An Alternative Formulation of the Fermi Paradox

The View from Oregon – 329: Friday 21 February 2025

In newsletter 325 I defined and discussed what I called the spacefaring inflection/expansion matrix that can be used to understand the different ways that a spacefaring civilization might come into being and develop. I’m thinking of further developing this material and integrating it with my earlier “The Large Scale Structure of Spacefaring Civilizations” and my more recent “The Coming Coeval Age,” which I could turn into a paper on the structure of spacefaring civilizations drawing on all of these prior sources. If I shifted the focus I could call the resulting paper “Technosignatures of Spacefaring Civilizations,” and this would in itself be an interesting project, but then it would be less of a pure theory of spacefaring civilization and more an exercise in what needs to be done to discover spacefaring civilizations by means analogous to SETI. This latter direction for these ideas would nicely integrate with a couple of unfinished papers that I have, so that if I finished all three papers I could have a good exposition of my views that might stand a chance of getting published. For the pure exercise in civilizational theory, getting published would be more difficult. Both projects—the pure theory and the application to SETI—are intrinsically interesting to me, so I can pursue this work and let it develop as it will, and I can be satisfied with any outcome, though I would ultimately prefer to produce something publishable because, like it or not, that is one of several measures of scholarly legitimacy. And, to be honest, I don’t like it, but I have to deal with it as it is, and not as I wish it to be. I would prefer just to record more spoken word episodes and focus my efforts of exposition in this format, but that’s not likely to reach the intended audience (though if the audience even exists for this is a legitimate question).

Those who are skeptical or suspicious of spacefaring playing a major role in human history have tried to stigmatize the spacefaring vision as “astrofuturism,” presenting this as though it were a particular phase in the development of human imagination (with the implication that this vision is already more-or-less defunct) but of no importance practically speaking. In the past few years we’ve seen many books, papers, and articles that are some variation on this theme (most notoriously Dark Skies: Space Expansionism, Planetary Geopolitics, and the Ends of Humanity by Daniel Deudney), trying to make the case one way or another that space exploration is a bad idea, misconceived, morally questionable, a moral hazard, or impractical to the point of impossibility. Needless to say, I reject all this nay-saying, and, while I don’t want to specifically engage with this nay-saying literature (partly because it exhibits a particular disingenuousness that originates in a seemingly willful blindness to possibilities), it may be worthwhile reviewing how I got to where I am.

I wouldn’t say it’s a presupposition of my reasoning about the human future that spacefaring civilizations will endure while planetary civilizations will go extinct, because if it were a presupposition I would take it for granted and move on from there, while I have, on the contrary, spent a lot of time thinking through the various possible scenarios for civilization into the far future. I don’t view anything as being inevitable in human history, and that means that I don’t view the development of spacefaring civilization as inevitable. That being said, there are some scenarios that are much more likely than others, and there are valid generalizations we can make about the origins, development, and eventual extinction of civilizations. Among the valid generalizations we can make is that civilizations that experience a spacefaring breakout (i.e., a viable population leaves its homeworld and is able to sustain itself either on other worlds or in artificial habitats) have at least the possibility of adaptive radiation on a cosmological scale, and therefore the possibility of enduring for a longer period of time than civilizations that remain exclusively planetary. Again, none of this is inevitable; a civilization might have a spacefaring breakout and still go extinct (I have an unfinished paper about this too).

You could argue that Earth will remain habitable into the future on a scale of time (about a billion years, maybe more) that is so many orders of magnitude greater than the average lifespan of any mammal species that we can confidently say that humanity will be long extinct before it is forced into any reckoning with the ultimate end of the biosphere, so that an exclusively planetary civilization is not limited in any meaningful way by the finite life of the biosphere. Therefore, a spacefaring civilization would enjoy no longevity advantage over an exclusively planetary civilization. This argument is valid as far as it goes, but I don’t think it counts against what I’m arguing, though it does mean that a detailed account of the human future must account for this argument as one among many qualifications that will affect any human outcomes.

Although (as I’ve already said a couple of times) no outcome in human history is inevitable, the likelihood of civilization becoming spacefaring if it survives is far greater than it remaining an exclusively planetary civilization, so it’s by no means certain, but it’s more likely than not. Say that there is no particular sense of urgency about space travel in the near and mid-term future. Civilization continues on Earth as it has continued for ten thousand years. But we are an industrialized civilization, and we can’t put science, technology, and engineering back in Pandora’s box. Unless something radical changes about our civilization (which is entirely possible), technology will continue to develop and to improve. This suggests to me that at some point technology will become so advanced that space travel technology would become sufficiently inexpensive that even a small minority could pursue it. That means in turn that even if there is not a broadly-based interest in undertaking space exploration on a civilizational scale, a small but highly motivated group could still undertake a spacefaring breakout. It doesn’t take many people. In my episode on Demographics is Destiny I talked about how a small but viable population could grow into billions in a few hundred years given a reasonable fertility rate (and I’m not talking about anything unprecedented, but a fertility rate that has often been exceeded in human history). Any fertility rate above replacement, if continued for a long enough time, will exceed any arbitrarily large population.

That’s the basic argument. Obviously, there are a great many ways that this scenario could be derailed. In fact, there are so many ways that his scenario could be derailed it’s like the Fermi paradox—there are so many proposed explanations of the Fermi paradox that we shouldn’t be surprised at the universal silence. What I’m arguing here could be taken as an alternative formulation of the Fermi paradox, with the question being, “Why don’t we have a spacefaring future?” instead of, “Why aren’t we able to observe any other civilizations?” These questions are equivalent insofar as our spacefaring future could have been the spacefaring future of some other, earlier civilization in the universe which we could have observed if only we knew what to look for. This, however, holds only if we acknowledge some basic uniformity of civilization over cosmological scales, which again means valid, if qualified, generalizations. A purely ideographic account of civilization, in which laws of development are carefully proscribed, would mean that no such comparison could be made between civilizations, and it would therefore be invalid to infer anything about our future from the past development of any other civilization, or vice versa. Carl Sagan’s hope that the discovery of a million year old supercivilization would prove to Earth that we, too, could survive and perhaps endure for a million years, is meaningless in a purely ideographic context.

