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Beyond “Fermi’s Paradox” XVI: What Is the “Dark Forest” Hypothesis? (universetoday.com)
178 points by Hooke 14 days ago | hide | past | favorite | 320 comments

To me the most likely back of the napkin answer to the Fermi paradox is that aliens are elsewhere in time. The Milky Way galaxy is about 100,000 light years across but about 13.5 billion years old. So it’s like 135,000x deeper in the time direction than the distance direction.

We’re in the light cones of all the stars we can see, and as far as we know, we can’t get out of them. If a civilization ended even 100 years earlier than our equivalent “now” in their light cone, we wouldn’t have seen them. And if they became visible even 1 year later than our equivalent “now,” we would not have seen them yet.

We’re proceeding through time at 1 sec per sec and basically if we’re going to see an alien civilization at this point, I think the only way would be if one happens to achieve the necessary technology to be detected while we’re looking at it. If there were existing civilizations that were easy to see, we would have seen them already.

I think it’s far more likely we will confirm alien life first by indirect means, for example spectroscopically detecting free atmospheric oxygen on an exoplanet, or finding tiny fossils on Mars.

This is the L constant of the Drake equation. Probably the hardest to find a value for until we've actually discovered other intelligent life or remains of such. The confounding part of it is that we can only guess at things that may end a civilization so completely that it will never recover. Things like the so called Great Filters, natural extinctions like impact events or gamma ray bursts, or other more speculative things that prevent expansion. The tricky part is that our existence seems to fly in the face of such events so far, is that mere luck or do all forms of intelligent life have enough sense to navigate around these problems? The last and most paradox defining part of the problem is that even if the tiniest fraction of civilizations can evade these filters then they should eventually be everywhere in the galaxy. Assuming the Copernican principle that we are not at a special place in the universe or time then there should have already been ample opportunity for such civilizations to develop and hence Fermi's question "Where is everybody?".

> Great Filters, natural extinctions like impact events or gamma ray bursts

you know what really alarms me? these things are only chances on a very, very short-time scale. they are inevitable, yet no one seems alarmed when meteors come between us and the moon and we dont see it coming until hours beforehand.

sun bursts blowing out the electric grid, nuclear war, antiobotic resistance, crop and animal monoculture, climate change, natural resource depletion... taleb is right. we need an agent of chaos to make anti-fragility valuable. otherwise we learn the lesson the hard way. by dying.

I think people are alarmed, but solutions to these problems are enormously costly and largely fictional. The techniques we have for living in space (or transiting through it) would not sustain us if we lost earth. They are enormously costly[1], which is fine for what we are doing, but we need multiple orders-of-magnitude improvement to be practically interstellar.

On balance, I think we could spend more, but I also think diminishing returns is very real. Giving the wright brothers 100,000 workers to build copies of their planes would not have gotten us to the space shuttle much faster. Ironically, it could have slowed us down because of sunk cost fallacies.

[1] https://twitter.com/sim_kern/status/1411304471934685184

> I think people are alarmed

I think your view is skewed. Every single person I've talked to about this as looked at me like they are bored. Of course, here on HN, I've found many like-minded people. That's great, but I think very few humans, especially humans in the power structures that run this planet, care about this issue.

I think that's a pretty healthy reaction, pretty much all of human history took place in an environment where investing time an energy in thinking/caring about "the big picture"/"distant future" would drastically lower your chances of survival. Even today there's still plenty of people who have to worry about having something to eat tomorrow.

We're slowly getting comfortable enough about our immediate situation, leaving room to start thinking on a bigger scale. But I think it takes actual effort to say: "ok brain, I understand our immediate situation is important but I think we've got that covered enough to allow us to start caring about the less immediate problems we might face"

I'm a glass half full guy so maybe it's naive but I think we're actually doing pretty well. Climate change sucks and we're pretty slow to respond but you wouldn't expect a hunter/gatherer to be able to see the importance of fighting it. Our situation is different but the brain isn't all that different when it comes to prioritizing things to spend time/energy on. Obesity is a good example of what happens when you combine ancient instincts with modern situations.

Same thing probably goes for racism. We're advanced enough to know better and responsible for our actions but we're dealing with a brain has evolved mostly during times where trusting other tribes and survival of the fittest were Incompatible. Xenophobia had some evolutionary benefit and now we have to deal with it's existence in a vastly different situation.

Like I said, people should know better and have to be held responsible for their actions and we should never be comfortable with the slow rate of change. Still I like to remind myself every now and then that its amazing how much progress has already been made changing things that evolution hasn't had time to value yet.

This turned out way longer than I expected but it's something I think about a lot. Hope you don't mind me using your comment to finally put some thoughts into words.

> I think your view is skewed

I suspect it's more that we have different definitions of how widely a feeling of alarm should spread before saying this. I agree the absolute number of people who are worried about the problem is small.

I guess I think about it in terms of "what proportion of the population that would be directly involved in solving this problem"? I would suspect that is close to 100%. Anyone involved in space work is aware that we may we wiped out and would not like that to happen. Government leaders are also, I think, aware, but unconvinced that more resource expenditure would be meaningfully helpful. Given how difficult it's been to convince people to deal with a much cheaper & easier problem that is much more obvious and immediate (global climate change) I have trouble critiquing people for being insufficiently zealous about this issue.

I think there's a correlation between the age of politicians and how much they care, and we have far too many old politicians. (I'm old, btw.) We need more young people to get involved and get into positions of power. They have a vested interested in seeing solutions implemented, rather than the current crop who know they'll be dead when the real shit hits the fan and they're just letting things stay as is, because they want to maximize their benefits between now and death.

Related to this age observation, I happened to be listening to a recording of Anand Giridharadas speaking in Seattle about how technocratic, engineering-oriented, "rational" mindsets (like most of the people here, like the people who work at tech-influenced foundations) very often do not understand or apparently don't consider the power component of their policy or solution efforts. Net net, more young people in power and more understanding of the power dynamics in society might go a lot farther in getting the "right thing" done.

To e40's point, sadly, when Anand asked the audience how many would be willing to commit to getting involved in the then upcoming election, it was a small minority despite generous applause at other points in his talk about effecting societal change. And this was for local changes in taxation if I recall correctly. I'm guessing they were mostly "old" and have their life's effort to lose in the latter halves of their expected lives.

This is where technical solutions seeking wide societal traction need a helping hand from that other side of our brains that relate to stories, myths, meaning, and purpose.

> you know what really alarms me? these things are only chances on a very, very short-time scale. they are inevitable, yet no one seems alarmed when meteors come between us and the moon and we dont see it coming until hours beforehand.

That is why Elon is so hell bent on making humanity multi planetary.

Carl Sagan had a similar take. From Pale Blue Dot:

> These are the missing practical arguments: safeguarding the Earth from otherwise inevitable catastrophic impacts and hedging our bets on the many other threats, known and unknown, to the environment that sustains us. Without these arguments, a compelling case for sending humans to Mars and elsewhere might be lacking. But with them—and the buttressing arguments involving science, education, perspective, and hope—I think a strong case can be made. If our long-term survival is at stake, we have a basic responsibility to our species venture to other worlds.

Elon Musk has the same chance of making humanity multi-planetary as the Pharaohs did. We are still far away from any semblance of a chance to do so.

Besides, anything at all that we can imagine hitting the earth (except a gamma ray burst or collision with another planet) would still leave the earth in a better shape than Mars is. It's entirely doubtful that humanity could be self-sustaining on Mars even in principle, it is certainly not possible with known technologies.

>It's entirely doubtful that humanity could be self-sustaining on Mars even in principle, it is certainly not possible with known technologies.

Citation needed.

What's the blocker here?

Energy production on Mars? Why not Solar or Simple Stirling Engines.

Food/Closed ecological systems? Hard, for sure yeah, but even not particularly well funded small ecosystems like Biosphere2 worked for several years.

The biggest issue seems psychological.

For a self sustaining colony on Mars you need to span a huge part of the Martian globe to get access to enough raw materials to build things like the microprocessors required for basic life sustaining devices.

But the more you scale to reach the required resources, the more of those resources you will need - especially when you'll more or less have to tunnel your way everywhere if you don't want everyone to die of cancer in their thirties.

And one of the biggest potential limiters is water: we don't actually know how much water there is on Mars. The reserves we know for sure exist at the poles are somewhat small, and it's hard to say how much of Mars' ancestral oceans froze and how much were boiled away and carried off into space along with the rest of its atmosphere. All of the water is frozen (very hard to extract) and likely full of corrosive salts (very hard to separate). Water used in industrial processes is going to be very hard to recapture, and water that evaporates is likely to be lost forever to space (slowly but surely).

You'll also need massive ecosystems to sustain an industrial chain with 0 access to fossil fuels, since you'll need to be able to produce bioplastics and biofuels in addition to food. Again, you'll consume huge quantities of water to achieve this.

Finally, energy production will be extremely difficult, as solar panels are extremely inefficient, efficient forms of solar require boiling water compounding your water problems (and so does nuclear), and both wind and solar of any kind will have massive dust problems, probably insurmountable with today's technology.

I appreciate the thought you put into this response. You make good points.

>For a self sustaining colony on Mars you need to span a huge part of the Martian globe to get access to enough raw materials to build things like the microprocessors required for basic life sustaining devices.

I don't see any reason that microprocessors are required for basic life sustaining devices. They are certainly convenient and valuable. Even if there were required, a simple microchip fab is a known technology. Expensive but does not require new technology.

An interesting question here is how big such a colony needs to be to be self-sustaining.We have clear answers because our present complex Terran economy assumes a planet wide network of trading industrial economies. Perhaps other, smaller solutions exist but we haven't bothered exploring them here because there is no market for it on Earth. Then again I suspect that as long as Earth has an industrial space faring civilization, there will be continuous trade between Earth and Mars. We might not be able to determine how self-sufficient Mars ever is because trade between Earth and Mars may never be shut off.

>And one of the biggest potential limiters is water: we don't actually know how much water there is on Mars.

I agree with you here and it is important point. If it turns out that extracting useable water on Mars is exceptionally difficult, a self-sustaining Mars colony is much harder to create. However we don't really know how true this is. This degree of uncertainly does not support the statement given earlier that "it is certainly not possible with known technologies."

>You'll also need massive ecosystems to sustain an industrial chain with 0 access to fossil fuels, since you'll need to be able to produce bioplastics and biofuels in addition to food. Again, you'll consume huge quantities of water to achieve this.

Yep, strong agree this is why most of these architectures assume large quantities of usable water. I wonder when we get the answer to this question?

>But the more you scale to reach the required resources, the more of those resources you will need - especially when you'll more or less have to tunnel your way everywhere if you don't want everyone to die of cancer in their thirties.

You tunnel for living spaces, you tunnel for resources, a self-sustaining Mars colony will likely require a sufficient investment to get going. Part of that investment will be in energy used for tunneling. Light weight nuclear batteries and generators. Bootstrapping a self-sustaining Martian colony would be extremely difficult but taking a dependent colony and growing it to a self-sustaining system seems easier.

Probably the longer Earth sustains it, the cheaper it will be to become fully self-sustaining.

>Finally, energy production will be extremely difficult, as solar panels are extremely inefficient, efficient forms of solar require boiling water compounding your water problems (and so does nuclear), and both wind and solar of any kind will have massive dust problems, probably insurmountable with today's technology.

I don't know the science but I would assume wind is out because of the thin atmosphere. Solar might be inefficient but how much electricity do you need? I suspect you want to build farms and living spaces that can survive at least a few days to a few weeks without electricity. Low electricity usage and dependency is probably a critical component of robust martian colony architectures.

You can run nuclear on things other than water. US and Soviet Submarines use liquid metal cooled reactors [0]. Why not run underground breeder reactors on Mars, if something goes wrong collapse 5km of soil on them?

While I think fusion is going to play a big role on Earth, I suspect it won't be well used on Mars for a while due to its inherent complexity and dependence on rare materials.

[0]: https://en.wikipedia.org/wiki/Liquid_metal_cooled_reactor#Pr...

> What's the blocker here?

Human nature, apparently. Just about all large-scale human activities at the moment are predicated on exponential growth. We're nowhere near achieving a long-term stable steady-state here on earth. The odds of achieving that in a vastly more hostile environment are even lower.

Will there be simple jobs on Mars base? Someone to sweep the floor, someone to bake a cake, etc? Will they produce enough value to justify enormous resources to keep them alive in such hostile environment?

And even people with important jobs, they would work maybe 50-60 hours a week, but consume resources 24/7.

On average, the value all humans produce in a week might not be enough to keep them all alive for a week.

> What's the blocker here?

To me the likely blocker is reliability/accident.

Most places where humans are on Earth, if one piece of equipment fails (say the engines fall off of your passenger plane while you're over the ocean), you survive and carry on for at least days. In space or on Mars, you're dead in minutes.

Well, but Pharaohs couldn't shoot a car into space.

I don’t think Elon could build a pyramid. He might be capable of tweeting about one though.

He could certainly get a pyramid built. And that is the best you can do.

Elon Musk will use child slave labor to build a Pyramid.

> The tricky part is that our existence seems to fly in the face of such events so far.

We've only been here for a few minutes. We aren't really making any efforts to save the planet or colonize space. It's totally possible that we will wipe ourselves out before our TV and radio signals ever make it far enough to be detected by aliens, even if there are a ton of them out there.

There's the other end of a technology curve, when a civilization ceases use of an outdated piece of technology. In our case humanity is looking for radar because we're currently broadcasting it. Why would anyone continue using radar to communicate within a few years of quantum entangled data processing, capable instantly transmitting data instantaneously across vast distances? There might be a few living that rock star lifestyle of HAM radio operation and messenger pidgeons, but at that moment our civ would go narly completely dark to our sister civ's SETI program. All humanity's existence so far has been nothing but spark swallowed up by the darkness of time. Our use of radio a fart in the wind.

This theory is incredibly type-zero-civ-pocentric. A species capable of interstellar travel will have mastered technologies we can't even comprehend. By the time humanity is able to meaningfully reach across the stars, we'll have spread life across our entire solar system and everything we'd ever need. Unlimited energy from our sun, a lush and verdant Venus and Mars, mining colonies across the solar system producing vast quantities of any desirable element, not to mention an Earth whose biosphere is a shining jewel - perpetually locked-in at peak biodiversity.

