Hermit Hypothesis: Intelligent beings never expand beyond their home planetary system, communicate, or in any other way become detectable over interstellar distances.
There are ways of making the Hermit Hypothesis more precise. Since we do not see—now, as well as in Fermi’s time—any physical reason why expansion (or just messaging!) over interstellar distances should be impossible, the Hermit Hypothesis actually means that they truly do not wish to expand or make their presence known. Under ‘physical reason’, I here subsume everything which would be universally valid for all places in the Galaxy and in all epochs. Counterfactually, if the Milky Way disc were full of marble-sized interstellar rocks in a density of about 1 per cubic kilometre, any interstellar travel (unless it were very slow) would be impossible; similarly, if interstellar space were filled with too much hot plasma, any long-range radio messaging would be impossible. We know such things are not true. And, while one should never be entirely dogmatic about the issue that some exotic physical effect may not lurk in the depths of interstellar space, the string of successes of galactic astronomy and astrophysics in the last century or so clearly makes it quite improbable, at least.
Another aspect of the problem is whether there is something universal in the cultural evolution itself and that it is this that makes the required tasks of interstellar travel and interstellar messaging impossible. That we do not know of and have not envisioned such a forbidding factor so far does not mean that such a factor does not exist. On the other hand, a mere glance at Figure 1.2 tells us that, to some extent, the complaint is vacuous: we have already, in the visible part of the electromagnetic spectrum as well as in radio waves, announced our presence to the universe. The wavefront containing information about our existence expands at the speed of light throughout the Galaxy and there is nothing we can do about it.62 The same, by very basic Copernicanism, is true for other technological civilizations, at least in their immature phases analogous to our stage in cultural evolution. So, why don’t we perceive them—or is it just the size of our ‘eyes and ears’ which is insufficient for the moment? The latter would mean that we may expect the great discovery (and the resolution of Fermi’s paradox) any time a new and more sensitive astronomical detector comes online. This in itself has some important ramifications, to be discussed in more detail in Chapter 9.
By itself, the Hermit Hypothesis is nothing new, and not only has been mentioned in reviews,63 but also is a sort of the ‘default’ reaction to Fermi’s paradox, especially if it’s given in its SETI version:64Why, they just don’t want to communicate (with us)! It has been present in musings of the SETI ‘founding fathers’ on the Galactic Club of advanced civilizations.65 Like Sparta in Hellenistic times, like China under the Ming (after the Zheng He exploratory voyages in the fifteenth century, which were regarded as aberrations) and the Qing dynasties, like Japan during the Tokugawa Shogunate, or like the totalitarian ‘hermit kingdoms’ of Albania (1945–90) and North Korea (1953–today), extraterrestrial societies do not wish to have any contact with the outside universe.66 An arguably extreme version of the Hermit Hypothesis has been described in science-fiction prose by Greg Egan in his novel Incandescence and his novella Riding the Crocodile:67The disk of the Milky Way belonged to the Amalgam, whose various ancestral species had effectively merged into a single civilization, but the central bulge was inhabited by beings who declined to do so much as communicate with those around them. All attempts to send probes into the bulge—let alone the kind of engineering spores needed to create the infrastructure for travel—had been gently but firmly rebuffed, with the intruders swatted straight back out again. The Aloof had maintained their silence and isolation since before the Amalgam itself had even existed.
