Dark Forest Theory: Uncovering the Scary Answer to the Fermi Paradoxon

[GTOM]

Dark forest is the title of the second book of Three Body Problem, IMHO, a masterpiece of science fiction.
Dark Forest theory is a really scary answer to the Fermi paradoxon.


Cixin Liu's book has the following axioms:
- life grows exponentially, but there is limited amount of matter in the universe
- chain of suspicion: how can you know another civilisation is friendly or not? Even if you don't want to attack, they might attack first, because they mistrust you too
- Technological singularity: see the development of the XX century. Even if an alien civilisation seems harmless at first, it can change in a short amount of time.

So the conclusion of the book: all ancient civilisations seek to destroy younger ones without questions... The ones who survive, do that buy hiding on generation ships, in artificially created dark areas that look like a big black hole, or in extradimensional mini universes.

What do you think about that?

 

[member 656954]

It's not a new idea in science fiction, with variants including machine intelligences that seek to obliterate organic life, and belligerent organics that go out of their way to kill everything, just because. The dark forest scenario seems one of the least likely in my mind, because it assumes homogeneity of motive, across every alien mindset, across deep time, and across technologies.

It also assumes that alien life is equally vulnerable. There are numerous (sci-fi) examples of aliens that live in the atmospheres of gas giants who would probably not see humanoid aliens as much of a threat. Might not even notice them at all. Why would they conclude that destroying those fragile inner-rocky world aliens is the only logical choice?

 

[GTOM]

It's not a new idea in science fiction, with variants including machine intelligences that seek to obliterate organic life, and belligerent organics that go out of their way to kill everything, just because. The dark forest scenario seems one of the least likely in my mind, because it assumes homogeneity of motive, across every alien mindset, across deep time, and across technologies.

It also assumes that alien life is equally vulnerable. There are numerous (sci-fi) examples of aliens that live in the atmospheres of gas giants who would probably not see humanoid aliens as much of a threat. Might not even notice them at all. Why would they conclude that destroying those fragile inner-rocky world aliens is the only logical choice?

Sure we mostly search life on Earth like planets. But we can expect radio waves or Dyson swarms from any advanced civ.

 

[Rive]

I don't think that this approach is logical. Compared to those who are wasting resources to suppress others there is an advantage in gaining allies.

 

[Ryan_m_b]

It’s a fun idea but it doesn’t hold out. It has an unspoken assumption that different sentient species are cultural monoliths who all perfectly agree and can be trusted to always agree.

The logic of:

1) Not a threat now
2) Could be a threat
3) Therefore should kill now

Could apply to any interaction between two agents. A culture that adopts this belief will constantly be at war with itself as any perception of a new sub culture or behavioural deviation is viewed as a potential future threat.

The book series basically plays with a very basic hawk vs dove game theory model and it’s entertaining but reality is more complex.

 

[member 656954]

But we can expect radio waves or Dyson swarms from any advanced civ.

Radio waves I think very likely.

But a Dyson swarm (or a Dyson sphere) is not necessarily 'expected', surely. The premise for those is very particular, and it does not automatically follow that a race that can build one, will build one.

 

[DEvens]

The only thing missing from the OP's explanation is that the alien civilizations are drastically more advanced than we are. And the cost of the weapons they use is small.

So, if one civilization among a large number has the characteristic of killing off rivals when they can, and hiding when they cannot, the Dark Forest situation follows. Those that don't hide get erased. Those that hide but don't do any erasing will leave rivals, and so eventually get over-taken and erased.

Spoiler: Spoiler for _The End of Death_

One of the "cleansing" weapons they use is called a "dual foil." This is a geometric thing that is flung at the solar system in question. When it gets there, it opens up, shedding its protective force field. Then it starts collapsing one dimension, reducing the targeted solar system to two dimensions. Literally everything in the solar system is killed. The escape velocity from the neighborhood of this process is the speed of light, and it expands indefinitely.

This weapon is also described as not very expensive, and requiring little in the way of resources. The individual who wanted to use it on our solar system needed to get permission from a superior, but that permission was given without question.

