So many answers to the Fermi question have been offered that we have a veritable bestiary of solutions, each trying to explain why we have yet to encounter extraterrestrials. I like Leo Szilard’s answer the best: “They are among us, and we call them Hungarians.” That one has a pedigree that I’ll explore in a future post (and remember that Szilard was himself Hungarian). But given our paucity of data, what can we make of Fermi’s question in the light of the latest exoplanet findings? Eduardo Carmona today explores with admirable clarity a low-drama but plausible scenario. Eduardo teaches film and digital media at Loyola Marymount University and California State University Dominguez Hills. His work explores the intersection of scientific concepts and cinematic storytelling. This essay is adapted from a longer treatment that will form the conceptual basis for a science fiction film currently in development. Contact Information: Email: eduardo.carmona@lmu.edu
by Eduardo Carmona MFA
In September 2023, NASA’s OSIRIS-REx spacecraft delivered a precious cargo from asteroid Bennu: pristine samples containing ribose, glucose, nucleobases, and amino acids—the molecular Lego blocks of life itself. Just months later, in early 2024, the Breakthrough Listen initiative reported null results from their most comprehensive search yet: 97 nearby galaxies across 1-11 GHz, with no compelling technosignatures detected.
We live in a cosmos that generously distributes life’s ingredients while maintaining an eerie radio silence. This is the modern Fermi Paradox in stark relief: building blocks everywhere, conversations nowhere.
What if both observations are telling us the same story—just from different chapters?
The Seeding Paradox
The discovery of complex organic molecules on Bennu—a pristine carbonaceous asteroid that has barely changed in 4.5 billion years—confirms what astrobiologists have long suspected: the universe is in the business of making life’s components. Ribose, the sugar backbone of RNA. Nucleobases that encode genetic information. Amino acids that fold into proteins.
These aren’t laboratory curiosities. They’re delivered at scale across the cosmos, frozen in time capsules of rock and ice, raining down on every rocky world in every stellar system. The implications are profound: prebiotic chemistry isn’t a lottery. It’s standard operating procedure for the universe.
This abundance makes the silence more puzzling. If life’s ingredients are everywhere, why isn’t life—or at least communicative life—equally ubiquitous? The Drake Equation suggests we should be drowning in signals. Yet decade after decade of increasingly sophisticated SETI searches return the same answer: nothing.
The traditional responses—they’re too far away, they use technology we can’t detect, they’re deliberately hiding—feel increasingly like special pleading. What if the answer is simpler, more systemic, and reconcilable with both observations?
Cellular Cosmic Isolation: A Synthesis
I propose what I call Cellular Cosmic Isolation (CCI)—not a single explanation but a framework that synthesizes multiple constraints into a coherent picture. Think of it as a series of filters, each one narrowing the funnel from chemical abundance to electromagnetic chatter.
The framework rests on four interlocking observations:
1. Prebiotic abundance: Chemistry is generous. Small bodies deliver life’s building blocks widely and consistently. Biospheres may be common.
2. Geological bottlenecks: Complex, communicative life requires rare conditions—specifically, worlds with coexisting continents and oceans, sustained by long-duration plate tectonics (≥500 million years). Earth’s particular geological engine may be uncommon.
3. Fleeting windows: Technological civilizations may have extraordinarily brief outward-detectable phases—measured in decades, not millennia—before transitioning to post-biological forms, self-destruction, or simply turning their attention inward.
4. Communication constraints: Physical limits (finite speed of light, signal dispersion, beaming requirements) plus coordination problems suppress even the detection of civilizations that do exist.
The result? A universe where the chemistry of life is ubiquitous, simple biospheres may be common, but detectable technospheres remain vanishingly rare and non-overlapping in spacetime. We’re not alone because life is impossible. We’re alone because the path from ribose to radio telescopes has far more gates than we imagined.
The Geological Filter: Earth’s Unlikely Engine
This is perhaps CCI’s most counterintuitive claim, yet it’s grounded in recent research. In a 2024 paper in Scientific Reports, planetary scientists Robert Stern and Taras Gerya argue that Earth’s specific combination—plate tectonics that has operated for billions of years, creating and recycling continents alongside persistent oceans—may be geologically unusual.
Why does this matter for intelligence? Because continents enable:
• Terrestrial ecosystems with high energy density and environmental diversity
• Land-ocean boundaries that create evolutionary pressure for complex sensing and locomotion
• Fire (impossible underwater), which enables metallurgy and advanced tool use
• Seasonal and altitudinal variation that rewards cognitive flexibility
Venus has no plate tectonics. Mars lost its early tectonics. Europa and Enceladus have subsurface oceans but no continents. Earth’s geological engine—stable enough to persist for billions of years, dynamic enough to continuously create new land and recycle old—may be a rare configuration.
Mathematically, this adds two probability terms to the Drake Equation: foc (the fraction of habitable worlds with coexisting oceans and continents) and fpt (the fraction with sustained plate tectonics). If each is, say, 0.1-0.2, their joint probability becomes 0.01-0.04—already a significant filter.
The Temporal Filter: Civilization’s Brief Bloom
But the most devastating filter may be temporal. Traditional SETI assumes civilizations remain detectably technological for thousands or millions of years. CCI suggests the opposite: the phase during which a civilization broadcasts electromagnetic signals into space may be extraordinarily brief—perhaps only decades to centuries.
Consider the human trajectory. We’ve been radio-loud for roughly a century. But already:
• We’re transitioning from broadcast to narrowcast (cable, fiber, satellites)
• Our strongest signals are becoming more controlled and directional
• We’re developing AI systems that may fundamentally transform human civilization within this century
What comes after? Post-biological intelligence operating at computational speeds? A civilization that turns inward, exploring virtual realities? Self-annihilation? Deliberate silence to avoid dangerous contact?
We don’t know. But if the detectable technological phase (call it Lext) averages 50-200 years rather than 10,000-1,000,000 years, the probability of temporal overlap collapses. In a galaxy 13 billion years old, two civilizations with century-long detection windows need to be synchronized to within a cosmic eyeblink.
This isn’t speculation—it’s extrapolation from our own accelerating technological trajectory. And acceleration may be a universal property of technological intelligence.
The Mathematics of Solitude
The traditional Drake Equation multiplies probabilities: star formation rate × fraction with planets × habitable planets per system × fraction developing life × fraction developing intelligence × fraction developing communication × longevity of civilization.
CCI expands this with additional constraints:
Ndetectable = R* × Tgal × [biological/technological terms] × [foc × fpt] × [Lext / Tgal] × C(I)
Where C(I) captures propagation physics—distance, dispersion, scattering, beaming geometry. Each term is a probability distribution, not a point estimate.
In 2018, Oxford researchers Anders Sandberg, Stuart Armstrong, and Milan Ćirković performed a rigorous Bayesian analysis of Drake’s Equation using probability distributions for each parameter. Their conclusion? When uncertainties are properly handled, the probability that we are alone in the observable universe is substantial—not because life is impossible, but because the error bars are enormous.
CCI takes this Bayesian framework and adds the geological and temporal constraints. The result: a posterior probability distribution that is entirely consistent with both abundant prebiotic chemistry and persistent SETI nulls. No paradox required.
What We Should See (And Why We Don’t)
CCI makes testable predictions. If the framework is correct:
1. Biosignatures before technosignatures
Upcoming missions like the Habitable Worlds Observatory should detect atmospheric biosignatures (oxygen-methane disequilibria, possible vegetation edges) before detecting techno signatures. Simple biospheres should be discoverable; technospheres should remain elusive.
2. Continued SETI nulls
Radio and optical SETI campaigns will continue to find nothing—not because we’re searching wrong, but because the detectable population is genuinely sparse and temporally fleeting.
3. Technosignature detection requires extreme investment
Detection of artificial spectral edges (like photovoltaic arrays reflecting at silicon’s UV-visible cutoff) or Dyson-sphere waste heat requires hundreds of hours of observation time even for nearby stars. Their absence at practical survey depths is predicted, not puzzling.
Importantly, CCI is falsifiable. A single unambiguous, repeatable interstellar signal would invalidate the short-Lext assumption. Multiple detections of artificial spectral features would refute the geological filter. The framework lives or dies by observation.