Begs the question of what we would ever need from another civ, and furthermore what a similar civilization would ever want from a bunch of squatting troglodytes such as ourselves.

This assumes that QM (and/or our current understanding of it) is the ultimate explanation of how the Universe works.

> Begs the question of what we would ever need from another civ, and furthermore what a similar civilization would ever want from a bunch of squatting troglodytes such as ourselves.

The need to fight loneliness and to find a kindred spirit?

That and the fact that civilizations probably only broadcast EM radiation out into the void for a short period of time before they start getting into energy efficiency and switch over to more efficient communication technologies.

Even broadcast emissions aren't detectable at long distances. If you parked an Arecibo-class telescope in orbit around Alpha Centauri the only signals you'd detect coming from Earth would be intentional directional transmissions from an Arecibo-class (or Goldstone class) radar.

Our television and radio broadcasts aren't detectable by an Arecibo-class telescope out much past Jupiter let alone outside the solar system. Even our high powered radar systems wouldn't be detectable out even half a light year from the solar system.

The only civilizations that can be detected with a SETI-like program would be ones intentionally transmitting directional signals. Even then out past a thousand light years even a multi-terawatt (EIRP) signal would be difficult to detect.

Like inverse square law is as unforgiving as the rocket equation. Anyone hand-waving either of those principals is not trying to have a meaningful discussion about interstellar communication or travel, they're just writing about science fiction.

> Even then out past a thousand light years even a multi-terawatt (EIRP) signal would be difficult to detect.

Not necessarily. Gravitational lensing may enable directed communication at much lower power levels : https://storkpaulo.wordpress.com/2010/04/26/gravitational-le...

Leaving the serious engineering difficulties involved in a solar gravitational lensing system aside, such a system doesn't necessarily help in picking up just random omnidirectional broadcasts from an ETI.

Say we had an SGL telescope positioned such to image an Earth-sized planet we know is in orbit of Alpha Centauri A. For ease of math we'll say this Earth sized planet is at a distance such the solar constant is the same as Earth. So that's a total power received from the Sun of 1.74x10^17 watts and with the Earth's mean albedo of 0.3 about 5.22x10^16 watts being reflected off into space.

We can use our SGL to image the planet around Alpha Centauri because it's reflecting 52.2 petawatts of sunlight out into space. So it takes the power of a star reflecting off a disc with a cross sectional area of 1.26x10^8 square kilometers for a proposed SGL system to detect and image a planet.

The amount of power an omnidirectional antenna can possibly emit is somewhat less than 52 petawatts. Broadcast antennas output at most a few megawatts EIRP because there's no utility in blasting out hundreds of megawatts for terrestrial transmission. Such broadcasts just aren't going to be detectable even with gravitational lensing from our Centauran neighbors.

Nor are gravitational lenses terribly useful for beacons since you need the right geometry between the sender, star, and receiver to use the lens. You could use lensing to increase the EIRP of your transmission but only at a specific target. Nobody outside the focal plane of the lensing system is going to benefit from the lens.

SGLs are a neat idea and an interesting topic but I don't think they solve many SETI problems.

This is my theory.

You look at human civilization and that's exactly what's happened. We started off by broadcasting everything as loud as we could (which isn't very loud) and we've slowly transitioned to signals that are both quieter and don't really survive escaping the atmosphere.

I can't imagine an advanced species wouldn't follow a similar communications path. The only way we detect them is if they specifically target our spot in the sky with focused EM for a very long time, generations! After all, they have no clue when we would be in our evolutionary path.

And for that to happen, the species would have to first find us. Not just find us, find us while we are still listening.

And this is all with the assumption that FTL communication/observation is even a possibility (It likely isn't).

IMO, the simplest answer is that FTL communication and travel is impossible. Advanced civilizations across the galaxy have all come to the same conclusion.

We might be able to explore our own neighboring stars throughout generations but it's unlikely we'll be able to ever send a message to another civilization that will get there while they are listening (without spending huge amounts of power).

But if you pursue an evolution over millions of years, at some point we'll have to miniaturise. Imagine we can make fully conscious silicon - let's say in 200 000 years (6500 human generations). At this point, we'd be tempted little by little to raise them as our intellectual children and find less and less need to make them with sperm and vagina.

After a long while, there might be this great replacement, totally peaceful, that would lead these conscious organisms with a vastly superior intellectual efficiency to probably become very small and self centered and not behave like the territorial monkeys we are. What do you think a massively singular electronic intelligence will think when it notices a planet like ours ? "nuke them all and rape their women" ? This is monkey behavior that we still haven't fully shaken up.

I have heard (can’t remember the source) that radar, especially military radar, continues to be a significant source of artificial-looking EM radiation leaving the Earth, even as radio and TV broadcasts have declined in power.

When we grow up and stop wasting so much money, time, energy, and resources on blowing each other up, then we will turn military radars off also.

If true, that ends up meaning that alien civilizations are short-lived, right? That doesn't bode well for us.

Short lived on those timescales, yes. But not necessarily short lived in terms of our perspective.

If we imagine that in the last 5 billion years, there have been a good solid 10,000 post-industrial civilizations, and each of those civilizations has lasted 10,000 years (in the post-industrial stage where they're detectable), then that implies that of the last 5,000,000,000 years, 100,000,000 of them have been host to a post-industrial civilization: a given year has on average 0.02 currently present civilizations in it.

Now, this hypothesis does probably imply that significantly interstellar civilizations are impossible, since it seems like if you've colonized say 20 stars, what disaster could possibly end your civilization?

(I think the most likely scenario is that we're the only civilization ever to have developed in the Milky Way. Everything else seems like it assumes a lot of additional stuff.)

> if you've colonized say 20 stars, what disaster could possibly end your civilization?

Unfortunately, war with another civilization.

I mean, maybe. Honestly hard for me to imagine war actually going on between two interstellar civilizations. But even if it did, it seems like in 99% of all cases, that would leave at least one of the two civilizations still around. We're looking for explanations, in this hypothesis, that leave 98% of all time with no civilizations.

Maybe war between two spacefaring civilizations is too "easy". eg something like: throwing asteroids at ~the speed of light is necessarily a cheap thing to do once you're at that level, and everyone just dies.

Like if on Earth nukes were something everyone could cook up in their backyard in an afternoon, we'd all be gone pretty quick.

Not sure that really makes any sense though.

> Maybe war between two spacefaring civilizations is too "easy". eg something like: throwing asteroids at ~the speed of light is necessarily a cheap thing to do once you're at that level, and everyone just dies.

The Killing Star[0] and Flying to Valhalla by Charles Pellegrino are based around the idea that it's natural for a species to annihilate all other sentient species. The characters define three rules that an alien species may be operating by.

Rule 1. Aliens will believe their survival is more important than our survival.

Rule 2. Wimps don't become top dogs.

Rule 3. Aliens will assume that the first two rules apply to us as well.

[0] https://tvtropes.org/pmwiki/pmwiki.php/Literature/TheKilling...

Given the relative emptiness of observed space, im not convinced that a civilization A would try to annihilate all life but would maybe war with others in their light cone who threaten civA goals/expansion. If you can traverse interstellar space you can probably make home most anywhere further reducing the amount of potential conflict.

How likely does it seem that if you can traverse interstellar space, your civilization splinters over time and your potential for internal conflict just grows without bound?

If you can traverse interstellar space you are pretty much required to "live off the land" as you go and especially so once you reach your destination. This means you possess the ability to produce all of the energy, food, material, etc. required for a civilization to exist from what is present in either interstellar space or a solar system. If we put our sci-fi hats on we can imagine a perfect system of recycling and matter conversion that can keep a massive generational ship functioning with the only input being hydrogen scooped from the space it crosses. If you possess that level of sophistication then you really could live anywhere. That gives you plenty of living space with little motivation to pre-emptively attack others.

Spoilers for The Dark Forest and The Remembrance of Earth's Past Trilogy below.

In the book that the OP article is based on, humanity is doing anything and everything to prevent/defend themselves against an alien invasion happening ~400 years in the future. The character who coins "Dark Forest" theory in the book proposes sending a 'spell' (just a signal containing coordinates) to a nearby star, which is then amplified throughout the universe via "Sci-Fi science". This reveals the location of the star, and shortly after the star is destroyed by some comet-sized object moving at the speed of light. It's later revealed that some other civilization listens for broadcasts on every spectrum, decodes them for coordinates, then destroys the ones that seem to have actually been sent by intelligent life.

I thought this made perfect sense - why wouldn't another intelligent species do this if they possess the technology? I personally agree with "Dark Forest" theory and think that we should /never/ make first contact (lest we are destroyed), but if we were to attempt first contact, we should at the very least have a weapon like you described available to us first.

> why wouldn't another intelligent species do this if they possess the technology?

I think the only question we can ask here is "Would we do this if we possessed the technology?". We only have ourselves as an example of intelligent life.

You may be on to something there. Nukes aren't something that you can cook up in your back yard yet but it seems inevitable that at a certain level of technology they will be. The same is even more true for biological warfare.

Society probably only functions below a certain level of technological advancement before everybody dies to an onslaught of engineered diseases.

If the stars are reasonably close together a supernova would do it. Even a relatively distant supernova (like 30-40 light years) would likely render most planets inhabitable for a long time.

But maybe war is a territorial animal's instinct and once we have shaken up a bit more of our animality, we'd understand this makes no sense ?

If we can control resource, exchange knowledge and techniques, and reproduce automatically (for instance if we become small electronic machines rather than the current inefficient chemical process we are), "war" might probably sounds both ridiculous and totally ineffective, both to cull us if we're abstract enough, and to cull potential enemies, probably just as impossible to reach "physically".

OTOH animals evolved those instincts because they worked in the game-theoretical circumstances that competition with other animals.

Perhaps we can shake off many emotional components of war (which would make war an irrational option in many of the cases that our monkey brain would have been dragged into) but that doesn't necessarily mean that war itself would be eradicated

Animals are stuck in local maxima (betrayal in the Prisoner's Dilemma). A more evolved group might discover and be able to reach the global maximum (solidarity in the Prisoner's Dilemma). Imagine if tigers or sharks developed pack hunting, or the octopus became more pro-social.

Also, multi-species symbiotic relationships are quite common in the animal kingdom. It would be surprising if that weren't true at other scales (and if it were limited to the sci-fi trope of "worker species, soldier species, leader species").

I'm not saying it's not possible to find other equilibrium points. I'm just pointing out that there are more fundamental forces at play and it's not just because of our "monkey/animal brain".

Selective pressures that permit the emergence of cooperative behaviour require participating individuals to exhibit a variation in behaviour and those who cooperate result in having a higher fitness in the environment than those who shun cooperation. The selection effect operates on over the whole population and over times that are longer than the life span of an individual.

An individual that is implementing what ultimately will emerge as the winning strategy, may on average be better off, but it can (and it will) be also often worse off.

Depending whose existence you're optimizing for (individual or species) changes the framing of what is the optimal strategy.

An existential risk for a species changes the framing of what is rational to do quite a lot.

Ours always rot from the inside out.

> if you've colonized say 20 stars

This is the sticking point for me.

The rocket equation, energy being quadratic with velocity, and the impossibility of perfect efficiency (and, possibly, limits on material properties) constrain speeds.

That means it takes a long time to get between stars. A long time.

Which means if you venture between stars successfully, you're adapted for life in interstellar space. If that's the case, why would you go down the gravity well? There are lots of asteroids and comets to use in Oort clouds and between stars, and those down-well enviroments are hostile.

Carl Sagan thought this, though he lived during the cold war so it's not surprising he did.

Considering where climate change is heading, it's surprising anyone doesn't think this.

Climate change is very real and worth addressing, but it's extremely unlikely to wipe out human civilization. It's just going to be costly and kill millions, not billions.

Climate change by itself could be extremely unlikely to wipe out human civilization but it could be the catalyst that sets other events in motion like nuclear war.

Extremely unlikely to wipe out all humans. I agree. Current civilization, I'm not so sure. For the reasoning: https://www.youtube.com/watch?v=IESYMFtLIis

I wouldn't say it's extremely unlikely. Maybe not the primary effects won't kill us. But when nations start to struggle with the primary effects, the resource shortages are going to cause conflict - which will almost certainly lead to wars, with these weapons, which will kill billions.

Can you clarify what you mean by "millions"? The Syrian civil war is estimated to have killed just short of half a million people. The pandemic easily has a global death toll of roughly 4 million people so far. The Chalisa famine of 1783/1784 is estimated to have killed 11 million people. The Spanish flu killed at least 17 million people, though some of the more dramatizing estimates place it closer to 100 million. According to some researchers, climate change is already killing 100,000 a year[1]. So I assume you're not thinking of just seven or eight digits unless you're exceedingly optimistic.

Climate change will make parts of the world inhabitable that are currently populated by humans. It will also result in crop failures, which will cause famines. In some cases formerly native crops will no longer be supported by the changing local climate or farmland may become completely unusable. Potable water will become harder to source. Water contamination is a source of many deadly diseases.

Even if we assume most of the deaths will be concentrated in places like Africa or the Indian subcontinent, the global economy relies on these places for resources and cheap labor. People in ongoing climate catastrophes also don't tend to stay put and die in an orderly fashion, they become refugees or riot against their governments. Things can get politically messy even in the nations next door as humans tend to be uncomfortable with political chaos and mass deaths.

But unlike the Spanish flu, or the potato famine, or COVID, climate change is not a temporary blip that happens and then goes away. If all the carriers of the plague have died, nobody dies from the plague unless they get infected handling the dead. Famines can starve millions to death but once there's another harvest the survivors have food again. Climate change isn't like that. If climate change creates a drought, that's not just a drought, that's now dry season and it will be dry season every year from now.

There are currently 7.8 billion humans. There's absolutely no reason to believe climate change can't kill billions, especially once it's managed to kill the first hundreds of millions.