Although there are countless ways in which a slowly developing planetary civilization might not eventually produce a low cost spacefaring technology, there are only a handful of ways that I think merit separate consideration. I will divide these possible factors into the political, the social, the civilizational, and the technological. Each of these factors comprehends several possible scenarios; by singling out these factors I am presenting an implicit taxonomy of threats to the development of a spacefaring infrastructure. I will take up each of these in turn. Any of these four factors offers up a rabbit hole that I could explore in much more detail; I’ve written about all of these problems to a greater or lesser degree in other contexts. Here I only touch upon them.

The political factor I imagine as primarily military or regulatory. Nation-states, or whatever institutions follow nation-states, determining that independent human communities in space is too great of a risk to planetary populations, could systematically limit the use and development of spacefaring technologies, as nation-states since 1945 have organized to limit the use and development of nuclear technologies in order to limit the proliferation of nuclear weapons. The regulatory regime governing nuclear technology has been reasonably successful in limiting nuclear proliferation—even though the technology of nuclear weapons is almost a century old, it’s still quite difficult to build a nuclear weapon—and I can see the same being the case with spacefaring technologies. As I pointed out some years ago in “Trading Existential Opportunity for Existential Risk Mitigation: A Thought Experiment,” the stringent regulation of nuclear technologies effectively strangled nuclear rocket technology in the cradle, so that the political factor overlaps with the technological factor, but I mention nuclear technology in relation to the political factor because here the motivation is political or military, not primarily technological. Technology suffers as an externality of a political policy. It is not beyond imagining that nation-states might collectively seek to ban space exploration, with only a few national space programs, tightly regulated, allowed to continue their operations in order to service satellites.

The social factor overlaps with the political factor, but culture can evolve and, in evolving, shape the human future without ever passing a law or using bureaucracy to regulate activity. Whether or not the maxim that “politics is downstream of culture” is true, culture can be the determining factor in any number of enterprises, including the development and use of technology. I imagine the social risk to spacefaring breakout as a profound social malaise in which no one has any interest in exploration or risk or danger; this is Nietzsche’s scenario of the “Last Men” who believe that they have converged on perfection even as they have made themselves contemptible. Our future could well be the contemptible Last Men, but it’s difficult to see how this could be universal unless the outcome were engineered, as it well could be (as in Huxley’s Brave New World).

The civilizational factor is the possibility that, over the longue durée, civilizations rise and fall, and the iteration of civilizations in historical time could mean so much disruption in the development of technology that no civilization in the future sequence of civilizations ever develops an inexpensive and robust spacefaring infrastructure. Every time a civilization verges on an advanced technology, it fails, and as it fails its most advanced technologies are lost. Insofar as civilizations are a necessary condition for any large-scale social organization, and insofar as any spacefaring breakout must be a large-scale project requiring social organization, the brittle history of civilizations implies that no such large-scale project can realize its ends. But my above scenario is predicated upon space technologies becoming so inexpensive that even a small group could manage an effort, and this would be an effort that would fly under the radar of civilizational collapse and social malaise, because it would not require large-scale social organization, only a small and dedicated community. This, then, becomes a matter of the intersection of a price point of an effective technology, and whether this price point can be reached before a civilization fails.

More than ten years ago in How We Get There Matters I discussed how the unknown viability of speculative technologies will crucially bear upon any future spacefaring expansion. One of my motives for reading more in philosophy of technology in the past few years stemmed from this post, since it made me realize that we don’t know how well a technology will function until it’s been built. To once again take the example of nuclear technology, no one knew for certain that the Trinity test would be successful, and what the exact yield would be, until the test itself occurred. The device worked as planned, and had a yield within predicted margins of error, but that isn’t always the case with a new technology. A technology may prove to be buildable, and still not practical. Its impracticality may follow from its expense, or its cumbersomeness, or from some other consideration. A particular technology may have particular conditions of its employment that are unique to some application, and these conditions only become apparent to us with the attempted use of the technology as intended.

The technological factor, then, is that, even if technology continues in development, continues to improve, and new technologies are built, we have no guarantee that these technologies will work as planned, or whether they will ever fall to a price and a convenience of use that would make low cost space travel possible. I wrote above that it is still difficult to build a nuclear weapon almost a hundred years after the development of the relevant technologies. Would it be possible to make it cheap and easy to build nuclear weapons? So far as my (very limited) knowledge extends, no effort has been undertaken to explore this. Nation-states that maintain nuclear arsenals have an economic incentive to make the production and maintenance of nuclear weapon stockpiles as economical as possible, but government entities also have built-in incentives to create self-perpetuating institutions, and, where secrecy is a priority, cost savings will be a distant consideration; it might be a different matter if private enterprise were let loose on the problem of constructing cheap nuclear devices. The manufacture of enriched uranium and plutonium continue to be expensive and to require a large industrial infrastructure, so whether or not this process could be scaled down would be an important question if we were trying to make it cheap and easy to build nuclear weapons. Analogous considerations come into play if we wanted to make space travel technologies cheap and easy to build. Building very large chemical rockets like SpaceX is a paradigmatically large undertaking, with a large and long supply train. Building something small that could take off from Earth and make it into orbit might be possible with several difficult technologies that have been studied, but we don’t know if any of these would be viable technologies.

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