At root, Fermi wondered why, if life should be bountiful in a vast universe, we haven't yet encountered any other civilizations. "The idea is that they're more advanced, but not much more advanced," Corbet told the Guardian. "It's like having an iPhone 42 rather than an iPhone 17,"Advertisement AdvertisementAdvertisement AdvertisementHe also suggests that even relatively advanced civilizations might send out a bunch of probes, find nothing at all — or nothing remarkable — and give up on exploration. In his paper, Corbet also entertains a variety of refutations of the mundanity theory. Obviously, if the aliens show up, the theory is disproven, as they would need very advanced tech to get to Earth.