The Daily Galaxy gives us (compliments of Mike Treder) three possible explanations for the Fermi Paradox, the apparent absence of advanced civilizations in a universe that should be teaming with them:
We are (A) the first intelligent beings ever to become capable of making our presence known, and leaving our planet. At this point, there are no other life forms out there as advanced as us. Or perhaps extraterrestrial life does exists, but for some reason extraterrestrial life is so very rare and so very far away we’ll never make contact anyway—making extraterrestrial life nonexistent in a practical sense at least.
Or is it (B) that many advanced civilizations have existed before us, but without exception, they have for some unknown reason, existed and/or expanded in such a way that they are completely undetectable by our instruments.
Or is it (C) There have been others, but they have all run into some sort of “cosmic roadblock†that eventually destroys them, or at least prevents their expansion beyond a small area.
This is a pretty good breakdown, but I see no reason why options B and C should be exclusive. What if it’s a 50-50 split? Half of the civilizations that come along wipe themselves out; half become so advanced that they are beyond what we can detect. Or maybe it’s 90-10 in favor of civilzational extinction, or 70-30 in favor of civilizational advancement beyond detection.
Whatever the relationship between the numbers, if such a mix is true — if a civilization inevitably meets one fate or the other — the implication is that continual advancement is the only option. We can’t stop where we are, building skyscrapers and computer networks; neither can our descendants, building Dyson Spheres and the like. We have to keep pushing on until we either shrink out of site or exit this universe altogether…or are destroyed in the process of trying.
In that case, the Fermi Paradox is really just the observation that nobody stops in the middle, and there probably aren’t very many civilizations “in the middle” within detectable range of each other at any given time.
So how do we proceed? Should we assume the odds are 50-50? Maybe we should assume the odds are 80-20 against us. That would require us to use a good deal of caution, but would still offer us a fighting chance for pushing on.