The Fermi Paradox: The Chariots of the Gods Hypothesis

Similar to the Aliens are Among us Hypothesis, the Chariots of the Gods hypothesis is that aliens aren't currently here, but that they were here at some point in the past. The COTGH suggests that evidence of this can be found in the mythologies of the world and in the help that they lent to ancient cultures in building large and complex structures, such as the pyramids.

Critics of the COTGH complain that mythological "evidence" isn't empirical evidence and that the structures the proponents of the theory point to could have been built by so-called primitive cultures. They further suggest that, had aliens visited us in the past, we should expect to have found some bona fide artifacts by now. Supporters of the COTGH respond that, even among human cultures, only a fraction of the artifacts of our cultures survive even a few thousand years and that, if the aliens were only here a comparatively short time, we shouldn't necessarily expect to find physical evidence. They further note that mythology can provide real evidence of historical occurrences, as the myth of the fall of Troy has demonstrated.