Keep in mind that it's not about "addressing" climate change. It's not a moldy bathroom tile that you need to clean up or replace before the mold spreads everywhere. It's a fire our entire way of life is fueling every single day. We know what needs to be done to slow it down to survivable levels (or at least levels that are lethal for less than 1% of us) but we can't just pass legislation or appeal to personal responsibility to do that because it involves changes that would be economical suicide for anyone doing it alone. The world economy is playing a game of chicken with each other and nobody is bluffing.

[1]: https://grist.org/climate/how-many-people-has-climate-change...

New equilibriums will form. Where it was once one climate, another will be, and the native crops that can no longer live in the first climate will be supplanted by new ones that can survive in the new one. This won’t be the case everywhere, but this sort of adaptation will happen. You’re talking as if everything will remain static except the climate.

Additionally, the entire worlds population at relatively sparse city density (say, Houston) can fit in like 1/3 of the United States.

That isn’t to say that climate change isn’t a big deal. It is one of the biggest deals and quite grave. But you don’t really propose any solutions. What you allude to though won’t happen, that everyone works together to address the issues. My speculation is that if our technology doesn’t progress fast enough, billions will die, but if tech does happen to progress fast enough then that will be mitigated.

That isn’t to say that the world couldn’t use a strong reduction in population. But given that we are causing this, I feel particularly bad for the wildlife whose habitats will be unlivable to them through no fault of their own and not through natural processes.

Climate change doesn't have to directly kill us all. It could be the trigger to something else that does.

I agree in our case but this wouldnt be universal. Life may thrive in very hot planets if their evolutionary track was different.

Civilizations are only detectable for a short period of time. Once they understand physics, they no longer need radio waves or Dyson spheres or to travel through what we call spacetime.

Why wouldn't they need megastructures and travel once they understood enough physics?

Space and time may be emergent, we don't know, all we do know is that our current model of physics is missing something. Quantum Gravity for example and We don't know what happens inside a black hole either.

That’s a non-answer though.

Do you mean they are guaranteed to discover another “realm” and move to it?

Why? It might not be possible, no matter how much physics one knows. Or do you take the Fermi paradox itself as a proof of the solution?

Yes, it seems that the Fermi paradox implies that other civs progress beyond what we consider signs of intelligent life. The great filter seems less likely as we get close to colonizing other planets, and then other solar systems.

I question your use of "implies" there. It implies no such thing. What you suggest is one possible answer, nothing more.

Yup, to me it implies a darker problem, that FLT is something that can't be surpassed. All civs might advance to that understanding and decide to maybe just occupy nearby solar systems and nothing more.

We may not talk to them simply because it's both incredibly expensive and will yield nothing more than "Yup, we're stuck here, so are you".

Why wouldn't they send out autonomous research/exploration vessels? At a sufficient tech stage it's trivial.

Sure, they could, but imagine they are 10,000 light years away. Such a craft would need to travel for a long time before it could communicate back it's findings.

Read more about the Great Filter, it's probable it's ahead of us.

is it _probable_?

AFA we know we've been insanely lucky up to this point (as earthling life we went past multiple mass extinctions, we got multi-cellular life, multiple brains iterations, a society which still didn't wipe itself out etc)

What makes it more likely for the filter to be ahead of us rather than behind us?

Is it more likely that I’m immortal or that I simply have thus far avoided things that would have killed me?

You know that most people are not immortal, but if you had no prior about the mortality of mankind it would be reasonable to expect you're immortal.

Few people expect to die at any specific day, they just know they will die at some point because mortality is a given.

Modern civilization is extremely dependent on fossil fuels. We've already passed peak conventional oil production, and we're now surviving on EXTRAORDINARY technical means of enhanced oil recovery.

If we can't make the complete transition to renewables in the next thirty years, it's game over for a VERY long time. Future civilizations won't enjoy the benefit of Spindletop. Cheap energy sources won't be available near the surface of the crust for another > 50 million years.

We won't go extinct, but it will be the 18th century for a very long time and nobody will leave this rock during that time.

The Great Filter is right here, in front of us, in our lifetimes.

> Cheap energy sources won't be available near the surface of the crust for another > 50 million years.

Wrong. We already have one: nuclear energy.

That's a good point. It's pretty easy to construct and maintain fission reactors without fossil fuels. I bet enriching uranium was a snap in the 18th century, too. It will be even easier even getting to the enrichment phase in the future, with accessible ores about 30% as rich as they were when the nuclear age began.

Looking forward to the fleet of electric concrete trucks carrying electrically-manufactured concrete loaded with batteries that were produced with lithium carbonate dug out of the ground by electric excavation rigs.

All of this construction work will also not be disrupted by any social unrest resulting from 3 billion people starving to death because the Haber process no longer has enough cheap feedstock to sustain modern agricultural processes.

Thanks for educating me.

Your snark is misplaced. All of the issues you raise apply to any source of energy, including "renewables". The difference is, "renewables" (a) are not controllable, and (b) don't have nearly enough capacity to support a global civilization. And if you're worried about social unrest, by far the best way to ensure it is to refuse to make use of an obvious source of plentiful energy to help maintain and improve people's standard of living, and instead insist on keeping billions of people in poverty in order to satisfy your ideological preconceptions.

We're on a steady path to extinction, no doubt.

Sure eventually, but there's no clear indication if that's 10 years away, 10 billion years away, or a mere technicality as our descendants evolve into something that counts as a separate species.

We're currently undergoing the largest mass extinction event that will easily rank in the top 6 of life on this planet and could possibly compete with the end-permian. What makes you think we could possibly survive? Because we're the cause? Plenty of species in the past that have caused extinction events also perished.

It seems far more questionable to assume we won't risk extinction in the geological near term. The parent is downvoted more out of existential fear rather than an honest assessment of the situation.

I think the parent comment was downvoted because it's not really contributing anything besides pessimism.

As for us, I don't doubt the likelihood of a serious mass extinction, including possibly a severe drop in human population, but I can't see it being so severe as to cause an existential threat to us. No other species on this planet has had the ability to change the environment to suit it, or the ease of mobility to move where they can survive. Short of earth being entirely incompatible with complex life on the surface, I don't see humanity disappearing because of climate change.

We need the pessimism. Irrational exuberance clearly doesn't work.

I have never seen anything remotely resembling exuberance around climate change. Everything I've seen is either pessimism or denial.

I'm talking about much more than climate change. Failure to cooperate, anti-intellectualism, and innate hatred of each other (among other flaws) are what will sink us.

If we don't expand beyond Earth, we've got maybe 700 million years tops, since past then the sun's changes will make multi-cellular life, if not all life, on Earth impossible.

Generalization. Would be interesting discussion with details. Pop is growing. What's your concern - global warming, fertility rates, pollution, nuclear arsenal, running out of resources? Doesn't seem like we are doing that badly and that pop can't drop if get below renewable resource level or adjust to new ways of making energy/food, etc.

Does seem likely that on an extremely long time scale, we need to get multi-planetary, which is "realistic" if we give a reasonable time frame of, say, 10,000 years.

As far as the sun dying, that's beyond even parent point's timeline. This is very things start to get questionable if we never get to even .1 of c (e.g. Project Orion "realistic" estimates). Alpha Centauri is relative close at 4.something ly, but other "potentially habitable/useful" star systems are way out there.

Agreed. The great filter and collapse theory in general are fascinating in theory and can motivate some great positive action but they can't undermine the fact that humans beings are doing better than they've ever done in our history by almost every imaginable metric.

Plus humans are extremely adaptable. Even before we invented agriculture, people had colonized the whole planet, except for Antarctica. It would be hard to kill us all off.

> humans are extremely adaptable

This is a strange claim I see repeated over and over, but it has very little evidence to justify it. The only piece of evidence people present is:

> people had colonized the whole planet, except for Antarctica

This is true of a fairly large number of organisms on Earth.

On top of this humans have only been around for ~200,000 years, that's not long at all. Humans have not survived a single mass extinction event.

So far we've seen humans travel around a planet that has been relatively stable for that period of time. There have been plenty of species that have traveled around with us that didn't even need to rely on extra tools, clothing or the use of energy to survive.

Humans share several vulnerabilities with other megafauna that have all gone extinct. A major one is a fairly long gestation, plus small number of offspring per generation. Human young likewise need tremendous amounts of care and energy to raise to mature adulthood. Additionally human have fairly high energy requirements to support their complex brains.

We've seen exponential rise in human population only because humans have had access to excessive amount of non-renewable, high-energy density sources of energy.

It just happens that humans have lived on a planet that has mostly been within survivable temperature changes, with historic climate changes happening on time scales that lead to easy migration. As you pointed out, the one continent that does not have an environment that supports human life remains empty.

Humans can't survive a wet bulb temperature of 35C. Until just recently we never saw that temperature on this planet. As we see more and more places reach that temperature more often, I suspect we'll see how frail human adaptability is.

In comparison to most other mammals (including the neanderthals), we are pretty awesome at adaption. Probably even better than bacteria, all things considered.

That is because we possess multiple different ways of adapting to our enviroment:


during childhood


culture and technology

This link provides a nice summary: https://www2.palomar.edu/anthro/adapt/adapt_1.htm

> his is true of a fairly large number of organisms on Earth

Is it though? How many other large, multicellular, organisms live on every continent without humans having brought them there?

Seals. Birds.

But we don't see the same species of seals or birds everywhere. There are different species which evolved to survive on each continent. Whereas humans are a single worldwide species.

Birds migrate from one place to the other they don’t live on every continent all year round. Even if we take these though (and as the other commenter said they aren’t the same species in every continent) that still leaves a total of 3 out of how many thousands, millions, of multicellular organisms on the planet.

Cooperation is the key metric I'm considering. It's becoming more critical that we learn to, and we are not even trying.

> the fact that humans beings are doing better than they've ever done in our history by almost every imaginable metric.

That's because we have had ready access to insanely abundant high-energy density source of energy.

The non-fossil fuel supported carrying capacity of the planet for humans is estimated to be somewhere around 1 billion people. When the fuel runs out (if we don't cook ourselves first), that will collapse.

It is nothing intrinsic about humans that have lead to our recent success, just access to lots of nearly free energy.

edit: why the downvotes? Is there even anything controversial in these statements? HN's fear of bad news is getting out of hand.

What is your source for the 1 billion estimate? Because that seems completely, non-credibly *low* to me.

I also strongly believe that we could cover all our energy needs with renewable sources within a few decades if we really wanted to (even assuming no significant advances in tech), and this seems mostly non-disputed to me (because that is literally what nation-states are currently planning/doing).

> Is there even anything controversial in these statements?

Yes. Your statements seem not credible to me and you cite no sources.

1 billion is a rough estimate based populations prior to the massive boom in the industrial revolution that saw massive changes in the way agriculture is done. It could easily be 2 billion or so, but definitely not 7.8 billion. You can see the population history here[0.]

To see the powerful impact of fossil fuels on carrying capacity you'll notice there's an important inflection point around 1920-1930. This is because of the advent of the Haber process[1] which allows us to use fossil fuels to create nitrogen based fertilizers.

Lest you doubt the impact of the Haber process just look at trends in corn yield per acre since then [2]. It's truly remarkable. Additional gains there are from other industrialized, fossil fuel driven agricultural process.

The Haber process requires hydrocarbons. In the wikipedia article you can see that it consumes 3-5% of the worlds natural gas production and 1-2% of the global energy supply.

We have completely disrupted the natural nitrogen cycle [4] and so would be unable to produce anywhere near as much food without fossil fuels. Because we have disrupted this cycle it's not even obvious that we could go back to a world of pre-fossil fuel agriculture.

So those are just some bit of information about my claims but let's take a look at yours:

> we could cover all our energy needs with renewable sources within a few decades if we really wanted to... this seems mostly non-disputed to me

This is wildly disputed, and I don't know anyone who credibly believes this without invoking "magic" future technology.

For starters we haven't replaced fossil fuels with "renewables" at all so far. We've just used them to supplement our energy needs. You can see here [4] that global fossil fuel consumption has continued to rise.

Then it is important to separate electricity from the more general subject of energy. Currently only 20% of global energy usage is electricity generation [5]. So even if you replaced the entire grid with renewables over night you would still be missing the vast majority of energy demands.

We currently have no viable pathway for renewable energy in transportation. Alice Friedman has more notes on this than I could ever fit in a comment [6]. Transportation inherently requires high energy density fuels, and outside of passenger vehicles, battery technology does not have the density required for industrial shipping.

It worth looking at our national energy flows to get a good sense of just how little of the energy we use comes from renewables [7].

But even if we look just at the electrical grid, in the US, we have some very obvious problems with "all" our needs. As you probably know, wind and solar are intermittent power sources that requires fossil fuel powered "peaker" plants to provide energy in down times.

This had two problems. One you need energy storage technology that we do not currently have (you cannot use grid scale lithium batters, pumped hydro has geological constraints, molten salts only work with concentrated solar, compressed air requires decommissioned oil field, etc).

The other problem is that even if you had perfect storage you need to now more than double the total energy production so you can fill those batteries.

The should be enough sources for you to get started, but I have feeling I'll still get down votes and "hand wavy" explanations of how it will all work out.

0. https://en.wikipedia.org/wiki/World_population#/media/File:W...

1. https://en.wikipedia.org/wiki/Haber_process

2. https://www.agry.purdue.edu/ext/corn/news/timeless/YieldTren...

3. https://en.wikipedia.org/wiki/Human_impact_on_the_nitrogen_c...

4. https://ourworldindata.org/grapher/global-energy-substitutio...

5. https://www.iea.org/reports/world-energy-outlook-2019/electr...

6. https://www.resilience.org/resilience-author/alice-friedeman...

7. https://flowcharts.llnl.gov/content/assets/images/charts/Ene...

Thanks for explaining how you arrived at your numbers.

> I have feeling I'll still get down votes and "hand wavy" explanations

Let me turn this around: you are getting downvotes (not from me) because your 1 billion population carrying estimate in a post-fossil age is implausible and borderline disingenuous:

1) It assumes that pre-industrial agricultural output is the maximum that our planet can sustain. Which is completely off for a multitude of reasons:

- Genetic improvements to cultivars still fully apply

- Pesticides won't cease to exist

- Automation in harvesting/monitoring also won't go away

2) There is no reason to assume that we're anywhere close to peak sustainable agricultural output, neither in pre-industrial times NOR now.

