Lonely civilizations face the dominant lion's problem.

M.C Escher's "Another World"

 Lonely civilizations face the dominant lion's problem. 

Lone civilization on the lone planet faces the dominant lion's problem. If on some planet is one intelligent species, it turns to dominate quite easily. Without the outside threat species can fall into internal disagreements. The size of the population grows too fast, and that means species will eat everything from their planet. A fast-growing population causes the need to create new solutions fast. Those solutions involve housing and energy solutions that are not analyzed as they should. 

Those quick solutions will just push the problem to the future, and same way those inadequate ones seem very effective. And when they escalate through the entire planet. They grow the problems that they cause to enormous scale. Those things are solutions that seem good in a short period. But in a long period, they cause more problems than they solve. 

The main problem with the brain in a vat thinking experiment is that "brain in the vat" doesn't know that it's a Brain in the Vat. Unless somebody tells that thing to that brain. This is the key idea of that thinking experiment. But can the entire species, or the entire planet be the brain in the vat? That is the key question in things like the SETI program. The Brain in Vat is dependent on the information that it gets. 

A brain in a vat that believes it is walking (Wikipedia, Brain in a vat)

The sensors give data to the brain, that lives in the laboratory. Then the brain controls robots by following that information. The brain in a vat can be connected with only one robot, and that means the brain in a vat doesn't even know that it lives in the laboratory. 

In this case, we must realize that making that kind of brain is not probably enough to make the brain have the same intelligence level and consciousness as humans. We know that the brain is not just the only thing, that thinks. We know the entire human nervous system to make the "brain in a vat". Which is a copy of human intelligence at all levels. 

But there extension of that thinking experiment is the human in a room, thinking experiment. What if we live our entire life in the house? There are screens outside windows that introduce the lunar landscape. When we go out, we wear space suits, and the system projects the same lunar landscape to this screen. 

We can walk on the streets, but we don't hear what people say. They see us from the outside, but our helmet's visors are black, and they cannot see that we are humans. What would you think? Do we dare to take our helmets off? This is a good question. If our entire world is in that house, and in that space suit, and we cannot see anybody else, do we dare to test the thing that we believed our entire life? 

When we think of the man in a high castle. That thing is the man who spends his entire life in the castle above the clouds. That person never sees what is below the clouds. That means that other people can claim that this person is at the Venus' planet's mountain areas. And if there is no outsider who to ask the truth. 

All data sources tell that the person can believe that he lives in the Venus' mountains, and the lack of a space suit will keep that person at the mountain. If the man in the high castle will not dare to test the limits and try to land through the clouds. 

The fact is that the human race is like the man in the high castle. There are no alien contacts. Another thing is that before humans come into contact, we don't have any idea what aliens are. We believe or we want to believe that we are unique, special creatures. And we are special creatures on our planet. We are the most intelligent and always superior species. 

That's why the human race has the dominant lion's problem. Because no outside force can destabilize the human race's position on our planet, we can fight with each other. The outside threat has united nations. And without outside threats, those unions fell into war. When we search the alien civilization our luck depends on the sensors. The alien life is not a synonym for intelligent alien life. The carbon dioxide in the atmosphere doesn't mean. That there are life forms. And the chlorophyll doesn't mean that there are animals in alien ecosystems. 

Even if we do not find aliens during our lifetime, which is quite short if we compile it with the speed of light and cosmic distances. The SETI is a fascinating program that gives information, scenarios, and ideas to people, who work with the newest AI and other technical solutions. 

https://bigthink.com/13-8/the-key-problem-with-the-brain-in-a-vat-thought-experiment/