In contrast to human historical experience, in which isolated societies usually lag behind their neighbours, Egan’s Aloof represent an example of technologically superior hermit sophonts.68
Note two important details about the Hermit Hypothesis, which are conveniently ignored in most discussions:
1. The emphasis on will. It implies that advanced technological civilizations, in spite of their wildly heterogeneous presumed evolutionary origins, have a unique will which could be enforced over all their individuals and groups. This is a rather strong constraint, for the following simple reason. By analogy with human history, the history of technological progress has been the history of empowerment of individuals and groups, in both a societal sense and in the sense of control over the natural environment. The average individual in Europe in 2018 has at his or her disposal resources comparable to or greater than members of aristocracy or even royalty did in, say, 1218. And in any case, the modern-day individual has much more time at his or her disposal to use such resources, taking the increase in life expectancy into account.2. The Hermit Hypothesis is not just the passive refraining from activities, such as colonization or communication. As discussed, the existence of a technological civilization, either a present-day human-level or an advanced civilization, causes detectable changes in its physical environment. Those changes are located at many levels but, for the sake of example, let us consider just Earthshine (Figure 1.2). It is a generic product of urbanization, ultimately resulting from the increase in human population and industrial activity. All this means that the Hermit Hypothesis implies active suppression of at least some generic aspects of advanced technology. It requires expenditure of effort and resources to maintain the hermit state through long periods of time. Unless the singleton state or any other way of total societal control of Point (1) is achieved, there seems to be no way how such a situation might evolve.69I have devoted much attention to the Hermit Hypothesis since it is a very important case study, not for research on Fermi’s paradox as such, but for its reception in both specialist and lay audiences. What is usually shrugged off as unanswerable (Why would they want to communicate/manifest themselves in the first place?) is, in fact, a quite specific scenario with a lot of additional assumptions, not satisfying most of the desiderata discussed in Section 1.5. It is quite reasonable to state that, taking all into account, the Hermit Hypothesis is already very unlikely, relative to many other proposed solutions. This shows how biased is the usual mundane perception of Fermi’s question.
Two sources of this particular bias exist, which again analysis of the Hermit Hypothesis clearly reveals. One is oversimplification. When people, upon hearing for the first time about Fermi’s paradox, invoke the Hermit Hypothesis in some form, it is because they think that the problem is much simpler than it really is. The simplicity of the idea that extraterrestrials do not want to communicate is quite appealing. The other is the anthropocentric concept of will and willingness. Since we all have experienced that some people do not wish to communicate with us, for reasons we often find mysterious, irrational, or inexplicable, we are likely to transfer this mode of behaviour to extraterrestrial intelligent beings as well. This is going to mislead us systematically more often than not.
The problem with ‘xeno-sociological’ hypotheses (e.g. the Hermit Hypothesis, or the Zoo Hypothesis or the Interdict Hypothesis to be described in Chapter 4, among others) is that they depend on the unknowable details of social organization of advanced technological civilizations. We know so little about the generic social organization of human societies, that any claim in the more general astrobiological context sounds preposterous and seriously decreases the credibility of any such hypothesis.
That said, the hypotheses are not all on the same footing. The degree of ‘xeno-sociological’ speculation obviously varies. It is one thing to postulate uniformity of behaviour over thousands of parsecs, millions of years, and the unimaginable diversity of evolutionary parameters, as in the Hermit Hypothesis, and quite another to postulate agreement between presumably a small number of independent agents required to ‘maintain the zoo’ in the Zoo Hypothesis.
(...)
Suppose that a sufficiently large fraction of Galactic civilizations is capable of overcoming both natural hazards and the urge for self-destruction and thus advances to technological maturity. Are they all possible SETI targets—and sources of the paradoxical conclusions with respect to Fermi’s puzzle? Not necessarily, since there are at least two problems which are likely to remain worrisome even after such a transition: self-limitation, and the threat from deadly probes, to be considered in this section and in Section 6.6, respectively.
Self-limitation means that a civilization decreases its detection cross section through some intentional process.39 Self-limitation can take many possible forms. One of them is the Hermit Hypothesis discussed in Chapter 1. ‘Self-limitation’ can be regarded as an umbrella term for many different scenarios. However, one of them is particularly worrisome: the establishment of permanent or near-permanent totalitarian control over all individual intelligent agents in the civilization, coupled with a set of goals leading to a small cross section for detection.Introvert Big Brother: If all Galactic civilizations, instead of self-destruction, slip into permanent totalitarianism, this will dramatically decrease the contact cross section, making them essentially undetectable. In addition, this circumstance will increase the civilizations’ susceptibility to other hazards, like those falling under The Gigayear of Living Dangerously category. Since permanently totalitarian civilizations are likely to be spatially small (in Galactic terms) and technologically stagnating, they are unlikely to leave traces and manifestations detectable over interstellar distances, so there is no Fermi’s paradox.
