Summary: The Fermi Paradox is no paradox - there really are no aliens out there that we can see. But that's only because there weren't many in the past. Now they're popping up more and more often, and soon the universe will be teeming with them. The earliest ones to harvest their own star's energy, maybe including us, start expanding at close to the speed of light in all directions, and soon these "Grabby Civilizations" control everything.

The good news: This means humanity is not necessarily doomed to annihilate itself, and we'll have the opportunity to build a massive enduring civilization. In fact, it's evidence against the Zoo Hypothesis or the risk of a Great Filter ahead of us. And even if humanity fails to spread, the universe will have many more tries with other civilizations in the future.

This the picture drawn by considering two fascinating papers together. I highly recommend both of these, and they complement each other well. After reading them, thinking about anything else in life just seems small.

Eternity in six hours: Intergalactic spreading of intelligent life and sharpening the Fermi paradox (2013, Stuart Armstrong, Anders Sandberg)
A Simple Model of Grabby Aliens (2021, Robin Hanson, Daniel Martin, Calvin McCarter, Jonathan Paulson) [website]

The first demonstrates that it's likely "pretty easy" to expand across a huge number of galaxies from a single origin star, at close to the speed of light. The second argues that advanced life arises more and more often over time, and builds a model showing that the first civilizations to begin expanding are likely to start at nearly the same time, and not see each other until later in the expansion.

Together, these ideas have profound implications on how to think about the Fermi Paradox and what we should expect for humanity's long-term future. This post will summarize the two papers and extend some further thoughts.

Who Am I?

My qualifications or lack thereof aren't that important, but I should emphasize I have no particular expertise in this field, and I've read very little of the literature. So I'll own up to likely mistakes, and I'm sure I'm missing other related work. I'd be really interested to hear expert opinion on what's new in these papers, what is already well-known, and what might be mistaken.

I just happened to come across b...

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