Imagine exterminating an ant colony at the expense of putting down one sheet of sticky paper. You would not be very likely to be concerned by the cost of the paper. If the ants were invading your house, many people would do it without hesitating. If you also expected that, some time within the lifetime of your species, the ants would develop technology that could kill you, many people would do it urgently.

 

[GTOM]

The only thing missing from the OP's explanation is that the alien civilizations are drastically more advanced than we are. And the cost of the weapons they use is small.

So, if one civilization among a large number has the characteristic of killing off rivals when they can, and hiding when they cannot, the Dark Forest situation follows. Those that don't hide get erased. Those that hide but don't do any erasing will leave rivals, and so eventually get over-taken and erased.

Spoiler: Spoiler for _The End of Death_

One of the "cleansing" weapons they use is called a "dual foil." This is a geometric thing that is flung at the solar system in question. When it gets there, it opens up, shedding its protective force field. Then it starts collapsing one dimension, reducing the targeted solar system to two dimensions. Literally everything in the solar system is killed. The escape velocity from the neighborhood of this process is the speed of light, and it expands indefinitely.

This weapon is also described as not very expensive, and requiring little in the way of resources. The individual who wanted to use it on our solar system needed to get permission from a superior, but that permission was given without question.

Imagine exterminating an ant colony at the expense of putting down one sheet of sticky paper. You would not be very likely to be concerned by the cost of the paper. If the ants were invading your house, many people would do it without hesitating. If you also expected that, some time within the lifetime of your species, the ants would develop technology that could kill you, many people would do it urgently.

Well, we like to believe that maybe we are fragile, but at least stars and spatial dimensions arent.

Also do the same thing with the solar system as the magic painter in the fairy tale is more like burn the room with the ants.

 

[member 656954]

@DEvens, thank you for putting that content in the spoiler, and in the spirit of not without wanting to give anything much away, I'll only say that it seems like a one-shot weapon, because 'indefinitely' ultimately makes it suicide for whoever uses it. So, I'm assuming there is some kind of antidote?

Can I also assume that is the text from the novel? I did not like Cixin Liu's first book, I felt something was lost in translation, particularly on the cultural front, but also that the 'physics' was deus ex machina. This seems similar. Something so dangerous, costing nothing and utilized with so little oversight, is not how weapons of mass destruction are handled. Not in a society that intends to maintain its own dominion in any event.

Peter F. Hamilton explores the implications of an alien race so aggressive that they pose an existential threat to all others in Pandora's Star, and that is well worth a read (as is anything from Hamilton, actually, even his worst effort is superior to most others at their best). It also puts a different complexion on this type of 'Dark Forest' thinking, because the universe is HUGE and the assumption that you're the biggest, baddest, and meanest aliens in the forest might only be true for a time.

 

[GTOM]

I read generally good things about Hamilton, i yet to read him.
At this point i think the third book is best from the Three Body Problem trilogy, no long boring parts, good twists, excitement, even more lovecraftian. The description of rotating space cities alone make it above popular stupid space operas (and i don't exactly think about Star Wars, which was never meant to look like hard sf)

 

[Chris Miller]

I really like Cixin, and that particular trilogy. But the "science" is way out in left field. The Dark Forrest, even though the worst translated, was my favorite because of the big space battle with the probe. The idea that there are advanced aliens out their lurking within light-speed range of any potentially competitive intelligence/technology, and yet unable to find unassisted, seemed wrong to me.

 

[member 656954]

I read generally good things about Hamilton, i yet to read him.

Well worth starting with his first novel, Mindstar Rising, which introduces protagonist Greg Mandel and sets the scene for Hamilton's style. If you like that, you'll likely enjoy all the others.

The idea that there are advanced aliens out their lurking within light-speed range of any potentially competitive intelligence/technology, and yet unable to find unassisted, seemed wrong to me.