Since we obviously know nothing about the distribution of historical trajectories of different intelligent species, this hypothesis is extremely speculative—no less so than those of Chapter 4. However, given the overall gravity of its subject matter, as well as its extreme relevance to the future of humanity, Introvert Big Brother should not be neglected. The Orwellian state is quite disinterested in the external universe; even if it were willing to communicate, its inherently paranoid nature would have made any opportunity for contact orders of magnitude more difficult.40 Remember Comrade O’Brien’s solipsist geocentrism in 1984:41
‘What are the stars?’ said O’Brien indifferently. ‘They are bits of fire a few kilometres away. We could reach them if we wanted to. Or we could blot them out. The earth is the centre of the universe. The sun and the stars go round it.’
Historians have demonstrated how classical totalitarian systems like Nazism and communism undermined science and technology for ideological benefit.42 Robert Zubrin has argued that ‘bad memes’ could even destroy a large Galactic civilization which would otherwise be immune to all other natural and artificial threats; this is Introvert Big Brother taken to the extreme.43 Lem’s novel Eden paints another bleak picture of extraterrestrial totalitarianism.44
How could such a state of affairs emerge? Obviously, there are many possible ways of establishing a totalitarian state, but one is becoming more and more actual with time: in order to avoid self-destruction or other global catastrophic risks, the infrastructure for such a state could be set up, with broad societal acquiescence.45 Such an infrastructure would include global and detailed surveillance, advanced methods of data processing, genetic screening, and so on. All such measures—and other more intrusive ones, not considered today in this relatively benign, nearly totalitarianism-free moment in human history—may have entirely legitimate justification within a liberal governance; however, once in place, they might be subverted for totalitarian purposes much more easily than in the case of setting up totalitarianism ab initio. We have witnessed that even the most liberal and enlightened human societies can take illiberal measures, with broad acquiescence of the population, if sufficiently threatened. The relevant insight is that such a development will likely lead to the decrease of contact cross section, thus enabling the hiding of older intelligent communities, and the paradoxical conclusions of Fermi’s problem.
A particularly troubling feature of this type of hypothesis is that a single type of totalitarian state could arise as a consequence of many different sorts of crises (including preventing global catastrophic/existential risks), but there are few ways—if any—it could be dismantled if it is technologically sufficiently advanced. In other words, it could be regarded as an attractor in the space of the possible historical trajectories of civilizations. If that is indeed so, the disturbing Introvert Big Brother must play at least some role in the ultimate resolution of Fermi’s paradox, since it is hard to imagine that at least some sophonts in any sufficiently big sample manage to avoid falling into the totalitarian trap.
The hypothesis also faces serious problems, however. At leastas much as Stop Worrying and Love the Bomb, it suffers from violation of non-exclusivity, since in contrast to, for example, Astrobiological phase transition, both warfare and totalitarianism on different Earth-like planets in the Galaxy are independent factors and are extremely unlikely to be correlated.46 However, while self-destruction is one endpoint of the historical trajectory of a civilization, totalitarianism does not mean extinction. No matter how advanced, a totalitarian government cannot have the same finality as extinction; even a very improbable event like the overthrow of a technologically advanced totalitarian government, can happen in the fullness of time. While this is good news for the enslaved populations of such a regime, it is rather bad news for Introvert Big Brother as an explanatory hypothesis. It has to explain the suppression of the detection cross section over much longer times than Stop Worrying and Love the Bomb. This automatically decreases our credence in it.
Again, totalitarianism might actually work in conjunction with other destructive process to suppress detectability. It is reasonable to expect that totalitarian regimes are more vulnerable to some kinds of natural or artificial disasters than more open societies are—even our limited human experience suggests it. (Consider, for example, the appalling inefficiency of Soviet response to the Chernobyl nuclear plant accident in 1986.) So, a mixture of the Introvert Big Brother and The Gigayear of Living Dangerously can be a potent suppressor of detectability over vast regions of space and time. There will be more on those synergistic solutions in Chapter 8.
