Part 22: Where Are All The Aliens?
Biology & Survival Series - A Possible Solution to Fermi's Paradox
The math says the galaxy should be crowded.
There are roughly 200 billion stars in our galaxy, a large fraction with planets, and two trillion galaxies in the observable universe. Even under the most conservative assumptions about how often life emerges and how often intelligence follows, there should be millions of civilizations out there. The universe should be loud with them. Radio signals. Megastructures around stars. Probes in our solar system. Visible evidence of galactic-scale engineering.
What we see instead is a universe that behaves as if advanced civilizations are either very rare, very good at hiding, or very short-lived.
Physicist Enrico Fermi noticed this problem in 1950 and asked the question that still haunts the field: where is everybody?
While we do have mounting evidence of non-human intelligence, what’s been disclosed doesn’t come close to what the math predicts.
In 2023, former Air Force intelligence officer David Grusch testified under oath before the House Oversight Committee that the U.S. government has operated a multi-decade UAP crash retrieval and reverse-engineering program, and that “non-human biologics” have been recovered from crash sites. In November 2024, former DOD official Luis Elizondo testified that “advanced technologies not made by our government or any other government are monitoring sensitive military installations around the globe.”
Retired Rear Admiral Tim Gallaudet testified about emails that vanished from Navy servers and a coordinated disinformation campaign to discredit UAP whistleblowers. Journalist Michael Shellenberger reported on Immaculate Constellation, an alleged DOD unacknowledged special access program operating outside Congressional oversight.
In September 2025, active-duty Navy Senior Chief Alexandro Wiggins testified publicly about a 2023 incident aboard the USS Jackson in which a self-luminous Tic Tac-shaped object emerged from the ocean and linked up with three others before disappearing at near-instantaneous acceleration. Congress passed the UAP Disclosure Act. The Pentagon established AARO.
Let’s say this isn’t all a psyop (more on the alien psyop in another article) - even if we take all of that at face value and assume every disclosure is exactly what the whistleblowers say it is, you still have a trickle, not a flood. A handful of craft. A handful of bodies. Some number of objects operating carefully, quietly, and apparently on their own agenda. So few that governments, filled with incompetent bureaucrats, have somehow managed to keep this concealed from the public.
That is not the signature of billions of years of unconstrained civilizational expansion across a galaxy full of habitable worlds. A single civilization 50 million years ahead of us, expanding at a rate our own species could achieve with known physics, would have colonized every star in the galaxy by now. We’d be tripping over their infrastructure. Instead, whatever’s out there seems to be operating at a scale small enough to hide behind government classification.
Something is keeping the visible presence of advanced civilization vastly smaller than naive math predicts. Either life and intelligence are much rarer than they should be, or civilizations that reach our level of technology tend to be very short-lived, or the ones that survive have strong reasons to stay below detection thresholds. Maybe all three.
The standard framework for thinking about this is called the Great Filter: some barrier exists that virtually all technological civilizations fail to cross. The comforting version places the filter behind us. Life itself is rare. Multicellular life is rare. Intelligence is rare. We got lucky.
The uncomfortable version places the filter ahead of us. And if you’ve been reading this series, you’ve been looking at what it might actually be.
The Fork
Every intelligent species eventually faces the same choice. Not a conscious choice, an emergent one. It shows up the moment a species develops enough technology to industrialize, and it branches into exactly two paths.
Path A: Stay planet-bound. Keep your technology below the threshold where you can build things that can destroy you. No synthetic chemistry that wasn’t already produced by biology. No nuclear physics. No recursive self-improving machines. No wireless infrastructure blanketing the biosphere. No industrial food processing. You survive as a species, but you never reach beyond your home planet.
This is the Amish version of a civilization, scaled up to species level. And it’s perfectly coherent. You can run a society this way indefinitely. But you’ll never build a telescope that can see another civilization, and they’ll never see you.
Path B: Industrialize. Build the tools that could eventually take you to the stars. Synthetic chemistry, nuclear physics, computing, biotech, telecommunications. Every one of those tools is also a tool capable of ending the civilization that built it. And the competitive dynamics that drove you to build them in the first place make slowing down irrational for any individual actor within the civilization.
The technology that lets us reach the stars is so fundamentally incompatible with our biology that it destroys it at every level.
I strongly suspect that there is no Path C. There is no “industrialize carefully” route where a species collectively decides to build spacefaring technology without building the destructive technology that comes with it. The technologies aren’t separable at a molecular level. Rocket fuel and nerve agents come out of the same chemistry department. Computing hardware and surveillance infrastructure come out of the same semiconductor fabs. The knowledge that lets you send a probe to another star is the same knowledge that lets you engineer an endocrine disruptor that suppresses testosterone at parts per billion. All technology is a double-edged sword.
Pick Path A and you survive, invisible to everyone else who also picked Path A. Pick Path B and the clock starts ticking on your civilization’s self-destruction.
This is the fork. And it explains an awful lot about why the sky is quiet.
