Everything about this paper seems legitimate, except for the content of the paper itself. Right away I will dispense with the false claim in the headline from above. The paper is not arguing that that a secret race of beings is living on the moon or in caves underneath us. It is, however, claiming that we should take the possibility of such a claim seriously. They argue, ostensibly, that “in a spirit of epistemic humility and openness” we ought not to dismiss the explanation out of hand. The context of this paper is the popularity that UAPs enjoyed last summer.

This paper was written to buttress the possibility that maybe the UAPs are not coming from above, but from below… or to the side.

The CTH suffers because it rests too much on special pleading. The dinosauroid alternative, for example, requires us to assent to the idea that not only could a 2.5m-long 25kg dinosaur survive and then evolve into a sentient creature, but also that such a creature could create a society with an infrastructure that could create highly advanced flying vehicles. Further, that all of this would remain undetected by the world at large.