- interstellar travel is never feasible for any civ, no matter how advanced,
I like the idea behind the concept of the Great Filter, but that point does not seems logic as it would imply that irregardless of how advanced a civ is, they would not be able to build anything that can even make just a one way travel to a star just a few year light far away. Right, it is not simple, but a civ even just a couple centuries head of us should be able to do it.
Also, probably nobody capable of traveling the stars wants to settle a planet. Once you figure out how to make huge spaceships (which you’ll need to travel interstellar space) you’ve essentially learned how to make cities in space.
I don’t think it is a valid point. Yeah, if we can build a ship that take us to Alpha Centauri it would lool like a small city, but that does not mean that it can last forever and the traveller would never need to settle on a planet. And looking what the humans did in the past, it seems logic that while a part would want to continue to explore, another part would want to settle on a planet.
Our solar system would support a lot of people if we just used the resources available for space habitats, and by “lot” I mean in the quadrillions. And it turns out that all you need to support that population is a star to provide energy, and some planets to source materials from.
So with that in mind, why bother finding another habitable planet?
Because it is habitable and can be used as a transit point, advanced outpost, refuelling base or any other use you can do of an habitable planet where to do things you have not to fight even with the environment (tourism for example).
Wait a moment, maybe I understand wrong (English is not my first language) but I understand that you said that the Great Filter is the reason why we don’t see them and point out 3 possible points.
I dispute your first point to be not really an explanation or an option since saying “never feasible for any civ, no matter how advanced” just seems to be a too harsh limit on what a civ could do, which looking at our past history seems an unreasonable limit.
Your point seems to be that since there is the Great Filter (btw, to be proven) then there is no one else out there.
You exclude way simpler possibillities like the option that a civ just a couple centuries ahead of use could already be colonizating the nearby stars, they just are 1000 LY away so we cannot yet see them (assuming we even know what to look for).