The Cosmos as Organism
There’s an almost biological elegance to this picture. The universe manufactures prebiotic molecules in stellar nurseries and delivers them via comets and asteroids—a kind of cosmic panspermia that doesn’t require directed intelligence, just chemistry and gravity. Call it the seeding phase.
Some of those seeds land on worlds with the right geological configuration—the awakening phase—where continents and oceans coexist long enough for complex cognition to emerge. This is rarer.
A tiny fraction of those awakenings reaches technological sophistication—the communicative phase—but this phase is fleeting, measured in decades to centuries before transformation or silence. This is rarest.
And even then, physical constraints—distance, timing, beaming, the sheer improbability of coordination—suppress detection. The isolation phase.
The cosmos isn’t hostile to intelligence. It’s just structured in a way that makes electromagnetic conversation between civilizations vanishingly unlikely—not impossible, just so improbable that null results after decades of searching are exactly what we’d expect.
Each civilization, then, is like a cell in a vast organism: seeded with the same chemical building blocks, developing according to local conditions, briefly active, then transforming or falling silent before contact with other cells occurs. Cellular Cosmic Isolation.
What This Means for Us
If CCI is correct, we should recalibrate our expectations without abandoning hope. SETI is not futile—it’s hunting for an extraordinarily rare phenomenon. Every null result tightens our probabilistic constraints and guides future searches. But we should also prepare for the possibility that we are, if not alone, then at least effectively alone during our detectable window.
This shifts the weight of responsibility. If technological civilizations are rare and fleeting, then ours carries unique value—not as a recipient of cosmic wisdom from older civilizations, but as a brief, precious experiment in consciousness. The burden falls on us to use our detectable phase wisely: to either extend it, transform it into something sustainable, or at least ensure we don’t waste it.
The universe seeds life generously. It’s indifferent to whether those seeds grow into forests or fade into silence. CCI suggests that the path from chemistry to conversation is longer, stranger, and more filtered than we imagined.
But the building blocks are everywhere. The recipe is universal. And somewhere, in the vast probabilistic landscape of possibility, other cells are awakening. We just may never hear them call out before they, like us, transform into something we wouldn’t recognize as a civilization at all.
That is not a paradox. That is simply the way the cosmos works.
Further Reading
Prebiotic Chemistry:
Furukawa, Y., et al. (2025). “Detection of sugars and nucleobases in asteroid Ryugu samples.” Nature Geoscience. NASA’s OSIRIS-REx mission (2023) also reported similar findings from Bennu.
Bayesian Drake Analysis:
Sandberg, A., Drexler, E., & Ord, T. (2018). “Dissolving the Fermi Paradox.” arXiv:1806.02404. Oxford Future of Humanity Institute.
Geological Filters:
Stern, R., & Gerya, T. (2024). “Plate tectonics and the evolution of continental crust: A rare Earth perspective.” Scientific Reports, 14.
SETI Null Results:
Choza, C., et al. (2024). “A 1-11 GHz Search for Radio Techno signatures from the Galactic Center.” Astronomical Journal. Breakthrough Listen campaign results.
Barrett, J., et al. (2025). “An Exoplanet Transit Search for Radio Techno signatures.” Publications of the Astronomical Society of Australia.
Technosignature Detection:
Lingam, M., & Loeb, A. (2017). “Natural and Artificial Spectral Edges in Exoplanets.” Monthly Notices of the Royal Astronomical Society Letters, 470(1), L82-L86.
Kopparapu, R., et al. (2024). “Detectability of Solar Panels as a Techno signature.” Astrophysical Journal.
Wright, J. et al (2022). “The Case for Techno signatures: Why They May Be Abundant, Long-lived, and Unambiguous.” The Astrophysical Journal Letters 927(2), L30.
Technology Acceleration:
Garrett, M. (2025). “The longevity of radio-emitting civilizations and implications for SETI.” Journal of the British Interplanetary Society (forthcoming). See also earlier work on technological singularities and post-biological transitions.
It all makes sense to me. I tend to have been slowly accepting these concepts myself as my thinking on astrobiology has matured over the years. Keep in mind, I, personally, do not WANT to be alone. It just seems to be inescapable. I only maintain my interest in the field with the hope that maybe we’ll just get lucky.
I would urge some caution on several assumptions that seem to be gaining followers, but which I do not feel are necessarily self-evident.
Among these are the life requirement for oceans and plate tectonics.
Liquid water may be an essential, but not necessarily oceans. As for tectonics, surely there may be other mechanisms to help further an active geology, even if that is indeed a prerequisite for techno-civilization. I could add to these “not necessarily necessary requirements” a massive nearby moon and a magnetic field. Since we have only our own planet as an example, simply accepting these filters is a bit premature.
The key insight here is temporal.
1) Life, even intelligent life, may arise in a lot of places, but not necessarily at the same time. And if it does arise, we have no reason to believe it will last a long time.
2) How common is it for planetary conditions to remain hospitable for a long enough time to allow biological evolution to result in a technical civilization?
3) Life, and even intelligence, may be relatively common, but the long term astronomical, climatological and geological conditions needed to support high tech (spaceships, radio telescopes, technosignatures) may not.
4) We have no assurance other civilizations are as aggressively expansive and innovative as we fancy ourselves to be.
5) “c” may very well be the universal speed limit. If so, interstellar travel (and communication) is a very slow and cumbersome affair. We have absolutely no a priori evidence alien psychologies are prone to engaging in multi-millennia long projects just to get around this fundamental natural limit.
6) We have no idea what a “natural” lifetime for a “typical” civilization is. If it is long enough to make contact between species possible, then doesn’t that suggest that these civilizations are extremely stable and conservative and cautious and otherwise not likely to engage in aggressive programs to find their contemporaries?
7) Perhaps its as simple as this: civilizations advanced and knowledgeable enough to understand the miniscule likelihood that another civilization is close enough in both space AND time to be a potential correspondent does not justify the immense expenditure (and potential risk, they might be hostile!) required to find one.
8) Maybe they just don’t care. Even among humans, the willingness to spend a lot of resources and effort to find interstellar companionship seems to be limited to relatively few of us.
Please forgive me if I seem to dwell too much on these aspects of SETI pessimism. I only do it in the hope someone can persuade me I am mistaken.
I also doubt that plate tectonics are that critical to the formation of life. The articles I have read about this seem sort of ‘manufactured’.
What does puzzle me is the rise of intelligence which, we are told, has everything to do with pre-humans emerging onto the Savanna. Lesser life forms existed for tens of millions of years without any obvious ‘trend’ towards intelligence.
That is wrong. Encephalization has increased with evolved forms. As one proceeds along the evolutionary tree, the intelligence of classes of animals has increased. Mammals are more intelligent than reptiles, which are more intelligent than amphibians, which are more intelligent than fishes. Stereotypical behaviors decline as evolution proceeds. It is purely genetic.
Where humans have made adances is due to culture. We are not more intelligent than our paleolithic ancestors, but the cultural information we have acquired and can pass on makes us vastly more capable than our ancestors, and indeed all other animals on Earth.
Whether there is any scope for a post-human to be more intelligent than we are is dependent on either a reorganization of our brains, particularly the cortex, or increasing our brain size cirrently limited by the size of the female birth canal. Maybe artificial wombs will be the technology that allows this latter change.
50-200 years for detectability seems a real stretch and James Benford explained quite well some years ago that unless they are purposefully beaming at us at high power on an intermittent basis and we are lucky enough to be looking in the right direction, at the right time and frequency then we will never find them. An omni directional beacon would dissipate within a few hundred light years into the noise no matter how great and ancient the civilization that tries to send it.
Back to the 50-200 year thing, we will almost certainly have a solar system civilization of some kind in the not too distant future. We won’t go silent as suggested. We will need to create a narrow band, high powered communications system to link this culture. Ephemeral leakage of just such a civilization within our area of detection is all we can hope for. We might find a few here and there never to repeat.
My complements! A really nice, compact, clear and persuasive piece of work.
Want to second WRA’s motion. As a premise from which discussion can depart or progress, this entry is very difficult to top. But its structure and conclusions should get some examination – and it is getting it in the entries below.
