Understanding dark forest

The universe is a dark forest. Every civilization is an armed hunter stalking through the trees like a ghost, gently pushing aside branches that block the path and trying to tread without sound. Even breathing is done with care. The hunter has to be careful, because everywhere in the forest are stealthy hunters like him. - Liu Cixin

Table of contents

Introduction

Before diving into the dark forest, let us have a quick overview of a very interesting paradox in the field of cosmology as Fermi Paradox.

Fermi paradox named after Enrico Fermi asks a simple question:- does intelligent life outside solar system exists. If yes, then why they haven’t contacted us. The more time you spent pondering over this question, the more complex it gets. Till now no one has a definitive solution for the paradox.

The dark forest attempts to provide a solution for the fermi paradox. The solution provided is a rather pessimistic one that stems from the core idea that all life forms in the universe are hostile

The Dark Forest

The idea of dark forest was first brought into mainstream by the Chinese sci-fi author Liu Cixin in the book of same name The Dark Forest, from Remembering Earth’s Past trilogy series though the concept predates the novel. The dark forest hypothesis states that many civilisations exist throughout the universe, but they are deadly and silent. These alien civilisations are referred as hunters and our universe as the dark forest. They cloak themselves in the fabric of universe and maintain their undetectability for the fear of getting targeted by another hostile civilisation.

In the book there are two types of civilisation, one with the hiding gene and one with the attacking gene. Aptly named these categories define the nature of these civilisations as offense type or defense type.

Approach with Game Theory

We can understand the hostile nature of the dark forest with the help of game theory

Suppose there are two planets: Planet A and Planet B having different civilisation and culture. Each of them has no idea the other exists.

For the initial run of our simulation, we will start off with the following assumptions:-

1. Both the planets have different culture, no common mode of communication between them.
2. The distance between the planets is huge, say 100 light years.
3. Both the planets are not aware of each other’s existence nor their capability and nature( hostile or friendly)
4. Both the planets are sending out radio waves in hopes of communicating with some other extraterrestrial civilisation.

Let’s say Planet A finds out about the existence of Planet B first. Now Planet A has 3 options:-

• Scenario 1: Destroy Planet B before they get a chance to react.
• Scenario 2: Broadcast and alert Planet B of their existence.
• Scenario 3: Do nothing.

Calculating payoffs for each scenario

Before doing so, we will attribute survival parameter with the highest payoff and extinction parameter with the negative payoff.

For Scenario 1, it will be slight negative payoff because one has to spend massive resources in order to do launch a planet devastating weapon strike, but it is negated as survival is the most guaranteed in this scenario.

For Scenario 2, there are 2 sub-scenarios:-

• Friendly: This would lead to a positive payoff for both civilisation as survival is ensured for both. Technological advancements, sharing of culture and bridging the gap from unknown to allies are likely to take place resulting in a win-win scenario. In this case, it is crucial the language barrier is resolved immediately, and peace talks take place after ensuring a common ground.

• Hostile : In this scenario, survival of both civilisation is at stake. Since both the parties couldn’t or didn’t have the chance to find out the common ground, now are in a race to annihilate the other before they get annihilated. In case of space faring civilisation this ultimately boils down which is more advanced and has more technological prowess and destructive capabilities

After receiving the message from Planet A indicating their existence and location in space, Planet B also has the same 3 scenarios to choose from. This cycle of message transmission can go on and on until someone eventually turns. For Player 1, in our case Planet A, this scenario may lead to infinite many negative payoffs in case of hostile situation leading undermining survival

This would amount to a high negative payoff

For Scenario 3, Planet A may seem to ignore Planet B due to them being a less technological advance society and in the given time frame pose no harm. But as we know rate of technological advancements of intelligent species are exponential rates. Take the example of humans, with respect to the time. Humans have been present on Earth, we have achieved so much technologically and as a society. Some famous laws that demonstrate the exponential rate include the Moore Law and many more.

So ignoring them would lead to drastic consequences for Planet A in future if Planet B would turn hostile amounting to a negative payoff in our case.

So the optimum decision is to go with Scenario 1 ensuring survival of one’s own civilisation that has the maximum payoff.

Conclusion

We have got somewhat of an overview regarding the hostile nature of the dark forest. The chain of reasoning gets complex in the grand scale of universe when we deal with more than just 2 planets. The optimum output is either to hide or seek and destroy other civilisation before they get the chance to do so. With this dose of existential crisis, I leave you with your own thoughts.