Our Own Fertility Collapse
Sperm counts in Western men are down 59.3% since 1973, per the 2017 Levine/Swan meta-analysis. The decline is now global and has accelerated after 2000, running at roughly 2.6% per year versus 1.16% pre-2000. Whatever’s driving this isn’t slowing down. It’s compounding.
None of this is cultural preference. You can choose not to have children. That’s a decision. You can’t choose not to have viable sperm, functioning ovaries, or balanced hormones. That’s biology, and biology is collapsing. Here’s part 1 of the series that covers the decline:
Part 1: The Countdown to Global Infertility and Human Extinction
In 2017, a team of researchers led by epidemiologists Hagai Levine and Shanna Swan published a meta-analysis in Human Reproduction Update that should have reordered every government’s priority list on the planet. They screened 7,500 studies, selected 185, and analyzed semen samples from
Each biological attack vector is independent and well documented. And each delivers its damage on generational timescales, which means the full consequences of exposures happening today won’t be visible for decades.
Every new technology starts a negative biological feedback loop that takes many years for us to analyze, realize is a problem, and then (usually) fail to do anything about. No amount of public awareness campaigns about glyphosate has slowed down the spraying. Even if one day it does, it’ll just be replaced with another chemical that takes us 30 years to realize is harmful. The wisdom lags behind the technological adoption, and by the time we react, our fertility has already taken a hit. As a species, we seem to perpetually prioritize short-term convenience and addiction over long-term health. Individuals can break the pattern, sometimes even small communities, but species-level the pattern is clear.
This is what the inside of the Great Filter looks like. Not a nuclear flash, but rather a population that gradually loses the ability to reproduce while building its own replacement. The first makes humans extinct, the second makes us unnecessary.
AI - Building Our Own Replacement
As our ability to reproduce as a species is collapsing, AI is becoming a reality, and both of these paths are roughly converging. We seem to be building our own replacement.
AI development has compressed timelines for transformative capabilities from “decades away” to “possibly this year.” Anthropic’s CEO has said AI systems “broadly better than all humans at almost all things” will arrive by 2026 or 2027. OpenAI, DeepMind, and the other frontier labs are building in parallel. The median AI researcher, surveyed in 2023, put the probability of human extinction from AI at 5-10%. Geoffrey Hinton, who won a Turing Award for the neural network architecture that made this possible, now puts his personal estimate at 10-20% within decades.
The AI Safety Clock, launched in September 2024 at 29 minutes to midnight, moved to 18 minutes to midnight by March 2026. The window is closing faster than the people maintaining the clock expected.
What the AI risk debate and the fertility debate share is the same underlying logic: competitive dynamics make slowing down irrational for any individual actor, even when the collective outcome is catastrophic.
Every frontier AI lab acknowledges that slowing down would be better for humanity. None of them do it. The public justification is always the same: “if we don’t build it, someone less safety-focused will.” This may be true. It’s also what every actor says when they’re caught inside a collective action problem closing in on them. This is a classic case of the Prisoner’s dilemma.
The chemical industry says the same thing about endocrine disruptors. “If we don’t make them, our competitors will.” The seed oil industry, the ultra-processed food industry, the wireless industry, the oil and gas industry all run the same defense. Nobody is ever the last hand on the lever.
This isn’t a species of bad actors making bad decisions. This is a species whose societal structure reliably produces civilization-level suicide as an emergent outcome.
The question is whether this is a universal feature of intelligent species? If any sufficiently advanced social species produces the same competitive and collectively self-destructive dynamic - then you’ve found your Great Filter.
The Dead End
The fork isn’t a prediction about the future. It’s a description of what industrial civilization is, at the species-trajectory level.
We appear to be building a civilization that converts biological humanity into industrial output, then builds machines to replace the humans it's burning through.
The biological decline this series has documented isn’t a side effect of progress. It isn’t something that can be fixed by better regulation, cleaner chemistry, or a more enlightened version of the same model. The damage is intrinsic to how the model works. Industrial production generates contamination and waste. Waste finds pathways into biology. Regulatory agencies get captured by the industries they were meant to constrain. Under our current fascistic/corporatist system, competition rewards whoever externalizes their costs most efficiently while passing legislation that protects them from liability. Socialist systems are worse - in those, the government simply directly does what corporations do under corporatism.
It’s arguable that a true free market economy, with full responsibility for consequences, the abolition of limited liability for corporations, and the abolition of governments that protect special interest groups, would yield better results. And of course we’d have to do something with the roughly 4-6% of the population who are psychopaths and sociopaths, the criminals who run the governments and corporations that are destroying our species in slow-motion.
But is any of this achievable, at a species level, before our fertility tanks to zero? I can’t see how. Most people fundamentally don’t want to be free (more on that in a separate series). They don’t want responsibility, they don’t want to work hard. They want junk food, TV, and being told what to do when there’s a crisis. Only a relatively small minority fall outside of this pattern.
This is what makes our current technological path a dead end rather than a crisis. A crisis has a solution. A dead end just keeps being a dead end no matter what you do once you’re in it.