I do note that expectations of a coherent VHF or UHF signal, say, from the depths of space seem like a long shot. Even if ETs wore gray suits to work and built radio dishes somewhere within 100 light years and already translated for our benefit, I suspect the broadcasts would be lost in attenuation and noise. Maybe someone has an assessment?
Whether broadcast probability would be from beings like us or radically different, can this be woven into the likelihood of ET sending a signal for such an inquiry?
Since we’ve never met ET, we are left with a question about someone or something that is inscrutable.
But the proposition of something with cognition out there that still remains. And for one reason is that our own consciousness is not well explained by bio-precursors; just given a seat and transmission basis. How does that fit into the picture? We’re left in much the same quandary as what’s the difference between us and AI. Our biochemistry is cleverer than we are, for example, but it has no interest in our existence (save in cases such as viruses fearing an outcome where they might go out of business). Correspondingly a very complex exobiology might not have any inclination to send signals or inquire about our philosophers. And for those that presume that A/I is likely to remain elsewhere where biological life originated but ceased, the argument is that their developers or predecessors would program such a compulsion into its nature. But to whom would they report this finding back?
A number of straw man ET’s are examined above. And in a way the argument proceeds to suggest that ET should have planetary conditions and geological history similar to our own ( plate tectonics, magnetosphere, oceans and continents, bacterial transformation of primitive atmosphere etc.). And should that be the case, maybe the odds are improved for our own recognition of ET, if not necessarily its ascent. We would suspect a similar biochemistry at any rate and relationship noted above with combustion. But in our own case, as a means of energy production, chemical combustion just might have been transitional vs. other energy means not fed by the atmosphere. If ET did not or could not gather around a camp fire, did that mean ET would never discover electromagnetism?
Secondly, the bio-precursors “here” might not be the same ones as “there”. One could deliver a sack of salt to early Earth for example and not expect much to happen. Bio-precursors needed some sort of catalytic action to propagate
life around the world. It might be that bio-precursors and catalysts might be different on other planets with different chemistry inclusive of stellar radiation, primitive atmosphere and surface fluids. We might have had it just right or maybe we were somewhere on the scale. Catalysts might already have been discussed, either here or on another topic, but maybe it can be reviewed.
Or does living in an ocean necessarily preclude the invention of tools? And if a world has a less clearly defined boundary between fluid states on its surface, is there necessarily a prohibition to complex biochemistry? Due to our ability to detect exoplanets in transit, we will probably collect more data about large diameter and massive planets in temperate regions than Earth-like ones. Even now, if we get “faint positives” for life, it is likely a super Earth or Neptune like exoplanet. But saying that, I should note as well that the bigger the planet the more difficult it is to deliver biochemistry through its atmosphere (entry) to either a liquid or solid surface.
While larger planets would appear to make life’s building blocks delivery through the atmosphere more difficult, the radius of the biosphere based on an altitude/radial segment might be many times larger than that on Earth. The critical point is whether complex forms can obtain a beach head where there might not be any beaches as we know them. Floating rafts of some sort perhaps, density and “development” concentration determining their depths.
Speaking of which, Life on Earth seems to have experienced numerous transformational, run-away processes. Earth today is not like the real estate that precursors to life and primitive life observed shortly after arrival. Geologists and archeo-biologists have identified more than I can count. Perhaps with improving space observatories there might be a way to either anticipate these biologically induced transformations on exoplanets or detect them. These worlds will not likely send the Morse code signals anticipated decades ago in the radio spectrum, but some exoplanet chemistries might be better explained by the presence of a biosphere.
Going back to the stellar base, observational techniques to support search for life or extraterrestrial intelligence has its quirks even though this past decade or so has increased the database tremendously. But it also has its quirks based o detection techniques, largely dominated by transits. Exoplanets we know the most about in putative green zones about stars are doing so around red dwarfs with distinctive characteristics: red-shifted luminosities for effective temperatures equivalent to Earth’s and data arriving quickly because years are matters of days.
Stars similar to Earth’s are going to have orbital periods about a year’s length, which means it will take nearly a hundred times as long to collect transit “sample” data. Moreover, even though G type stars can be acquired at greater distance, they are a much smaller fraction of galactic population. If the red dwarf environment is not sufficiently conducive to life’s proliferation into complex multi-cellular organisms, then the search for ET is going to be more difficult than the full buckets of red dwarf planetary transits suggests at first glance.
This lack of results thus far brings to mind the old riddle about why the chicken crossed the road: “To show the armadillo that it can be done.” So for that exoplanet out there full of hesitant armadillos…
Compliments, perhaps?
I question some of your assumptions and logic.
Adding 2 terms doesn’t change anything. The probabilities are included in the 2 Drake Equation (DE) terms f_sub_l (p(life)) and f_sub_i (p(intelligence)). We had another post like this some time ago, to increase terms to make the DE more granular. Add them in if you want, but this would be compensated for by increasing the probabilities of the terms excluding the new components. Otherwise, one could keep adding probability terms until even our existence would be highly improbable. N needs to be around 1 just to indicate our existence.
While it may well prevent 2-way communication, the original source may be long extinct or not using radio or optical methods, but the period of emission is irrelevant. Remember the DE has rates of star formation, so that unless this value changes hugely over the last few millions of years, when the signal source is generated makes no impact on the number of transmitting civs N at any given moment throughout that timeline. Suppose a civilization transmitted a signal 500 ly distant, and 500 years ago, if we can receive it, we will. If that civilization has disappeared in the last 500 years, it just means that we cannot usefully send a signal back, hoping they will receive it in another 500 years. The distance/time may be more relevant due to signal strength and degradation to noise (reduced signal-to-noise ratio). IIRC, we had a post on this about civilizations transmitting “Encyclopaedias of their civilization that could be eventually received and added to the “Encyclopaedia Galactica.” Imagine N civilizations dispersed in distance and time, but with the property that their signals all arrived at the same time. There may be no “extant civilizations” (if we could ignore the meaning of spacetime), yet the sky would apparently be filled with transmitting civilizations from our location and POV, a veritable “Galactic Club.”
A repeating signal for 10 years would not invalidate your CCI, other than a civilization transmitted at some time in the past with a lower bound of 10 years and no upper bound than the age of the observable universe. Also, see my previous response. If we receive only one signal from the same apparent location for a long time (millennia?), then we might consider that there was only one civilization transmitting to our system for that length of time. How far away it originated and hence when it was transmitting would be unknown.There is also the issue of transience and detection. Consider the “Golden record” on its way to teh stars. Suppose it arrives in another system in 100,000 years, and takes a decade to cross that system. Unless there is an ETI looking for the probe and able to intercept it to retrieve the record, then it will miss our message. An example of “Absence of evidence does not imply evidence of absence.”
That asteroids and comets can produce these compounds does not mean that they are the sole source, or evena source. All these precursors have been produced in the lab. Therefore, production of the prebiotic precursor important biological molecules could well have been produced in situ on the living planet. I also note that the Bennu amino acid complement is only 14 of the 20 life uses. It would be important to look at the 14 and determine if these were the essential ones sufficient to create early life, and the missing ones created by life on Earth.
While we have no evidence to date, we might as well ask whether panspermia, rather than extraterrestrial precursor molecules delivered to potentially habitable planets, is the important mechanism of life seeding in the galaxy.
To sum up, the “ubiquity” of life, but lack of signals due to sparsity of technological transmitting civilizations in space and time, is also answered by local production of precursor molecules to initiate abiogenesis, not requiring “seeding”, and the sparsity of intelligent, communicating ETI explains the lack of signal alone, and not the separation in time.
Thank you for your thoughtful critique. You raise several important points that deserve careful consideration. Let me address each systematically:
On Drake Equation Parameterization:
You’re absolutely right that f_oc and f_pt could be subsumed within f_l and f_i. However, that’s precisely the problem I’m addressing. When researchers estimate f_l = 0.1–1.0, they often implicitly assume Earth-analog conditions without explicitly modeling:
The fraction of habitable-zone planets that are ocean worlds (no continents)
The fraction of terrestrial planets locked in stagnant-lid tectonics
The fraction with excessive water content (high-pressure ice layers preventing ocean-crust interaction)
My contribution isn’t to add filters arbitrarily—it’s to make explicit what has been assumed in overly optimistic estimates. Consider: if someone estimates f_l = 0.5 based on “liquid water = life,” but then we discover 80% of habitable-zone planets are pure ocean worlds, we should revise f_l downward accordingly. My framework forces this accounting.