It is not quite a trope, this idea that the aliens are lurking, but it is common enough. And I agree, you have to really constrain the plot for it to make any sense. I read a novel a little while ago that had an alien base on the far side of the moon, but it was set right now in our decade, that remained hidden. The novel was a stinker in all respects, but the author was particularly clueless about how we are probing the moon and how impossible it would be for the base described not to have been detected. Pity he wasn't interacting on PF while it was being written, might made for a far better story!

 

[Chris Miller]

Totally agree. I write sci-fi and PF has been a huge help (probably much to their chagrin if any of them found out).

 

[member 656954]

Totally agree. I write sci-fi and PF has been a huge help (probably much to their chagrin if any of them found out).

Oh, I think they know what's going on, @Chris Miller

But yes, this forum on PF is a huge help - and privilege - and I'm just wrapping up my second novel with a minor plot twist involving an antimatter bomb that the PF community helped me batter into shape!

 

[GTOM]

Oh, I think they know what's going on, @Chris Miller

But yes, this forum on PF is a huge help - and privilege - and I'm just wrapping up my second novel with a minor plot twist involving an antimatter bomb that the PF community helped me batter into shape!

Bit off: antimatter, i think about levitating neutral metallic antihidrogen.

 

[GTOM]

The only thing missing from the OP's explanation is that the alien civilizations are drastically more advanced than we are. And the cost of the weapons they use is small.

So, if one civilization among a large number has the characteristic of killing off rivals when they can, and hiding when they cannot, the Dark Forest situation follows. Those that don't hide get erased. Those that hide but don't do any erasing will leave rivals, and so eventually get over-taken and erased.

Spoiler: Spoiler for _The End of Death_

One of the "cleansing" weapons they use is called a "dual foil." This is a geometric thing that is flung at the solar system in question. When it gets there, it opens up, shedding its protective force field. Then it starts collapsing one dimension, reducing the targeted solar system to two dimensions. Literally everything in the solar system is killed. The escape velocity from the neighborhood of this process is the speed of light, and it expands indefinitely.

This weapon is also described as not very expensive, and requiring little in the way of resources. The individual who wanted to use it on our solar system needed to get permission from a superior, but that permission was given without question.

Imagine exterminating an ant colony at the expense of putting down one sheet of sticky paper. You would not be very likely to be concerned by the cost of the paper. If the ants were invading your house, many people would do it without hesitating. If you also expected that, some time within the lifetime of your species, the ants would develop technology that could kill you, many people would do it urgently.

Just read that exact part. Really scary...
Although still pretty illogical for me.
We see a swarm we don't know whether sparrows or locust, but nuke them anyway...
How theese kind of people achieve anything before exterminate themselves?

Otherwise cosmic zoo is a milder version of that theory.

 

[member 656954]

How theese kind of people achieve anything before exterminate themselves?

Exactly, @GTOM

That's the key question and one that is hard to answer. Such unthinking aggression makes it unlikely that the species would ever cooperate enough to build a civilization, let alone make it into space. I've always wondered that with the Prador in Neal Asher's Polity series. The Prador are ridiculously aggressive, and while it leads to Asher's fun was stories, it also makes little sense.

Asher may have had another species give the Prador a helping hand, I can't actually recall, but that would certainly work. Something along the lines of a benign species uplifting an aggressive one, then the aggressive one overwhelming and exterminating the benign one. Nasty, but plausible.

 

[member 656954]

Bit off: antimatter, i think about levitating neutral metallic antihidrogen.

Sorry, @GTOM, I missed this when you posted it. I looked at antihydrogen but for reasons of a fun production method, went with positrons instead. My protagonist, Guardian, asked how they were created and this was the answer:

The sky reset to the original view and I changed the topic. “Tin, how did you create so much antimatter? It doesn’t sound a lot, but even I know that five grams is impressive, and if you’ve tested this device, then you clearly created more.”​

​

“Gold film, a laser, a vacuum, and a lot of patience, Guardian. All easily obtained out here in the Belt, aside from the patience, of course, that’s down to self-control. Anyway, the laser fires short, ultra-intense pulses to irradiate a millimeter-thick gold target. That ionizes and accelerates electrons, and as they burrow through the gold target, they interact with the nuclei and create positrons. Each pulse creates billions of positrons, which I both protect and catch with magnetic fields.​

