3 ms·
I agree with your sentiment but not your specific number. The leap from uni- to multi-cellular life might be a "great filter" in Fermi-paradox parlance. But I
by sqeaky 2y ago
I agree with your sentiment but not your specific number. The leap from uni- to multi-cellular life might be a "great filter" in Fermi-paradox parlance.
But I think it would need to be more like one in a million or one in a billion. I think even one civilization becoming a slow interstellar (less than 0.1C ships for their) civilization could colonize the galaxy in less than a million years.
Consider what we could do if we could get a slow ship to Alpha Centauri in some absurd time like 1000 years and actually settle there. Maybe we try ever If us here on Earth and Sol could only do that once every thousand years and then if each colony could too. We would only be doubling the amount of stars we inhabit every thousand years. Presuming this slow pace we would also be adding 5~10 light years to our civilization in that time too. But in a million years that 5k to 10 light years would be a sphere with diameter about 10% to 20% the diameter of the galaxy. Allow those jumps to be 50ly and we could get a whole Milky Way galaxy in that time.
That is all predicated on very slow stuff, no FTL, slow ships or project taking massive time. And since the dinosaurs died we had 65 such time periods and another 300 while the dinosaurs lived...
And I could go on for hours about this stuff. But my point is that if unicellular life is common and there is a single great filter and that is the jump to multicellular life then the odds of that event dictate how often we would see other civilizations. A 1 in 1000 we would see civilizations all over the place. We would certainly be withing radio range of at least a few. So it would need to be much worse odds.
- pfdietz 2y agoI don't think multicellularity is a plausible Great Filter, since it's easy to achieve in laboratory evolution experiments -- just get cells to stick together after fissioning. https://en.wikipedia.org/wiki/Multicellular_organism#Experimental_evolution https://en.wikipedia.org/wiki/Multicellular_organism#Experim...
- silver_silver 2y agoThe assumption that colonisation and endless population growth are inevitable goals of any intelligence is a flaw of the paradox, in my opinion. I see it as something we just haven’t outgrown yet as a species. That colonisation could of course be in the form of probes simply exploring, but there are timescale and resource issues with that which make me question if it would be worthwhile for a civilisation considering the limited energy in any given system and tremendous effort involved in getting to another once it runs out.
- sqeaky 2y agoIt isn't an assumption. Not every civilization needs to expand but the ones that do will expand more than the ones that don't. And the expansionist subset of any civilization will wind up representing the whole of that Civilization on the larger scale. Any proposed great filter to the Fermi paradox needs to be non-exclusive. As in it can't be something that will only impact some of the group, it needs to impact all or very near to all in a statistically significant way. In the previous example if even just 1% of civilizations wind up having just a subset that go out and explore we would still expect to be able to have seen some here in the Milky Way because that would be 100,000 or so planets or Stars producing multicellular life and with the presumed odds we were discussing civilizations that expand. We presumed for the ease of math, because we're not pulling out the whole Drake equation, that the one in 1000 was just for the one filter. Of course you can do the math with whatever percentages you like at any filter. And each set of numbers you plug in means something slightly different with regards to what we're seeing and why we're seeing it out here in the real world.