Your point about “N must equal ~1” via the anthropic principle is well-taken, but it works both ways: knowing N ≥ 1 doesn’t tell us which factors dominate. My framework suggests specific geophysical constraints may be more important than previously appreciated—not that they make our existence improbable, but that they help explain why N ~ 1 rather than N >> 1.
On the Temporal Filter:
You make a sophisticated argument about signal propagation independence, and I need to clarify my claim. You’re correct that for one-way detection, we don’t need temporal overlap of living civilizations—we can detect signals from extinct sources.
However, L_ext isn’t just about transmission duration—it’s about the rate at which detectable sources enter the observable universe versus the duration of detectability. Even if signals from extinct civilizations propagate indefinitely, the relevant question is: How many independent detectable sources exist at any given time?
Your “Encyclopedia Galactica” thought experiment actually illustrates this: even if we receive signals from multiple extinct civilizations simultaneously, the rate at which new civilizations become detectable still matters. If L_ext is short, fewer civilizations are in the detectable phase at any epoch, reducing the total number of independent signal sources.
Think of it this way: Suppose civilizations universally transmit for 100 years then go silent (transition to laser communication, quantum channels, or extinction). Even though their 100-year burst propagates forever, the density of detectable signals in any given epoch is determined by:
N_detectable ∝ (Rate of civilization emergence) × (Duration of detectability)
This is why L_ext/T_gal appears as a factor—it’s not about whether signals exist, but about how many independent sources are detectable at any moment.
You’re absolutely right that signal degradation and S/N ratios matter more for practical detection—but that’s a separate (and equally important) filter I don’t dispute.
On Falsifiability:
Fair point—a single repeating signal establishes a lower bound, not a falsification of short L_ext. I should have been more precise: widespread detection of multiple long-duration signals would challenge the framework, but a single detection wouldn’t. I’ll refine this claim.
On Prebiotic Molecule Sources:
You’re correct that in situ production is demonstrated in labs and likely occurs on planets. I overstated the necessity of extraterrestrial delivery. The key point isn’t where prebiotic molecules come from, but that the building blocks appear common while complex technological life remains undetected. Whether those building blocks form in stellar nurseries or planetary atmospheres doesn’t change the core argument: abundance of precursors ≠ , abundance of civilizations.
Bottom Line:
I agree that “sparsity of intelligent communicating ETI” is sufficient to explain the Fermi Paradox. My framework simply asks: Why is ETI communication sparse?
I propose:
Geophysical rarity: Not all habitable-zone planets have the right geology
Temporal dynamics: Detectable phases may be brief (affecting detection density, not just signal existence)
Communication probability: Cultural/technological factors affect detectability
You could argue these are just sub-components of “ETI sparsity,” and you’d be right. The question is whether making these factors explicit helps us design better SETI strategies (targeting specific planetary types, expanding search modalities beyond radio, etc.).
Where I’ll Modify My Claims:
I’ll clarify that Drake parameterization is about making implicit assumptions explicit, not adding fundamentally new filters.
I’ll distinguish more carefully between “temporal overlap for two-way communication” vs. “temporal dynamics affecting detection density.”
I’ll soften the “prebiotic delivery” requirement—in situ production is equally plausible.
I’ll refine the falsifiability claim to focus on widespread detection patterns rather than single signals.
Thank you for pushing me to clarify these points. Scientific frameworks improve through exactly this kind of rigorous critique.
Best regards,
Eduardo Carmona
N doesn’t have to be ~1. Remember the Drake equation asks about the number of observable civilizations in the galaxy, our galaxy (this is why you add the star formation rate of our galaxy at the beginning). Yes, we are one civilization in our galaxy. But what if life is so rare in the universe in general that you have to, on average, and at any one time, look at several hundred galaxies to find one single civilization? Then, N ~ 0.001-0.01.
Then the DE would be for 100 or 1000 galaxies, and N ~ 1 for this number. The DE would then have star formation for 100 or 1000 galaxies, and the corresponding probabilities would be reduced to arrive at N ~ 1.
I think what you are really saying is that we couldn’t even ask the question if we didn’t exist, so we have a “survivorship bias” built in. The probability that any star has an intelligent species may be exceedingly low, but as we exist, there must be at least one, us, to ask the question.
Talking of the Golden Record I saw this humorous explanation of the Fermi Paradox on Twitter, recently:
https://x.com/i/status/2011193737381364066
“Never forget: we sent nudes, a mixtape, and directions to our house on Pioneer. No wonder the aliens are lying low.”
Funny!
“Anyone who believes in infinite growth on a finite planet is either insane or else an economist.” Global population will peak in 50 years just shy of 10 billion. The world will probably have noticeably fewer people in 2200 than in 2100 even without war or global warming. Who needs space colonies
Ads in the consumer society say, “Enjoy Life! Buy this, buy that, travel the world!” That is an alternative to staying home, wearing secondhand clothes, and raising a big family. Time will tell.
Our technological growth has coincided with an expanding population, which is probably necessary for that to happen. What happens when population seriously declines? Without the population to support it, advanced technological civilization could collapse, which would collapse entire industries and accelerate the population decline. Long term, Earth could go through a cycle of expanding population, collapse, and then re-expansion. The only alternative is expansion into outer space in a self-sustaining way before Earth civilization goes through a collapse phase. If any alien species have built interstellar colonial empires of significant extent, we should have already detected them. This may be one of the greatest filters of all – seeding colonies on distant worlds before the home civilization goes through a collapse phase.
I disagree. Only a fraction of our global population is involved in increasing and peripherally supporting technology development. Larger human population increase global GDP which does support more R&D. However, a declining population with greater productivity increase would allow a smaller population, if that can be managed. If instead we ensured that a greater fraction of the population could be productively engaged in R&D. the science and technology would still increase. It may be that R&D might change directions, focussing of lower cost discoveries, but that isn’t necessarily a bad thing at all. [Look at the huge sums spent on “atom smashers” and the almost paltry fundamental science gains from that endeavor.]
FWIW, I’ve seen it argued that if our industrial civilization collapsed, a subsequent one would have a much more difficult time getting started than ours did, because we’ve already used up the easily-accessible stocks of things like coal and iron ore. The same argument is used against the idea that an ancient Atlantis-like industrial civilization could have existed — that civilization would have already used up the the resources that ours used to get started.
I would appreciate a more thorough explanation regarding why the development of technology and civilization required the specific time frames mentioned. For instance, it would be helpful to understand why significant technological advancements have occurred over the past 150 years, whereas similar progress did not occur a thousand or even 10,000 years ago. CCI primarily outlines humanity’s historical trajectory without addressing the underlying reasons for this timing. I find the argument unconvincing, as it merely describes what happened without clarifying the factors or processes that contributed to these developments. Because it doesn’t address the factors or processes involved, it is a stretch to extrapolate to other civilizations, whether extraterrestrial or the known civilizations of Earth.
@ Dean
“…it would be helpful to understand why significant technological advancements have occurred over the past 150 years, whereas similar progress did not occur a thousand or even 10,000 years ago. ”
Good question. And fortunately, it has a plausible answer!
The fact that industrial civilization took so long to arise, yet exploded furiously once it did appear, suggests that “industrial civilization” is not an inevitable, or even expected, result of the history of intelligent species. This is exactly what one would expect of a process or event which is accidental or unexpected, as opposed to what one may consider an evolutionary development. In other words, just because you have a civilization composed of organized and intelligent individuals does not necessarily mean the next step in evolution is automatically spaceships and radio telescopes.
Human beings have existed in pretty much their present configuration for hundreds of thousands of years, but civilization required the development of agriculture just a few thousand years ago. And the burst of technological development you allude to did not occur until the development of steam and electricity in the late 18th century, probably due to the bootstrap discoveries of Isaac Newton. There were sophisticated and complex societies on Earth several thousand years ago such as Rome and China, but the technological boom potentially leading to space travel seems to have been a fluke. We cannot believe it was an inevitable development. It may very well have been the result of living on a planet with accessible fossil fuels and a few exceptional individuals arising at just the right time.