​

“Billions per pulse might sound like a lot, but there are considerably more atoms in five grams of matter–or antimatter, of course–and even with an array of thousands of lasers firing a pulse every other second, it takes a couple of years to collect enough antimatter to make a worthwhile test, let alone a workable bomb and that is not including the years it took to set the production lines up.​

​

“But time and tide, as they say, Guardian. If there is nothing else, I best go check on things. I’ll see you shortly, yes?”​

 

[DEvens]

@DEvens, thank you for putting that content in the spoiler, and in the spirit of not without wanting to give anything much away, I'll only say that it seems like a one-shot weapon, because 'indefinitely' ultimately makes it suicide for whoever uses it. So, I'm assuming there is some kind of antidote?

Treading on spoilers. But...

Spoiler: What to do about the 2-D bomb

In the book _The End of Death_ there are aliens who use dimensional manipulation as a weapon. Toss the device at the enemy in 3-D, blip, they are 2-D, and their various processes stop and they are most thoroughly dead. But the process expands indefinitely. One dimension curling up along the lines of a Kalusa-Klein theory.

This is set in a backdrop of a long-term war in which things started out at 10 dimensions. And various warring factions have been blipping their opposition down one dimension so long and so widely that most of the universe is now 3-D with little pockets here and there of 4-D.

So when this particular alien species tosses 2-D-ifier weapons, what's their plan for dealing with it when it gets to their back yard?

There were three main ideas. One: pocket universes to hide in. Two: convert to 2-D and live with it. Three: Some species were rumored to be able to reverse the process and produce pockets of 3-D out of 2-D, or even higher. But nobody had managed to acquire any of those secrets.

 

[member 656954]

Treading on spoilers. But...

That all makes (kind of) sense, might even be a reasonable explanation for our universe

 

[S Holtom]

Hi guys, I just joined Physics Forums because I think there are more fundamental issues with the Dark Forest.

The first is, who is going to do the genocidin?

Because, let's say we detect the presence of a species less advanced than us. The safest thing (according to DF logic) would be to preemptively attack them, right? Well, hang on, what if such a large-scale attack is the very thing that draws the attention of another species, that's more advanced than us? I mean, either we're scared of threats or we aren't, and our hostility may well put us on the very top of an advanced species' threat list.

So, you might say, what if there's a species that is confident they are top dog of the galaxy and so are not worried about any other observers? Well, in that case, why would that species passively wait for sentients to reveal themselves? They should just seed probes to every planet and proactively find all the sentient life (this is again assuming that DF logic works).

Finally, why is the forest dark? If the galaxy really were this Hobbesian nightmare, and the logic worked, there should be a cacophony of communication messages and other displays. Not to broadcast the location of some advanced species' homeworld, but to lure out naive species. Certainly any broadcasts being sent out by a species that gets blasted will not get snuffed out -- why would anyone do that; they'd rebroadcast the extinct species' "Is anybody out there" messages again as bait.
So, all together, it doesn't work well as a Fermi paradox solution.

 

[Office_Shredder]

Spoiler

at one point in the book it's mentioned that some species will just ping the location of any existing enemy species to the universe at large so someone will kill them off. And there are some active groups that pretend to do this to waste the resources of the killing groups.

 

[DaveC426913]

The logic of:

1) Not a threat now
2) Could be a threat
3) Therefore should kill now

Could apply to any interaction between two agents. A culture that adopts this belief will constantly be at war with itself as any perception of a new sub culture or behavioural deviation is viewed as a potential future threat.

I think you are using too broad a brush.

The differences between two unrelated civilizations will vastly, vastly overwhelm the differences between two factions in one civilization by any metric you care to employ.

One civilization could easily have a billion year advantage over another in terms of cultural, knowledge and technological evolution. The analogy to humans versus ants is germane here.

So a billion year advantage is enough that the more advanced civilization could virtually kick a hole in the other with both hands closed and one eye tied behind its back.