A further line of criticism of Introvert Big Brother and similar scenarios suggests that, in fact, without a more extensive sociological and political theory, we cannot be sure that technologically advanced totalitarian regimes will not be extrovert and colonization oriented. At least, without any further specification, we cannot be more sure of that than we are in their long-term stability. The Orwellian vision encompassed the entire surface of the globe, but we can imagine totalitarian dictatorships willing to go much further. Philip K. Dick, in the most classic of all alternate history novels, The Man in the High Castle, has victorious Nazi Germany vaguely attempting to colonize Mars.47 Another canonical literary dystopia, Yevgeny Zamyatin’s novel We, even revolves around a protagonist who is constructing a spaceship for a totalitarian state.48 Perhaps a totalitarian regime in the Scutum-Crux spiral arm might wish to arrange local stars into an image—including details of the mandibles and pseudopodia—of the Beloved Leader?49 After all, most monuments of extinct human civilizations not only were created by oppressive social systems, but also were created for purposes intrinsically linked to the oppressiveness of such systems (pyramids, cathedrals, mausoleums, etc.). If, contrary to most of our intuitions and recent trends in our history, the current expansion of individual freedoms and human rights is just a fluke or a lull in the storm, and the future belongs to totalitarian ways of governing and social regimentation, could it be the case that human macro-engineering projects or artefacts will become likelier? While it is difficult to conclude either way in the absence of further insights into the social dynamics of totalitarianism, this very uncertainty ought to count as a weakness of Introvert Big Brother and similar hypotheses.
An Orwellian superstate governing through ‘Ignorance Is Strength’ is not the only form of self-limitation, though. Another is the (in)famous concept of ‘return to nature’: the either voluntary or involuntary relinquishment of technology, reversing the technological progress which on Earth has lasted for many centuries before suddenly accelerating with the Industrial Revolution. The latter is usually seen, according to ideologues of a return to a simpler, pastoral lifestyle, as the chief culprit for all of humanity’s problems. Of course, pastoral civilizations are, by definition, Hermits, since they have no means of communicating over interstellar distances, let alone leaving traces in the form of astroengineering. And, in contrast to totalitarianism, where stability is the ultimate goal of a system to be actively pursued, pastoral civilizations are unstable against both natural catastrophes and, ahem, progress.50 Preventing all members, everywhere, from engaging in science and technology tinkering would require efficient totalitarian enforcement—which is likely to be impossible in the absence of technology. So, without going into the merits and demerits of ‘return-to-nature’ pastoralism, we can say that, although some intelligent species may opt for it, there can be few more exclusivist and hence unlikely options around.
The opposite of pastoralism, namely rapacious industrialization and exploitation of natural resources, presents a more serious catastrophic threat. This is the subject matter of another of the ‘almost-default’ hypotheses discussed by Brin, Hanson, and others, and one which becomes more and more of practical interest for intelligent beings here, on Earth:51
Resource Exhaustion: Interstellar expansion by technological civilizations tends to consume the material resources of any planetary system on an exponentially short timescale. Thus, interstellar colonization creates a bubble of systems with exhausted resources, and eventually leads to the collapse of large civilizations. Within these exhausted bubbles, natural processes lead to slow, gradual replenishment—which, in turn, leads to the whole cycle repeating itself. We have emerged within one such bubble, at the ‘down’ part of the cycle (which is no coincidence, since it could be argued that no young sophonts could evolve in the ‘up’ part of the cycle), so there is no surprise that we do not perceive large Galactic civilizations around us. It is yet another observation-selection effect.
