[h4nkoslo]

Uh oh.

The "great filter" hypothesis is essentially that the rarity of intelligent life has to be explained by some parameter of the Drake equation, and that whatever the "small" parameter is is either in our past or in our future.

If the "great filter" is the rarity of habitable worlds, then clearly we don't need to fear it, since we already found one. But if habitable worlds aren't rare, then it's more likely it lies in our future (e.g. global thermonuclear war, plague, difficulty of space travel, etc).

Thus things like discovery of exoplanets, bacteria on mars, etc should make us rather concerned.

https://en.m.wikipedia.org/wiki/Great_Filter

[root_axis]

The theory as described in your link seems to hand-wave away the difficulties incumbent in the "colonization explosion" step. As it stands, intergalactic space travel (at scale) is utterly inconceivable in practical terms, and to simply assume that it is inevitable seems like a major flaw in the theory.

[idbehold]

> then it's more likely it lies in our future (e.g. global thermonuclear war, plague, difficulty of space travel, etc)

Difficulty of space travel is one of the possible filters.

[svachalek]

Actually, the article explicitly calls out that step as one potential "great filter". It also (click the link) lists the theoretical ways it could be accomplished.

It seems to leave out the Von Neumann Probe:

https://en.wikipedia.org/wiki/Self-replicating_spacecraft

This is not exactly colonization but possibly an easier step. Either way, the point is that if either we or our machines can get to another star system and repeat the process from there, exponential growth means it pretty much doesn't even matter how long it takes. In astronomical time, we'd cover the galaxy in the blink of an eye.

[pshposh]

But what if we are the first and no filter exists at all?

[idbehold]

That's almost equally depressing. "Really, we're the best the universe has to offer?"

[kk_cz]

Isn't that highly unlikely due to the age of the universe vs age of the Solar System?

[joeyspn]

The "Transcension Hypothesis" is a possible solution to the Fermi Paradox...

http://www.sciencedirect.com/science/article/pii/S0094576511...

[ionwake]

Great link, thanks.

Cant help but be reminded of the premise of the Halo games, and the objectives of the alien race.