Ask Lemmy

For us it's conservatism and its synonyms.

Pushing Ice by Alastair Reynolds is one of my favorite scifi books and it deals with this question in an interesting way. It proposes that Time is the great filter. Life exists in this galaxy, but intelligent life is so fleeting when considering galactic distances that the probability of one sentient lifeform finding another during their "peaks" is vanishingly small. Extinction, societal collapse, evolution to a higher form, whatever you want to imagine, it all gets in the way of the fantasy of meeting a thinking being from another planet.

I don't think there is a single universal Great filter, and living and then potentially sentient beings with various traits will face various obstacles.

First, life needs suitable materials for polymers and a lot of energy. Most places don't have both.

Next, basic blocks of life that would be self-replicating and adaptive should be randomly generated, which is extremely unlikely and literally took over a billion years on Earth, a planet with generally great conditions for such process.

Then, those blocks should be able to get together to form complex structures - ideally, many separate ones, so that one event wouldn't destroy the entire effort. Earth had it easy, with billions of super simple life forms.

Next, assuming life survived up to this point in a potentially unfriendly and ever-changing environment, bombarded by UV light and exposed to myriad of sources of damage, it should not destroy itself or environment too badly to never recover. Earth had periods when life generated too much carbon dioxide or too much oxygen (yes, that too was a thing), and those were critical points at which our story could very much end.

Then, life has to evolutionize and get into complex forms, either by forming multicellular organisms or by making a cell a powerhouse of everything.

Then, life has to get sentient, and some kind of response system should be available and get highly complex.

Then, most of the sentient creatures just won't be tribal, and civilization requires society and a common effort.

Then, many more won't be expansionist, and will die out in some small region.

Many also won't be competitive, which would slow down evolution.

For those species who are competitive, they shouldn't destroy each other while they're at it, and this is currently one of the risks of our own.

And after all that, they should develop space travel and either get as developed and decisive and resource-rich as to send a generational ship to some random planet named Earth populated by genocidal monkeys, or to somehow hyperdrive here. They can very much decide it's not worth it, and they may be so far away we couldn't see signs of their civilization.

I think that for a technological civilization to rise, you need some things to line up. First, life has to be evolved enough to have animals, beings with a brain. Then, a species has to evolve intellence to become a tool making species. This species also has to become the dominating species on the planet. Meanwhile, extinction events, ice ages, climate change and population bottlenecks are always influencing the evolution process.

This is for me the great filter, to have all these conditions line up perfectly for an intelligent, tool making species to evolve and thrive.

Capitalism I can imagine how capitalism could be inevitable. I can't imagine enough controls on it to make it sustainable

the internet. or some other mass communication methodology. we have developed it before we're responsible enough to have it. there are too many bad actors ready to take advantage of our innate biological tribalism. we'll kill ourselves before we reach very far into space.

Maybe it's wisdom.

Every species that might have grown advanced enough, would have gotten over the point of fighting themselves. So they would be wise enough to have something like the Prime Directive in Star Trek (not interfering with less advanced species' until they reach a certain milestone).

If there really is a cosmic web and information flows through it, the other solar system will know that we're coming to destroy another world, but it will have developed defensive techniques against a known disease, humans. The same our immune systems does to known viruses.

I went a bit creative with this one.

There's a lot of possibilities.

My top contender would be a desire to explore, which probably requires consciousness. Given that we have pretty much no idea what leads to consciousness, it can be guessed (dubiously) that if it arose more easily then we'd have an explanation by now. It could be that it's an extremely rare phenomenon, and there may even be other planets with "intelligent" but mechanistic beings that act entirely for their own survival and don't build civilizations or explore much.

Second would be intergalactic and to a lesser degree interstellar travel. If we assume both 1) intelligent civilizations are extremely rare and 2) faster-than-light transportation is impossible, it could be that everyone is just too spread out to make contact.

Third, and the one I most feel is right but it requires pretending I understand quantum physics (which I don't) and probably offending many that do, is the notion that the concrete universe is not large but small and has no objective existence independent of our respective perceptions, and any part of the universe that's invisible is a mere wave function that will only have concrete reality upon our perceiving it. I make the further dubious assumption that conscious beings can't be part of the wave function. So there.