This explanatory hypothesis is related to neocatastrophic, as well as solipsist, and logistic options (to be considered in Chapter 7). Obviously, it presupposes sudden, catastrophic processes violating gradualism; but, at the same time, it subtly assumes that the ‘obvious’ absence of any traces of other Galactic sophonts from the Solar System is an illusion. If the Solar System had been colonized even in the very distant past, say 2–3 Ga ago, some traces of that event should, in principle, be found, most probably in the asteroid belt or possibly on the Moon.52 This should in no way be confused with the ‘ancient astronauts’ speculations discussed in Chapter 4: in sharp contrast, it is exactly the lack of apparent traces which makes Resource Exhaustion a functioning hypothesis. After so much erosion and local changes on the billion-year scale, there is hardly any chance of ‘archaeological’ evidence to be found on Earth; however, the question of the evidence in the asteroid belt (and other low-erosion environments) could be regarded as open, especially if it is of a purely geological nature, namely the traces of ancient mining activities.
There is no reason to doubt—and all reasons to suspect—that Resource Exhaustion could cripple civilizations, irrespective of their age or other parameters, up to some critical technological level. As long as we stick to the laws of physics as the only ultimate constraint and do not concern ourselves with the extreme timescales of physical eschatology (i.e. we consider only our astrophysical environment up to 1015 years in the future, the epoch in which galaxies remain as well-defined bound entities), Resource Exhaustion should not happen at all! Namely, the elemental composition of any particular material resource could, in principle, be replicated using nuclear transmutation, starting from any other chemical element, including hydrogen. After all, nature has created all isotopes heavier than helium (apart from a minuscule primordial abundance of 7Li) in exactly that manner, mainly by thermonuclear fusion in stars, with additional fission of unstable nuclides and occasional spallation reactions with high-energy cosmic rays. There is no fundamental obstacle to recreating all these reactions in a lab and even to perform them in bulk for industrial purposes, provided sufficient energy is available. The real question is not one of fundamental physics but is rather one of an economic nature: will bulk nuclear transmutation to create a particular resource X ever become cheap enough for a sufficiently advanced civilization to outweigh the costs of bringing the same amount of X from elsewhere in the universe?
If the answer is yes, advanced technological civilizations need not fear resource exhaustion, as long as they have any matter to work with and a sufficient energy supply. As previously argued, energy is plentiful both in the era of shining stars (when it can be captured via Dyson spheres and similar contraptions) and even later, in utilizing the gravitational collapse. On longer-still future timescales, exotic energy sources, like the bulk annihilation of CDM particles and antiparticles, or even Hawking evaporation of black holes, could be put to industrial use.53 Baseline matter also need not be too big a problem if the civilization is compact—that is, far from being a Kardashev’s Type 3; we observe a huge amount of unused matter in our astrophysical environment anyway. So, Resource Exhaustion will not really resolve our difficulties in this case.
If, for at least some vital resources, cheap transmutation always remains unfeasible, civilizations will really have an economic impetus to expand (which is the default position in many superficial treatments of Fermi’s paradox). In this case, the expansion might form a roughly spherical wavefront which will gradually turn into a sphere of mostly exhausted planetary systems, surrounded by a thin shell of ‘normal’ activity. If this were to occur with the full knowledge of other sophonts who were doing it in other parts of the Galaxy (knowledge which would be easy to get with miniaturized robotic interstellar probes), we could have a particularly nasty form of the Hansonian ‘burning the cosmic commons’ scenario.54 Considering the fact that there are some weak analogies in humanity’s history for how quickly this form of escalation can ruin otherwise prosperous cultures (e.g. Rapa Nui), we should take the lesson seriously.55So, Resource Exhaustion can, with some auxiliary assumptions, explain at least weaker forms of Fermi’s paradox. On the other hand, the very dependence on these assumptions of a sociological and cultural nature—and the fact that it utilizes disequilibrium conditions (although conditions that are very slow—on timescales of the billions of years necessary for the natural replenishment of resources—to relax)—count against it in comparison with those hypotheses which offer at least a prospect of explaining the equilibrium. To one of those, and a particularly disturbing one, we now turn.
From: The Great Silence
The Science and Philosophy of Fermi’s Paradox
Milan M. Ćirković
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