Most of you have likely heard of the ‘Fermi Paradox’: the puzzling fact that, despite the uncountable multitudes of stars in the sky, and the overwhelming likelihood that myriads of them have habitable planets, we have never seen any conclusive evidence of extraterrestrial life.
Why is this? Given the immense age of the Universe, and the rate at which life got moving here on Earth, it seems the Galaxy should be positively teeming with life. Yet as far as we know, we are alone.
What this means is that somewhere there is some obstacle, some existential blockade, that has kept extraterrestrial life from getting to the point where we’d notice it from here. This mysterious off-switch has come to be known as the ‘Great Filter’.
Why do we imagine that we’d know it if other races were out there? Because it’s reasonable to think that were they not obstructed in their technical development, they’d start doing things that we’d be able to see. In particular, as civilizations advance, they consume more energy, and so they will progress from consuming whatever’s available on their homeworld to consuming the energy of nearby stars. There’s a ranking system called the Kardashev scale that rates civilizations on just this criterion: a K1 civilization uses all the energy that comes to its planet; a K2 civilization gobbles up everything its star produces; and a K3 civilization consumes the output of its entire galaxy.
When you combine this idea with the obvious attractiveness of expansion through replication — whereby a civilization makes drones that colonize nearby solar systems, harvests those systems’ mass to make more drones, and so on — it becomes clear that given enough time, a sufficiently advanced race should be able to make its presence visible, and most likely palpable, from pretty much everywhere. And time is exactly what we have already had plenty of; thirteen billion years is a very long time indeed. Yet here we are, alone.
So what might the Great Filter be? Perhaps it is that life itself is not at all likely, or that intelligent life is a one-off, and has happened only here on Earth. This would mean that the Filter is behind us, that we are alone because we are the first, the Elder Race.
But maybe not. Maybe life, even intelligent life, is a commonplace. This is a horrifying thought, because it means that the Great Filter lies before us. It is horrifying because the Great Filter, as far as we can tell, is 100% effective. It does not hamper, or hinder; it exterminates. We know this because, having had so much time, it is reasonable to assume that any race that had slipped past it would be everywhere by now.
This has been a lively topic among the ‘transhumanist’ and futurist community that shares some intellectual real-estate with neoreaction, and now that I’ve raised the topic here (and hopefully, piqued your interest), I’m going to send you off to do some reading.
‣ Here is an excellent overview of the Fermi Paradox, the Great Filter, and some reasonable questions and objections.
‣ In this paper, Nick Bostrom explains that finding any sign of life elsewhere in the Solar System would be a very bad thing indeed.
‣ One possibility (perhaps much more than just a possibility) that many have worried about as an existential threat is “unfriendly” artificial intelligence, know for short as UFAI. But as bad as that might be (which is very, very, bad), it’s no Great Filter. See here, for example, and here.
Finally, our man Mangan takes up the topic, and gives us this:
It’s leftism. All civilizations eventually become leftist, and after that they accomplish nothing, or even actively die off.