These are the bottlenecks, or filters, that will determine the likelihood of ETI:
1) The appearance of microbial Life. (4 Gyr)
2) The arising of multicellular organisms. (500 Myr)
3) The appearance of a nervous system capable of initiating language in a species of social, tool-using creatures. (100 Kyr?)
These biological factors are nested, each requires the previous one, and they require increasing orders of magnitude of elapsed time to materialize as we look back into the past. We have no reason to believe they are inevitable, or evidence of some Grand Design inherent in evolution. Add to that the fact that the development of our type of physical technology requires a planet with plentiful and convenient energy sources, a transparent atmosphere (for the development of astronomy), lots of silicon (for making glass lenses and test tubes), abundant metals in the crust, and enough dry places for the discovery of fire and so on.
Science fiction has speculated on the possibility of innumerable civilizations without technology (not to mention all the ones that have existed on earth) but the ones with spaceships and radio telescopes require a long list of prerequisites which may not be as ubiquitous as we like to think.
@ henry
“Good question. And fortunately, it has a plausible answer!”
This is more like it overall, but I think we can greatly improve it with some fertile questions. 1st let’s borrow some Copernicus and Bayesian concepts. We can assume that these biological bottlenecks and filters are early filters that we and other ETIs will have passed. This is the Copernicus and Bayesian concepts part.
The next area of focus concerns the relationship between civilizations and technological development.
Consider the observation: “The fact that industrial civilization took so long to arise, yet exploded furiously once it did appear, suggests that ‘industrial civilization’ is not an inevitable, or even expected, result of the history of intelligent species.” Historical advancements support this perspective. It is important to critically assess the concept of industrial civilization; for instance, the achievements of the Mayan and Egyptian societies challenge a simplistic definition. This raises questions about why certain civilizations did not progress further. What mechanisms enabled their advancement, stagnation, or eventual decline? These mechanisms likely represent general patterns rather than being unique to specific societies.
As noted, “This is exactly what one would expect of a process or event which is accidental or unexpected, as opposed to what one may consider an evolutionary development. In other words, just because you have a civilization composed of organized and intelligent individuals does not necessarily mean the next step in evolution is automatically spaceships and radio telescopes.” This suggests that technology, and its interaction with civilization, can alter organizational structures and foster innovation. A key question emerges: what characteristics of certain technologies promote these transformative steps, and how can these features be described, evaluated, or modeled?
For example, the development of the steam engine during the age of steam illustrates this phenomenon. What aspects of steam technology—here referred to as ‘steampunk’ technology—appear to drive technological advancement and corresponding changes in the structure of civilizations?
Are there additional technologies that exert a comparable influence beyond their immediate applications? For instance, agriculture results in a more stable and abundant food supply, which enables permanent settlements. This, in turn, facilitates the development of permanent structures and subsequent innovations such as kilns and pottery. Thus, agriculture exemplifies a technology that catalyzes further technological advancements.
Each of these technologies, along with their associated civilizations, carries inherent risk factors. For example, agricultural societies may face drought, excessive rainfall, or wildfires, all of which threaten crop yields. These risks are not isolated to a single year but accumulate over time, compounding their impact.
What additional cumulative risks exist? Could such risks associated with various technologies and civilizations have contributed to the decline of earlier societies? Might these cumulative risks represent a form of ‘great filter’? It is possible that civilizations must advance through successive technologies and their attendant risks without stagnating or succumbing to these challenges.
Therefore, could the development of certain technologies collectively constitute a ‘late filter,’ even if humanity has only recently overcome them? Might cumulative risk factors also serve as a significant late filter that civilizations must successfully navigate?
Is it possible for a civilization to reach only a certain technological level and still achieve spaceflight? For example, if a society advanced only to the level of ‘steampunk’ technology, could it nonetheless develop spaceflight and radio communication? This scenario evokes the speculative works of Jules Verne.
Numerous technologies exist beyond the ‘steampunk’ stage, yet attaining them is not necessarily more assured than acquiring earlier technologies. Could the acquisition of these advanced technologies, along with their cumulative risks, serve as a late filter? Furthermore, might the technologies that are currently only conceptualized, along with their associated risks, constitute a late filter that humanity has yet to overcome?
This is enough fertile questions for a start. Working through these kinds of questions in my mind is much more scientific than just listing things that have happened and hand waving that they must happen to all civilizations. Saying that just because a concept is falsifiable does not necessarily make it scientific. The truism that for something to be scientific it must look scientific may be true, but the reciprocal that just because something looks scientific does not necessarily mean it is scientific can also be true. These are what I see as the shortfall in CCI: it doesn’t address the means and mechanisms as much as it lists observations.
@Henry
>why significant technological advancements have occurred over the past 150 years, whereas similar progress did not occur a thousand or even 10,000 years ago.
Lewis Munford (see below) will partly answer to the question: indeed there is a kind of rather “logical progression” in the development of techniques by mankind. A very crude example from his book: it was only by moving from the age of wood to iron mastery that we were able to exploit mines in depth, thus developing transportation, mechanization (18th) and later industry & chemistry (19th) then the concrete with which we were able to make nuclear reactors etc. As well as without the principle of the microscope it would be impossible today to engrave electronic chips.
Of course, there are other factors such as the quality of life which has improved; fewer wars and more stability in our societies in the 18th century, which allowed us to focus on Science and therefore to find new things etc.
Of course, all this has to be seen in a very broad way but LM demonstrates it very well unfortunately he took the Middle Ages as the starting point for technology but there are other studies.
in other words, we could not have exploited nuclear before the industrial civilization of iron and chemistry. Note this important difference between *discovering* something and being able to *exploit* it. Iron has been controlled since prehistoric times, but it has only recently been exploited on a large scale because we are subject to the Technique.
It’s ONE explanation, not necessarily the best but interesting BTW there is something fascinating in this progression.
The question now is to know which new technological step we are heading towards. we always return to the keyword: energy…
https://en.wikipedia.org/wiki/Lewis_Mumford
https://en.wikipedia.org/wiki/Technics_and_Civilization
@fred
Another example is Hero’s [steam ]engine from ancient Greece that rotated a cylinder of water with the steam/water from the heated water. Aeolipile. It was before its time. Similarly, the Antikythera device was a dead end at the time. I would add Babbage’s “Difference Engine” which was ahead of its time, and Ada Lovelace’s ideas on programming it.
The economist Brian Arthur has shown that technologies build upon each other, with a combinatorial explosion driving the pace of new technologies. Create a technology that cannot be used with another, and it becomes dormant at best, only to be revived when complementary technologies can be used with it to build further new technologies.
Just imagine if the jet engine was invented at the time the Wright Bros were building the first powered aircraft. It wouldn’t have been able to be used. It was only with the wartime development of very fast fighter mono-wing aircraft with stressed metal skins that the jet engine was a complementary technology to allow aircraft to fly faster and higher, displacing propeller-driven powerplants.
We don’t even know how long industrial civilizations last.
Macroscopic life has existed on Earth for over 600 million years.
Industrial civilization on Earth has existed less than 300 years.
I found this article quite persuasive in arguing away the word ‘paradox’ in Fermi’s question about where are they. Civilizations using radio or other electromagnetic means of communication could be exceedingly rare in both space and time, so it’s no wonder we haven’t detected any obvious communication attempts or leakage, and it’s also probable that we never will. It still doesn’t mean they aren’t, haven’t been, or never will be there, and it doesn’t mean we should stop looking.
I also found this article (link below) about how red dwarfs stars don’t provide enough energy for multicellular life to develop. The argument is also convincing and throws another damper on the chances for complex life to develope on most if not all of the earthlike worlds around red dwarfs in our galaxy.
https://www.universetoday.com/articles/red-dwarfs-are-too-dim-to-generate-complex-life
I would be quite happy if both arguments are wrong and the galaxy and universe are teeming with complex life and advanced civs that we can talk to (eventually), but given the current data and the above logical arguments, it looks more and more like we are probably alone, at least in our neighborhood, if not the entire galaxy.