3) Furthermore, it implies that land utilization, cultivar choice and consumer behavior in general would stay similar/comparable regardless of cataclysmic change in supply/demand (pricing). Which is obviously wrong: If avocado price went up to 50$/kg then people would just put potatoes on their toast instead, and total agricultural output (in calories) would "inexplicably" increase.

Regarding power:

Renewables (solar/wind) are a perfectly fine source of primary energy. Storage/grid stability does not depend on "technology we do not currently have"--Batteries and inverters are perfectly usable, mature technologies--but right now slapping down natural gas plants is simply cheaper. This is exclusively a matter of price/ROI, and installation could be jumpstarted immediately if there was the political will to pay for it (and thats not blaming politicians exclusively to be clear--average citizen is simply unwilling to pay 1$/kWh right now for residential electricity).

> Renewable energy in transportation

Friedman selfdescribes as "energy sceptic" which is already...unfavorable... to me and after stumbling over "running out of fossils is gonna solve climate change better than anything else" (transcribed), I gave up on the author completely;

Viable pathways are:

- Batteries

- Biofuel

- Fuel cells

- Hydrogen in combustion engines

We literally built all of those already, but same story here: It's less cost efficient than burning diesel right now, so why would anyone do it.

> It assumes that pre-industrial agricultural output is the maximum that our planet can sustain. Which is completely off for a multitude of reasons

I agree it's off because we've done significant damage to the biosphere since industrialization. As I've pointed out we have disrupted the natural nitrogen cycle.

If we where to immediately rewind our population back to 1850 and try to life that lifestyle we would have a much harder time since we have depleted natural resources. We cannot go back because we the earth would not support us the way it once did.

> There is no reason to assume that we're anywhere close to peak sustainable agricultural output, neither in pre-industrial times NOR now.

Our entire current agricultural system relies on fossil fuels, so I agree, where nowhere near close... we're way past.

> Viable pathways are

- batteries: not for commercial transport, the energy density is still way too low. Your battery becomes your cargo. Modern global trade is impossible in a battery based economy. Nobody that is serious on renewables will disagree with this, they will claim that new battery technology is going to solve this.

- Biofuel: require more energy to make they they provide [0]. So again, not only do you need to double the grid to handle intermittent power, you now need to expand it by the total biofuel energy required times 1/efficiency, so we're looking at at least tripling our current power output and trying to do it with only renewables. Please tell me how much silicon and lithium it would take to build a grid that large in that sort of a time span and you'll find it dwarf's annual production.

- Fuel cells: same problem again, currently fuel cells are made with coal or natural gas today 95% of fuel cells are made with natural gas [1]. If you want to switch to electrolysis you come up with the same problem of having to double our current grid power.

- Hydrogen in combustion engines: I'm not sure how this is different from hydrogen fuel cells, but the hydrogen production problem is the same.

Please if you want sources, provide some of your own. Come up with some back of the envelope estimates on the total grid capacity needed to cover 100% of our energy needs. Then do some research on the energy costs to produce solar cells at that scale (or wind farms, hydro is already near full capacity at least in the US).

I know you yourself don't really believe what you are saying. It's based on no research, you have provided no meaningful sources, and even the most die-hard solar/renewable proponents realize that grid scale storage is still an unsolved problems. What you have given are "hand wavy" explanations without sources, exactly as I expected.

0. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7320919/

1. https://www.energy.gov/eere/fuelcells/hydrogen-fuel-basics

On a long enough time line, the survival rate for everyone drops to zero.

I am Jack's existential dread

And to add the evidence we do have; in the billions of years of life on earth, there has only been <200 years where any species had the will and the way to send deliberate communications into space. Observational evidence suggests that the time span of civilizations existing is vanishingly tiny compared to the vastness of time overall

This makes sense to me. I feel we're in a small room peeking through a tiny hole in the wall and asking why the outside world is so empty.

It's much easier to traverse 1 year in time then 1 light year in space though

Is it? I can move all sorts of distances, in different directions, at all sorts of rates. It's surely harder to go certain speeds than others, and in certain directions than others. But to move 1 year in time - I only have one speed and one direction to move.

What makes the dark forest hypothesis not so conving to me is that it has the presupposition that it is indeed possible to hide. An advanced civilization close to us that is surveying the sky for signs of life would have very likely identified earth as a very promissing candidate due to the presence of methane and oxygen in its atmosphere at the same time. So our star system would have long been under surveillance, before we had the chance to develop a technology that would reliable disguise our presence.

If such a technology is possible at all, only the very first advanced civilization had the ability to hide from all others. And only if they were able to develop it before any other civilization had been able to track them.

To some extent it might nevertheless be a reasonable strategy to keep as quiet as possible. But this strategy is less and less useful for the latecomers. If they were already tracked by a multitude of other advanced civilization they would hardly benefit from keeping quiet. Unless they (wrongly) think that they are an early advanced civilization.

However, if a couple of these civilizations start to openly seek contact to others, what can the hidden ones do? If a hidden civilization starts to fight one of these latecomers, it would need to leave its cover and make itself known to all other civilizations in its vicinity. If it follows the dark forst hypothesis, it could only do so, when it is sure that it is the only dangerous civilization in its forest.

This leaves me with the following alternatives:

- The forest is dark, because there is only one civilization out there that is very capable in hiding and has the ability to exterminate any latecomer efficiently and without traces.

- The forest appears dark, because it is thinly populated and we just have not looked enough for the others.

- We are the only ones in our cosmic vicinity.

I agree with your logic but would add one more thing to it: There is no compelling reason to wait until a planet conclusively proves it has intelligence on it to nuke it into oblivion with a kinetic kill projectile. You don't really know how long it will take for an intelligent species that could compete with you to arise. Humans have moved pretty quickly on cosmological scales, there's no particular reason to believe we're moving at the max speed and a lot of reason to think otherwise. Compared to the amount of energy you can obtain over cosmological time periods, the expenditure of a kinetic kill projectile is nothing.

In fact, if you don't mind waiting a bit, it can be almost trivial. All you have to do is basically get a factory to the target system; it can use local resources to build a kinetic kill projectile efficiently out of a big, local hunks of rock and local hydrogen. Launching near-light-speed projectiles from lightyears away is the emergency "oh crap! They're smart already!" option. Killing a planet that only has dinosaurs on it is dead easy for these hypothetical intelligences and there's little reason to believe they wouldn't.

So I think the dark forest hypothesis falls down on the fact that not only has Earth been broadcasting loud and clear to the stars that it has life on it ever since the Great Oxygenation Catastrophe, which was somewhere around 2 to 2.5 billion years ago, the Dark Forest theory implies that any surrounding intelligence that arose and was capable of seeing Earth on that time frame should have hit it. That has not happened. And 2.5 billion years is actually significant even on cosmological time scales.

(Also, no, the dinosaur asteroid or other events were not kill projectiles. If an alien intelligence is going to kill-projectile Earth there's no compelling reason to just sort of inconvenience life... it's going to eliminate it. Hypothesizing a race capable of launching projectiles but being too stupid to realize it wouldn't do the job is too precise a level of incompetence to believe in. As they say, there's no kill like overkill.)

Fun science fiction premise... not a solution to the Fermi paradox.

"Too precise a level of incompetence to believe in." That's the most beautiful wording I have read in some time...

Hat tip: https://www.shamusyoung.com/twentysidedtale/?p=615 "That is a very specific level of tired."

You don’t destroy the system because you want to inhabit it yourself. This assumes that life is looking for similar habitats and that it’s not simpler to create an artificial planet anyway.

If there is oxygen breathing carbon based intelligent life that wants our planet they could've easily spotted and taken it anytime within the past 2 billion years.

It seems safe to say that there isn't life that wants our planet.

Why would anyone come from light years away to inhabit a planet. It would be cheaper to just build habitats or colonize a planet in their solar system. There is almost nothing we can provide to a civilization capable of traversing between start systems.

All resources are scarce.

But if nobody wants our world and they're scared of intelligent life then just send out Von Neumann probes to ensure intelligence isn't showing up elsewhere. First mover's advantage nullifies the entire dark forest.

relatively scarce, sure. There are millions of times more of all the resources Earth has between us and any civilization coming from light years away. By the time they needed Earths resources they’d have to have gobbled up large chunks of, if not the whole, Galaxy.

Right but the whole premise of the Fermi Paradox is that it doesn't take long (on a galactic scale) to gobble up the entire galaxy using STL transit if you're dealing with a constantly growing civilization.

So either they'd - already have gotten here & already have destroyed the earth when we showed intelligence OR - already have gotten here & don't care about destroying intelligence.

>So either they'd - already have gotten here & already have destroyed the earth when we showed intelligence OR - already have gotten here & don't care about destroying intelligence.

Or... civilizations don't experience unbounded growth over millions of years across millions of light years to begin with.

Well okay but I believe that premise is flawed. It still takes millions of years for one (which is a long time on human timescales) and it’s more likely civilizations Balkanize and begin fighting each other if they even were to be so resource driven they wished to colonize the galaxy that quick which I don’t think we have any reason to believe is true.

> Why would anyone come from light years away to inhabit a planet.

Many motives from the age of exploration could apply - imperialism, religious beliefs, religious or political differences, cultural exchange, scientific discovery, competition with others, etc. People don't always take the cheapest option; the same could be true of aliens.

This seems to be projecting a human trait that is itself obsolete to us unto civilizations that share no common culture or genetics and are leagues ahead of us technologically speaking. Not to mention the age of exploration was driven by economics. Seems foolish to me.

Or maybe that carbon based intelligent life that wanted our planet it's us.

We were almost wiped out after the first large impact. The impact that happened a few millennia after we killed all those awful looking smarty octopus that lived in this planet. But we could not defend against the large Comet, it come from behind the Sun and way too fast. We had minutes notice.

Some microbes survived...And here we are again typing on our keyboards. :-)

The aliens in Scott Westerfeld's Fine Prey invade Earth for a novel reason. It's ROT-13 (https://rot13.com/) encoded to avoid any spoilers.

Gur nyvraf ner ynathntr areqf. Gurl bpphcvrq Rnegu fb gung uhznaf jbhyq perngr n arj qvnyrpg bs gurve ynathntr.

Or they did want it and used it for seeding more complex life so they could eventually create homo sapiens. Like the start of the film Prometheus.

Which would mean that the dark forest is still false right?

If I use humanity as a model, then we don't see other great apes as dangerous competitors. Rather we see them as interesting curiosities. We want them to stay alive. But it's hard to resist the desire to turn their habitats into something economically productive.

Colonizing other planets and making them into homes for aliens long before a native civilization has a chance to arise seems more plausible than just destroying them.

For the purposes of this conversation, colonizing other planets effectively is destroying them. After that, no natural intelligent competitor will arise and surprise you, because you're right there to keep an eye on everything.

(Of course, you may still have any amount of conflict with your fellow settlers, or your someone in your original species' descendants two systems over, but that's a completely different conversation.)

(Major spoilers for The Expanse below.)

> There is no compelling reason to wait until a planet conclusively proves it has intelligence on it to nuke it into oblivion with a kinetic kill projectile.

Or send a technologically engineered molecule that can hijack single-cellular life to help establish your needed technology in the target solar system.

That's a variant of what I discuss in another reply, but well underscores my point of just how easy this is if you happen to get there anywhere in the 2.0-2.4 billion window Earth has had prior to intelligence. If you colonize the system in any manner, be it biological, technological, whatever, for Dark Forest purposes that's equivalent to destruction; there is no longer a threat of natural competing life.

You've got two major approaches: Fling a kinetic kill projectile, or if you have the tech to get "something" into the target system at roughly orbital velocities, send some machines to do the job with local resources.

None of these things appear to have happened in Earth's past. Ironically, trying to spin yarns in which they did anyhow still end up countering the Dark Forest hypothesis, because all such attempts must either include significant probabilities of failure of the attempts or the possibility that the life out there is benevolent (to some degree, at least sufficient to avoid simply wiping us out, which on this scale is "benevolence" despite whatever else they may be doing) which itself would imply the forest isn't that dark.

It’s funny that that wouldn’t have been a spoiler if you hadn’t mentioned the name of the work.

How far away from earth is it still possible to detect oxygen and/or methane levels in the atmosphere?

If I was a technologically advanced civilization, I would send robotic Von Neumann probes around the galaxy to keep tabs on things at close proximity.

If I was also murderous, I would have programmed the probes to destroy any signs of life.

So, the fact that we are still alive after broadcasting the presence of life through out atmosphere for the last couple billion years is quite reassuring.

Wouldn't that be the most difficult and expensive way to simply monitor for life or technosignatures? Compare that to simply (relatively speaking) building massive space based optical and radio observatories that can observe every visible star. The light reaching you has already made the trip, you just have to collect it. If you were murderous, you could launch an attack from your home system rather than waiting for the probes to spread from system to system.

Granted there could be some technical limitations that prevent you from observing certain systems but that pool will be much smaller than an entire galaxy of stars.

Also, don't forget that a Von Neumann probe is at a disadvantage when it arrives in a system since you want to send the minimum number of probes to each star and then have them replicate on arrival. If your probe accidentally shows up in a system that contains an advanced civilization capable of detecting and capturing it then you've given away the fact of your existence and your intent along with all the information that can be gained by studying the probe.

So have your replicators approach a system from an unexpected vector; one course correction in interstellar space should be enough.

Also I'd expect the probes would communicate with the homeworld via relays (where they were replicated) rather than directly, so it'd take a fair amount of effort to unravel a replicator network unless you caught one of the very first probes.

And also it'd be conspicuous if there was a volume of space in your network where your probes always failed.

I wonder if everyone is therefore incentivized to not send out such probes, then. Since no one can guarantee they are advanced enough that their probe won’t get captured by someone more advanced who just sends back a scarier probe as a thank you gift.

You just need enough light to do spectroscopy. I’m not really aware of a limit other than being in our light cone.

Light years with the right telescope. It’s just spectroscopy.

Yes but only a tiny fraction of our sun's light would pass through earth's atmosphere on its way out of the solar system, I didn't think spectroscopy would be possible very far away.

Why get a factory to the target system when you can launch kill projectiles to all the systems in the galaxy from home?

