forms? Are we alone in the universe?1 Astronomy seems like an obvious place to seek answers to these questions. But compared to the enormity of astronomical space and time, our lives can seem short, small, and meaningless.2 An antidote to this malaise is Carl Sagan’s vision of an open-ended, enduring technological future for humanity3—a future in which we wake up and find out we are the eyes of the world.4 Adam Frank et al.’s paper “Intelligence as a Planetary Scale Process” (hereafter FGW) makes a provocative contribution to such narratives in which humanity plays a leading role.
But before we can reach our potential as a species, we find ourselves at a tipping point.5 Will we, in our selfish immaturity, continue to pillage and ruin the Earth, eventually leading to our extinction? Or, will we reverse our exploitative relationship with the Earth and become, as FGW suggest, the brain of the biosphere—the stewards of a mature and sustainable technosphere?6 FGW not only suggest that our current immature technosphere is facing an existential challenge, they also speculate that if exocivilizations exist on distant exoplanets, these societies may also be similarly challenged on their way to technospheric maturity.7
In order to survive this crisis, the authors suggest that humanity needs to acquire more maturity and intelligence. FGW begin by pointing out that although intelligence has conventionally been applied to individual organisms, there is much evidence for collective intelligence to be found among quorum sensing bacteria, bee hives, fungal networks, and eusocial animals, to name just a few examples. Thus, the concept of intelligence can be broadened from something an individual has to something a group can have. FGW go even further and argue that intelligence is something the entire biosphere could possess, and that the same could also be true for the biospheres of other exocivilizations—if they exist. Under these assumptions, the authors ponder whether the Earth is indeed smart, concluding that: “Even though Earth might be full of intelligent life, at this point in its cosmic history, it certainly doesn’t seem very smart.”8 Artificial intelligence, nuclear weapons, biotechnology, and climate change threaten our existence. We are eroding natural resources, changing the climate, ravaging the biosphere, and driving many species to extinction.9 All these are problems of our own making, and mitigating them is the central issue of our time.10
The Gaia hypothesis plays an important role in FGW’s vision of planetary intelligence. This is the idea that the Earth can be usefully viewed as a living organism, Gaia, with its own planetary physiology.11 Not content with this conception of Gaia, the authors ask: “If a planet with life has a life of its own, can it also have a mind of its own?” Indeed, FGW are seeking to improve upon the original notion of Gaia by making her more intelligent. The authors want to give her a brain and propose that if we humans can stay alive, we are destined to be that brain.
Human intelligence, or intelligence of any kind, has not played a significant role in the various versions of the Gaia hypothesis.12 Thus, giving Gaia a brain is an interesting new development. Not content with only our Gaian biosphere being intelligent, FGW also postulate the existence of Gaian biospheres on other Earth-like planets and argue that the concept of planetary intelligence will be “a useful framework for understanding and predicting the possible paths of the long-term evolution of inhabited planets.”
The authors propose that the evolution of planets like the Earth follows a linear chronological sequence. Such planets start as a geosphere without life. Then the emergence of life creates an immature biosphere, which then evolves into a mature biosphere. The next step is the evolution of an intelligent species, such as Homo sapiens, who produce an immature technosphere. This is the stage where Earth finds itself today, in the midst of an unsustainable Anthropocene crisis. Finally, if an intelligent species, such as ourselves, can mature into a trustworthy steward of a sustainable biosphere, the planet will evolve into a mature technosphere.13
This sequence postulates two potential branches in humanity’s future. One branch leads to human extinction; the other leads to a mature technosphere. We are afraid of branch one and hope for branch two. Yet the notion of maturity as a culmination for our species seems incongruous. Maturity without senescence or death implies that human technology—after shifting from unsustainable to sustainable—will have an enduring, open-ended future. But doctors and biologists agree that after maturity comes senescence and death. The same is true for species. New immature species evolve into mature species and across timescales that span tens of millions of years, they eventually disappear—either because they go extinct, or because they have evolved and diverged into different species. If we manage to avoid extinction, we will evolve into something so different from our present condition that we will no longer be human in any sense we now value.
