Nick Bostrom explains why finding any evidence of life on Mars would be bad news for the human race, and finding relatively advanced life would be even worse. To summarize, Bostrom observes that science has yet to detect evidence of intelligent aliens. Since there are many planets in the universe similar to Earth, this implies that there is some “great filter” that makes intelligent like very unlikely to reach the stage at which we would be able to detect it. Its possible that the filter is behind us. It could be that life is very unlikely to spontaneously develop, for instance. The filter could also be in the future, say an asteroid impact or an existentially catastrophic war.
I find the war scenario very likely. Weapons have thus far rode the cusp of human technological advance, and the arrow of progress always goes from less to more destructive. A very short chronological list might go something like: club, knife, arrow, sword, spear, catapult, cannon, gun, machine gun, bomb, rocket, missile, nuclear weaponry. If we expect military technology to continue producing ever more destructive weapons, it seems unlikely that the human race will last long, at least in terms of astronomical time. Even if deterrence would tend to stop rational actors from pushing the red button, to borrow one of Bostrom’s metaphors, it only takes one match to light a fire.
Its oddly poetic to think that intelligent life may have developed many times, always to be destroyed at the threshold of technological greatness. I can’t decide whether this fate has more in common with that of Sisyphus or that of Prometheus.
Hat tip: Tyler Cowen
It's All Endogenous 