> An advanced civilization close to us that is surveying the sky for signs of life would have very likely identified earth as a very promissing candidate due to the presence of methane and oxygen in its atmosphere at the same time.

Signs of carbon-based life - who is to say all forms of life are carbon-based? The universe is vast, what are the odds of aliens being in our vicinity and time (light cone) stumbling upon our galaxy or star?

> Signs of carbon-based life - who is to say all forms of life are carbon-based?

There's a limited number of elements, and their abundance in the universe decreases rapidly beyond the first few. Carbon is by far the most advantageous for life due to its vast ability to form complex molecules. Silicon might be a distant second. If there is other life in the universe, and if there's nothing special about us, it might not all be carbon-based, but it's extremely likely that a large amount of it will be.

>However, if a couple of these civilizations start to openly seek contact to others, what can the hidden ones do?

Stay hidden or destroy anyone close enough to put you at risk along with themselves. This is a spoiler, but IIRC from the books the ultimate safety net was to make your solar system not only invisible... but impenetrable in either direction but essentially trapping yourself in a black hole... thus removing yourself from the equation and hopefully satiating anyone watching.

The time scales and distances involved meant that you weren't really perceived as a threat until you approached the ability to reach light speed, which made you stick out enough to be noticed in far corners of the universe. We broadcast radio, but it's not loud or far-reaching enough to be noticed by the far-out civilization destroying overlords. It was loud enough for a different nearby civilization to come destroy us in an attempt to save themselves from being destroyed along with us.

Of course, when applied in reality who the hell knows.

Am I missing something, or is this article very narrowly missing the most damning criticism of the Dark Forest hypothesis according to the article's own logic? The first paragraph of the “Criticism” section says:

> Overall, the Dark Forest Hypothesis has an internal logic and consistency that makes it an appealing (if somewhat somber) potential resolution to Fermi’s age-old question. Unfortunately, it also suffers from an inherent flaw that is capable of unraveling the whole thing. Like many other Fermi-related hypotheses, it only takes one exception to this rule to prove it wrong.

Given this, I thought it was going to follow on to point out that we are the exception to the rule, but instead it goes on to talk about malevolent exceptions. But, as the article mentioned earlier, we have made many active attempts to communicate our existence to other hypothetical civilisations, and we make no effort in obscuring our radio signals.

Is it possible that other civilisations follow the “Dark Forest” principle? Of course it is! But why would we happen to be the only civilisation that doesn't really worry about getting seen? The possibility that we are not alone and we are the only ones trying to communicate sounds even more fanciful and anthropocentric than any of the alternatives.

As other commenters have said, we can't take our own viewpoint as an example of what kinds of civilizations survive because our technological age is so young.

But IMO Dark Forest is bunk anyway, because it assumes that projecting power over interstellar distances is easier than defending yourself. That's not true within terrestrial history ... even though the arrival of colonists was massively disruptive to populations in (for example) the Americas, they couldn't have outright destroyed them. To survive, they had to trade and mingle with their neighbors, ultimately changing both cultures.

The sequels to The Three Body Problem kind of discuss this, and extend the dark forest idea to consider that any population that splits off from you is now a dark forest alien. I find that crazy xenophobic and ultimately an impractical black and white view of self vs other. On Earth, successful civilizations have been capable of trade and cultural exchange in addition to force.

>because it assumes that projecting power over interstellar distances is easier than defending yourself

This seems really obviously true to me. Accelerating a rock to relativistic speeds is pretty easy, defending against a rock potentially coming from anywhere in space traveling at relativistic speeds is extremely difficult.

1) I think you're underestimating the difficulty of accelerating any massive object to relativistic speeds, 2) doing so with enough accuracy to hit a relatively small moving target many light-years away is not exactly trivial, 3) a civilization with the capability to accelerate a massive object to relativistic speeds is probably also capable of building self-sufficient artificial habitats around its star, which is a lot of targets you'd have to take out for complete obliteration.

So in summation, I think defending against an incoming relativistic rock is at least as easy as using relativistic rocks to obliterate a distant civilization.

You're definitely not thinking creatively enough.

You don't need to hit the planet directly with anything, all you need to do is destabilize the orbit of all the planets or even just the Earth itself. You could send a gravity wave for example, that would cause the Earth's near circular orbit to shift to a very eliptical orbit. The vast change in temperatures would kill all life on the planet, and then you could come and mine all the resources that you needed and leave.

If you have the capability of engineering such a gravity wave then Earth's resources aren't worth your time.

Resources not the point here, the point is removing the possibility that our civ could ever be a risk to them

another thing: I believe at relativistic speeds hitting any debris in your path would cause a pretty large BOOM, and for a multi-lightyear route that seems somewhat risky.

IANAAstrophysicist but it seems like targeting that rock gets proportionally hard with the speed and distance. Throwing a dart and hitting an ant on the other side of the world, etc.

And the other side of that equation is: does the species who can do that have anything to fear from us? Or does the same technology make them likely able to stay ahead on defense, making it uninteresting to destroy us?

Three Body Problem introduces all this dimension folding tech that makes being the first to strike totally dominate. But the closest equivalent on Earth hasn't (yet) led to nuclear holocaust, because preventing others from getting the tech and establishing mutual detente with those who do has been better for each actor.

We can already hit tiny (Ed: planet sized) targets at interstellar distances. Planets are relatively speaking quite large targets especially if you’re tossing several rocks.

This stuff doesn’t need sci-fi style new physics, just the kind of infrastructure we could actually build.

....we have never hit anything at interstellar distances, which are several orders of magnitude farther than interplanetary distances.

I didn’t say we have, just that we can.

The closest Star is ~268,770 AU where voyager 1 is only 152.6 AU. However, being able to target a probe within 50 feet at 150AU, means hitting a planet sized target at 4.25 light years. Building a probe large enough and fast enough to do significant damage at the other side is the hard part, not targeting.

Calculating where a planet sized object would be by the time our probe got there is a different story.

Voyager is not traveling a relativistic speeds. We could definitely defend against someone sending voyager at us.

That’s moving the goalposts. I said we could hit a planet at those distances not that we can create a relativistic impactor.

No it isn’t since the whole topic here is that any civilization capable of accelerating an object to relativistic speeds and hitting a target from light years away is capable of defending against one. We can send voyager to target an object on the other side of the solar system but we are also perfectly able to defend against a potential voyager.

Just because you now claim to not be addressing the actual goal at hand doesn’t mean I moved the goalpost; if anything you’re now implying you did.

Voyager 1 isn’t a weapon so defending against it is kind of a meaningless argument. The Parker Soar probe is aiming for 0.064% the speed of light and covered in scientific instruments and shielding. So that’s arguably a solid baseline of what we could do in terms of speed. Even at those speeds we are still talking 8,000 years to the closest planet making it a poor weapon.

Still, I doubt we could detect a barrage of incoming 0.0005c weapons designed for minimal levels of stealth in time to do anything about it.

What tech are you thinking of? Remember it's not just the distance but the speed. How would we course correct a relativistic object once the target was close enough to estimate the desired change?

Well, you do that with the same kind of engines that propels them at relativistic speed.

Anyway, it's not a target and forget situation, because relativistic ships get a (relatively) lot of drag in space.

> Well, you do that with the same kind of engines that propels them at relativistic speed.

Which don't exist except as fantasy, and even most of the fantasy ones wouldn't work for targeting adjustments.

Right, if you have the tech to allow you to course correct an object traveling at relativistic speeds you have the tech to defend against on by moving it out of the way.

Yep, that's probably correct. Even more because you can just throw something into the projectile too, and destroy it... And they can throw something into your projectile, and etc.

I don't think anybody can make any claim on what side is easier. But targeting the attack does not seem to be the hard part.

The belief is that detecting the attack in time to do anything makes defense more difficult. Your warning is limited by light speed, so detecting something moving .99c at 100 AU and you get just over 7 minutes to respond.

Worse, it doesn’t need to be some solid object. A loose field of debris 1,000 miles wide could sterilize a planet with enough mass and enough velocity.

Fortunately, it is possible to imagine other scenarios. For example; it would take relatively little energy to deflect such a missile and there is likely to be a lot of time to detect it's incoming presence assuming that some sort of planet-like mass is required to host all the technology to create a relativistic speed accelerating engine.

> Accelerating a rock to relativistic speeds is pretty easy

Huh? How? I haven't seen any proposal that doesn't start with the assumption that we can inject a rock with a preposterous amount of energy let alone hit (in astronomical scales) a ridiculously small target, not to mention navigate all the gravity wells in between.

Multistage rocket using ion engines. Remember this is over interstellar distances (>4 lightyears), so you have multiple years, if not decades or centuries to accellerate.

This does get back to the "Why didn't we RKKV it millions of years before intellegent life even existed, much less had a opportunity to hide, based on biosignatures in the atmosphere?", though.

Ok, that gets us to maybe 0.3% of the speed of light on something small, which isn't very interesting.


> defending against a rock potentially coming from anywhere in space traveling at relativistic speeds is extremely difficult.

Also, while 'proper' stealth is difficult, you can make the rock pretty close to invisible for practical purposes by coating it in vantablack and cooling it to liquid helium temperatures.

> On Earth, successful civilizations have been capable of trade and cultural exchange in addition to force.

Forget about what monstrosities we have done to other human civilizations throughout history. Instead, think about what we have done to animals. We have hunted many animals out of existence, or we have farmed them and made them basically the equivalent of the Matrix, sources of energy and food.

We are trying to eradicate mosquitoes for crying out loud, and entire species, without giving it a second thought. I will use insecticide to kill today entire colonies of ants without blinking.

All it takes is for one advanced alien civilisation to come across us and deem us the equivalent of their mosquitoes to eradicate us and take all the resources from the Earth. That's the whole point of the Dark Forest theory. If there's an infinite number of civilisations out there, and one of them is so advanced that we are insects to them, why wouldn't they just exterminate us, or use us as food?

> If there's an infinite number of civilisations out there, and one of them is so advanced that we are insects to them, why wouldn't they just exterminate us, or use us as food?

We want to exterminate mosquitoes because they're actively detrimental. Nobody's advocating for the extermination of, say, daddy long-legs spiders even though they're everywhere; and nobody would be advocating for the extermination of mosquitoes if they were all located in Antarctica.

So it takes a very precise level of inferiority to be extermination fodder. If you're too unassuming, there's no reason and so it doesn't happen. If you're dangerous enough that you can fight back and hold your own, it doesn't happen either.

That aliens would find us just the right shade of annoying seems... implausible.

John Varley's Eight Worlds[0] series has an alien species called the Invaders. They invaded Earth to protect cetaceans from the effects of human civilization.

The Invaders divide sentient life into three tiers - species like themselves that evolve in gas giants, cetaceans, and vermin; we're in the third category.

[0] https://en.wikipedia.org/wiki/Eight_Worlds

We are early in our "Space age". It's possible that inexperienced civilizations emit their position only to start hiding after realizing the dangers. Other possibility is that we are in a short period until we are wiped out because we broadcast our position.

All of this would drastically reduce number of visible civilizations at any time making the detection of civilizations much less likely.

Wouldn't the counterpoint be that those civilizations like us that do not obscure their location are quickly eradicated by others in the forest? So the forest also acts like a filter for those that are not careful enough.

I don't see that as a counterpoint, but more of a post hoc theory. How could the eradicators detect and destroy their victims before we detected any signal at all from the victims? And why haven't the eradicators come for us yet?

Of course, this could always be explained by the distances involved and the limitations of light speed, but that would make the Dark Forest hypothesis redundant as an explanation as to why we haven't yet detected any alien civilisation(s).

>How could the eradicators detect and destroy their victims before we detected any signal at all from the victims?

Even if they destroy them within say a thousand years, then at any given time there would be only few civilizations at the right age to be broadcasting. And not very loud at that.

We listen only to a miniscule portion of the Galaxy. IMO, Fermi's question shouldn't be "Why can't we hear the few civs that are close to our level".

It should be "How come we don't detect Kardashev >2 civs collonizing most of the galaxy?" Why can't we detect a single Dyson Sphere?

(I don't consider dark forest explanation to be probable though.)

The Fermi question is a lot closer to "how come Earth wasn't colonized before we even appear?" than "how come we can't see anybody?".

Yes, that's a cleaner way to put it.

How do we know we aren’t the colonists?

There have been a couple science fiction novels with this premise:

Protector[0] by Larry Niven

David Weber's Dahak trilogy, available as the Empire from the Ashes[1] omnibus

[0] https://en.wikipedia.org/wiki/Protector_(novel)

[1] https://en.wikipedia.org/wiki/Empire_from_the_Ashes

You mean how we know the Earth wasn't seeded with something similar to archeo-bacteria on purpose? We don't but that doesn't solve the problem.

Or how do we know that we, humans, aren't the colonists? Well, all the life we know comes from the same ancestry, including us.

That doesn't solve the paradox though, unless we are quaranteened in a Zoo.

> How could the eradicators detect and destroy their victims before we detected any signal at all from the victims? And why haven't the eradicators come for us yet?

Because most civilizations are probably still a 100+ light years apart and we just haven't been around and listening for that long? Even if we've theoretically had the chance to detect another early civilization the other listeners have been listening for aeons longer than us and are much better at it.

I think what would explain this is our very limited timespan when we started listening to universe. There might have been 10 strong signals in last 2000 years, but last one could have happened around the time US declared independence.

And 2000 years is nothing timewise on scale of universe. Plus we talk about signal that can maybe travel few hundred / a thousand light years before they blend into galactic and intergalactic noise.

I don't see there being that big a technological leap between annihilating another civilization and starting a colony in another star system. If you're the type of civilization that would be interested in killing a competitor off you're probably the type that's going to colonize and fill the entire galaxy in a few million years. We evolved, so that hasn't happened, in a galaxy thirteen billion years old. I suspect we're alone.

The energy requirement to send a life destroying device to a far away planet might be much less than the energy requirement to send colonizers. That may be the big leap so to speak.

If you can send a weapon you can probably send some kind of Von Neumann probe with genetic and cultural data to create a seed colony

I don’t see why that necessarily follows and I don’t see why one would want to send such a probe. It does nothing for me if I can send a probe to start humanity on another planet when I have no connection to said planet and won’t be able to see the result or have a connection to that colony. In the dark forest view one would never seed such a colony as they will quickly become competitors.

