> So our galaxy, which contains a few hundred billion stars almost certainly has no other intelligent life in it for the simple reason that it'd be everywhere.

> So our galaxy, which contains a few hundred billion stars almost certainly has no other intelligent life in it for the simple reason that it'd be everywhere. By that account another civilisation as advanced as us would say they're equally alone in the galaxy no ? yet here we are. And you forget time, they might have done that 2b years ago and there is nothing left for us to detect, or they might do it in 2b years and we might not be there to witness it. Also there might be barriers we're not aware of, for example advanced civilisations could go through things like extinction through pollution, over consumption of resources before reaching a tipping point to being multi planetary, &c. Plus we're far from the only galaxy, there might be galaxy wide civilisations out there, far far away. And more important, nothing guarantees the premise of multi-planetary civilisation has any validity outside of sci-fi It's like going in the woods twice a year, not seeing mushrooms and concluding mushrooms don't exist on earth because surely you'd have seen them by now! The bottom line is that we just have absolutely no clue