Ignoring senescence is one problem. Another is that the history of defining and measuring human intelligence is a long-running tale of woe in which Social Darwinism, sexism, racism, and eugenics have all featured prominently.14 Indeed, the comparison between human intelligence and the intelligence of other species is plagued with unacknowledged speciesism and characterized by self-serving logic: human-intelligence is the best. It is the standard. Therefore, species possessing an intelligence most similar to our own are the smartest. Chimps are smarter than dogs. Placental mammals are smarter than marsupials. Eusocial organisms are more intelligent than nonsocial organisms. Animals are smarter than plants. Multicellular organisms are smarter than unicellular organisms. And eukaryotes are smarter than prokaryotes.15 Such systematic speciesism, genusism, and kingdomism is the propagation of familiar systematic prejudices at the subspecies level to larger cladistic levels.
Even more challenging are attempts to measure intelligence at different levels of organization. Which ecosystems are more intelligent? Jungles or savannah? Deserts or tundra? Assessing the relative intelligence of biospheres is even more baffling. Is an atmosphere with oxygen smarter than one without? Is Earth smarter than Krypton? There are so many different ways of making a living, so many different adaptive behaviors, so many different ways of acting intelligently and staying alive, that to reduce such n-dimensional diversity onto a one-dimensional scale of intelligence is an unhelpful impoverishment.
There is also an intrinsic contradiction between the notions of human exceptionalism and human stewardship of the Earth. Rather than helping us become better earthlings, the power of human intelligence and technology seems to be making us more arrogant and dismissive of other animals and the rest of the biosphere. Self-preserving behavior has been deeply integrated into the ethical circuitry of our brains. Can humans evolve and learn to act for the benefit of other species besides our own? Even if we are able to enlarge our circle of empathy to include all humans,16 what about the rest of the biosphere? Currently, we only take care of the biosphere to the extent that it benefits us. This is the human–biosphere alignment problem that FGW and environmentalists of all stripes are anxious to resolve in order to make our civilization sustainable.17 The perplexing part of this problem is that we are the only reason the biosphere needs saving. Are we supposed to save it from ourselves?18
Perhaps the strongest evidence against planetary evolution resulting in a long-lasting mature technosphere is what Paul Davies has described as “the eerie silence”19—the lack of any evidence for technological intelligences elsewhere in the universe; no radio messages, no Dyson spheres, no self-replicating robots, and no technosignatures.20 If mature technospheres evolve across the universe and endure for billions of years, then where are they?
Most of the community involved with the search for extraterrestrial intelligence believe that the reason we have not found any signs of life elsewhere in the universe is simply because we have not looked hard enough.21 They argue that if you take a bucket of water from the ocean and do not find any fish, this does not mean there are no fish in the ocean. But, if you take a bucket of water from the ocean and find no viruses, that is fairly good evidence there are no viruses in the ocean. Thus, the interpretation of the eerie silence depends on expectations. Are exocivilizations more like isolated fish and confined to their planetary system of origin? Or would they instead be more like viruses—spreading everywhere once they become capable of interstellar travel? In the latter case, absence of evidence is evidence of absence.22
Since the entire span of human civilization only stretches back a mere 10,000 years into the four-billion-year-history of our planet, and technological civilization occupies just the last few hundred years, it seems quite speculative to claim a mature technosphere as an enduring culmination of our future. And it seems even more speculative to claim that mature technospheres are what biospheres elsewhere evolve into. FGW seem to be aware of how speculative their proposal is, describing it as “an exploration of an exploration of planetary intelligence.” They hope that by pointing out the destructive immaturity of our current technosphere we will recognize our immaturity, reform ourselves, and become the mature stewards of a mature technosphere. They hope that this recognition will make us better earthlings and help us solve the current crises. To this reader they have produced an adaptive useful fiction—a myth that humanity may need to survive.23 If this Gaian-inspired planetary perspective on the future of humanity succeeds in inspiring us to protect the future of the biosphere, the authors should be proud of their redemptive narrative.