You don't think species chauvinism is a thing? If I had to lose an interstellar war and be wiped out I'd prefer it to be a human offshoot doing it. At least that way my species survives.

In the dark forest view it’s best to just kill off the opponent and not replace them with a potential new opponent.

Not really, the weapon does not need to slow down. If its just a big enough chunk of rock that is aimed at a planet and it speeds up the whole way reaching some impressive fraction of the speed of light before impact, the only hard part is the math to aim it. We are reasonably close now to being able to strap some engines on an chunk of rock and send it on its way randomly in one direction. We are very far away from being able to start a seed colony in another solar system.

1 exception doesn't disprove this rule. There could be any number of reasons for one or some civilisations to broadcast but not be destroyed:

* it takes time, we've only been broadcasting for 70 years or so. 70 light years isn't that far.

* we are far from dangerous listeners (we are right out on an arm in the milky way galaxy)

* all planets broadcast for a while at least (we did so without any serious consideration) and not all broadcasts end in annihilation. Up until just 40 years ago we seemed pretty likely to wipe ourselves out with war, even if an alien were planning our destruction, why not wait and see if we did it ourselves?

* Popular methods of destruction might not apply to our solar systems. If you rely on near by asteroids or free-floating planets to destroy civilisations and there happen to be none near sol, then we are safe to broadcast even if no one is safe to reply.

* if more than 1 alien actively destroys planets we might be lucky and have the aliens who detected us assume other aliens will destroy us. As long as they are happy to wait, we can broadcast in blissful ignorance believing we disproved the dark forest when we're actually just in the middle of a Mexican standoff...

* If a civilisation destroys other civilisations as soon as it detects them, you can use the abrupt destruction of civilisations to triangulate that civilisation. And destroy it. And that's a high priority since that way you find hidden civs AND ones which pose an immediate and serious threat to you. The best defence against this is to allow plenty of time between detecting and destroying a civilisation, especially a harmless unarmed (in the cosmic scale) one like ours. The lack of many close neighbours to us means a would be destroyer needs to wait even longer before striking us to maintain their annonimity.

Ironically this last point is the best argument against the dark forest: why destroy soft targets like earth when doing so reveals your existence? Why not wait, let someone else hit us and then hit them since they were a much bigger threat. So you'd expect a certain amount of noisy "prey" to be left as bait by one predator for another...

Also, I don't think we are broadcasting very much anymore. The move to digital broadcasts (lower power) and to Internet based comms/media (99% undetectable even from orbit) mean we're a lot less visible than we were previously.

The book responds to most of the "not there yet" concerns. The idea is that if there are 1,000 species aware of even primitive life on a particular planet, chances are at least one of them will be close enough for it to be worth the effort to destroy it. This is because technological development is exponential and you can't predict if/when a planet will produce dangerous technology equal or greater than your own. If you wait, you only increase the risk of being destroyed.

I haven't read the book, does it answer these points:

There are only 76 type A stars within 100ly of us (100 light years because we've had powerful radio about that long). So even assuming every star had a civilisation capable of destroying us, that's only 76 of them.

Similarly, we've had primative life on earth for millions of years. If a civ exists that can detect primative life and wishes to destroy it, it would have done so by now on earth since the milky way is only about 100k ly across.

That's without getting into whether technological development is actually exponential, whether it caps out or how fast it is...

There is no way to underestimate the stupidity of people in groups, and our eusocial stupidity might be unique to our species.

If someone knocked on your door, quite unexpectedly, in the middle of the night, can I err on the idea that you would be quite panic-struck?

But if humanity got a signal from another civilization tomorrow, do you think it is safe to err on folks being quite happy?

> If someone knocked on your door, quite unexpectedly, in the middle of the night, can I err on the idea that you would be quite panic-struck?

Quite likely, but only because the socially acceptable reasons to knock on someone's door in the middle of the night are usually something pretty bad. I wouldn't fear that they're attacking me. I would fear whatever they are waking me up to tell me about.

> If someone knocked on your door, quite unexpectedly, in the middle of the night, can I err on the idea that you would be quite panic-struck?

But if a stranger knocks on your door in the middle of the day you might just open up and say "no thanks, I don't want your pamphlet/vacuum/encyclopedia".

I mean, even if a stranger knocks, it seems weird to kill them assuming they're dangerous, even if we have "don't let a stranger in" etched in our collective consciousness.

> The possibility that we are not alone and we are the only ones trying to communicate sounds even more fanciful and anthropocentric than any of the alternatives.

Well, yes. But it could also make the (possibly) few blithe spirits who do want communicate be in general much further away, and thus much harder to communicate with.

I don’t think the Dark Forest principle asserts that all civilizations adhere to it. We might simply be the naive (or stupid) ones that get destroyed. That wouldn’t discredit the hypothesis.

We are also the only civilization we know of so we again may just be the dumb ones with a sample size of 1.

Becoming truly detectable - on a cosmic scale - might require a higher technological level than our current one.

Attaining that technological level could be inherently linked with the ability to realize the dangers to begin with.

> we have made many active attempts to communicate our existence to other hypothetical civilisations

Spamming aliens with nude selfies, among other measures, which in retrospect may not have been a wise choice: https://en.wikipedia.org/wiki/Pioneer_plaque

Ah... the "Dark Forest Theory". People really put way too much unnecessary time on it.

If the theory was true, then the first thing those "tree-body man" would reasonably do is to just destroy the solar system straight away with that super illegal (to the law of physics) raindrop probe. A civilization with the intention of discover and kill will definitely make their probes efficient kill devices, right? Why pay the expense of identify and kill the "Key actors" one by one when you can delete a entire system for cheap? Just turn the probe into a blackhole to kill the sun, it should be easy if the probe was really that dense.

A more direct attack is rooted in the theory itself: for the theory to be true, a state/condition called 猜疑连 (Chain Of Suspicion) must be created. The content of Chain Of Suspicion is simple:

    - A civilization cannot determine if another civilization is evil
    - A civilization cannot determine if other civilizations will view itself as evil
    - A civilization cannot determine if another civilization will launch an attack against it
    - A civilization cannot determine if itself is evil
    - A civilization cannot determine if another civilization view themself as evil
    - A civilization cannot determine if another civilization will treat itself in such way that been determined unevil
    - ... ... (The article that I quoted from has this at the last line: https://wiki.mbalib.com/wiki/%E9%BB%91%E6%9A%97%E6%A3%AE%E6%9E%97%E6%B3%95%E5%88%99#.E5.8F.B6.E6.96.87.E6.B4.81.E6.8F.90.E5.87.BA.E7.9A.84.E2.80.9C.E5.9F.BA.E6.9C.AC.E5.85.AC.E7.90.86.E2.80.9D.E5.92.8C.E4.B8.A4.E5.A4.A7.E9.87.8D.E8.A6.81.E6.A6.82.E5.BF.B5)
Have you see the hole here? For a civilization that advanced, what are the chances that they're not equipped with also advanced social and science knowledge and skills? Heck, their advanced probe could probably even do all the observation and tests fully automatically and report the result back. The Chain Of Suspicion will never form to begin with because they CAN determine the facts if they really wants to. And then so the Dark Forest will never form too (at least not for the advanced side).

Now, let's talk about some serious thing. Because I've noticed some people uses the Dark Forest Theory to explain the relation between nations (yes, Earth nations). So it is really important to realize that the entire theory is nothing more than a plot device that Liu Cixin employed for his novel, among many other plots. Most of them are there to make the story more convenient, instead of more logical (as I have said, based on the theory, the logical thing to do is to wipe everything out at contact, how convenient that the probe "JuST cAnT" huh?).

So, if the theory inspired you do to something good, then nice, go ahead, have a good life, help people, communticate with others, try to understand others, have fun. However, if you believe the "Dark Forest Theory" is THE true governing rule of the universe, then you probably overthink it too much, stop it, it's not healthy. And guess what, the planet we're living on hosts multiple civilizations, you stick with us now no matter what.

I love that series -- just an incredible, imaginative, unique perspective -- but the dark forest hypothesis just doesn't make sense.

It's orders of magnitude of orders of magnitude less energy to communicate with (including obscuring your origin, if you want) than destroy a civilization. And communication has potential benefits (cooperation) that destruction does not.

Civilizations that communicated would very quickly and easily out-compete/out-advance civilizations that did not. "Malevolent" civilizations would inevitably run into more advanced cooperating civs sooner or later and be checked, either learning to cooperate themselves or lose.

Put another way, the assumptions used to build out the hypothesis, "Chains of Suspicion" and "Technological Explosion", don't make sense either. "Chains of Suspicion" assumes civilizations cannot communicate, yet the dark forest hypothesis assume civilizations can destroy each other. That's a contradiction. If you can physically interact, you can communicate (and as I pointed out before, with much, much less energy/resources than it takes to destroy). And "Technological Explosion", as written in the book, assume exponential technological growth could occur at any point, which seems to be nonsense to me. Any kind of exponential growth necessarily depends on a medium primed with the resources for that growth and stops when the resources are expended (which is never all that long, given the nature of exponential growth).

I cringed every time this idea was forced into the forefront of the books. They are such great and imaginative books, I don't mind at all that not all the ideas really pan out, but it was a little hard to stomach every time the plot turned on this weak idea.

I think dark forest is the best explanation so far.

If what you say is true, it should've been true for earlier human civilizations too.

Why didn't the Chinese and Japanese civilizations unite to conquer others?

Why didn't the Mongols unite with whoever else to conquer, instead of Genghis Khan doing it all with a bunch of Mongols in horses?

Human civilization is a dark forest that only changed with global trade. The communication challenge is language and culture. And civilizations have always been technologically distinct, with the more powerful one almost always conquering.

With interstellar communication and technological advance it would be orders of magnitude higher stakes.

Each of those civilizations you mentioned rose to the heights of their power by uniting multiple smaller tribes into one larger civilization.

You've got a fantastic point. It reminds me of Chinese history, full of war between clans until it was finally United.

What I keep thinking about is that we are all... Humans. Like, the same animal, same way of thinking etc. And yet our answer so many times is conflict.

The only reason conquerors didn't kill all the conquered was for taxes and slaves and so on. Imagine if resources were not an issue ( advanced enough tech) and you wanted to avoid confrontation.

Sending a near light speed bullet to explode a star seems a good trade-off to keep your dominance.

Historically it's extremely rare that the conquerors killed everyone in the cities they conquered. Instead they enslaved some, or let them mostly live and just taxed them. Even with other species that regularly attack humans (tigers or even mosquitos), we have not exterminated them.

We're trying our best to exterminate certain species of mosquitoes. We haven't done it because we lack the technical ability as of yet.

Also, have you met any Aztec? There are barely any American Indians left compared to the millions there were originally.

Mammuts? All the giant marsupials of Australia that went extinct the moment humans set foot there?

We've been on top of the food chain for very long. Now imagine if we discover another race may take our place and the only option is communication or total obliteration?

I wish it was different, we only have a sample size of one.

But just like the three space ships that first found out about the dark forest and ultimately killed each other, it's what makes most sense from game theory

Not many neanderthals around these days. Just an observation.

We carry them with us in our genes, that seems to indicate more than just war was going on.

We don't know that happened to them, or to any other human species for that matter.

But we're pretty sure we obliterated a entire species in our way up the food chain ( giant marsupials for example)

We very likely obliterated a few along the way but that seems to be the exception rather than the rule.

Humans had the power to exterminate many more but chose not to, and continue to choose not to.

Is that really true though?

Saying "we didn't kill them all" doesn't exempt the fact that we did it for many of them.

There's no easy answer to this. We are what we are. But it points to the disregard powerful beings have over weaker ones when they get in their way.

Sure, but the interesting thing is that the powerful beings typically do not have disregard. Why do we care for all the species that we have power to exterminate?

Especially the predators that compete with us.

> "Chains of Suspicion" assumes civilizations cannot communicate, yet the dark forest hypothesis assume civilizations can destroy each other > If you can physically interact, you can communicate

I think you misunderstood what they meant by "communicate". They don't mean "reach with a message", they mean "engage in back and forth communication with both sides understanding the conversation".

We're still struggling to talk to dolphins, but technically we could nuke them all to death if we ever got scared they were rising up.

But we're not struggling to talk to dolphins, they're struggling to materialize Shakespeare. We understand their structures and concerns more than they understand ours, and we observe them when they're still in the original soup.

ALl this to say: if they were rising up, we'd probably be able to create a bidirectional connection. We can only make sense "nuking them all to death", like you say in america to mean "defend our freedom and way of life", if we are able to communicate and are faced with a refusal to submit. The dolphin, so far, accept american hegemony - there's no purpose to nuking them.

So it is correct what you say, but here we're talking of civilizations. Civilizations worth nuking will always have a way to understand each others, otherwise there'd be no threat worth suppressing.

> Civilizations worth nuking will always have a way to understand each other

Again, we cannot talk to dolphins. Closest we’ve got is teaching monkeys sign language - and to be fair, that’s pretty good, but we’re also very similar to them. My reason for the dolphin analogy is that they’re an intelligent species here on earth that have incredibly different physiology and behavioural patterns to us. We can’t assume that any other ‘intelligent’ species in the universe we find will be similar enough to us where we can figure out rudimentary sign language with them, we have to assume the worst, in this case trying to communicate with an entirely foreign species.

Also the phrase ‘’the dolphin, so far, accept American hegemony - there’s no purpose to nuking them’’ is the funniest thing I’ve read in a while, lol.

I also adore the series. It's become my favorite sci-fi I've read in years.

You're leaving out the time required to communicate. Yes, communication would require less energy, but time is a constant that even type 3 civilizations could be in short supply of.

The chain of suspicion calls this out explicitly, it's not that the civs cannot communicate, it's that due to the extreme lengths of time required for back-and-forth communications their societies are likely to significantly change during communications, leading to higher probability of the technological explosion.

What medium was primed for the technological explosion on Earth since the industrial revolution? I mean, I reckon we could point to an array of things that have seemed as though they would be a limit, but thus-far we've always found ways past that (see: peak oil). I'm not trying to indicate I think our trends _will_ go on forever, just that it seems possible they could.

