Fermi wondered why we have not met aliens. He recreates an equation which we are still just figuring out some of the constants. Part of it wonders how many civilizations wipe out themselves. This Great Filter makes people concerned any time life on our planet is threatened.

During the Cold War, the concern was a nuclear war would wipe out human civilization or even all life. Olivia Butler’s Xenogenesis series is a little dated as it concerns this period. I heard about the Fermi Paradox back then. A distant second was an asteroid impact. Lately a popular concern is global warming being the Great Filter. Artificial Intelligence seems a close second.

Whatever is our current social concern for how we are going to kill off ourselves seems to be what we think killed off other intelligent species. We wonder how they could have survived it or why they died off in failing to.

At least these Great Filter concerns get us discussing how humanity can survive. Though, I wish we are further along in space travel as we need to spread out in the universe to survive.