@Ross
I need to read teh paper, but they certainly take an interesting approach that I hadn’t considered before. We know that complex animals can live on the chemical energy provided by a planet, as hot vent ecosystems prove. Isolated cave dwellers seem to survive without photosynthetic carbon fixation, but will oxygen available.
This paper argues that without oxygenic photosynthesis provided at a rate available by a yellow star, eukaryotic life could not evolve within the needed lifetime of the star. That is an interesting question.
Now that I have read the paper, their assumptions are exposed. Firstly, they assume an Earth 2.0 in the Archaean placed in the orbit of Trappist-1e. They assume that the forms of microbial photosynthesis are similar to those on Earth, and that the photosynthetically active radiation (PAR) is approximately the same as that on Earth, albeit with the caveat that it may be extended further into the red end of the spectrum. They assume the ratio of PAR on Trappist-1e vs Earth is linearly related to the time to reach the GOE. On Trappist-1e, the time is several times longer than on Earth, and the Trappist-1e “Cambrian Explosion” is also extended, beyond the age of Trappist-1.
As a simplified approach, this looks interesting, suggesting that multicellular life needing oxygen for energy generation would never get the chance to evolve.
The authors acknowledge their simplification to make their calculations tractable.
What could change this result?
1. That life finds different means to trap sufficiently energetic radiation for oxygenic radiation.
2. That oceans on Trappist-1e have a better distribution of nutrients, so that cyanobacteria can be denser than on Earth, especially in the open oceans.
3. That M_dwarf flares might have a greater photolysis rate, allowing this abiogenic creation of O2 to offset the lower rate of photosynthesis.
IOW, different planetary conditions and the evolution of oxygenic photosynthesis using different molecules could ensure that multicellular life requiring O2 could emerge in a shorter timeframe.
Lastly, the assumption that multicellular life must use O2 may be false. There are multicellular species that use anaerobic respiration. Even we humans can do this for short periods. Life forms that have more leaflike phenotypes may have emerged when the dissolved O2 in the oceans was lower.
Bottom line, I wouldn’t assume that Earth is the necessary model for the evolution of complex life. Evolution may be more effective at creating complex life under different conditions.
Research shows that complex building blocks of life form spontaneously in space.
https://phys.org/news/2026-01-complex-blocks-life-spontaneously-space.html
We limit ourselves to what we believe should exist in the universe, even though we don’t really know what’s out there. We only go by what we observe on this planet, similar to when the church preached that we were at the center of the universe. In a sense, we’re at the center of the biological universe, applying the same criteria. Now, we’re discovering other things that could develop and lead to what we’re seeing now, including the possibility of direct extraterrestrial contact with us.
Eukaryogenesis
This all assumes that the only way civilizations in the universe will interact is through radio signals. Some civilizations may destroy themselves or collapse and never recover, some may turn inwards forever, some may be replaced with artificial life forms that might then not be interested in communication with “primitive” civilizations.
But *all* of them, really? No civilizations that are successful at settling other planets, at a rate such that they always expand further, diversify biologically and technologically, into a multitude of space-adapted forms of life and intelligence, which all communicate in various ways? A cone of civilizational mess expanding forward in time and space, and engulfing everything in their way? Sure, this obviously hasn’t happened in our past light-cone, or we wouldn’t be here. But are these space-colonization-events-by-intelligence really so rare that this observation, or rather lack of observation, is likely?
This, to me, seems a much more interesting question than whether or not we see some radio signals.
I really like the concept and I’m going to play devil’s advocate :)
The universe produces matter…full stop. It IS in the ontological sense of the term. In other words, there exists in relation to nothingness or nothing can exist (for those who have aspirin: “is nothingness something particular then?” :)
The fact that we are part of the “organized matter”* which itself has shaped the matter of its planet – and is already planning to terraform other worlds – may only be the result of an infinity of circumstances and an exceptional chance. The universe creates matter and doesn’t give a damn about what it becomes…
Statistically, there is therefore almost no chance that this same pattern of development will reproduce –at the same degree of biological and technological development– in the universe. Sorry for E.T. (Which does not mean other possible developments of primordial organic compounds that would lead to other ‘advances’.
one can have the same ingredients to make a cake, in the same proportions, in different places a) each place will have different [infinitesimal] external conditions that will make the cake swell or not b) there will never be a cake if an intelligence or “structure” does not assemble these ingredients in a precise order. c) I don’t think we will get our good cake by throwing all the ingredients it looks…
why we absolutely want two (almost) identical development patterns to have developed ? Of course it’s comforting but maybe not very realistic. It’s a bit like a rock trying to communicate with your favorite celestial object: it doesn’t make sense. What development could then take the subject and how to communicate with it IF it has this receiving faculty? (I’m going to get some aspirin :)
Consider the problem in another way: if we are alone, is our own development (planet + living species + some junk sent to space) is not itself a simple variable that will allow the universe to continue evolving towards something else and why not towards other forms of life that we will never see? It’s frustrating but that’s how it is. To summarize: communicate but to search for what? or leave a trace for the future (which is a way to communicate through time)
Finally, what is our ‘role’ in the universe?
* Sharon Stone is very well …”organized as a material” (especially in skirt) ;)
@fred
I would add that natural selection determines what the abundances of various elements create as molecules, and molecules as something transcendent. Hazen’s group has applied this to mineralogy as an adjunct to biology. Prebiotic molecules were selected by autocatalysis, and circular reactions driving some molecules to rapidly become the dominant molecular species. Once life appeared, then this natural selection really drove the evolution of forms. These processes reversed entropy locally, even as the universe increased it.
I wonder what other forms will be subject to this selection, e.g. technology certainly appears to be one. What other forms and processes will be driven in similar ways?
Matter is Energy & vice versa
Perhaps the answer is simply pollution. You might describe it as an increase in chemical entropy at the planetary scale. All our accomplishments – cars, rockets, domesticated plants and animals, even solar panels – can be described, broadly, as chemicals or organisms getting where they’re not supposed to be, in new combinations. The planet keeps catching bullets – mass extinctions, DDT killing plankton, ozone holes, global warming, fluorinated hydrocarbons. For a couple of generations, maybe we can stop these threats and even avoid nuclear war; but over the course of a hundred generations? We won’t spot every DES mistake before it becomes ubiquitous. Sooner or later a chemical will get into the environment that epigenetically modifies chromatin so that all babies are born autistic, or a common low-risk pollutant will cause chloroplasts to mutate until they become inviable… or any of a million other scenarios that entropy can provide. The chaos that allows a civilization to become detectable seems fated to end it.
@Mike Serfas
Or a metal-eating microorganism as in Simak’s scifi short story, “You’ll Never Go Home Again”, produced as the episode Beach Head in the BBC’s Out of the Unknown scifi tv series.
Or perhaps as we are doing now for plastics, fictionalized back in the 1970s. The Plastic Eaters.
More likely, it will be a highly lethal virus that jumps from an animal, e.g., birds, to humans. We are one major mutation away from a bird flu that will do it today.
Perhaps we are not quiet enough to hear what were are searching for.
Given sufficient time will all intelligent groups/tribes invent the wheel: the quintessentially important invention upon which all technology and progress depends. I suspect the answer is ‘yes’ but I dont actually know, of course.
Don, it’s important to bear in mind the social and environmental contexts in which invention occurred. With the wheel, for example, it was originally developed and used by Mesopotamian cultures not for motive power or transport, but rather as a device to simplify the turning of pottery. Beyond that, its first application for motive purposes was for toy carts/wagons; it took some time before its use was extended to utilitarian carts, wagons or chariots. And among peoples in Mesoamerica, where no animals lived that could be readily domesticated and used to pull wheeled vehicles, thousands of years elapsed before European settlers brought horses and oxen into that region, and with them, carts and wagons.
I also question whether there is a single, “quintessentially important invention upon which all technology and progress depends.” As I’ve argued before, the history of technology is rife with contingent factors and cultural disparities that enabled *some* cultures to *progress* (a loaded word) at a more rapid rate than other cultures. The development and application of simple machines offers a case in point. The need for water, for example, led peoples who lived in arid climates to develop, and make robust use of, screws and pumps to develop hydraulic technologies; conversely, peoples who enjoyed readier access to water supplies relied less on such technologies.