> They are such great and imaginative books

Those books are pretty awful. They can't make up their mind whether they belong to sci-fi or fantasy. Sometimes they veer towards hard scifi but then make naive mistakes with current science. The characters are cardboard cutouts, very shallow, and make nonsensical decisions. The general atmosphere is depressing and ends in the complete failure of basically everything.

> It's orders of magnitude of orders of magnitude less energy to communicate with (including obscuring your origin, if you want) than destroy a civilization.

IIRC The Dark Forest addresses this directly - saying that wiping out a civilization must be cheap and casual. There's a chapter where an alien scout detects Earth, puts a dimensionality attack cartridge in a gun or something, launches it and goes on with their business.

I wonder if we're making too many assumptions about how civilizations would live and spread. I've always wondered why our species puts so much focus on planetary colonization instead of building smaller habitats. We seem to assume we'll terraform Mars, maybe build habitats on some of the Jovian moons, then jump to the next star. It seems more logical to me to take the ISS and iterate on it, building larger habitats and learning how to live in them.

There could be trillions of habitats out there and we'd never know it. From small low-orbit stations orbiting home planets to larger complexes orbiting their stars instead up to generation ships moving to the next star to mine for more resources or to build more ships due to population limits being hit. Once you've perfected the building of habitats that are large enough and are tailored to your species specific needs, why mess around with planets that can kill you in so many different ways?

Maybe the reason we don't see anyone is because we can't resolve even very large habitats at light-year distances and the reason we don't run into them is because we don't have anything they can't get somewhere that isn't already inhabited. Perhaps they avoid inhabited systems because of the dangers involved.

I agree, for an advanced species space habitats seem far superior to planets. A constant supply of free energy (solar), easy access to endless metal (asteroids), no earthquakes/tsunamis/volcanos/wildfires. If we're talking far-future, to me the Culture and their Orbitals represent the ideal utopian endpoint for humanity.

The O’Neillian movement is predicated on the answer to “is a planetary surface the best place for an expanding technological civilization” being no. Long run, this view will be most influential.

My favorite answer to Fermi's Paradox is a paper (which I do not have on hand) showing that it can be explained by the approximation error in doing a raw product of probabilities.

If, instead of doing a product of the probability of each event, you actually take the various distributions into account (nowadays you can easily test a wide variety of distributions with monte carlo methods) then, the probability of getting into contact with another life in the universe becomes vanishingly small.

I guess this is the paper you're talking about: https://arxiv.org/abs/1806.02404

My interpretation of that paper is that it is saying "We don't have hard enough bounds on the parameters of the Drake Equation, so one (or more) of the parameters could be much lower than expected". But without specifying which parameters are much lower than expected, the paper is just saying "our current understanding/uncertainty about the universe is consistent with someone solving the drake equation in some unknown way at a later point in the future". Which I don't think is actually a solution. The real question we are interested in is which parameters are lower than expected and why.

What would that be a "favorite" answer? It's just one of the hypotheses. Drake's equation and how exactly must it be applied has been fiercely discussed for decades.

Unless, of course, saying it's your "favorite" is your way of saying "I like to believe in this one hypothesis".

It removes the paradox without requiring additional hypotheses, just refining the math. That makes it the most convincing solution to the paradox for me.

I disagree. It looks like you simply choose to believe one of the hypotheses. Or need I mention other areas of life where choosing one hypothesis eliminates all others? Hint: it's the "R" word. ;)

> In other words, the finite nature of resources will ultimately pit one civilization against another as they all struggle to sustain their growth.

I'm not sure this constraint is so strict to force a strong competition for survival, given how vast the universe is. It seems to me this projecting our earth-bound mentality of limited resources to a whole different scale, where it may not really apply.

Precisely. IMHO any civilisation capable of interstellar travel (at any speed) has solved all necessary questions/problems of resource/energy acquisition and control and has no need to plunder the resources of others.

According to this theory, the resource consumers in the universe are just as vast as the universe itself. At the end of the series the final resource constraint they deal with is running out of physical matter in the universe. Once the civilizations depicted in the book are done mastering survival in this universe, they all turn their attention to surviving the death of the universe. Stability simply moves the survival goalposts, and “we could probably last a few billion years” (or rephrased, “we will probably perish in a few billion years”) becomes the new existential crisis to solve.

that is what I thought when I read the three-body problem.

If you can manipulate space-time at the levels exposed in the book you can trivially build orbitals that will host trillions of beings and live in a post-scarcity society for millennia, after which your society is likely to disappear waaay before you run out of space and resources.

Why or how would a post scarcity multi planetary or even multi stellar civilisation disappear? I agree that there is no need for plunder, but I don’t think highly advanced civilisations are in risk of extinction.

Well, I don't know.

It is just a common topic in fiction that great civilizations just fade out, and it seems reasonable to me. I do not believe the average individual would want to live forever, and at some point I feel the same would apply to civilizations. But for the sake of fun, I can recall some ideas from literature :)

Maybe they evolve into higher states of being and leave our plane of existence.

Maybe they stop reproducing and slowly die out.

Maybe they reach a level of self-introspection where they believe continuing existing is pointless.

Maybe they migrate to a more reliable virtual world in a sub-space computer.

Maybe each individual gets its own universe.

Maybe the society splinters over some trivial concepts and the old knowledge is lost when the machines start to fail.

There's a lot of interesting things that can happen, let's hope we'll find out late enough :)

Once we are earth loose we will be solar bound and human factions will fight for solar resources/domination.

During star formation up to half of the matter can be rejected. During planetary formation a lot of fairly large bodies will be ejected, think moon size, along with a lot of smaller stuff too. Interstellar space probably has a lot more to offer than we generally think.

Given that most complex life is probably carbon based, and given the one planet with complex life we can observe, my guess is that most complex life runs into one of two paths:

1. You don't have enough easily accessible hydrocarbons in ground to build a civilization advanced enough to even get you into space.

2. You do have enough hydrocarbons which leads to inevitable overshoot, and accompanying collapse before you ever get close to figuring out interstellar travel. Exponential growth patterns lead you to either exhaust the carrying capacity of your planet, or you end up warming your planet too much and die off (or a little bit of both).

We're a pretty good case study between 1 and 2. Right now we're in a race to see if we can exhaust our hydrocarbons or overheat our planet first, there seems to be no realistic alternative (plenty of nice fantasy ones though).

If we had reached peak oil in the early 80s (or sooner) we would have likely avoided catastrophic climate change, but would have started a major population shift downwards towards 1 billion, where we would have likely stabilized but with no major technical progress (technological progress is largely a function of energy).

We didn't though, so now it seems like we are going to continue to increase the rate we combust hydrocarbons until we create an unlivable planet (at least for us). A few billionaires are making some cool toys, but we don't seem to be able to survive until we're anywhere near interstellar travel.

In the near future it is more likely we will wipe out ourselves either due to Nuclear War, Global Warming, rogue AI or similar, than some hostile alien civilization will get us. It seems that we are those hostile aliens for ourselves.

Do you think there is a "real" (>1% over the next century) risk for humanity to wipe itself out, or just that the hostile-alien risk is way beyond negligible in comparison?

Because all current climate doom-erism notwithstanding-- humanity extinction seems impossible to achieve to me via climate change or nuclear war; rogue autonomous self-replicating systems might be a danger, but are too far beyound current tech to estimate risk IMO...

Very curious if/how/why you disagree on this!

We don't need to go extinct. Our global economy is very fragile, relatively speaking and it's not at all clear we could sustain the economy necessary to perform space exploration if bad things happen.

To avoid an extended argument about all the ways in which climate change will screw things up, let's focus on nuclear war: a nuclear war between, say, India and China would not only wipe out huge swaths of the human population but also ruin the global economy because industries in Europe and the US depend on these countries. And that's without going into the ecological effects of a nuclear war.

The economy relies on layers and layers of extremely convoluted supply chains and can't sustain a loss of even 1% of the human population, let alone 10% or more. The US has only seen a death of around 0.2% of its population due to COVID and is already facing labor shortages in retail. The blockade of the Suez canal was a big concern but imagine the Suez canal is simply gone.

> The US has only seen a death of around 0.2% of its population due to COVID and is already facing labor shortages in retail.

Pretty certain these two metrics are absolutely unrelated, given the fact that people who would have died were probably quite old in the first place.

> The economy relies on layers and layers of extremely convoluted supply chains and can't sustain a loss of even 1% of the human population

I think you are underestimating the ability of humanity to adjust and innovate, especially over time. I mean we literally essentially lose 1% of the human population to old age every year.

Those convoluted supply chains are a recent phenomena. Some international trade is necessary but large countries like the United States are capable of producing almost everything they require domestically. Trade is only preferable if you can import something for less money than you can manufacture it locally.

If civilization as we know it ends but humanity survives it would be very difficult for future generations to reestablish because we've used up all the easy to access hydrocarbons. Without easy to reach coal there won't be another industrial revolution and humanity would be stuck for millions of years until the hydrocarbons reform.

That is some kind of Oil centric thinking that got us in this mess in the first place. Renewables and fusion can do the much better better job at any point. By the way coal will not form ever again, only reason why coal/oil formed is because bacteria has not learned how to decompose cellulose at the time. https://www.nationalgeographic.com/science/article/the-fanta...

I believe that theory is no longer valid. It was supposedly fungus that feeds on woody plants that resulted in a drop in lignin rich coal but that doesn't seem to quite work out. Coal is formed when there's a lot of organic matter that gets trapped in an oxygen poor environment and then buried and compressed over time. That process is certainly still happening though not at the same rate it has in the past. This article has some good details https://arstechnica.com/science/2016/01/why-was-most-of-the-...

There's still quite a lot of coal though.

I don't think renewables and fusion will be an option in a post apocalyptic society. After a few generations of anarchy the knowledge will be lost.

True, solar and nuclear need a bit more tech, but wind and hydro are quite simple they need a bit of wire, magnet and something to spin.

I disagree on this, because biofuels are a viable substitute in almost every situation.

I'm fairly certain that our accumulated knowledge would make a second industrial happen even faster in spite of fossil-fuel-lack (but it might play out slightly differently, because of higher fuel costs...)

Doubtful that there's enough biofuels to produce high quality steel in large quantities and that's a pre-requisite to a post-apocalyptic neo-Industrial Revolution. Only coal burns hot enough and was available the huge quantities necessary.

Sure, producing iron without coal sucks; but there is already enough scrap metal around to power several additional industrial revolutions, and an arc furnace is really simple, especially if already know how electricity works beforehand.

Long term, there are alternative routes that could be taken (capable of processing fresh ore) but using scrap metal just seems easier/more likely to me.

That is not true methane, propylene, hydrogen can be easily produced and they have temperature >2800C while burning of coal can produce combustion gases as hot as 2,500 °C (4,500 °F). https://www.thoughtco.com/flame-temperatures-table-607307

Just a feeling or rather educated guess is:

That general AI going rogue if it gets conscious is small, more probable is narrow AI that has mistake in setting goals, given too much power by either military or corporations.

Global Warming is highly probable but we still have chance if we find energy to cooperate around mutual goal. Key points:

- Siberian permafrost and releasing huge amount of CH4 topping up all efforts.

- Amazon forest now release more CO2 than sequester (this week news)

- Species are being extinct on a rapid rate

- Wildfires/droughts continue to increase devastation

- Floods and heatwaves are stronger (losing ice caps will increase this to Equatorial heats once planet albedo of caps is lost )

Now, critical is next 10 years That does not mean that humanity will be wipe out in 10 years, but will set course for final destination. As no technology or amount of money will help us past that point, weather pastern and issues will be out of our hands. In bad scenario 99% reduction of population till 2100. Again guess. Underground pocket of sparse scientific communities could survive bit longer past this point, using geothermal energy and nuclear power.

Nuclear war is quite probable, I think critical is next 20 years: https://www.thedrive.com/the-war-zone/41421/pentagon-warns-o... If all weapons are fired, simply put, some people may survive, but they would wish they are dead. Let me put this way, we all have romantic dreams of surviving, go to Hiroshima, ground zero, then straight to museum, and then imagine something 2000 times more powerful multiplied by 16000. And of course everyone forgets Nuclear power plants, ~450 with similar yield. If you do not have Cheyenne Mountain complex at your disposal, your life expectancy is between 0 and 3 years. (acid rains, nuclear winter, no food, no medications, no drinking water, no animals ...). Even if someone survives it would be back to stone age - killing each other for basic necessities (even human meat), as there is nothing else to eat.

China vs US, US vs Russia, India vs Pakistan, rogues nation getting a weapon on some black market ...

Anyhow, if our civilization was cooperative society with higher goals, it would be fine, but from my experience, and from what I saw during my life, all governments are nothing but aristocratic mafia organisation sponsored by big business having one goal to increase wealth of their share holders justifying all means by what ever ends they have.

But regardless what I wrote or how many arguments I give as Friedrich Nietzsche "Hope in reality is the worst of all evils because it prolongs the torments of man." many especially those in power to do something, will have tendency not to believe in the final outcome until it happens, so instead of taking actions they will continue business as usual.

When I was young I lived in different country there one post WW2 leader used to say "Work and enjoy like we will live in peace 100 of years, and at the same time prepare like there will be a war tomorrow", personally I think it is a good policy for Global Warming or WW3, we should imagine the worst and then work as hard as possible so it never happens, employing all possible strategies at our disposal to save all life on planet, (DNA bank, 5d crystals, space travel, multi-planet, multi-suns ... whatever).

Similar like in IT we protect systems, for me who ever uses "doom-erisam" and similar shaming terms is nothing better than those person. Ostrich burying head in the sand like will not save you from the lion. In IT good network security guys imagine all possible scenarios, and they are not afraid that by the so called "new-age quantum vibration field" if they imagine bad scenarios they will attract it just by the power of thought. Admins/devs frequently must imagine and test all bad scenarios, even play roles of bad actors, so they can employ protective techniques.

In the similar way we should explore bad scenarios and see is it possible to do anything, but unfortunately, we who talk about it and comment a lot, our circle of concern is significantly bigger then our influence, and those who have huge circle of influence (money) the do not give two dimes about our concerns, and that is the reason my friend I am not optimist about our future in next 10 years...