The math of the dead end is straightforward. If the fertility decline trajectory continues, the population reproducing itself shrinks generation by generation. The economic base supporting industrial civilization contracts. The tax base contracts. The workforce contracts. The consumer base for the ultra-processed food, pharmaceuticals, and wireless devices that are partly driving the collapse contracts. The whole system is built on the assumption of endlessly unending consumption - while simultaneously destroying the next generation of the very humans who would be doing the consumption.
Think about what we depend on every day: Plastics. Pesticides. Wireless infrastructure. Industrial food. Pharmaceutical medicine. Financialized economies that require continuous growth. Computers. Just-in-time deliveries. A civilization could theoretically abandon any one of these things. None have ever abandoned all of them voluntarily. By the time the damage becomes undeniable, the civilization is too dependent on the systems causing the damage to give them up.
Have you ever tried showing a friend or family member studies about the health effects of using cell phones? There are hundreds of studies proving that cell phones cause cancer. What do most people do when you show them this information? Nothing. They go right back to using their cell phone as much as before. Nothing changes. They’d rather get cancer in 20 years than reduce cell phone use.
Even if we somehow stop and reverse our declining fertility,
What This Looks Like From the Outside
Imagine observing Earth from a civilization that somehow made it through this filter a thousand years ago and became technologically advanced enough to reach out to the stars, without eviscerating their own biology in the process.
You’d see a planet with a technological civilization advanced enough to detect and reach. You’d also see that civilization’s biosphere degrading on multiple simultaneous tracks. You’d see birth rates collapsing. You’d see chemical load in organisms rising. You’d see infrastructure being built at breakneck pace while the population that built it was quietly losing the ability to reproduce itself. You’d see an intelligent species racing to build more powerful AI systems while being unable to coordinate on even the most basic protections against the biological damage it was already causing.
You’d recognize the pattern. You’d have watched it before, on your own planet, probably. You’d know how it ends.
Would you intervene? Probably not. The damage is internal. It’s being done by the civilization to itself, driven by competitive dynamics no outside force can really alter. Showing up and announcing your presence wouldn’t stop any of it. It might accelerate the collapse by triggering resource conflicts or religious panics. Observing quietly from a distance might be the only sane policy.
Why the Filter Is Invisible Until It’s Too Late
Every other Great Filter candidate has a visible crisis moment. Nuclear war has a flash. Asteroid impact has a countdown.
The slow-motion technological destruction of our own biology has none of these.
Chemical contamination of biology has no sudden crisis. It’s generational, cumulative, and delivered through the same products that deliver the conveniences people want. Your phone isn’t going to kill you tomorrow. Your shampoo isn’t going to sterilize you tomorrow. The Teflon pan isn’t going to give you cancer tomorrow. Each exposure is individually negligible. The damage operates on decade-plus timescales. By the time population-level fertility collapses enough to be visible, the chemical load is three to four generations deep in every body on the planet. Reversing it would take longer than the population could sustain itself.
AI collapse has the same property, different mechanism. By the time capabilities are unambiguous enough that consensus forms around the danger, the infrastructure is already woven into financial markets, critical infrastructure, military systems, healthcare, and scientific research. Pulling AI out would itself cause enormous disruption, possibly as much as the problem you’re trying to solve.
Both filters work by the same trick: they entrench before they’re recognized. The civilization notices the danger at exactly the moment it has lost the ability to respond.
This is also why the filter is hard to describe as a filter while you’re living through it. It doesn’t feel like doom. It feels like progress. The chemicals making us infertile arrived as convenience. The AI that might replace us arrived as productivity. The wireless infrastructure permeating our biology arrived as connection. Everybody chose the products, one at a time, at checkout.
Solutions?
We are probably inside the filter right now, on multiple tracks simultaneously.
The biological track has a 2045 endpoint where median Western sperm counts reach zero if the trend continues unchanged. Shanna Swan has been careful to call this an extrapolation, not a prophecy. But the decline hasn’t slowed, it’s accelerated. Long before the math hits zero, population-level fertility falls below the point where natural conception is reliable for most couples. We may already be watching that happen with the rise of IVF.
The AI track has a comparable timeline. Serious researchers put the window for transformative AI capabilities - the kind that might pose existential risks - somewhere between 2028 and 2040. The upper end of that range overlaps with the fertility endpoint. Both tracks converge on the same generation.
The generation that, right now, is least connected to what being human is. The people spending 8+ hours a day on their phones, doom scrolling and watching porn. The people who have probably never touched dirt in their lives. Will these people wake up and do something in time? Will they rise to the occasion? Or will we all fade into obscurity?
I think human civilization will bifurcate into two groups. Part 17 addresses this.
At the end of the day, we don’t need to save all of humanity - in fact, I think we’re well past doing that. What we need to focus on is what we can actually do - real actionable steps. They start with you - as an individual, or your family unit - deciding to exit the system & build resilient alternatives. In the final part of the series I will discuss the blueprint for human survival.
This is Part 22 of the Biology & Survival series, which covers the science showing that by 2045 the average person will become infertile, and explains all the reasons why, so that you can protect yourself, your children, and your grandchildren.