If a case could be made for determinative technologies that markedly shaped human development, I’d point to much further back in our prehistory to those associated with the practical use(s) of fire several hundred thousand years ago, for cooking, warmth, and working raw materials (e.g., smelting ores, fusing sand into glass, firing clay, etc.).
Biological wheel organelles
My pet theory is that intelligence couldn’t arise until Earth’s rotation slowed to 24 hours. Until then, accounting for 8 hours of sleep and 12+ hours of hunting, gathering, reproducing, etc, there was no time for intellectual pursuits. We were just too busy.
I think my theory is just as well founded as most others I’ve seen.
Now that an increasing part of our extended days is spent staring at screens I expect intelligent life on Earth to gradually recede. Fermi paradox solved!
Since the article address the math of life, here is a simple probability relationship that must be answered before ever addressing the likelihood of life. proliferating in the universe. Every time I bring this up I get lots of responses questioning my intelligence, lack of education, etc. so if that’s your response, I am not offended.
Having amino acids, sugars, etc., available is far removed from a living cell. The first thing that must occur is a group of amino acids must get together somehow. Let’s consider the probability of a group of 20 amino acids concentration in one place so a small protein of 100 amino acids from the group of 20 necessary ones polymerizes. Since proteins chins must be assembled with left-handed chirality, that means there are 40 candidates for every link in the chain. Basic probability says the chance of that protein being assembled by chance is 1 in 10^160. That’s the math. Scientists tell us that there can be no intelligence applied, chemistry and physics tell us there is no proclivity for the amino acids to assemble in any way other than random chance.
What one is left with is a volume of misformed amino acid chains that would fill several billion universes. Extend this to the thousands of proteins necessary to construct a ‘simple cell’ and science has no possible explanation . On the contrary, known science demands that there must be intelligent input for life to exist.
@Jeff Jones
You are peddling creationist/ID rubbish, so you don’t know what you are talking about. [It isn’t that you are stupid, but that you have accepted the disinformation of the religious fundamentalists who want to push for a creator. ] Life isn’t about probability as you describe, but about natural selection that rapidly finds successful routes in chemical space that eliminates the vast numbers of useless combinations to be tested.
Read Dawkins’ The Blind Watchmaker to get a sense of where you have been misled and where the reality resides.
You have a point, Jeff.
I don’t think anyone who has an interest in science, or even professional scientists, hasn’t asked himself similar questions. We may not be able to “prove” rigorously your ‘intelligent input’ plays some role in the development of Life, but at least emotionally and intuitively, it does seem self-evident.
But the usual human response has historically been to assign this role to some deity or god, an intelligent entity existing somehow outside reality but nevertheless who created that reality, controls it, and in addition has an elaborate list of requirements, beliefs and rules that all self-conscious beings must accept–or else. Personally, I find that interpretation of nature unacceptable, if not downright ridiculous. The Godhead does not answer any questions, it just postpones them.
There is an alternative way to invoke the possibility of the role consciousness and intelligence have played in defining the architecture of Nature, from the cosmological to the quantum. Perhaps consciousness or intelligence is a property of the universe itself, as is space-time or matter-energy. Perhaps it permeates everything, as did the ‘Force’ in the film ‘Star Wars’. Scientists today recognize this, and we hear a lot about ’emergent complexity’, the ‘evolution of complex systems’, as if there is something about how the universe is constructed that encourages and supports the spontaneous generation of temporary, local eddies of negative entropy. Right now all this ‘filazawfigal’ hand-waving (to quote Dr Feynman) is just that, sheer speculation. But a lot of smart people trust their intuition and recognize there is something going on, even if they have no clue as to exactly how it works. All they need are the mathematics and the technology to be able to systematically assault the problem.
We do know one thing, at least, due to our experience and history. The universe always surprises us, it always reveals an answer that is much more wonderful and elegant than what we originally expected.
And that answer only brings up an entire storm of new questions that we never thought of before.
Someone “out there” managing things? The only certainties that one has is that one exists and that one is aware. The “am” in “I am”. All else is based on awareness of non-self. Indeed even the “I” is a matter of conjecture.
In the Eastern traditions for those who choose to acknowledge a deity, there is the Self of all selves. For those who decline to acknowledge a deity (Buddhism, Jainism and some sects of Hinduism) the Infinite allows no existence of any finitude. No “non-god” nor “God”. Awareness without an “of” – objectless awareness – abiding in Universal Consciousness is all of Reality.
Hey Jeff I wouldn’t question your intelligence or lack of education. I think many of us have wondered how inanimate chemicals can lead to life by chance alone. As you pointed out the probability looks to be about 0, without some other governing factor, such as some organizing principle inherent in the universe itself. Google’s response to whether intelligence is an inherent or emergent property of the universe is this:
“Whether intelligence is inherent or emergent in the universe is a subject of ongoing debate spanning physics, biology, and philosophy, with strong evidence supporting the view that it is an emergent property arising from increasing complexity. However, recent theories also suggest it may be an inherent, fundamental property of matter and energy that is accessed rather than created.”
If you just google this “Is intelligence inherent or emergent in the universe” you’ll get the AI response as well as a bunch of links with varying opinions for and against.
The AI conclusion was:
“Ultimately, whether one sees intelligence as inherent or emergent often depends on whether one defines it by its most complex manifestations (like human reasoning) or by its foundational capacity to process information and order chaos. ”
If intelligence is foundational and helps order chaos, then maybe our chance of finding other life in the universe is greater than a purely random estimate of probabilities. My opinion is an organizing underlying principle/rule/law/… exists and is necessary for life to get started. Without it, we are left with the conclusion that we are probably alone, probably in the universe, given the miniscule probability that amino acids could ever form a working protein, and then a single cell, by chance alone.
Maybe given enough time, the probability would be reduced, since that 10^160 would be for a particular moment in time, but are billions or trillions of years enough to make the need for an underlying organizing factor go away, so that a single cell eventually will form by chance? I don’t know, but I doubt it.
“are billions or trillions of years enough to make the need for an underlying organizing factor go away, so that a single cell eventually will form by chance?”
That’s the Broca’s brain argument.
Not Broca’s brain, Boltzmann brain.
https://en.wikipedia.org/wiki/Boltzmann_brain
I knew it didn’t seem right when I first typed it in but I failed to confirm before submitting my comment. Reference included for those interested.
Self organizing systems
As a child in the seventies and eighties, I read a lot of science fiction, including much Andre Norton. She also wrote a lot of fantasy. Her sci-fi books usually included the concept of deep time, and the protagonist was often a human stranded on a planet with ruins of ancient civilizations- ones that were dead before mankind ever evolved. (The fun part was their tech still worked!)
@Jason
Where would the stories be if that ancient technology was a non-functional as the Antikythera mechanism? Imagine what a non-story “Forbidden Planet” would be if the Krell machines had died. It would have to be rewritten as a fantasy with magick, rather than as fantasy with imaginary hardware.
If there are “lurkers” out in space, wouldn’t functional ones be more interesting than ones that were irreparably broken and eroded by micrometeoroid impacts and radiation?
Conditions have to be perfect for intelligent life to exist and thrive
– the planet must orbit a stable star in a stable part of the universe where radiation levels are minimal
– a magnetosphere must exist to protect from radiation and maintain an atmosphere
– a planet can’t be too large or escape velocity for travel and satellites will be impossible
Just those 3 conditions vastly reduce the number of locations intelligent life can exist in
@D Wolfarth
I don’t see why this should have any effect on a planet developing an intelligent species. It only reduces the possibility of star-faring species that may be able to colonize new exoplanets.
The boundary zone between molecular cell biology and life
Non-equilibrium thermodynamics
R.D.,
I hear you, so to speak. Maybe 6 months to a year ago, these issues came up before. And it sent me back to the “Physical Gas Dynamics” text we used in grad school back in the 70s. The authors, around chapter 5 set off into statistical mechanics to explain fluid behavior – gas flows largely, and then some time after that a certain Ilya Prigognine, credited in the references won the 1977 Nobel Prize for for his
“contributions to non-equilibrium thermodynamics, particularly the theory of dissipative structures.”