> "doom-erisam" and similar shaming terms is nothing better than those person

First: I use the term because I see NO factual basis for assuming that humankind is going extinct. Your post did not change my view on that:

1) I fully agree that global warming is a massive problem.

But assuming that it's going to lead to human extinction is IMO straight up delusional.

The only plausible mechanism is full-runaway "hot-venus" greenhouse effect (evaporating our oceans), and that is a scenario that--pretty much all scientists agree--we are NOT going to reach no matter how much fossil fuel we burn (https://en.wikipedia.org/wiki/Runaway_greenhouse_effect#Eart...).

Rising sea levels and climate change might lead to international crises and cost countless human lifes, but there is simply NO WAY for this to kill ALL humans by itself.

2) With nuclear threats it's a similar situation: There are simply not enough nukes to cover the inhabited surface (even assuming worst-case full escalation!):

The highest estimates I found were between 1.6 and 3 billion victims, assuming that every last nuke was used on the most effective target and killing every person there (which are both completely unrealistic assumptions).

Both fallout and nuclear winter are completely insufficient for extinction purposes, because there is not enough radioactive material for the fallout and not enough dust in the atmosphere for nuclear winter to kill all (we had somewhat comparable volcanic events in the past).

3) Corrupt leadership is something humankind has survived with since leaders exist; there is simply no reason to assume that they are suddenly going to cause our all extinction.

> I use the term because I see NO factual basis for assuming that humankind is going extinct. Your post did not change my view on that:

There is a huge difference between I do NOT want to see, and there is NO factual basis.

From https://worldpopulationreview.com/world-cities only 1170 cities have population of 2,179,929,822, RS-28 Sarmat yield is 10 heavy warheads, each yield of 1.5Mt. Currently there is 3,700 nukes deployed and 13,132 nukes total. We do not know what China has so those number are without it. With the new hyper-sonic weapons time to react and go to shelter which in London practically does not exist except underground transport, so to get to nearest station you would need 30 min but nuke needs 15 min to arrive. Let's suppose that one Sarmat is enough to level town size of London or Paris. So only with firstly deployed there would be 2200 nukes to spare. But what about heavier nukes those 10Mt yields, what about revamping Tsar Bomba with 50Mt (8km fireball, 68 km mushroom cloud and shock waves circling Earth 3 times). So, what exactly will intercept hyper-sonic? So when you say estimate 1.6 to 3bn I would rather say it is very optimistic, and that only from the blasts. Next goes fallout... are you saying no one will die out cancer in full exchange? It will be all ok after 5 years? EMP would wiped out grid and internet, what will exactly pump water? What are you going to drink? Quickly made filter from charcoal and that will do? And to what hospital are you going to go if you scratch on rusty nail for instance? Next, what are you going to eat, 80% of food in UK is imported, https://www.businessinsider.com/no-deal-brexit-percentage-br... there is no more ships with food and oil? Where are you going to get money banks are out, no plastic cards, cash does not worth anything? do you have silver or gold? How many will die out of hunger in next 10 years?

And what about nuclear power plants 450 of them? They are not the same like nukes, nukes burn their fission material, but as we know from Fukushima Daiichi Accident and Chernobyl disaster, they were quite tricky, and there we managed to do something about it. Who will go to "fix" nuclear power planets after exchange, so plenty of fallout there?

As I said it would not be extinction but 99% reduction, and those who survive would wish they have not. By the way I am not trying to convince anyone people have had too many video survival games with happy ending, and to test reality you just need to go to near by woods for 7 days without food and water, and what ever experience you have just multiply by 300 times.

Going back to first line,

> your post did not change my view

I somehow find more frighting and delusional that way of thinking, as it leaves possibility to use mentioned as solution for fixing problem as people optimistically believe they are the one that will survive.

There is a reason why "Mutually assured destruction" and "nuclear deterrence" exist as such, as no one will ever attempt any such idiotic thing. As what we model usually does not correspond with reality. And when you know that everyone will loose like in the move "War games" then only way to win is not to play a game. And if current narrow AI can do it today I hope you as far superior intelligence can come to the same conclusion.

> I somehow find more frighting and delusional that way of thinking, as it leaves possibility to use mentioned as solution for fixing problem as people optimistically believe they are the one that will survive.

I'll give you the other perspective on the doom-erism:

People preaching about the inevitable extinction of humankind just provide ammunition/"strawmans" against progressive climate policies because these doom-prophecies are obvious bullshit and everyone not in an echo bubble knows it.

Just consider how easy it was to dismiss your "humankind is going extinct because of climate change" points-- because it IS BULLSHIT. Climate change is NOT going to lead to human extinction, and preaching this just steals credibility and hinders much more than it helps by polarizing society/preventing consensus.

As for the nuclear threat:

> only 1170 cities have population of 2,179,929,822

First: These are metropolitan areas, not cities. One warhead per area is not even going to kill a fraction of the people.

Consider: Tokyo metro region is 14000 km^2. Fireball size for a 10Mt warhead is <20km^2 (no larger warheads are in use and there would be no point). The highest estimate I found (3E9 victims) assumed 3 warheads per region I think, which is pretty similar to the numbers you came up with.

Taking all the aftereffects into account, you'll maybe get past the 50% population mark, but that is still not human extinction.

> Just consider how easy it was to dismiss your "humankind is going extinct because of climate change" points-

You have to understand that you have not dismissed anything, you do not have knowledge you have beliefs, judging by the angry typing. There is no point discussing with believes.

Regarding full fledged nuclear exchange I would ask you to write a paper and make computer model, I do not know what is your field of work do you have a sufficient knowledge to do it?

Regarding Global Warming it is fairly uncharted territory, now we know that models from 10 years ago were overly optimistic and that things are happening at much faster rate than expected.

Anyhow, to cut the long unfruitful story short, lets remember this and check in 5 and 10 years what happens.

> You have to understand that you have not dismissed anything, you do not have knowledge you have beliefs, judging by the angry typing. There is no point discussing with believes.

I'm not a believer. Show me scientific papers that credibly warn about human extinction because of climate change, and I will change my view immediately (hint: the IPCC reports DONT, and those pretty much mirror the current scientific consensus).

But what would it take to change your belief that humankind is likely to go extinct because of climate change?

> Regarding Global Warming it is fairly uncharted territory, now we know that models from 10 years ago were overly optimistic and that things are happening at much faster rate than expected.

Maybe. But projected outcomes have not really changed. Hansen et al (in "Science", 1981) alluded to potential flooding of ~25% of Lousiana/Florida, given the total loss of the west-antarctic ice shield (= +5m sea level). This is WAAAAYYYYY worse than what any current model predicts for even the absolute worst case in 2100, but even this scenario would not lead to human extinction, not by a long shot.

> Regarding full fledged nuclear exchange I would ask you to write a paper and make computer model, I do not know what is your field of work do you have a sufficient knowledge to do it?

There is no point: We agree on the facts, basically that there are not enought nukes to blast even half of humankind and fallout/nuclear winter won't suffice to kill the rest.

But if you want an interactive computer model check this out: https://nuclearsecrecy.com/nukemap/

> I'm not a believer.

Yes, you are equally believer as I am, and everyone on the planet, scientific paper do not mean much (don't get me wrong continue reading), that was the thing I was trying to say, in papers, we have estimates and models, we do not know what will happen exactly in real events. (and that is the point if you are scared enough, you never attempt to attack your enemy) You asked me for an opinion, not the knowledge about the outcome - therefore, I believe that your estimate is low, and you believe my estimate is too high - but neither of us knows what will happen.

> There is no point: We agree on the facts

No, we have not. I just listed the initial blast losses and ask you bunch a of questions on what would follow, on which you have not gave any answers. Regarding the map, I know about it, and it is not a model. It is more of a joke. I can list all the things you need to include, and you build a model; again I do not know your field of work? What do you do?

Humanity can survive in multiple ways, and let say, if we build an artificial womb and save DNA samples, and then after waiting for 100000 years, AI restores humanity and the animal/bio world - is that a real survival? Also, if we lose 99% and 1% continues, is that acceptable? For me, "The death of one man is a tragedy. The death of millions is a statistic." does not really work and it is not acceptable in any case or capacity.

How long will those need to get back on track? What about the amount of suffering they will go through? And after 10000 thousand years, will they repeat the same mistake, but this time with more powerful weapons? According to Mahabharata Indian legend, we already had a similar war with similar weapons a very long time ago, ok it is a story, not a real history as we know, it is more of as Science Fiction of old age in which weapons described are just amazing (self-navigated weapons, explosives, flying ships...)... anyhow I went sideways, I am trying to say the cycle of repetition is boring and at the end can get us extinct due to multiple other causes/agents.

Also while thinking about nuclear exchange we have not even touch that govs will not stop with nukes, there will be plenty of chemical and biological weapons exchange to finish what is left enhanced Ebola, black death and everything else you can and you cannot imagine currently at the military of the world disposal.

If humanity would drop to 100 million (1%) (population approximately 2000 years ago), how spread the population would be? How many gangs? How many tribal wars? Again, what with 450 nuclear power plants around the world? Surrounding of the Chernobyl will not be habitable for 20000 years. https://www.nationalgeographic.co.uk/environment/2019/05/che...

Now, in the time we need to recover, let say in all best conditions where people will not get hugely religious, and instead they turn to science, start learning as much as possible, that there will be no wars for resources, and gangs and criminals, that they will be very cooperative and not repeat same mistakes of the human nature as greed and lust for money, how many years would we need to recover from ashes and radioactive waste? 1000 years, 500, 100, 10 years? Damage would not be comparable to WW2 recovery, as scale of damage would be much bigger. And how would you organize society and make them do any work? How would you secure leader, aristocracy and politicians that caused this issue in the first place? Would they become primary target?

So, let say those 100 million left would need 100 years to recover, fairly optimistic time as nuclear winter would play a good part in the recovery time. During that recovery period, just a bit larger space rock can end the story, the same way like with the dinosaurs. You could say that even now we do not have the technology, but current state + 50 years of new technology, we could have protection in the future. But set back of just 100 years + same space rock few miles wide we would not have any protection, and it would be a game over.

All these scenario are hypothetical and we do not know really, but I would rather choose those probable scenarios that will increase our chance. As I know one thing for certain, I do not know where you live and what are your survival skills, but here in London my survival chances in the case of event are equal to zero and I have to admit I love internet even when we do not agree on things we do not have any influence whatsoever. :)

The universe could still be a dark forest of AIs ready to smash each other as soon as they spot each other.

Do you think that most/all civilisations end this way before becoming spacefarers?

I don't think, or rather I hope there are civilization that as a part of their evolution had cooperation, sharing, exploration and innovation embedded as main and prevalent strategies of survival and thriving. I would like to think that there is as in magic fairy tails of old, civilization where good prevails. Where leaders (or what ever mechanism of decision they have) and those in power - are not easily corrupted as here.

You're describing humans. Up to the point where you hope their leaders aren't corruptible. The problem with humans mostly comes down to centralization. We're an extremely cooperative species until we're put in an environment that promotes competition and punishes cooperation. Centralization of power is one such environment. And it's very hard to undo at this point.

https://www.youtube.com/watch?v=rStL7niR7gs Corruption is not just leaders it is a network of beneficiaries, like a snake with thousand heads, and regardless how many you cut new will grow. And we do not know how to get out of that mold. And democracy in uneducated society simply does not work. And we do not have it. All governments are aristocracies. News media displays of "busting" corruption is just "bread in circuses" of this age, media manipulations of wide populous while business as usual continues, hypnosis of population by spin offs and demagogues narrative.

> All governments are aristocracies.

All states are. Not all systems of government are states.

> media manipulations of wide populous

The media is owned by the same "aristocracy" that controls the state.

In the US and other capitalist countries the aristocracy mostly consists of billionaires and a few political "clans" (usually with ties to "old money"). In the USSR the aristocracy was the Bolshevik intelligentsia and former capitalists that formed the bureaucracy. The problem isn't inherent to humanity, it's inherent to centralized systems.

The video you linked actually supports this somewhat: a ruler can't rule alone, they need a staff of advisors and delegates to carry out the ruler's orders. But this is only a problem if you try to have a ruler, or a committee of rulers.

The usual counter-argument is that decentralized systems don't work at scale. You can have small communities decide things with direct democracy but clearly that doesn't scale because it's harder to reach consensus the larger the group becomes. To address this I would invite you to read into Democratic Confederalism or watch Anark's aptly-titled video "after the revolution"[0] that explores a very similar anarchist/mutualist governance structure.

In most of these scenarios the answer to "direct democracy doesn't scale" is a delegate system and it's easy to mistake this for the same representative democracy we're used to but the important difference is that the delegation is not only proportional but voluntary and consent can be withdrawn, either generally or on individual votes. NonCompete's video[1] has some poorly aged off-hand comments about how technology might help with this but he gives a good explanation of how such a delegate system can work. CGP Grey actually also has videos on alternative voting systems[2][3] making such a system feasible.

The main difference with these systems is that they're decentralized in the sense that power is granted explicitly and voluntarily, i.e. it can be withdrawn at a moment's notice, making it impossible to hold on to it over technicalities (like receiving a minority share of the votes but then joining a coalition government that appoints your party leader as chancellor and then passes an Enabling Act to disempower the senate like in 1933). At first glance this may sound like sovereign citizens rejecting arrest by exclaiming "I do not consent" but the important difference is that a delegate's vote is only worth as much as the number of people backing them.

[0]: https://www.youtube.com/watch?v=sMoTWFZjoYA

[1]: https://www.youtube.com/watch?v=1yuok9TQfpo

[2]: https://www.youtube.com/watch?v=s7tWHJfhiyo

[3]: https://www.youtube.com/watch?v=3Y3jE3B8HsE

Thank you for reply, I meant to say that abstraction of all currently existing political systems is aristocracy, democracies/communism/socialism what ever else label we are using is just aristocracy in disguise. Representative democracy is not democracy, as you pointed and I do agree, problem is centralization. You have gave me few valuable insights so I will try to explore more about the topic.

It's a common proposed solution to the Great Filter idea.

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