Speaking from a perspective decades later, I admit that I didn’t even realize the significance of the name when I took the course; nor did I find Prigognine’s name in the book until recently. But chemical non-equilibrium related to the origins of life had snuck into an engineering text book
Introduction to Physical Gas Dynamics, by Walter Vicenti and Charles Kruger, Jr. Stanford University, Aeronautics and Astronautics, Mechanical Engineering departments respectively. It would be interesting to have obtained their impressions of Prigognine’s work with regard to non-equilbrium thermodynamics and dissipative structures culminating in life here and elsewhere.
Assuming we are alone because we haven’t found anybody yet doesn’t make sense to me. If we have the capability to survive as an advanced civilization and conduct ever more powerful searches for ET for the next ten thousand years and find nobody it might convince me there is nobody to talk to in our galaxy over that time frame. The ten thousand years is just an example of how big and long I think the search needs to be.
The formulation of questions is essential for advancing problem solving processes. Often, questions are posed that do not address the underlying problem effectively. Surprisingly often, the definition of the problem results in unproductive and/or misdirected efforts.
On its face, the problem appears to be why don’t we hear extraterrestrial intelligent civilizations’ technology? All of this connects to the Drake equation and the well-known Fermi paradox. People sometimes call this ‘listening for noisy aliens.’ Although some might think we have, we have not yet become the ‘noisy aliens’.
We are not aware of any confirmed examples of technologically communicative extraterrestrial life. However, we do have at least one documented instance of life forming and diversifying into multiple complex forms on Earth. Additionally, there are several examples of tool-using intelligent species, although these species are closely related. This form of problem-solving intelligence has a relatively long history across various regions of the planet.
Over the past 12,000 years, multiple civilizations have emerged, advanced toward technological communication, then declined, only for new civilizations to subsequently begin this trajectory. There is no reason that we are aware of why this period of time does not stretch back into many hundreds of thousands of years. This brings up an interesting related question: not whether there have been other older civilizations, but why there have not been others?
As we have at least one example of life and no examples of technology and civilizations, working on this part of the problem seems the more productive path. The questions about life and intelligence, while interesting, are likely misdirected attempts to address the fundamental problem.
This gives the appearance that the fundamental questions should be directed toward technology and civilizations. What about technology either advances or retards a civilization from becoming ‘noisy aliens’?
So the better question here may not be why we not heard the ‘noisy aliens’, but why we are not the ‘noisy aliens’ for some other extraterrestrial civilization?
This will require much more than simple pat answers; instead, a more systematic approach to the fundamentals of technology itself and the resulting emergence of civilization.
The decline of our current global civilization may come fairly quickly. We may just be seeing the beginnings of it now. I think back to my first encounter with The Limits to Growth from the Club of Rome. It struck me as very important and prescient when it came out. They give a general outline as to what might happen which includes overuse and exhaustion of non-renewable resources, pollution, the worry of overpopulation (at the time in the sixties this was indeed happening). They weren’t if I remember right overly concerned about Climate Change but that is obviously coming to the forefront now and driving a host of other problems. Another deeply worrying issue is the re-appearance of fascism in many countries and militarization as if we might be preparing for another world war? It looks very possible. Are we a stable species that will continue to look for other advanced civilizations for thousands of years? Hmmmm.
The assumptions used in the Club of Rome report did not take into account substitutions. AFAIK, it did not assume humanity would use other forms of energy, especially renewables, nor substitute materials that become scarce, e.g. copper.
OTOH, I don’t recall that they worried about water shortages, and as you say. factored in climate change.
I have a book by Donella Meadows, “Thinking in Systems,” on modelling global systems. She was the lead author of “The Limits to Growth”.
@Gary
“They give a general outline as to what might happen which includes overuse and exhaustion of non-renewable resources, pollution, the worry of overpopulation (at the time in the sixties this was indeed happening). They weren’t if I remember right overly concerned about Climate Change but that is obviously coming to the forefront now and driving a host of other problems.“
These are examples of risk, some of which represent cumulative risk factors. Focusing on climate change, it is notable that relatively few absolute facts are established regarding this phenomenon. The most critical point is that climate change is an ongoing process; global temperatures are either increasing or decreasing, and only appear stable during transitional periods. This dynamic characterizes climate change as both a risk factor and a cumulative risk factor. Even with greater knowledge of the factors influencing temperature changes, current capabilities do not permit the undertaking of highly risky planetary geo-environmental engineering projects.
This risk factor can be analyzed in relation to various technologies by assessing which are more susceptible to climate change, which are less susceptible, and which may help mitigate its effects. Technologies that are less susceptible to climate change or capable of mitigating its impacts include the following:
High-voltage direct current (HVDC) long-distance power grids are equipped with advanced control systems.
Small nuclear reactors, which can be located closer to areas of energy demand, can produce both electricity and industrial heat.
Sub-gridding and micro-gridding of the power grid are enabled by the aforementioned technologies.
Expansion into a multi-planetary civilization, particularly at the scale of Type II or Type III.
These systems address underlying challenges by enhancing resiliency through increased excess capacity, thereby supporting growth.
Technologies that are more susceptible to climate change, and therefore increase risk factors, include the following:
Continued reliance on the existing, outdated high-voltage alternating current (AC) power grid.
Terrestrial solar and wind electricity generation is limited by suitable implementation locations and is highly susceptible to environmental changes. This does not include space-based solar power.
These technologies make micro-gridding significantly more difficult and render the entire system more susceptible to various risk factors. They substantially decrease resiliency and constrain growth.
A systematic investigation of technology and the interactions among these risk factors may enable a civilization to identify emerging trends and implement necessary changes in its trajectory before challenges become unmanageable.
This is just a small example, but it gives me hope for a future where we might become the noisy aliens.
Resiliency of power distribution is best served by grid interconnections. Texas is the best example of the consequences of refusing to do that. Subgrids and microgrids may help with outages if the purpose is better control of power distribution, but is the wrong solution if trying to isolate sources of power to smaller areas. Neighborhood grids sound fine in the abstract, but they need to be connected to a larger grid. Apart from isolated communities, what examples of such local grids are there with the needed data to support their use? The only sort-of example I know of is the Palo Alto power supply in the Bay Area. Locally, where I live, there are irrigation and power supply companies. The cost of power is no cheaper than that of the major power utility, although anecdotally, power outages are fewer. However, gas supply for heating and cooking has to be delivered by another means. This may be phased out in California over the long term as decarbonization is the state’s goal.
Small nuclear reactors (SMR) are the worst form of power generation. They are costly and have all the end-of-life disposal issues of GW-scale nuclear reactors. If civilization starts to break down, the land could be littered with aging reactors that are a danger, but without the expertise to locate and dispose of them. If we cannot reliably dispose of spent fuel today, then how would that be solved with SMRs? And all this is before the risks of nuclear proliferation and criminal state and non-state actors.
You do not indicate what global heating effects will impact renewable energy generation systems. Drowned offshore wind turbines? Overheated PV panels? We know what is causing the heating. The solution is to decarbonize energy generation. Renewables are the cheapest and most flexible way to do that, without the risks of the nuclear strategy. Power distribution resiliency helps overcome the local intermittency of wind and sunshine.
Regarding power distribution AC vs DC, there are good reasons to consider before choosing which system. If grid connection is the best resiliency solution, then sticking with one system, probably AC, is the better solution, at least for now. With the proliferation of electronic devices, there seems to be perennial talk of having a DC power supply to a residence. It sounds attractive until one considers the issues that arise, just to avoid “wall warts”.
My comment was not to prove any points, nor to gore any sacred cows. The comment was not intended to start any endless debates, nor was it an invitation to do so.
It merely uses some items to illustrate an underlying concept. The illustration of the underlying concept was the only intent.
Thank you for your thoughtful responses Dean and Alex. I hope governments are conducting the same sort of internal discussions and reviews. One fact is clear. We still burn an enormous amount of carbon the we can ill afford in the medium and long term. Nature won’t care why we burned it. The impacts will be enormous.
Our current global trajectory looks deeply worrying. A number of factors have arisen that may lead to civilizational decline in a very short time frame. Thank you for the fascinating article Eduardo.
Thank you all for these exciting (and passionate) comments of great intellectual richness ; it’s nice to read :)